 Okay. Good morning. Good morning, California. On behalf of my co-director, Professor William Chair and myself, we would like to welcome you to our Storage Act symposium again. Professor Doron Alba is a professor at Bar Island University. All the people in the battery field know he has been working on the battery for a long time. It's a very extensive program on many things related to batteries. Let me just mention a few. We all know Doron has been very instrumental and tried to figure out the SEI structure. The whole battery field has been used in vitally. You remember the patterns, the schematic drawing we all cite over all our career. And also Doron's name is also associated, which we call a method in my lab along Alba method to determine the Colombian efficiency of lithium metal. So Doron, your name is clearly associated with that all my students using your name for this methodology. Doron has achieved quite a bit of, you know, I think have a lot of discovery, having educated the whole community quite a bit. He has won numerous awards. For example, the International Society of Electrochemist, she's from King Metal and Electrochemical Society's Alambard Metal Award. These are all highly prestigious award. Dr. Kang, she is from Army Research Lab. Kang is well known for his work in electrolyte. If you look at his publication, right, I mean, I remember when I get into the battery field by reading about Kang's electrolyte reveal, very long one in chemical reveal, I learned tremendously from his reveal. He has becoming a classical papers for nearly everybody in the battery field to read. Kang certainly has done a lot of nice work related to electrolyte interface. He's also a winner of the Battery Research Award and the Electrochemical Society. With this short introduction, now I would like to turn the podium to Professor Doron Alba to start his presentation followed by the Kang. Doron, please come on to the stage and take over. So good day, morning, noon, afternoon, night, any place in the world for all of you. And thank you very much for the Stanford team for this challenging invitation. I'd like to entertain you this time with frontier in R&D of high energy density rechargeable batteries. Here there is a list of my officers, of my group. I should acknowledge collaboration with other groups from my university working on surface treatment, computational work, Solis et NMR. I also should acknowledge collaboration with BSF, with General Motors. And also here in Israel, all the electrochemical, electrochemistry groups working on batteries and in power sources are gathered together in the Eastern National Research Center for Electrochemical Propulsion that I lead. And we, in fact, in Israel, we turn competition to collaboration. So we work together on batteries, fuel cells, whatever can help for propulsion. There are four major use of rechargeable electrochemical power sources. We have portable devices, mobile electronics, communication, power tools. Here lithium batteries are conquering the markets. Energy density is important, of course, safety. Well, this is commodity, everybody depends now on lithium and battery technologies, so this is well familiar. The success of powering mobile electronics led to the next challenge is electromobility. Here we need high energy density, with some compromise on durability, cycle life, safety. And this is, I would say, our main challenge today in batteries to promote the electromobility revolution. We have another issue, another challenge of propulsion, which is very high density batteries, especially for unmanned aviation and robotic mobility. Here we need lithium metal electrode. You want to see the renaissance of lithium metal anodes. Lithium oxygen batteries would be the best if they would work, but we need a lot of research time in order to make it true. Lithium sulfur is better, is working. But today we discussed today the issue of lithium metal anodes in high energy density batteries, and of course there is large energy storage for large energy storage. Here we need huge quantity of materials. We have to use a banner element, we're talking about terawatt hours, if you think about how we really help to use sustainable energy, we're talking about a huge amount of materials. In fact, if I have to think about the best battery for low-leveling application and for large energy storage, lithium iron battery technology can provide the task combining lithium titanate, LTO, and lithium iron phosphate, LFP together. We have excellent batteries for low-leveling application as well. The thing is that if we succeed with electromobility revolution, we will be able to see more and more lithium going to the roads, and there may be a shortage of lithium, but here comes another field which is not competing, but rather complementary, which is fuel cells. Fuel cells, the field of fuel cells, progresses very well, and so the progress in the fuel cells and the propulsion by fuel cells can leave some lithium also from other uses, also for large energy storage. Today, the most important challenges now are we want to show, develop, demonstrate, confirm the best lithium-ion batteries for transportation to promote the electromobility revolution, and here the key factor are the cathodes, and also we want to see the renaissance of the lithium-ion meta-enotes in rechargeable batteries in order to obtain very high energy density. So here solid electrolytes is a very valid option, but I vote for liquid electrolyte solutions with fluorinated solvents. So the cathodes. In fact, I would leave graphite as a major anode material, although we show nice work with silicon, and there are efforts with silicon or silicon carbon composites throughout the world, I still vote for, if you think about electromobility, if we think about safety, we think about durability, I'm voting for graphite, because anyway the key issue is the cathode, and here we have two families, in fact we are converging into two families which can really produce very high specific capacity and together with graphite high energy density, and these are the nickel-rich material, N-C-M, N-C-M is nickel cobalt manganese, this is the major formula here, and here the stoichiometry of lithium is one. What is nice about this compound is that we can extract the maximal capacity, which is quite sufficient, while charging up to 4.3V, not too high, we are not endangering too much our electrolyte solutions. So here in the middle you have the voltage profiles of several compounds, we see plateaus, due to the olivine structure and due to spinel structure, and we see the sloping voltage profiles of the layered compounds. So here the blue one relates to the layered what we call N-C-M materials, and here as we increase the amount of nickel, we can get higher specific capacity but more problems, and we have this very interesting discovery of the so-called lithium manganese-rich N-C-M, so whenever the stoichiometry of lithium is more than one within this compound, we have a segregation, we have a structure which contains also this lithium 2M and 3 monoclinic phase, which is initially inactive, and there is an integral structure here between the warm-bohedron and monoclinic phase that can be activated and with activation we can obtain a high specific capacity that can then approach even 300 mAh per gram. And in fact what was discovered recently is that this, the high specific capacity is because of oxygen activity in this system. So this is the typical first cycle voltage profile. We see here the activation process. We have to push the potential up to 4.6 volts, what endangers our electrolyte solution, so the selection of electrolyte solution is critically important, and we have the high specific capacity. Now the structure is very complex and we can discuss ours, the structure that still open questions, but one thing we discovered quite clearly. A key issue here, because we expose the electrolyte solution to oxygen species and because we have an issue of oxygen evolution and because we have also issue of the solution of transition metal, ketones into the electrolyte solution and these ketones in solution have terrible impact on the passivation of the negative electrodes. A key issue is to isolate the active mass from the solution species. Remember, we have on these materials very electrophilic and basic species, especially when oxygen enter into electrochemical reactivity and in electrolyte solution we have acidic species and electrophilic species like the acyl carbonate, so we have very rich chemistry between the solutions and the active mass, so we have to prefer buffer zone and there are many ways to do so. We vote for ALD, the gas treatment, the ALD and what we can see now, what we can see and what we can say that we have several treatments and we can offer I would say even a plethora of treatments that form good buffer zones that stabilize the material. When we talk about stability, we have two issues. One is the specific capacity stability and also the voltage stability. It appears that the ever voltage fade also, go down and down during cycling due to structural changes within the material. So what I'm demonstrating is that we can manage. Here you can see results of three coatings by ALD. I cannot disclose everything. These are different kinds of alumina compounds in which we look for three different coatings and the experiment is that we do several cycles at low rates then at one C-rate and then at three C-rates. So we fluctuate between different rates and we compare between a reference, the black curve and all the other colored which a curve would relate to coated material. And we demonstrate stabilization. We demonstrate that at least with the green, with the coating number three, the green one, we demonstrate quite nice specific capacity stabilization having more than 200 mAh per gram at one C-rate is not that bad and when we have slow rates, we exceed the 270. And here you can see cycling over 500 cycles which is not too bad. But also what is very nice is the effect on the voltage. So you can see the voltage, average voltage. Discharge, charge along 400 cycles. And here you can see the hysteresis. We also count the hysteresis difference between the discharge and charge voltage. This is also a very important parameter and we can see very, compared to the reference, along 400 cycles we see the increase in the hysteresis and here with the coating we get stabilization. Whenever we have good electrochemical stabilization, it is well reflected by the thermal studies. So here in this charge you can see results of DSC, difference scanning calorimetry, where we react the active mass with electrolyte solution, star electrolyte solution and we measure the onset of reaction and heat evolution and you can see here the number. When we talk about the reference material, the uncoded reference, the heat evolution is by far higher. So we see nicely here the correlation between electrochemical and thermal stabilization. So I would say that here we are going to win with the materials, but there is still a question of stabilization of the electrolyte solution which is not that easy because we have to push the potential of charging to high values in order to extract the high capacity and we have here still a challenge. So we can go to the nickel rich materials. Sorry, I have to go to get back to this. So we have to go to the nickel rich materials. So this is the formula of the nickel rich materials and here the stoichiometry of the lithium is one and we play with stoichiometry of transition metal all together is one. So as we increase the amount of nickel, look here, we go along this road, we go steep, up, up, up with the concentration of nickel starting from one, one, one, which is 33% nickel up to even L and O, 100% nickel and we steep up with the energy with specific capacity, but the road becomes more and more troubling because we have issue of cracking with instability here. You can see images of particles after cycling when we have high concentration of nickel, you see the cracking, cracking is a big problem here because we have issue of phase transition and the stresses, especially when we want to extract the high capacity. Fortunately, we have, we can go up to 4.3V. Here we do not endanger our electrolyte solution, but when we go up to 4.3V, we have stresses in the material and when we have electrochemical instability, structural instability, we have also a thermal instability. Here we can see results of arc, exergent rate calorimetry testing and when we have high concentration of nickel, we have even explosions. So what we can do, in the rest of my talk, I will concentrate on these important materials at two different aspects. So what we can do is doping. It appears that when we dop these materials with our methods like, like zirconium, I'll show you more example, but zirconium is a good example. We have both bulk stabilization and surface stabilization and you will see, you see here several aspects of our results. First of all, we see this is the electrochemical chart with capacity versus cycle number and the red curve relates to our stabilized material. We see the stabilization as better rate capability. Impedance spectroscopy show very nicely the stabilization, much lower impedance. We see that we mitigate undesirable spinel, layer-to-spinel transformation and the computational work confirmed that from an electrical point of view, it is true and this is another, another, this is a voltammetric curves demonstrating the sharper curves of the dope material because the kinetic is better. So the electrochemical response reflected very well. So this is one example. I'll show you another example. The next example relates to here, we take different kettiles. We take the compounds in ethanol solution. So we have organic salts of the compounds. So we evaporate the solution containing the dopant compound. So we have now the coating on the surface and now by heat treatment, we can force diffusion of dopants inside and now we can do like a nearly combinatorial study with several dopants like zirconium, magnesium, titanium, aluminum, sodium, silicon, tantalum and we hear this is capacity versus cycle number and we see the stabilization by the stabilization of the capacity. Now it's very important to emphasize and it's important because of the next stage of my talk that here we concentrate on the cathode. These are experiments which demonstrate the weakness of the cathode. The lithium anode here, it's versus lithium anode doesn't affect the capacity of the cell in these experiments. By line scanning and by cross-sectioning, we can see the dopants all over. So this idea works at heat treatment. Here we can see further results related to in situ XRD. This is less important. So the idea is to coming from the surface, going inside and we can control doping by the heat treatment that provided thermodynamic basis for diffusion of dopants inside. Maybe one more example. The previous one was 811. Now we go further to 85% nickel and here you can see results. In this case, this specific case relates to aluminum. So you can see the difference between reference cycling. This is at 45 degrees C. We get more chance for degradation and problems. So point cycling in situation where the cathode is the limiting factor, we see degradation of the cathode-specific capacity with reference materials. Very typical for nickel-rich materials, but we reach nice stabilization with doping by aluminum and the electrochemical when we derivatize. When we derivatize the voltage profiles, we see this response that demonstrates stability of the cycling while with the reference as the capacity goes down, also the electrochemical response diverses and we see it well by the differential curve of the voltage profiles. Thermal analysis always go well with electrochemical stabilization. Here we in this experiment to see results from DSC measurements, where we demonstrate that with the reference we have much more heat evolution in this experiment, but the most important results is the morphological studies. Here we cut by fib electrodes before and after cycling and we do a cross-sectioning looking at the cross-section and always whenever we have such a behavior, we see cracks. So we see here the cracking, this is the problem of we have. This is the reason for the instability while whenever we have stabilization the cross-sectioning shows that we have smooth situation we don't have cracking and this is because of stabilization it's both bulk and surface. So now I want to move to our next challenge to combine lithium metal with these materials. So the idea is I want to have a lithium metal anode to gain high specific energy and the advantages are clear. The problems are also clear. We have dendrite formation, we have side reactions, lithium is very reactive, lithium may be very dangerous as well. So we have strategies how to stabilize lithium metal anodes in the chargeable batteries and we have modification of the surface by various mechanical, physical and chemical techniques. This is the surface area and then we decrease the specific current density in such a way we have low current density at high surface area. This may help. Also, there is a by selecting catechic etions like a cesium or bilium that act like healing species in this electrolyte solution they can avoid dendrite formation. Of course, sodium electrolyte helps but we vote for modification with fluorinated solvent. These are our two stars the fluorinated ethylene carbonate and defluorinated ethylene carbonate and we demonstrated by using these co-solvents we can stabilize both the lithium and the negative and the negative electrode. So first of all, let's see what the fluorinated materials are doing with lithium. These are slides demonstrating performance of symmetrical lithium cells with two types of solutions. Here, these are solutions containing FEC and this is standard electrolyte solution based on EC and DMC. The experiment is very simple. We take symmetrical cells and we apply high specific current and we're talking about high loading we work on with here you can see something like more than 3 mAh per square centimeter we even can come up to 6 and now we cycle now in standard electrolyte solution upon cycling we see these changes of the voltage profile so we do galvanostatic cycling and we record the voltage profile here we record voltage profile along very long experiment of cycles each line contains many voltage profiles like this one and this one and here what happens with the standard electrolyte solution we see this behavior which means dendrites of the lithium surface while here we see the stabilization stabilization reflected also by visual test of the separator of the lithium electrode impedance so and what happens is because we use the fluorinated solvents we have options of surface chemistry which are very useful the fact that we have fluorine atoms means that we have more options for surface reactions going further now we combine NCM and lithium and here you can see 602, 60% 80% and 100% nickel and here these are tests of a capacity versus cycle number with FEC containing electrolyte solution with standard electrolyte solution the capacity goes down very quickly while with FEC we demonstrate hundreds of cycles and with NNO is a very problematic material and we demonstrate stabilization going further we see that we have a by F19 NMR we can see what is the difference between symmetrical lithium cells and a full-cell lithium NCM we see that symmetrical lithium cells are more stable so by NMR we can see to what extent we have increased consumption of the FEC since we have a little extra fluorophosphate we have like an internal reference inside and this is the initial ratio and we compare what happens between symmetrical cells and full-cells and we see that the ratio increases we see that we have in fact consumption on FEC the signal of FEC compared to the lithium extra fluorophosphate decreases so we have here consumption of lithium consumption of the fluorinated solvent because of the cathode we have cost between the positive and the negative and this it deteriorates this cost of deteriorates the passivation of the lithium so we have more consumption of the reactive species which is FEC going further here we see here we see the case of LNO LNO is a very important example because LNO has a high specific capacity among the nickel rich materials and this is a very problematic material that we demonstrate that can stabilize the material obtain very good capacity of full lithium and LNO cells at practical loading thanks to this combination of electrolyte solution we demonstrate that nothing happened to the cathode after hundreds of cycles we see that both the XRD and the polymeric we have this because we have surface chemistry on the cathode you see here the formula here we have polymerization on the cathode on the cathode also we have nucleophilic and basic species that can extract HF and can promote polymerization and formation of protective surface films so we have protective surface films on both negative and positive which helps us to demonstrate prolonged work with full cells lithium metal versus LNO and these are these can be considered as high energy density cells going further here we can demonstrate the mechanism whatever is in fact that we have cracks in the material these cracks when they reach the surface we have a penetration of solution inside so we have like exfoliation type reactions so we have propagation of the cracks they start with stress but they continue to propagate with reactions with electrolyte solutions and now we can get a complete disintegration of the material in certain cases now it appears that this is work from my colleague and friend and it appears that as we push the potential to 4.3V where we want to extract the maximal capacity it's reasonable with electrolyte solution but it's bad with the material because here we come up to some phase transition which put more stresses and lead to to cracks so what happens with the fluorinated solvents we have coverage we have coverage of the cathode by surface films and now we don't have a chance of the electrolyte solution to go in and even if we have stresses, strains and cracks or micro cracks we don't have this propagation of cracks with solution reactions that finally destroy the particles and the results is stabilization during hundreds of cycles of full sets another aspect so in fact with this with this aspect I think I can start to conclude the talk just to meet one slide more yes so there are two sets of conclusions which are important first of all nickel rich and manganese rich are candidates of most suitable cathode materials in lithium ion batteries for electric vehicle in an oxide of transition metal with this formula as the nickel content increases the specific capacity increases delivering more than 200 mAh per gram at high rates but they suffer from structural instability as I demonstrate and capacity fading during prolonged cycling stresses that develop in cycling little cracks that propagate by reaction with solution species so we can use doping as I demonstrated doping helps both both the bulk stabilization but we believe that we have segregation whenever we have dopants we have segregation so we have different structure at the surface which stabilize most of dopants also stabilize the surface and there are a variety of dopants that were proven to be helpful high energy lithium and manganese rich what we call LMR NCM cathode materials can deliver specific capacity more than 200 mAh per gram however this material suffer from severe capacity and voltage fading because of undesirable oxygen evolution layer to spinel phase transformation so similar structural changes and detrimental surface reactions between the active oxygen moieties and solution species we have developed several types of surface treatments that provide effective buffer layers for these materials that can mitigate oxygen release avoid side reactions between active oxygen moieties and solution species reduced pronounced the dissolution of transition metal cations for the cathode demonstrating impressive stabilization of the of this material so definitely we can say that material wise this cathode this family of cathode can be stabilized but I leave an open question related to the stability of the electrolyte solution now also concluding the lithium rich lithium metal anode high loading and I mentioned and emphasized the high loading practical loading means that we are talking about several mAh per square centimeter and very small amount of solution I didn't emphasize it too much it appeared on the slide so when we say practical loading we mean both several mAh per square centimeter but also very small amount of electrolyte solution so the lithium anode are the limiting factor so it appears that excellent passivation of lithium anode is rich when we have FEC and 2FEC it appears that these species work very well together we can form initially surface field by FEC but 2FEC and then FEC in solution continue to work as a healing agent that keep the surface films at a good shape during prolonged cycling so the presence of fluorine atoms enable elimination reactions that form species with double bonds that undergo further polymerization this lead to the formation of elastic surface films with superb SCI properties so the electrolyte interface properties now in the presence of FEC and 2FEC the cathodes are also covered by protecting surface this is very important so the major capacity fading mechanism of these cells becomes consumption of the electrolyte solution by side direction with lithium but it appears that what happens on the cathode affect not the cathode but rather the negative electrodes we have costoch so the passivation of lithium deteriorates when we have cathode instead of the measurements of symmetric cells there is a detrimental costoch between the NCM cathode and the lithium metal anode species form and the cathode by oxidation deteriorate the lithium passivation we analyze some gases CO2 obviously is being formed and their bi-lithium-lithium cells show much longer cycling than lithium NCM cells at the same loading the use of fluorinated solvents enable excellent cycling of all kind of nickel-rich NCM cathodes because their major capacity fading mechanism is mitigated as I demonstrate due to the protective surface films that avoid propagation of cracks and reactions during now the solution containing both FEC and 2FEC are effective due to synergistic and complementary passivation phenomena first by 2FEC and healing during prolonged cycling by FEC now these studies definitely open the door for elaborating rechargeable batteries with very high gravimetric and volumetric energy density that can deliver hundreds of cycles at 100% the death of discharge they have the chance to outperform also lithium-sulfur batteries due to the limitation arising from the lithium-methylenol they are not relevant for electric vehicles but they can be used for drones so these studies combining lithium-methyl fluorinated solvents within the electrolyte solutions and high nickel-rich NCM materials can demonstrate high energy density lithium ion batteries and this may cover very well the needs of unmanned aviation and robotic transportation and with this I thank you very much okay thank you very much Doron for the very nice presentation a lot of good data right there well we probably have 15 questions right there from audience already let me also share with you these storage axon-positive event now it's becoming the European folks becoming the very nice afternoon evening you know routine now and for US people it's a really good morning you know starting section for California early morning for East Coast just a little bit a few hours later so I want to start from the first question we always have Professor Stan Wittingham in the audience so he I think attended probably of this symposium I will start from his first question he asked is there any chance to eliminate all fluoride containing materials as they create PFAS species I assume that's a per fluorinated you know LQ species right which create problem of cycling that's his question I'm not sure that I really understood exactly the key points in this question what I guess is these fluorinated compound start to polymerize generating those you know long chain containing fluorine organic compound first of all is that a problem second of all if it's a problem what type of problem it can create on the recycling when you do recycling of the batteries I guess that's probably what Stan mean well I don't I'm not at this moment I cannot discuss recycling if we recycling means to extract back the transition metals and all the elements so I'm not there yet I'm still struggling with performance and performance wise I think that a fluorinated solvents open the door for a very impressive performance so we can demonstrate pronounced rate capability and specific capacity and we have here we take the lithium batteries to their horizons I think at the edge yeah got it so the next question what is the mechanism behind the doping stabilization what are the principles for choosing the element I think this is a good question yes so we are I have to confess that we started our work with let's say trial and error we found that when we have a multivalent cations like zirconium tantalum tungsten niobium this can be even vanadium this can be helpful and indeed we found that with many multivalent cations we are able to demonstrate stabilization and then we turn to computational work now we are guided by computational work so computational work definitely can show which dopants first of all can affect the structure for instance avoid a possible a layer-to-spinel transition in the material and also now we explore the segregation situation we have evidence that whenever we use dopants the last process is a heat treatment at nearly 800 degrees C where segregation and the dopants go to the surface and we have surface stabilization and this is something that we explore but I would say that now after we did enough experimental work we can be guided by computational work and we can select more judiciously the elements for doping yeah next question based on energetic calculations yeah I understand this is still in the process of trying to understand this chemistry so the next question what do you see as the promise in chemistry that could enable us to get more than 99.9% columbic efficiency and lithium metal cycling is fluorine based chemistry the enabling chemistry here not necessarily I think that we demonstrate that in terms of cycling we are limiting whenever we have a liquid electrolyte solutions we have a lot of gains but we have also disadvantages in terms of unavoidable reactions sooner or later a major problem would be the cells would become dry because there is no way to obtain hermetic passivation so I believe that solid state batteries solid state batteries can bring us to very nearly 100% cycling efficiency but we pay a price we pay a price of we may pay a price of rate capability and also cost effectiveness and limited usage but with with electrolyte with liquid electrolyte solutions and lithium metal I think we always will be limited and what I show is maybe close to the horizon that we can reach yeah okay so actually just a minute let me just add of course when we talk about solid state we talk also about polymers polymers I only got to go back polymers is also an option and definitely even a combination of ceramic and polymeric materials serving like composite polymeric matrices can also help to reach very nearly 100% cycling efficiency of lithium metal yeah this is good point future will bring in more speakers on the solid state batteries as well previously we have Linda Nassar and Yogan Jannet already will have more of that topic so continue on the fluorine chemistry so what is your hypothesis behind the effect of fluorinated solvents in mitigating dendritic deposition of lithium metal so we demonstrated that from the very beginning from the birthday of lithium batteries it was clear that passivation is a key issue and sometimes we have to use even reactive solvents in order to have surface reactions that will form passivation so in some cases one would say let's use the least reactive solvents so we'll mitigate or we'll avoid surface reaction but it's not true here with lithium lithium compound, even lithium graphite little silicon we need passivation we need reactive materials so we need reactive materials that will react properly at high enough potentials and will form the solid electrolyte interfaces with good properties now what is the best properties that we can think about is flexibility we want a surface film that will accommodate the morphological changes this is true for silicon this is true for lithium metal where we have pronounced morphological changes when we charge discharge and we dissolve deposit lithium so when we have fluorine we have more health we have more options for we have elimination and then we form double bond and then we have polymerization so we may have different kind of polymers we have of course a reduction of the fluoride the fc bond we have a lithium fluoride we also have some lithium carbonate so we have a very interesting situation in which we have polymeric matrices only lithium compounds are embedded and these matrices are flexible and allow a reasonable transport of lithium reasonable transport of lithium iron through them and I think don't go on speaking of that this is a really interesting point speaking of this and indeed another question related to this is FEC decomposition can produce lithium fluoride and polycarbonate product an audience ask which of these two do you think is the critical SEI ingredient from FEC is it lithium fluoride or is it polycarbonate it could be both not necessarily I'm not sure that lithium fluoride is formed anyway and when we have small enough particles of lithium fluoride despite of its intrinsic impedance for lithium migration this is not a good material for lithium migration but since we have nanoparticles, small particles embedded with the matrix we have more than one mechanism of lithium iron transport through the surface fields so I'm not sure the carbonate is not the only one necessary option we have several type of carbonates we have we have alken and alkan type carbonates for sure and also we have polycarbonate as well so we have several blend of polymers and this blend of polymers is good it provides the right flexibility of the entire matrix that protects the surface in the case of electrolyte solution containing FEC let's start this panel with both of you right here I have a few questions very interesting one also from audience also for myself to discuss with you first question is this is from the audience I think very interesting he asks does kan agree with DORON that electrical vehicles must use graphite end nodes and that lithium matter will not work and also asking me I mean kind of discussion is supposed to be having a little bit of debate as well it's okay to have different opinion kan do you want to start and then I will have DORON to also come back to comment on this yeah actually despite the factors that I am in the battery 500 program I still I'm still very conservative about the lithium matter I observe the thermal runaway of lithium matter and at the end of charging the lithium matter battery in different scenarios both through video and through real thing in my lab so I tend to think that maybe in the near term for the near 5-10 years it's way too dangerous to put lithium matter in the car maybe we can apply those in some other smaller format applications such as UAV or drones but on this matter I sort of agree with DORON your turn I want to I think that what is great about our community and in fact lithium matter is the greatest success of model chemistry and material science because of the reliability and high fidelity we produced today billions of cells we have amazingly good line production lines and we can now distribute billions of lithium matter batteries everywhere in the world we can put our cell phone in the car in the summer it can reach 80 degrees C it can drop on the on the ground it can be abused and nevertheless it will move so we see here the high reliability and we work very hard to reach it I am within this field more than several decades and we are working days and nights to gain this high fidelity to gain this prestige now it's very easy to lose this prestige one successful accident and you are 20 years back so when I think about electric vehicles and I think about billions of cars and billions of cars contain, each car will contain hundreds of cells and we still have to maintain the high fidelity, the high reliability we have to work in a zero fault manner because electric vehicle is very risky and a successful in parenthesis accident somewhere can kill our prestige and we work very hard on our prestige thereby I tend to be conservative I think that with graphite we are in good shape so we can struggle with the cathode I think that we can now demonstrate high energy density batteries with graphite and one of these either lithium and manganese rich better even nickel and ncm and we have and we can drive 500 kilometers the rate capability is being improved so I think we are done with electromobility let's gain experience let's increase our penetration to the market let's see the electromobility revolution accelerating and then we think about more risks so at the moment I think that if we stay with graphite and yet we have some way to go with the cathodes we can come up with extra rich amount of batteries and retain retain the high fidelity retain the reliability retain the prestige this is my point well thank you Doron let me also express my real from a slightly different angle I think I largely agree with both of you when you go to application you need to be conservative because of safety things shouldn't go wrong that's from the application angle from research angle like academia research what can prepare us for the next we can go aggressive we can have different choices but often times people might miss this up from research academia research prepare for the future versus the current application once they miss this up this is dangerous I think we want to do research on for example new annual new cathode prepare for the future but be aware of they are not ready in terms of application needs to do a lot more research before we can get there so that would be my thinking I think largely agree with you both of you in application go conservative but research wise can be much broader to do so so next next question I want to touch upon what is so important from both of you we know the interface is so important like Dong and Kang and this is from the audience this question also myself thinking about that as well I want to ask you so how reliable do you think acetic to SCI characterization is as a community how do we improve the quality we are having a better technique to understand the SCI it's looking into the future what do we need to do to understand this better if each of you give about a minute or two of thoughts of ideas to the audience that would be fantastic Dong first you mentioned EQCM EQCM is indeed excellent and we work hard with EQCM as well we have EQCM EQCM can really provide a very nice to to understand the dynamic situation and we can work with in terms of morphological characterization we have AFM going together with EQCM which is very nice I think that we can do we can do model chemistry we did it all over since the very beginning and so we can do model chemistry and to come up and then compare with the FTIR and XPS FTIR and we have also another important tool which is solid state NMR solid state NMR is becoming a very good characterization for interfaces and we see more and more progress we have an Israel expert we have the legendary Claire Gray so we have now solid state NMR and we can use multi-nuclear more than one nuclear we have fluorine we can do lithium for carbon FTIR solid state NMR Raman is less important for surface characterization and we have EQCM AFM so I think we are in a reasonably good shape in understanding what's going on FTIR and solid state NMR together we can enter and provide fingerprint of surface compounds which may be valuable we have been trying to work closely with the instrumentalist and spectroscopist so I mentioned the EQCM work there there's another work I briefly mentioned but didn't emphasize that they are liquid seams in the NAL group that turns out to be very very useful for the very first time that we observed the change of the inner Helmholtz layer when you change the electrolyte composition and change the potential one example shows us even we use the traditional analytical tool adding new twist we can still get a lot of new insights into the ACI this is an entirely new frontier we should spend more time on this well that's really good I think these two of you thought adding together is just fantastic let me add in a little bit as well to this question so from the ACI looks like we need a technique we need to understand the solvation structure coming in and then the ACI also need to have spatial resolution down to nanometer scale or molecular scale both in their depth resolution as well as the lateral resolution so besides thinking in mind like some of the two you already mentioned of MMR can you just mention about the Sims technique I think there's a new technique coming out has been demonstrated quite useful in the past two years is cryogenic electron microscopy the cryoEM that can stabilize the ACI to a certain degree so you can study that that one now having spatial resolution having some chemistry functional group can be identified by doing either ears or elemental analysis or EDX and so on so I think probably more tools will be needed I really want many people in the audience right there to think about one new tool starting this problem that would be fantastic so with that, I think I really like to thank both of you Kang and Doron for your fantastic talks and also very nice discussion and I learned a lot today for the next symposium that's on July 10th on Friday remember next week, next Friday July 3rd we don't have it because it's close to July 4th the national holiday here in the United States many people are probably nodding on July 3rd so we'll have it on July 10th we'll have Professor Yeming Chang for MIT certainly a very well known scientist to join in and it also looks like it's my turn to do some really hard work to also give the presentation in the next symposium at the end let me thank all of you all the audience particularly the people in Asia stay very late with us every Friday and also for European people you have probably very nice dinner time go along with this speech let me also thank Kang and Doron for fantastic talk and participation thank you very much thank you for the invitation for this nice discussion leadership very nice I second that I also want to thank Justin and Tracy for supporting alright I'll see you in the next symposium bye now