 So it's a great pleasure to welcome everyone back to today's symposium. And the reason why we are holding the symposium at a different time is to have the opportunity to invite colleagues from Asia. As our frequent viewers know, we have not yet had speakers from Asia because it's nearly midnight during our normal seminar time. So for today, in order for us to invite key contributors from Asia, we're switching to Thursday afternoon in Stanford. And therefore, it is my great pleasure to welcome two outstanding researchers from China and from South Korea. We're really delighted to be able to have their perspective. We have Professor Han Lee and Professor Kisu Khan, who will join us today to share their academic perspective on battery research, but also to give a little bit inside to what is happening in China and South Korea, which are, of course, key powerhouse in energy storage today. So first, we're going to have Professor Lee give a lecture. So let me go ahead and introduce Professor Han Lee. Professor Han Lee is at the Institute of Physics in the Chinese Academy of Sciences. I will make a personal note that he is basically my academic uncle because he and my PhD advisor share a common root in their postdoctoral training at the Max Planck Institute in Stuttgart. So it's great to have my uncle here today speaking to all of us. And Professor Lee is extremely experienced in solaceaionics. This is his fundamental area of research. And he has been able to apply these understanding to many technologies, including battery and related application. Professor Lee is a very prominent researcher in China, having founded a number of Institute focus on developing energy storage, for example, the Tianmu Lake Institute for Energy Storage and the Yangtze River Physical Research Center, where he directs a very large team trying to pioneer a fundamental understanding and also translation for energy storage. And I know that recently he has been very interested in solid state batteries. I know this is a topic of great interest to many of the listeners as well. So today, we're delighted to have Professor Lee speak about solid state batteries specifically from fundamentals to application. So Han, thank you very much for joining us from China. And we are very much looking forward to your lecture. Oh, thanks, William. Yeah, it's really my great pleasure to be invited by William and Yi. And also, I would like to thank Tracy, Justin, David, Jimmy, and Kelly to organize in this wonderful symposium. So dear friends, good morning and good evening. It's my pleasure to share our experience on the solid state batteries towards practical applications. Today, we are sharing some results from full affiliations, including Institute of Physics and Beijing Vila new energy technology, accompanied to develop solid state battery and also TM Lake, excellent animal materials to use the silicon animal materials and also nano-sized solid electrolyte and also TM Lake Institute of Advanced and Historic Techniques. As you, as everybody knows that battery now is really have a broad applications, including every fielding in the human societies, including 3C electronics and very important the transportation, including the bicycle and car and bus and even ship and the train and also airplane. So electric airplane has been proposed now. And also, another very important topic is to join the renewable energy and smart grid to balance the electricity. And those two market from transportation and the stationary energies is very large market. According to a rough estimation, it could be larger than the 10 Pegava hour markets. So also, a battery can be used in many other niche markets. So those things, the batteries will be very important in next 10 or even 30 years. So if you look at the current status of commercial energy and batteries, here I just make a summary of the 3C electric vehicle and the stationary storage of three types of the batteries. So the 3C care about the volumetric and its density. Electric vehicles care both gravimetric and its density and volumetric and density and the cycle life, especially the safety and also stationary storage care about the cycle life and the calendar life and also both of them care about the read performance and also the temperature range. And especially for electric vehicle and the stationary care a lot about the cost. So however, although we have spent the 30 years for developing the lithium battery still, the energy density, charging rate, cycle life and also operating temperature range. And in some case, especially for high energy density batteries, the volume deformation are still a problem and also cost is slightly higher. So another very serious concern is the safety. We have heard a lot of accident. So because the use of the non-equious electrolyte, so when we increase the temperature, it costs back a lot of reasons. So the battery will go to the summer runaway and finally could cause the fire and even explosion. So this is really a very serious concern, especially on the big batteries used in the electric vehicle and the stationary applications. So today I want to introduce briefly about the advantages and also challenge of all solid state lithium batteries and also propose the problems and the possible solutions. And also I will especially introduce our effort on the in-situ solidification and finally give a roadmap of commercialization. As well known by the audience that the solid state battery is really different with the liquid one. Yes, you change the contact from the liquid to solid to the solid to solid contact. With the application of the solid electrolyte, you can have the possibility to use the high voltage cancer and also even lithium anode. And also because of the free of the summer runaway, you can increase the safety and also because like of the capacity far over. So the cycle life could be extended for very long and also because the free of the liquid electrolyte, you can concede to those the internal series to get a very high packing efficiency. Those are possible advantages but have not confirmed by the commercial product of the solid state batteries. Those are we expected advantages. So now I want to introduce currently, there are four types of solid state lithium batteries. Firstly is the polymer. The polymer type of solid state battery has been started since 1978 from the Michel Amand. So the polymer electrolyte has this advantage of low electronic, low ionic conductivities and also the advantage is high transference number but it has poor mechanical stress. And especially for PEO, it could be oxidized even about 3.9 volt. And also for the anode interface is still not very good. So currently because of the limitation of the oxidation voltage. So the polymer based ASRB has not been used widely only for some demonstration in electric vehicles. And there are some, there are also a lot of great effort to improve and like to design the composite and the multi-player electrolyte and also introduce the polymerization of lithium salt and also surface modification of cancer to decrease the surface oxidation and also change the stability of the lithium. So those effort have still are going out. For the same film, light and based this has been developed the way aware especially used for the IOT applications. But this type of the solid state battery has a high cost and the low production rate. And it's very difficult to scale up and also has a limited energy density especially volumetric energy density and grammatical energy density in the pack level. So in order to increase the energy density you can consider 3D and also thicker electrolyte and multiple layer pack. But however limited by the same film production technology steer you cannot increase the production rate very quickly. So this is still limited significantly. And another very important solid state is a battery is used to survive. Survive electrolyte has very high ionic conductivity. So it's very attractive and there are a lot of effort from Japan, from Korea, from USA, Germany and China. But currently the certified because it's very air sensitive. So the production processing should be very careful in the very dry room and also the precursor and the processing are very highly cost. So currently it's really difficult in view of the cost performance issues. And also currently still the scaling up technology has not been developed very well for the large production but those problems can be solved by developing the electrolyte which are not air sensitive and also which can shield it for the dry coating technology. And also to do some other technology to increase the production rate. So those effort have been developed very well right now. And by steer it's in this year and I was in I think in a few years it's still very difficult to get a very large scale production. And oxide based electrolyte that has been attracted attention for a long time because the stability issues. However, the ionic conductivity is not so high. The highest one is garnet is like a one millisiemens per centimeter but it could be used for the designer batteries. However, if you use the ceramic pellet so it's quite fragile. So it's difficult to do the stacking technology and also of course the physical contact between the solid electrolyte and also the electrode is very difficult to deal with especially during the cycling which has the significant volume change and also the interface stability to lithium for some oxide electrolyte steer problem and also steer if you use this kind of design steer difficult for the mass production. So according to this summary looks like the oxide solution battery are still difficult to scale up because of all kinds of challenge. And for the real applications the demanding for the performance is a combination. So we need high safety, we need high energy density and we need a long cycle life and the reason of a rate and also we should operate at a very low temperature up to a high temperature and especially the cost should be comparable to the non-equious lithium batteries. And in order to rear mass production you need to consider the performances the combination of performances should be superior compared to the lithium ion batteries non-equious and also the production speed should be very fast and also you should have a major supply chain for developing these all solid state batteries but steer very difficult. So how to solve this problem? So we have proposed is it a pass that we just do the hybrid solid liquid electrolyte which could have the opportunity and could be prepared in a faster way. So if we have a hybrid solid liquid electrolyte so we could consider several switching. So for example, we can call it a solid electrolyte on the electron material particles to decrease the surface oxidation and also we can introduce the solid electrolyte particle or the polymer electrolyte into the separator between the particles in the electrode. And also we can form in the solid electrolyte in the electrode on the cell where in-situ solidification. If we have this kind of consideration and a strategic it looks like it could be easily to be produced and also could have the high safety and the low cost which is very important and for the production it could compatible with the existing processing technology and the equipment and also could use a lot of available materials. So with this demanding and consideration we propose the so-called hybrid electrolyte lithium ion batteries where in-situ solidification. So I will explain briefly. Firstly, we use the anode side which high energy density anode which we could consider silicon and also this a carbon and with the solid electrolyte and also the ICI anode side. In the Kessler side we could use the solid electrolyte coated Kessler particles and with the solid electrolyte and also the in-situ formed ICI and also CEI at Kessler side. And for the separator. So at the first generation we could combine with current the ceramic coated separators we can consider still use the polyolefin based the separate at PPP as a substrate and the coated inorganic oxide solid electrolyte on the one side and also on another side and combine with jam polymer compositions. So with this technology we can fabricate the batteries with the similar technology but we inject a new electrolyte with this new electrolyte we will convert liquid into the solid electrolyte where the reaction like ICI, CEI and also the polymer releasing are precisely. So with this kind of design in principle we could have the possibility to balance the requirement and to use the high voltage Kessler and lithium content anode and also could free of thermal runaway and also with the reasonable kinetic properties is a reasonable read performance and which could operate at low temperature or high temperature at the same time. And also possibly we can control the volume variation this is very important issues. And of course, so you see this processing and it's a design so it does comparable to current technology. So the cost is not we could not, we do not increase the cost of processing significantly. So and it could be produced in a fast speed. That's our idea how to combine the R-solid state battery idea and the non-alqueous lithium battery's idea. So now I want to give the example how we do this. We have developed the oxide electrolyte coated Kessler materials just the contrary this slide and also we do the in-situ solidification because you cannot coat it or the surface of the Kessler or anode particles by the solid state oxide electrolyte or the other electrolyte completely in order to have an electronic conducting pass. So in order to further modify the surface of the Kessler so we do the in-situ solidification by several ways for different Kessler we find we need to design different precursor and also the initiator. So for example here, we have published a few papers about this with the cobalt lithium cobalt oxide we use the VC as a precursor after polymerization we get the PVC based electron polymer electrolyte and then we can fabricate these kind of batteries. With this kind of battery we use the PEO also it's the battery PEO type to demonstrate that surface coated Kessler can even operate with the high voltage lithium cobalt oxide. You can get the result from here you see with the coating. So even this kind of battery can be cycled over 500 cycles. So this is a very encouraging information for us that counter the surface of the Kessler is very important to extend the operation voltage range of the polymer including polymer electrolyte or polymer binder and also those solid electrolyte which has relatively lower oxidation voltage like some sulphide electrolyte. And also here demonstrate another type the effort. So here you see after this kind of in-situ solidification PEO can operate it properly. With this kind of a stretchy you can both improve the chemical and the electrochemical stability and also you can use the in-situ polymerized electrolyte to compatible with the large volume variation of the Kessler and anode during the cycling. This is very important. And also we have demonstrate those kind of in-situ form the polymer electrolyte is thermostable. And here we show some other examples to see. We have published paper and other groups has also published paper. This is the first early paper in the 2016 but we use the LHGP coated separate to initiate the formation of the ICR at anode side. So this is our result. And the very important issue is the thermostability. So we have considered and compiled the thermostability of the different solid-state electrolyte. With this summary you can see all kinds of solid electrolyte which has a much higher thermostability compared to the liquid one. This is very good news, at least, although it's well known. And however, so it looks like that oxide electrolyte is most stable and that's certified than polymer. But what's the real case? So you need to do the experiment. So we compared four types of oxide electrolyte coupled with lithium to do ARC experiment. So it is not surprised but we have the clear data to show here that R8GP and R8TP you see, it has a similar runaway behaviors about roughly 300 degrees C. So this means even the oxide electrolyte has been centered about 1,000 degrees C but when it meet with the lithium, when it contact with lithium, it still could cause the summer runaway. And if it has calculated the mechanism and we have published paper last year. And fortunately, the R2 and R0 do not have such kind of summer runaway behavior. So this is very good news. So that means when we design the solid-state batteries we need to consider we need to consider which type of the solid electrolyte to be selected for different anode and different cancer. This is the key message I want to share with the audience. And with the order effort, so we have already know how to deal with the incident of solidification, the mass production levels and we have the experience how to produce the fast ion-conductor coated cancer to decrease the surface oxidation. And we have the technology to fabricate the ultra-synthesized fire to do the pre-releasing at anode side. And we also develop the solid-state electrolyte coated separator to increase the ionic, increase the kinetic performance of the battery and also increase the safety issues. With those combination of the technology, we have tried to develop the battery with the high ionic density like this case, 300 watt-hour per kilogram for electric vehicle applications which can have the acceptable performance like over 1,000 in a cycle life, 100% of the DOD and also the low temperature performance and the high read performance like 3C we still achieve 98% capacity retention. And the very important thing is that the safety issues. So this is a combination of reasons. You see the liquid one and the hybrid solid one. So for hybrid solid one for this part cell with a large capacity part cells, all the samples have passed the linear penetration. This is very difficult for high ionic density cells. And also for the thermal shock testing you can see it can pass and without a significant voltage decay. And even for this linear penetration, the customer has tested that all the cells has kept the voltage if when we do the 100% SOC linear penetration testing. With this kind of concept is possible that we can also fabricate the very high ionic density and battery when we change the different anode. So in the last year, we do the third party company to attend battery raising in China organized by the government by the some government organizations. So we send different batteries to the testing that we get records like high gravity metric ionic density over 500 per hour per kilogram and the volume metric ionic density over 1800 per hour per liter and also the combination of the high volume metric ionic density and the charging rate and also the combination of both temperature and volume metric and the gravity metric ionic density and the high rate. So it looks like with the high, with the combination of this kind of electrolyte strigy you can design and develop the high ionic density batteries which could have many different applications. So here is our production base in the Beijing, Liyang and the Huzhou cities that we can deliver the gigawatt hours batteries at the end of this year and next year. So with the experience to fabricate high ionic density batteries, we have our consideration what's the roadmap of the future's high ionic density? For us, we can see that especially is it possible to fabricate in large scale and how about the cost and also is the material available. We draw different roadmap like a liquid one and also the hybrid one and also the our solid one. Why our solid one has the higher because our solid one could use the anode contained lithium or at the beginning not contained lithium but during the second contained lithium, this is a danger. So we hope so the our solid state battery can solve the safety issue of the lithium but it's not so not so confident. But for hybrid one, we have the demonstration for our solid one, I think it need a long time to develop still need a long time. All the time here is just a rough estimation. So and also this is a brief summary that's the research of such a battery is a very hot topic in word. So here is the company comparison of word and China and covered new materials and the new battery technologies deal with the solid state battery technologies. And this is a map to show the activities in the world to develop the solid state batteries including the North America and Japan, Korea and China, European. So you see there are a lot effort especially certified based outsized battery has been developed very well in Japan and also USA the solid state lithium matter battery have been developed by many startup company and also in China has several startup company and also some other institute and the car company and battery company involved in the development of these technologies now. So with that, so we show this kind of the roadmap for the energy density improvement with different material combinations. This year, there are four types of the national project that will be issued to support the research on the solid state battery in China. And this is rough expected timeline of the solid state battery for mass production time since this year. And also solid state one could be issued from the 2004 according to our experience. And for developing the solid state battery and also hybrid one. So we need a combination of the scientist thinking and also business thinking and engineer thinking. With the team collaboration we could have the possibility to turn our dream of solid state battery into the reality. So the detail we can discuss later. Okay, that's the conclusion of that one. So our solid state battery is still difficult and hybrid one is promising and quite practical for the large production. And so I think the next year, the 355 while hour per kilogram could be delivered to the market. So thanks for all the collaborations, collaborators and the funding as audiences. Okay, thank you for your attention. All right, Holm, thank you very much for the overview of the research in solid state batteries in China and of course for sharing your latest results. So now we have some time for questions from our viewers. So maybe let us get started. We talk about the, Holm, you talk about the high level advantage of the hybrid approach. You show some very exciting safety results. Can you tell us some of the trade-offs versus a all solid state battery? What is the price that you have to pay in comparison to the all solid state approach? Okay, so in principle, if you design the hybrid solid liquid electrolyte, so the key issue is, what's the ratio of the liquid in the cells? If the ratio of liquid one is very high or even comparable to the current non-acqueous one, so there are no advantage or less advantage for improved safety. So the ratio of the liquid one, the liquid electrolyte should be very, very low. Another issue is you should design new electrolyte, new liquid electrolyte, which has higher high temperature stability and also has thermal stability for use this kind of hybrid concept. So without one, so in order to improve the safety, you see, firstly, we decreased the surface reaction of the cancer by coating the solid state electrolyte. That's an inorganic one. And also second step to the in-situ polymerization. So we coated relatively electrochemical stable and thermal stable polymer interface, the CEI layer. And then remaining the liquid one and solid electrolyte one has a higher thermal stability. And we have checked, there are no thermal runaway behaviors. So it looks like the hybrid one could design a battery which can operate or even can have the highest thermal stability over 200 degrees C, thus could be relatively enough for the product because currently the international standard is 130 degrees C. And for the solid state one, we expected, we used the inorganic, especially inorganic electrolyte, which has a much higher thermal stability. So it could be designed with a intrinsic safety, intrinsic sieve batteries. That's the expectations. But currently, if you do the outsize the battery, you know, we have a lot of challenge. Still, we have a lot of challenge. We still need to design the good materials and also the interfacial engineer technology and then how to fabricate. So these are the advantage of hybrid one is it cannot be regarded as intrinsic systems, but it can regarded as safety significantly improve the systems. It can be much better than current worry. Okay, that's my idea. Home, that's a terrific answer. I think really safety also has to have a specification, right? So extreme safety may come at an extreme cost. So I think this approach of understanding the cost in terms of manufacturing of materials and performance trade-off and the safety implication, I think that's a good one. Maybe let me ask you a provocative question. Do you think the hybrid approach is a stop-gap solution before the all solid state is realized or do you think this two technology will coexist in the long-term? According to the current status of the companies, some companies to develop the hybrid one, it looks like within the next two years, hybrid one could appear in the market, but when you look at the all solid state batteries, so the raw material supplier have not been developed. So we cannot get the large-scale supplier for example, certified electrolyte and also the outside electrolyte and all solid state electrolyte membrane. Those materials are not available in the market and still to be developed, it's still not satisfied for the real batteries. So at the beginning, I think maybe two or three years or even five years early than the large production of all solid state is run batteries. But gradually, if really the ASRB can be realized and can have the significant safety issues. So in some market, the safety is the top one of cost, top one requirement. So for those at the beginning, maybe some expensive niche market could accept the all solid state this one battery and then follow the large market like EV and stationary applications. And also you have to consider how to decrease the cost of all solid state this one battery. Currently there are no reliable solutions that the ASRB is very cheaper. Now that's a great point. Maybe let's get a high-level question before we go down to the specific details and the technical question. So Hong, you show some very nice photos of production equipment. Can you discuss a little bit of the scaling up challenges for the hybrid battery that is unique to it say compared to a traditional liquid battery? What makes the production scaling up challenging for this technology? According to our experience. So we do not feel significant challenge. So we were used most of the available equipment and machines, but of course we need some new machines. Like we need to develop the low cost the pre-leasing machine to do the electric lever pre-leasing. But this is depending on the development of pre-leasing the silicon materials. If the in the material level pre-leasing can be performed then the requirement on the pre-leasing technology on the electric lever could be not so serious. But we have the experience to do the pre-leasing technology on the electric lever. So it's really helpful to extend the cycle life and also decrease the internal resistance and even increase the safety issue. So this you have to design the new machines. Of course, some company have developed for a long time but the key issue is cost. How to decrease the cost of this kind of machine and the processing technology. And then secondly is when you do the in-situ solidification you need to change the formation pre-leasing and also you could counter the lot of issues. So you have to change the procedures of this kind of machine and also change some design. So those two machine could be changed. But for a long period of view point, so if the ISEI and the CEI have been already good during the fabrication instead of currently standard formation. So the formation processing will be changed significantly. This is a big change and also could decrease the cost. Thank you, Han. So let me get into some technical questions we have received here. So you have shown some very impressive performance result in terms of cycle life. How about the calendar life? Does this in-situ solidification also improve the calendar life of the batteries as well compared to liquid? So the calendar life is mainly limited at high temperature, in some case high temperature, dissolution of transition matters. And also the dissolution of the organic component in ISEI at anode side and also cost gradually deformation and the construction of the structure of the cancer than anode. So if you use the hybrid electrolyte which can operate at high temperature and also nearly it's already formed a solid electrolyte on the surface of anode particle and cancer particle. So it's hard now to have the further side continuous side reactions. So at high temperature, we have the published paper, the battery can be operated at 80 degrees C. Normally 80 degrees C is not possible for the non-equious lithium batteries. So with the introduction of the new hybrid concept, so the battery can operate at a room temperature, relatively low temperature and also very important high temperature. So it's not only increased the calendar life but also increased high temperature cycle life. So this is very important and advantage of the hybrid side compared to the liquid one. So with this property, we need to consider to design the modular or pack in a new way. So to decrease cooling system or to even free of water cooling systems. Thank you, Han. A related question was on the rate performance. So you should also show some very impressive high rate charging performance of the hybrid battery. Is the in-situ solidification also preventing lithium plating as well? Okay, this is a really good question. So this is really depending on the energy density and also, I mean the energy density of achieved energy density and also depending on the NP ratio and also the anode side. So if you want to avoid the formation of the lithium danger completely, you need to have the large NP ratios and the anode side can contain lithium in the lattice or in the macroporos at least with this idea. And if you have the relatively not so aggressive design or excuse me, if you want to have aggressive design with very high energy density that in the anode side, the lithium has to appear during the cycling. So with that, we, you can see, we use the organic electrolyte coated separator which have the two advantage. One is to block the penetration of the lithium dendrite also to surprise the formation of the lithium dendrite. And then when the lithium wants to, when the lithium dendrite penetrate through the first contact layer, so it will react with the lithium. We use the active oxide electrolyte coating, not inactive one. So most of people develop the garnet type. So we use the RATP type, it's a really different idea. So with the RATP design, you will react with lithium. So at the beginning, the RATP will be covered by the ICI but when the lithium come, it's a multi-layer particle coating. So the lithium cannot penetrate through this special design, the separate. That's our advantage of this design. And we have tested the second life and also this kind of possibility for the formation of the lithium dendrite or the even the depletion of the lithium. So it seems quite good. Terrific. Han, I'm afraid we don't have more time for questions. There are a number of other questions. So I apologize, I'm not able to go over them. Han, thank you again for sharing these really exciting results. And yeah, we're very much looking forward to seeing more of these results and perhaps in the commercial setting as well. Thank you. Okay, thank you, thank you for hosting. Terrific, terrific. Well, I'm also now delighted to introduce our second speaker. So we just heard from Professor Han Li from China. And now we will hear from Professor Kisuk Khan in South Korea. So Kisuk is a professor in the Department of Material Science Engineering at Seoul National University. And he has been doing really breakthrough work in material chemistry on battery materials and other energy technologies for more than 20 years. And he's contributed not only from discovery of new materials and experimental methods, but also in the computational side as well for predicting and understanding new materials. And he's also has done great deal of service to the society and the communities. For example, he was recently elected on the Board of Directors for the Materials Research Society. So I'm glad I see the person who I voted one. So congratulations, Kisuk. Thank you for serving the community. And he's also the editor of the Journal of Materials Chemistry as well at the Royal Society of Chemistry. And Kisuk today is gonna focus on a very important aspect which is developing new cathodes for various battery chemistry, lithium and sodium. And Kisuk, we're very much looking for your talk. And then please go ahead. Hey, thank you. Thank you for all the introduction. I'm very happy to be part of this storage X symposium. I hope that this is going to be a good opportunity for us to communicate regarding the state of the art of lithium battery technology. The title of my talk today is new battery chemistry from conventional layered cathode materials for advanced lithium ion batteries. In this presentation, I will talk about how we can take a full advantage of the layered transition metal oxide as cathode, which has been the dominant cathode materials for the current lithium ion batteries. As we know, the current limitation in achieving higher energy density battery actually lies in how we can gain more lithium and electron from the electric without jeopardizing stability of the electric materials. So in this respect, I will discuss about our new findings on the layer of the change metal oxide when more lithium ions are stored by the additional reaction to the oxygen activity, which is so-called a little bit short if you access layer of the change metal oxide. So probably you saw one slide from the professor Hony's talk about the roadmap for the future for the higher energy density batteries. So I will show that the lithium inter-collation mechanisms are significantly different in these materials. And this is correlated with various stability problems of these materials. And based on this understanding we developed a new layer of lithium-access transition metal oxide that can circumvent the problem which will be presented today. Since I'm the first speaker from Korea in the storage acts one, let me have a few words on the situation in Korea and how we do a battery research here. With respect to battery research and development, Korea has a very good balance among the industry, academia and the government's strategy support. The battery research funding has increased steadily by average annual 4.3% for the past 10 years, which actually fostered the basic research activity in the academia. And the third active collaboration with the battery manufacturers, Korean universities like Seoul National University, I could provide the battery experts who would have the balanced view of the fundamental battery science and the need from the industry. So among the top seven electric vehicle battery manufacturers in the world, Korea has three major companies like LG Chemistry. Now it has changed the name as LG Energy Solutions, Samsung SDI and SK Innovation which occupy more than 30% of the world market share. So we are looking very positive. So let me come back to the science again. Just for recap, lithium-ion batteries is composed of three major components, cathode, anode and the electrolyte. And with the charge and discharge of the battery, lithium-ions are extracted from the one electrode and reinserted together. And this is actually the crystal structure of the layer of the transition and oxide. And then one thing that used to be reminded is that in the cathode side, which requires high redox potential, the redox reaction relies on the oxidation and reduction of the transition metal which allows the electrolyte storage. And the transition metal are redox exhibit generally high potential and high reversibility. And this is why most of the cathode materials contain transition metals in it such as lithium-combal dioxide, N-C-M, L-F-P and then L-M, et cetera. One of the interesting findings in recent years was that not only the transition metal, but also the oxygen in these materials can participate in the overall redox reaction at certain circumstances, offering additional room for the capacity. In the conventional cathode, the capacity is provided by the redox of transition metal and the typical capacity is around 140 to about 200 milliampere gram at the best. But when the anion redox is additionally allowed, we have more sites for the electron storage. Simply speaking, therefore the capacity can be much more enhanced. So in a very simple picture, it is a transition from these redox reactions solely occurring at the transition metal to this cumulative redox reaction, both from transition metal and the oxygen so that we can store more lithium and more electron. There have been heated discussion on what can make these anion redox reaction possible and how these can be stabilized. I'm not gonna go into the details of this discussion, but one of the consensus and the simple explanation was that when the local environment of oxygen in the layered structure, such as three transition metal above and three lithium ions below in the layered structure, then when these local environments shift from this in conventional layered structure to this with additional lithium in the surrounding in the lithium excess material, and it's going to happen. So this particular oxygen generates a new state in the density of states and allows additional and excessive capacity. So this kind of local oxygen environment is typically made in, of course, the lithium excess material which has some of the lithium occupancy in this transition metal. And as you can see here, in the conventional layered structure, they all, the transition metals are all occupied by a transition metal here, but some of the lithiums are occupied here. So those kind of oxygen which has lithium oxygen, lithium bonding is going to be produced in this particular material group. Despite this promise for a higher energy density due to additional anion redox reaction in this lithium excess material, there have been several chronical problems that need to be resolved. And one of them was the gradual voltage decay which is typically observed when the lithium excess material is cycled as cathode multiple times here. It suffers from the user capacity fading, capacity fading, but also the voltage fading, voltage fading over cycles. Considering the energy density is the product of the voltage and the capacity, the decay of both values make the energy density decay double times. So regarding the voltage decay problem, our group have previously reported that it is actually correlated with the local phase retention from this layer of the structure to the disordered or spin unlike structure like this. And we suspected that in my cause, the unwanted change in the redox reaction. So inspired by this previous finding, we hypothesized that the decay of the voltage is partly induced by the structure transition and the activation of the low potential redox reaction such as manganese. So taking one of the representative excess material, lithium 1.2, nickel 0.2, manganese 0.602, which has about 20% of lithium occupying the transition metal layer. Therefore the anion redox reaction is supposed to be possible. We envision that the redox reaction is going to take place like this. So first, during the charge when lithium is extracted, the electrons are extracted from the nickel cation redox reaction contributing about 0.4 electrons while remaining 0.8 lithium ions are being calculated with the oxygen oxidation. So in an ideally reversible situation, the discharged reaction is going exactly the opposite reaction. On the other hand, if there is a loss of oxygen during the oxygen reaction, during the charge, oxygen states will be partially lost. So that during the discharge reaction, some of the originally unoccupied state like manganese will participate in the reaction. And it is well known that the manganese 3 plus and 4 plus redox reaction is low in potential and typically triggers the formation of spin like structure. So if this is the case, we thought that it simply deterred this problem by introducing additional empty state of high redox change of metal in the density of states. For example, if we increase the nickel contents from 0.2 to about 0.4 like this, then the overall oxidation state of nickel becomes 3 plus. And it will generate empty state of nickel 2 plus just below the manganese states. And even when there is a loss of the oxygen during the charge and some of the unoccupied, the level from nickel is going to be occupied due to the alignment of states. And then you know prevent the manganese redox participation. And we call this as a redox buffer. So having this simple idea in mind, we designed three samples with slightly different composition of nickel and manganese having the same amount of lithium excess in the layer of the structure. The x-ray diffraction and the neutron diffraction confirmed that all the three samples were successfully synthesized in the layer of the structure and proof of x-ray absorption spectroscopy was verified. The samples had the oxidation states of the transition metals as we intended like this. Interestingly, we find that the simple tuning actually works good in suppressing the voltage decay. As you can see here, the original sample shows gradual decay of the voltage with the cycles and is more clearly displayed in the differential curves here. But as we add more redox buffer, nickel, so that we can make the nickel 3 plus more and more, the voltage decay behavior is significantly mitigated. And after the cycles, we analyze the samples to see how the formation of disordered or spinel-like structures were affected by the presence of the redox buffer. And these experiments confirm that the phase transition was also substantially inhibited with the sample with the redox buffer in here. Finally, we want you to verify whether this redox buffer concept really worked in suppressing the voltage decay. So the investigation of oxidation states of each sample clearly shows that the original sample with the magnet is 4 plus and nickel 2 plus produces mainly magnet is 3 plus after the multiple cycles. And then we know that this actually caused the decay of the voltage. On the other hand, the sample with the redox buffer showed that even after the cycles, mainly the 3 plus is not produced. Instead, nickel was reduced from 3 plus to 2 plus to compensate for any kind of changes in the structure, serving as the redox buffer. So it clearly demonstrates that a simple change in the competition in the next generation of excess layered material can actually result in the suppressing the voltage decay, this chronical problem of this material. So we are happy to solve this problem and assume that this new material would be a good high-energy density lecture. But it was not the end of the story and then we found out that unfortunately there are some other problem actually emerging with this new material. It showed a comparatively lower power capability. When it operates at slow charging rate, like C over 20, which corresponds to about 20 hours of charging time, it was okay. But when it's charged at a practically important rate like a one C, which is about one hour charging time, its capacity, the 244 is our sample, is notably lower than the usual excess material. And we found that this low power capability problem is not from charging process, but interestingly from the discharge process. As we can see here, when we increase the current density during the charge from C over 20 to one C, the reduction of the capacity is not so notable. It's not significant. On the other hand, when the same experiments was conducted in the discharge, capacity reduction is much more appreciable. And it is a very interesting behavior and has not been observed in a conventional lay of the lecture of the material where the intercollation and intercollation are regarded as the symmetrically opposite reactions. So the behavior should be similar. And we also could confirm a symmetric behavior of sluggish discharge and fast charging reaction here. First, we discharged electric until the normal voltage cutoff and forced the further intercollation to achieve about 250 milliamperes gram. And it naturally exhibits a voltage plateau lower than two volts, which is not usually observed in conventional operation voltage, but is attributable to the tetrahedral occupation in the lay of the structure. Surprisingly, during the charging reaction at the same current density and the same temperature, this low voltage plateau was absent and the normal charging curve was observed, which indicate that all the lithiums were successfully intercollated from the octahedral side. So it was integrated to the tetrahedral side because of the sluggish kinetics, but suddenly it comes from the octahedral side exhibiting the low normal voltage charging curve. Intrigued by this unexpected observation, we repeated experiment at series of other temperatures from 10 degrees C to about 60 degrees C. And in confirmed that it is reproducible. And more interestingly, it showed that the discharge reaction is much more temperature dependent than the charging reaction. If you look at the low voltage plateau here, it is the longest at 10 degrees C, but it almost disappears at 60 degrees C where the normal discharge curve is recovered at this 60 degrees C. And it strongly supports that the discharge reaction is symmetrically more sluggish than the discharge reaction. From the series of the investigations, we found that this asymmetric behavior is coupled with the outer plane transition metal migration in the layer structure. So this is the atomistic picture of the layer structure where the bright spots are the transition metal and the dark layers are lithium layers. And at 16 degrees C, it was found that with charging a significant amount of the transition metal ions migrate to the lithium layer, which is supposed to be completed back, but the presence of this bright spot means that transition metal are reflected in this layer. But they reversibly migrate back to the original layer during after the discharge, covering the perfect layer structure. On the other hand, when operated at room temperature, the transition metal ions migrate to the lithium layer up on charge, but do not completely come back with the discharge with the T-tuval. Here you see that a substantial amount of the transition metal ions remain in the lithium layer, as you can see here. But interestingly, when we first, the lithium intercalation up to 250 milliampers grand, those transition metals are no longer observable in the lithium layer, indicating the recovery of the layer structure. So there is a clear correlation between the transition metal presence in the lithium layer and the voltage curve. And the series of the pictures imply that the lithium intercalation and the deintercalation in this lithium-accessed layer material is moving together. It's a strongly coupled with the transition metal migration. So according to these observations, we propose a new lithium intercalation and deintercalation mechanism coupled with the transition metal migration in the layer structure. First, during the deletion, the transition metal can easily pop up. So these are the original transition metal layer and these are the original lithium layer. The charging in the deletion of the lithium, this transition metal can easily pop up to the vacant lithium layer. And the transition metal should migrate back to the transition metal size during the deletion for normal discharge reaction. But unfortunately, some of the transition metal in the lithium layer that has migrate can also migrate in the vacant lithium layer, hopping farther from the original side. And if it happens, it very much complicates the path backward during the deletion deletion and requires longer migration path. So deletion process and deletion process can be symmetrically different. So compared to with the simple hopping up of the transition metal during the charge, the complicated and longer path of transition metal during discharge is believed to result in the particularly sluggish discharge reaction because those coming lithium, coming incoming lithium have to interact and then push these transition metals back to this. This asymmetrically diffusion is quite contrary to the conventional lift on the lithium intercalation and the intercalation mechanisms. In the classical model of intercalation, the lithium insertion and the insertion process should be identical and the only mobile ions and the lithium ions. And in this conventional intercalation model, diffusion model, only slight structural expansion and contraction were conceived. And then this was model and then that offered that have been perceived for many years. And the asymmetric properties about under this model cannot be explained. But our new lithium diffusion model as illustrated in this slide reveals that lithium is not the only mobile ion and their motion is coupled with the transition metal migration. And this involves reversible but a symmetric transition metal migration which illustrates our experimental findings. So one thing that should be noted is that transition metal migration into lithium layer is actually thermodynamically favorable. It's at the extreme at low lithium stoichiometry and is an almost unavoidable phenomenon of very charged process. When the lithium stoichiometry is low and of course the rockstone phase or spina phase are the thermodynamically more stable phases according to the calculations and also from thermodynamic the data. And once this transition metal in the lithium layer is distracted much longer migration path awaits during discharge. This actually results in two consequences in lithium excess material. One with the redox buffer as we have seen so far the sluggish kinetics and low capacity. On the other hand for the material without the redox buffer conventional one which induces probably magnitude plus ions this transition metal migration to trigger the massive phase transition of the material to spina like phase causing the significant voltage phase. Then how do we resolve this? If the transition metal migration to the lithium layer is almost inevitable because of the thermodynamics it's not that the substantive key to minimize this negative effect it's the streamlined structure so that transition metal migration only occurs at this path. So it comes up but it doesn't distract but it comes back. So that I mean so the transition metal migration occurs only at this path and inhibit other paths like this in plain migrations in the lithium layer and this will block if we can lock here then the further migration of transition metal is going to be inhibited. So then how do we do that? Then how do we actually ensure the transition metals do not go astray in the vehicle lithium layer and readily come back to its original side when the lithiums are re-intercollated? So we believe that we can control this transition metal migration by altering the stacking sequences of layer of the structure from the conventional old pre-structure where ABC, ABC stacking to auto structure with ABCBA. So it seems like the same layer of structure but the oxygen stackings are different so that the local transition metal environments are quite different. So if you look at a little bit closely at the local environment during the transition metal migration in these two different layers of structure they are substantially different. In the conventional old pre-structure the transition metal hops to the lithium layer via this intermediate side and it jumps to the nearest octahedral side. And these octahedral side, these are the lithium layer these are the transition metal layer and these octahedral side are relatively stable and therefore this process can readily occur. On the other hand in auto structure this transition metal can go to the intermediate side but when this hops to the nearest octahedral side then this octahedral side is strongly repulsed by the transition metal underneath. The reason why there is a transition metal underneath this octahedral side is because of the different octahedral stacking which allows the occupation of transition metal right here. So this strong repulsion should prohibit the migration of transition metal to this so that the transition metal should migrate back to its intermediate tetrahedral side so it's locked here. So this difference in the stability of the age range site arises from of course different stacking sequences of octahedral and octahedral layer structure. So this argument to be supported by our first principle's character relations on each side. As we can see in the graph showing the relative side energy of the transition metal here is observed that a transition metal in the original ortho structure can easily go to the intermediate side and finally ends up the octahedral side with a negative energy slope. On the other hand in the auto structure the transition metal can hop into the intermediate side but it cannot further migrate to the neighboring octahedral side because of its high energy barrier. So inspired by this idea and the theoretical calculations we decided to synthesize the auto lithium excess layer structure. But unfortunately we cannot obtain the phase using the conventional solid state reaction because it's not the thermodynamic stable phase and high temperature is all three. So we had to go through the indirect method. So it has been well known that this kind of auto structure can be derived from the p2 type structure and this p2 type structures are easily synthesizable at high temperature by the sodium phase formation. So we prepared the sodium version of the lithium excess in p2 layer of the structure and iron exchange the sodium, the lithium through the soft chemical method and then attempted to obtain this auto structure. So these are, this shows the final products. As you can see here the x-ray diffraction patterns on the left on the left confirm that we successfully obtained the auto type layered lithium excess material from this p2 type of sodium phase and then the particles were around a few micron sizes as we can see from the SEM picture. Through our surprise this shows that we found that this auto structure is very effective in retaining energy density. This figure presents the first and second charge in discharge terms of the auto layer of the charge and deliver capacity more than 230 milliampere grams. And the voltage profile of the discharge was almost unchanged over 40 cycles without the decrease of the voltage indicating the success of our strategy. The comparison with the conventional auto type structure sample, as you can see here they show the gradual decay of the voltage over 40 cycles, but we can see that our sample shows steady voltage at high voltage here. And because of suppressed voltage decay the retention of the practical energy density of the auto was a very well retained. It is about more, about 600 watt per kilogram after 40 cycles, which is spiritual to that of the auto type structure. We found that this stability in the voltage and the energy density is attributable to the reversible and the asymmetric transfer metal migration during charge and discharge. And as we can see here, after the charging the transfer metals are visible in the liquid layer but they disappear completely upon the discharge indicating the reversible migration of transfer metal back to its original one when it didn't come coming back. And this reversible migration of transfer metals so inhibit the unnecessary formation of the disordered or spinelike domains in the structure as can be seen from these Raman spectroscopy. However, the structure stability could be maintained even after the long term cycles do not show any signatures of disordered or spinelike formations. So in summary, we show that there are still such interesting new chemistry in the layer structure have been studied over several decades. And our findings on the lithium excess material requires rewriting of the classical lithium diffusion or intercollagen model. So we have to think about it again. And the proper structure we're designing of the layer of the structure can offer the stable and higher energy density for a defense lithium ion battery. Finally, I'd like to acknowledge my crew members and then these works were primarily done by Donggeun Eung and Byung Kim and Dr. Gyujin Gu who is now in our organizational laboratory. Thank you for your attention. Thank you. Kisa, thank you very much for sharing the science of cathodes, a topic that's very near and dear to my heart. So thank you for sharing. Let me also begin with maybe a high level question. The O2 structure you show has a very exciting performance. But if I remember, you also concluded in that paper that practical scaling up of this ion exchange could be challenging. Can you maybe give us some insights into what it would take to do ion exchange at scale for cathodes? Okay. So the ideal synthetic routes is going to be the one by the solid state reaction as we have been doing for making conventional lithium cobalt oxide or NCM and just mixing precursors of lithium and the treasure metal and by having different ratio and the heat it up and it ends up with our structure. Unfortunately, the thermodynamically stable structure, I mean, the phase of this composition of lithium excess is O3-type structure and O2-type is the kind of metastable structure. But the fact that it is metastable structure doesn't necessarily mean that we cannot synthesize in a massive scale of weight. In our paper where in our presentation, we focused on our proof of concept. We wanted to verify that this kind of altering of stackings and regulating the treasure metal migration in the layer structure is going to be effectively solved or mitigate the problems that we encountered in the lithium excess material. And that's why we did the focus on more on the synthetic size. But I think there will be some the pathway that we can produce this O2 structure in a more scalable and more cost-effective way, especially there is one more steps that have been added here. We synthesize the sodium phase just like in high solid state reaction, high temperature, just like we do in NCM. But we put in the bath of lithium and then we ion exchange about 280 degrees C. So this is not like high temperature, but it requires an additional process. And then also we have to do the washing and drying steps like that. But if you can find out the way you can do this additional process in more cost-effective ways, it's going to be more interesting. Or if you can find out some way that we can do the high temperature synthetic method by having altering the atmosphere so that these metastable states, slightly metastable states appear even at the high temperature state, then it's going to be a very, very good and fortunately situation scenario. Okay, so I think that's a really great point. And maybe a related question is the stability of this metastable O2 structure. How persistent is it? If you were to able to cycle the battery, say for 1500 cycles or 10 years, do you expect the O2 to be persistent over that time scale? I think so. It is because, you know, thermodynamically, I mean, we know that all the nature wants to go to the very low energetic states, okay? But the matter, the practical, the life, in the practical situation is that how high the barrier is going to be, okay? How high is going to be? So let me give you one example. If you cobalt oxide in itself is thermodynamically stable, but when we dilute the air so that we can take some of the lithium so that, for example, if it becomes lithium-point-9 cobalt oxide, the thermodynamically stable phase is not a label structure. The thermodynamically stable phase is a phase segregation between whole lithium cobalt oxide and some spinel or the rocks of space. But still, we can operate more than 200 cycles or 300 cycles, okay? It is because the thermodynamic workforce energy of the barrier is not sufficient to make this transition occurs. Coming back to our material, so then we have a view that all three structure is more stable than all two structure. Then what's going to determine the area to phase transform to all three structure over multiple cycles? If you look at those two structures, you can see that all two structure cannot slide into those three. By having the metal oxygen bond breaking, you can only obtain all three structure. So all three and one are compatible with this sliding and then it can easily transform from one to the other without breaking the transition metal oxygen bonding. But on the other hand, all two and all three are completely different stacking and they are different family so that if we want to transform the all two to all three structure, the bond breaking, major bond breaking has to occur and it will require very high energy barrier. So I'm quite sure that this phase transformation to the more stable or three structure is not going to easily happen during the operation time of our interest. Thank you, Kisuk. Maybe let me also follow up with a question here. In my encountering of various road maps and reports about the next generation batteries, cathodes and so forth, it's not often you see the lithium access material on the roadmap, although you know very well that it's been highly investigated in academia. What is the challenge here that prevents the lithium rich material to be on the roadmap say in addition to the nickel rich material? What's the consideration industry has in mind right now in terms of the roadmap? Okay, so with respect to the cost and the feasibility of the technical extension, the nickel rich nickel, high nickel one is going to be immediate future, okay? So we had the one-third, one-third, one-third NCM and six to two, eight, one-one and now nickel composition goes about 90%. And we know that by having this nickel, there are dimets rich like stability and like this one, but clear merits is the higher energy density. And then the technology developments has found out how we can manage the safety issues. That's why energy density wise we have gone to the high nickel. But I think the end is now right here. What happens we have a nickel 0.95 and 0.98. What's going to the next? I think the high nickel one is going to become very, very soon, okay? And we have to look for other chemistry, okay? Then what's going to be the one? As I said in the beginning of my talk, we have to change the paradigm thinking. We have focused on transition metal, redox reaction, but the NIME redox reaction can offer additional capacity without compensating for the redox reaction and the transition metal. And there are very much high technical barrier in adding this additional NIME redox reaction to this conventional redox reaction, okay? With respect to the only conventional redox reaction from the traditional metal, we can go up to 0.98 or 0.99 or whatever. But the next thing that we have to add should be the NIME redox reaction. And the most actually feasible way to utilize this NIME redox reaction, I believe, is in the layer structure is a mid-tune success or mid-tune rich chemistry. And practically in the company, I have worked in many companies so far here, the one-to-one comparisons between high nickel and this little rich one right now is not valid. I mean, because high nickel one still shows a very high energy density and the little rich one does not show the capacity that is expected because of the boldest decay. And one of the most important problem was the boldest decay and the rich actually decreased the energy density to the level to the high energy, and that's why people were less interested and people from the industry were less interested in here. But by having this one breakthrough by one breakthrough, I think now we can solve the multi-problem and solve other gas evolution problems. Then there are more room to hear for the oxygen redox reaction. So I think in the academia side, we have to further our continued to work on this NIME redox reactions. I fully agree, maybe in a self-serving way as well. So thank you very much for those comments. Maybe for my last question, let me also be provocative as well. So this field of high valent redox mechanism really has received a lot of attention over the past 10 years. And in your presentation, you really highlighted this importance of the out-of-plane transition metal migration. But I would say recently in the past couple of years is also being increased reports on the importance of in-plane migration as well. Could you give us some insight in how your mechanism could be relevant to the in-plane migration? Okay, so that's the paper that is submitted. The relation between in-plane disorderly and out-of-plane disorderly is on the review on the revision. So I have to be a little bit more careful. But our recent finding is that in-plane disorderly and out-of-plane disorderly are quite coupled with each other. Our understanding, purely mirror understanding, I cannot disclose it fully here, but the in-plane disorderly when those are like, so the in-litum excess material, the in-plane migration of transition metal in the transition metal layer is possible. It is because unlike the conventional layer structure which has a full occupation of transition metal, now you have a vacant site because some of the lithium are occupying the transition metal layer and those lithium are supposed to be extracted or go to the lithium layer in certain circumstances. So those vacancy mediated migration of transition metal in the transition metal is going to be possible. So when this in-plane disorderly or migration transition metal occurs, then some of the specific oxygen environments are actually occurred. So sometimes oxygen-oxygen dimer or some of the unstable oxygen environment is going to be caused by the transition metal migration and because some of the vacant situation lithium, so some of the this oxygen is highly reactive. So these causes, these promos, some neighboring transition metal pop up to the lithium layer so that it can stabilize, it can be stabilized itself. So this in-plane disorderly and out-of-disorderly is actually covered. So some of the material which has been reported that there are no out-of-plane disorderly but there are some voltage decay is coming from this in-plane disorderly and afterwards we found there's some disorderly out-of-plane disorderly actually occurred if you look at very closely. Great, I look forward to seeing that work. All right, so in these symposium, we typically have a spirited discussion afterwards. So I have the job of asking some interesting questions to get the discussion going. Maybe let me just get started by asking this question about road mapping. And recently there's been some very interesting movements in the road mapping I would like to get your thoughts on. So there was some recent announcements from Chinese battery developer who really saw the benefits of improving the anode. For example, by using high silicon content and so forth. And now we're seeing this opposite trend where then the cathode is being replaced with something that is the lower energy density. So I wanted to get both of your thoughts on this unusual trend where anode is really getting higher energy density and we are now seeing trends in which the cathode are being replaced with lower energy density. For example, one pairing is silicon, rich and lithium-ion phosphate which together can still achieve pretty interesting energy density. So since both of you work actively on the cathodes and the solid electrolyte and anode, I wanted to get your thoughts on this trend we're seeing coming from some developers. Hong, do you want to maybe have a comment on this first? Okay, so thanks also for kissing very excellent talk. I learned a lot. So for these questions is the safety issue is the key issue. Yes, for some, for the EV application, the safety is the top one concern. If you, from many experience, so lithium-ion phosphate is really very stable at abuse applications. So if we can see the RFP is the most safe cathode, then is it possible to increase the energy density of the cell? Then so the combination of silicon with the RFP become a new design, like proposed residency by Gaussian company. But silicon, you know, it has a very poor cycle life, the relatively poor cycle life, but RFP can have a cycle life over 10,000 cycles. So the combination of this kind of design may not use the full stationary application, but could be your concede for the EV application compared to the, if you're covered a carbon with the RFP. When you introduce the high silicon content, you have to concede how to deal with the volume expansion and contraction. So then the previous issue has to be introduced also. So the total combination of those technology still need to concede the cost issue. And another issue is, so one tendency is to, as mentioned by Tiziu, is the high nickel, there are a lot of effort, that also the low nickel content, but charged to high voltage is another possibility. So some company and also many researchers are trying to understand for like five to three type, typical five to three type, R613, R622. So if we charge to 4.4 volts to get the same capacity as high nickel, so what's the, which one is more safe? So safe because it's the, as I mentioned, it's first concern. So for that kind of consideration, so the low nickel and low energy density can start have been conceded because also the improvement of anode side. So if you change the high capacity anode and you use the low nickel, so you can still increase the anode density compared to previous one and get the high sieve. So that's the tendency, but for long term, so if you check the history of the least one batteries, the increased anode density is of course, the always the tendency. So how to increase the anode density to get the balance of other performance? I really agree with the Kisiu's consideration that after high nickel, what happens? So you have to concede the next one. So I really agree that the nickel, at least on reach should be the first choice compared to other like a sulfur or air battery, at least on high battery, at least on sulfur battery, compared to at least on air and at least on sulfur, at least on reach is more practical. And you need to consider how to design the stacking like O2 structure and also the surface coating to avoid oxidation gas release and also the side reaction. So there are a lot of efforts still need to be, to be paid and to improve the performance. So that's my idea. Kisiu. Hey, I think I view this kind of movement roadmap using like a silicon high capacity anode and with a low capacity cathode like lithium ion phosphate, I view this one as the technical, difficulties in making safe enough and cost effective enough batteries. So in ideal situation of course, you have to adopt the high capacity cathode when you employ the silicon high energy once, not reducing the capacity of the cathode. But the problem is that when you make the anode as a silicon, there are so many, so much problems like safety and the cost, even though there are gains, large gains in the energy density. So the only practical options to like mitigate these is to compensate the use of cathode so that we can have a better safety and then a little bit less cost. So if you use as high nickel ones then this safety one is going to be double times more the dangers and the cost is going to be like that. So it is not practically feasible. That's why I think the cathode side, they had to compensate, but overall energy density is going to be plus because you have higher energy density silicon despite the low capacity one. So it is not going to be the ultimate answer, but it can be an alternative way before we fully accomplish high energy cathode and higher energy in the full cell. Thank you, Kisa. Maybe I can also build off this question a little bit more. So certainly when I look around in the United States, there are many innovators in the anode area, right? There are dozens of companies trying to commercialize and scale up manufacturing of silicon and so forth. And also companies like MPRIES that came out of Stanford. But when I look for the cathode side, in the United States, there is very little innovation in the startup world. So I wanted to ask Hong and Kisuk in China and Europe, in China and North, South Korea, is there's a similar trend of a emphasis on the anode versus the cathode? And if so, why is this the case? Why do we see this trend? And this is a little bit related to my first question as well. Can you give your thoughts? Yes, that's the same case in China also. Just for the cancer, you know, this is quite costly. So in China, we have top-tier manufacturers. Each company has been supported by large investing. So for the anode side, it's not necessary to have such kind of large investing to initiate a company. And also the progress in the cancer side is not very quickly. So the progress is kind of gradually step-by-step. So from the nickel, like 80 to the 84, 88, 90, like mentioned, Kisuk also. So this kind of progress need not to have a new company to compete with current companies. It's not, it's really hard. But for the anode side, the silicon is not easy to be fabricated by the previous company. So you have the possibility to have the new company. In China, I think also we are the one of the startup company to produce the silicon, including amperes also, and others. But still we have some companies startup company to produce the decent rich cancer. This is just the beginning. There are three companies try to produce the decent rich cancer. Some application does not require a very high cycle life, but it requires high energy density. And also does not care about the voltage range because this rich has a wide voltage range. So I think the progress of cancer in near future also will appear some new one. I, for my opinion, the decent rich is one of the possibility. And also the modification of the current cathode will become a very important directions. Because to increase the safety and increase and the possibility to use in the solace battery, you need to change the, you need to modify current cathode materials. So I still can see the opportunity in the next three years to have a cancer effort. I'm not sure in USA or in other countries, but I'm sure in China, we will have such kind of new company to produce the new cathode. Kisuk, what's the Korean perspective? So in Korea, we can say, as I said, we have three major battery manufacturers. Compared to United States and compared to China, we are relatively small country, but still we have three major companies. And then those three major company have a very good, very well established supply chain of materials. So practically, it is a little bit difficult for the small venture company to penetrate into this established supply chain. I think that's why some of the activities of small companies working on these new electrode chemistry is not so, I mean, there are some, but not very much active like China or in United States. But if you look at the, so my interpretation about more companies on the energy side is because if you are the, like a beginning company, like a startup company, your idea should be distinct from the conventional one. So you have to start from some other material that has not been covered from the conventional one. And let me say this. So in the material science point of view, the energy has a more variety of chemistry than the cathode. It is because energy by definition requires material with high lithium chemical potential. And there are so many materials that can observe what's stored in them at a relatively high chemical potential. On the other hand, high-reports, all of these cathode history cards, very low stable lithium storage, low chemical potential is very seldom. You have to have a very well-structured material like a layer where all of it was spinning like that. So in terms of the variety of chemistry, there are much more variety in the case. So that's why there are some, I think, more chances for the startup companies to dig into the new chemistry for the annual. That's one of my interpretation from the academic point of view. So anyhow, so, and then if I add one more things, the culture in the battery research culture in Korea is like we are focusing more on the practical materials rather than like a very challenging materials to be adopted because of the three major companies. We have very much common sense what's material is going to work and what material is not going to work. Seeing the pre-existing line or the manufacturing processes. So in the lab scale university or research lab scale, you can see that, oh, this material is great. It works well and the high intensity cycle very well. But if you look at the line or the company side, there are so many other things you have to consider. So once you have those ideas, it's a little bit difficult for one person to pursue this new chemistry to the existing line. Kisug, what a great point. Our speaker from two weeks ago also commented on the 10 year duration between lab and product, right? So I think you just further emphasizes points. Both of you are working between academia and industry. Do you, what do you see as the opportunity to really shorten this 10 year timeframe, right? From introduction in the lab and prototype all the way to the product. What's the opportunity here? And maybe you guys are already practicing this now. Hoh, can I ask you to share your thoughts on maybe how do we spend not 10 years by five years for the next iteration? Okay. Me or Hoh? Whoever would like to go first. Kisug, it sounds like you have something to say. Please go ahead. Oh yeah, yeah. So as I briefly mentioned about the culture of research in Korea, battery research culture in Korea. For the past 10 years, I have been more than 10 years here in Korea working in the academia. I thought that, as I said, the discovery and invention in the laboratory does not necessarily lead to the successful employment in the commercial sector. And as I have more of the interactions with the company, I realize that there are some reasons, okay? So nowadays, our strategy is that we actively collaborate in the industry. For example, we get supply from the company like a precursor or other real practical materials. And then start from that reliable precursors and then develop our own ideas. So in that way, we can reduce the steps that in some laboratory, we have to start from like very low level precursors and then develop here. And then once you bring those material to the real site, then somehow there are so many problems in each step, so then we can reduce those kind of steps. So we have multiple joint program in our university in our lab with the companies to work together so that we often communicate what's the real practical point of view and what's the future or from the fundamentals. So we work together so that I think it's actually very much expedites the speed of the development. Okay, so this is a really difficult topics and I have also the same experience because we have set up a institute so called TM Lake Institute for Advanced Energy Story. The purpose of this institute is to accelerate this transfer technology. There are so scientists, a lot of scientists have new ideas but have no place to do the pilot production and the demonstration. And for the company, normally for most of big company they have no time to wait for you to direct to demonstrate from the lab to the large scale production. So if they are platform which can help the scientists or other smart team to demonstrate and the scale up in the pilot level so that we could accelerate this transfer speed. Such kind of platform, I think not so many in the world actually. Yes, this is, we have this kind of third party. So now we have kind of so called scientists, the studio systems. So we attract the seven scientists from the university and institute to do the technology development. In this institute, we have a lot of facilities not only for the testing but also for the fabricated big batteries and the industry standard. So if the scientists have an original idea he can scale up the materials in this institute and also test and fabricate the battery with the engineers have and then test with the industry standard and also do the simulations. After that, then you can tell the company is this technology really promising or not. The most difficult thing is the sometimes some scientists thinks it's a promising but for industry people the cost is the issue and also processing technology is not available. So you need some kind of the platform to bridge the gap between the company and the scientist. That's my idea. And also that's our effort in the last three years to do this. And I think this is one thing but another thing is of course if the scientist has some original very important idea you can directly transfer technology to the large company. They have the very big teams to do this. They are two choice but the last one depending on whether scientists would like to see the idea or not. Sometimes the big company do not want to pay much money to the scientist. Okay. There's a message there. We're coming to the end of our session here. I thought maybe I would solicit your advice. So I think there's been a lot of development in the United States just even in the past month. And you have seen announcement from the national leadership expressing that we need to have better supply chain of battery technology in the United States. And I think it goes without saying that we are catching up to Korea to China as well. So what would be your advice to the United States as we now sort of realize the importance of this aspect and trying to play catch up here? What would be, you know if our president knock on your door and ask, you know what would Professor Kong and Professor Lee tell us? Can you share with us your insights and recommendations to the US government? Well, this is a very difficult and sensitive topic. So I know the question from the ESGC discussion. So ESGC want to build up this kind of leadership in the innovation chain, in the production chain, in also the intelligent people's chains to form a very developed chain, but it takes time. So if you want to do this, so from the raw material to the precursor to the key materials and also to the machines and the fabrication of the cell modular pack and also the BMS and the counter system and the sensor, such kind of the whole production chain should be developed at the same time. If you check the investment, so in China, Korea and Japan and the European, so right now from the big company, the investment is a huge money now. I think much higher than USA. So this competition and also the investment is really may not be in the same level now. So firstly, a big investment. And secondly, you need to attract people to do this because doing the battery business is a tough, tough experience. Yes, you cannot see a high price. You have only choice to see a cheaper battery compared to the Asia product. That's very tough experience of course for USA because the labor cost and also the material supply chain is not developed. So it's really tough, but I think if you want to do this, you have to do step by step and from the raw material to the finer the systems. So there are no other faster paths. There are no short circuit chance. Okay, I think it's a very difficult question, but the battery business is going to be huge, okay? We often compare with the semiconductor or the conventional car company, I mean, car paradigm may change. In that respect, the battery is going to play a pivotal role in there. And then the national competition is going to become much more harder and harder. But I think we have to, so that's why I think maybe the United States, the researchers or the people in the battery field maybe go to the politicians or then look at this business as a whole. But if you look at a little, we have to, I think, but we have to look at this matter from a little bit more, from the bigger point of view. The battery as a whole of the international, international or as the effort to shift, convert from conventional fossil uses to this more environmentally friendly kind of a way to the electric vehicles. I mean, there will be some national competitions, but it's movement shouldn't be go together as a whole team. So United States, China and Japan and Korea as a major kind of a battery research team and a production ones, we have to work together, not only from the like a solid national kind of interest or national point of view, but from the whole like an international kind of aspects. Actually the basic research and also the data analysis and also large facility experience are really leading the world from USA. Contribute a lot of original idea, but the problem is how to scale up those kind of new ideas because there are very few battery factories in USA. So without big battery companies, so it's hard to transfer all the technology, all the original idea to the real one. That's the problem. This, if you want to solve, you can consider, introduce some big battery companies from Asia or from USA itself. And then of course, as Kisu comment, so the battery is connected the business, it's harder to separate from the country. Each country contribute some key materials or key technologies right now. That's the key already. Well, these are excellent messages and I hope if there are governmental leaders listening that they have taken a lot of notes from our colleagues in China and Korea. So Hong and Kisuk, I want to thank you again for taking your morning to share your technical insights but also higher level insight for the battery industry. I really have learned a lot and I appreciate your time. Thank you very much. Hey, thank you very much. And I just want to briefly share with the audience that we have several exciting events coming up that is hosted by Stanford's StorageX initiative. We have two talks that are going to be given by students and postdocs at Stanford. You can see here, we're going to have talks on modeling of degradation as well as on safe design for lithium-ion batteries. So you can sign up for these talks that are given by Stanford students. And two weeks from tomorrow, we will also have another very exciting symposium. We're still finalizing the speaker, but the topic will be a very crucial one, which is the sustainability of battery materials. So I hope you will join us two weeks from tomorrow at our usual time to learn more about sustainability. With that, I would like to close today's session and thank you everyone for joining and thanks to Hong and Kisuk again for taking the time.