 The upcoming talk is done by Frank. He has delivered the first episode of that yesterday already. Yesterday he focused on the first part of the title, why we are addicted to lithium. Today he's going to focus on the second part and how we shake that habit. Frank is actually working in the science department of the online news magazine Golem. In case you've missed it, go see part one as well. It's recorded and now all the best and enjoy the talk. Frank, stage two us. Thanks and of course there are lots of heralds that also really help with the talks and I thank Katzen point for being my herald today. Yesterday I talked about lithium ion batteries and why we became addicted to lithium. So what can we do about it? And I already hinted that we are going to talk about sodium and last year one of the big announcements was that CATL, I used to call them cattle, which is the Chinese company contemporary MPREX technologies announced that they will produce sodium ion batteries and they will produce them starting in two years. They're starting to build up all the infrastructure, all the factories that they need to actually build these batteries. In terms of the cells that has been developed as guys like Elon Musk like to say prototypes are easy, production is hard. So production takes a little bit longer but they will come and what they announced was a battery that has 160 watt hours per kilogram was fast charging, retained a lot of the capacity even in cold temperatures and much more than most other batteries. They're more heat resistant and they're also safer than lithium ion batteries. They use no lithium, no cobalt, nickel, graphite, no copper and they're much cheaper and a lot of people just rubbed their eyes and thought what is going on is that can that be true? And the point is yes it is. It is true and in fact it's not even possible to build such batteries but it has been done a long time ago. First examples of the same kind of construction of batteries even though they were worse, a little bit worse then, was done in the United States funded by the RPRE project that's the Department of Energy that funded the development for 2.9 million dollars, not much money and that was done in 2012 to 2016 and they developed the exact same kind of battery even though it only had 20% less capacity. Was quite stable, could last over a thousand cycles, many more than 1000 charge cycles so very nice technology indeed. It's just that well they then went on and funded the company called Novasse's and tried to sell it and they didn't find any investors or buyers and that was that. A similar story happened with lithium ion phosphate that we talked about in the last talk that was also invented and completely developed in the United States and nobody really cared. There are also other companies and I listed them here on the slide like Ferrari which is certainly one of the biggest, also Tiamat and Altras. Altras has the chance to become one of the biggest they also developed similar chemistry and so the problem was never is the technology there the problem was always is there investment will there be enough money to to actually build those batteries and CATL is the biggest producer of batteries worldwide and when they announce they will build these batteries you can pretty much believe them they have the money they have the resources they know how to do that. Also the technology is very similar to how lithium works it's really just the same you have a cathode on the left side and you have an anode on the right side and when you charge a battery the sodium ions go from the cathode to the anode are stored there in the hard carbon it's hard carbon it's not graphite we will talk about that more and when you discharge it it goes in the other direction and the ions go back from the anode to the cathode and the electrons also go back from the anode to the cathode and yeah it's just that you can use the electricity from the electrons that are flowing through wires for whatever you want to do. So sodium is worse than lithium it's not the first choice for building a battery because it's slightly worse it's three times heavier than lithium and it's actually not that bad when you look at the entire thing because a typical battery weighs about four kilograms per kilowatt hour that's maybe not the best possible battery it's slightly less than four kilogram for the newest kinds of batteries but the lithium inside is about 130 grams and when you if you just replace that by sodium it would be 300 grams heavier it's not that much and also when you use sodium you don't need copper as you have seen on the other slide both sides are aluminium normally on the right side with the hard carbon on the anode you would need copper because lithium just combines with aluminium and starts to destroy it so you cannot use aluminium so you use copper and copper is much heavier and so you're saving like one or two hundred grams of of material by replacing it with aluminium and so the difference is just negligible almost the big difference is really the voltage you lose about 0.3 volts and that's about 10% of the voltage and voltage is well it's almost the same as energy it's the energy per electron that is flowing and so you lose 10% of the energy and that's a that's a much bigger difference actually so all in all you can you really lose from the physical properties about 20% a bit more than 10%. What has been developed from from sharp labs and also from CATL is a battery using prussian blue as the cathode and this cathode has iron as its main as as the atom that the sodium has to react with and the rest is carbon and nitrogen in a nice crystalline grid that just takes up the takes up the sodium allows it to react with the iron and be extracted from it and that works just fine it's just that the structure is fairly large has a large volume and that's why it has a low density density is about two grams per cubic centimeter and that's quite low for a cathode material but otherwise it's quite okay it's almost the same as lithium iron phosphate it's just that it takes more space in the battery. Okay the other the other point that that people look at and where incredulous is well they must be promising too much battery is charging so fast it works better in the cold how is that possible and the point is with sodium because sodium doesn't react so easily with all the stuff around it the sodium ions can flow easier through the through the electrolyte and you get higher ionic conductivity in the same kind of electrolyte and you use the same kind of kinds of electrolytes and yeah that's how you can charge them faster also the electrolyte that you you can use is properly in carbonate and normally you cannot use a lot of that because it would destroy graphite and you'd use graphite in the lithium ion battery as the anode with sodium graphite doesn't work you use graphite because you can put the you can put the lithium ion ions in the layers of the between the layers of the graphite but sodium is bigger and it's too big for graphite and so you cannot use it and so you can use you can use the property in carbonate and just benefit from that because it has much lower melting point and you can use it at freezing temperatures and yeah yeah hard carbon is not as regular and it has been used for the last 20 years actually in the year 2000 where the first reports of using hard carbon as sodium anodes and this material is now very reliable has very long lifetime very long cycle life the performance has been improved over the last 20 years ever further and yeah it's it's not experimental it's absolutely sure that this is going to work nobody really has any problems with carbon except for some of the performance issues like lower density it's not it doesn't have the same density as graphite because as you get not very ordered graphite is neatly stacked and very well ordered so it has higher density the hard carbon does not and you also get higher first cycle losses this has been improved recently but it's it's not quite up to the standards of graphite with graphite you lose about four or five percent with hard carbon it's more like 10 percent also it used to be 20 percent and that's a major reason why the current why the current batteries by from cattle are much better than the sharp red batteries on the other hand you don't it's it's not graphite so you don't need the high temperatures that you need to make graphite as a synthesis and you like to have synthesized artificial graphite not natural graphite because it has better properties you can control about the properties lower temperatures means it's not as energy intensive it's more environmentally friendly to do this synthesis and it's also cheaper the the other advantage is it's not neatly stacked it's an irregular structure and because it's an irregular structure you don't have a hard limit as to how many atoms you can store in this structure and you can actually get beyond the amount of atoms that you can that you could store in in graphite it's just fairly hard to reach that and it hasn't quite been reached at least not not reliably um c atl is claiming 350 milliamp hours per per gram and that is very similar to what graphite what pure graphite would do another thing that a lot of people really get wrong and i mean people like scientists working in battery in the industry as well they keep saying well sodium ion batteries are not good enough for cars um i don't understand why i i really don't a lot of people talk about that and they never argue with numbers they just say well it's worse than lithium and because it's worse than lithium it's obviously not good enough for cars uh and but when you look at the numbers uh you can say uh well it's the same numbers as you would get in a tesla model three and that's a car that is sold for over 40 000 dollars if it's good enough for car to cost more than 40 000 dollars um you can assume that it's probably good enough for a car and not just a short range very cheap car but cars in general um uh the volumetric density that i've uh that i have here is an estimation because c atl didn't publish that figure but you can make very plausible assumptions uh how high you can get how high you can get the volumetric density my estimate is about 180 watt house per liter if you want details please ask me in the q and a uh time is unfortunately very short um so yes uh sodium is good enough for cars uh by the way that good enough is not a mistake by me uh john good enough had a hand in developing the prussian blue uh he he has still he's still working at university and has a research group there and uh in uh i believe 2011 uh when he was about 90 years old um his group published the research on prussian blue and that he could be used for a sodium ion battery it's incredible um john good enough is really uh despite his uh old age uh he's going to have his 100th birthday next year um it's still very active in the community and in the uh in development yeah okay um sodium ion batteries uh don't just need uh anodes they also need cathodes the cathode is uh the core of the battery actually that's where all the chemistry happens and prussian blue we talked about this uh it has a very decent performance uh the material itself if you only had the cathode material is 500 watt hours per kilogram in energy density but it has a low density it's only two grams per cubic centimeter and that's quite low the problem with that is uh you need more volume and all the gaps in the volume uh need to be filled with electrolyte and uh so you need more electrolyte and that means uh it weighs more and uh so the the ultimate energy density will be worse than if you had a material that has a higher uh higher energy density also the cells take a little bit more volume um there's a second material that is very popular it's vanadium phosphate uh is great for very high power applications you can charge and discharge at 10c or 20c for thousands of times with that material but it has a much lower energy density or a somewhat lower energy density um especially at high power it's it's much lower um uh but it works has been developed by tiamat in france uh and actually it it's originally from the uh from lithium that has been adapted to to sodium uh and then there are a lot layout oxides uh layout oxides are the same kinds of materials that you would have in lithium ion batteries mostly lithium ion batteries um what is usually used here is my name is manganese it's not so much nickel based uh you can use nickel and sometimes nickel is used um to improve the the energy density but um there have been very good results with almost pure manganese oxide with just some uh stabilizing other materials and you can get 600 watt hours per kilogram and some of the best uh lithium materials only reach about 750 so it's about 80% of what you would get with uh lithium but there are some other problems um the problem with sodium is uh because the sodium ions are bigger than lithium uh the structure is um somewhat different uh in the materials and you can choose you can choose between either having a material that is very stable and that can reach very high energy densities but uh you have to synthesize it in a way uh where you only have two thirds of the sodium uh inside the material and the rest of the sodium has to come from the outside and usually when you have a battery you have all the when you have a lithium ion battery you have all the lithium inside the battery inside the cathode of the battery when you uh when you build the battery and then you just charge it and move the move the lithium over to the anode side uh when you want to use these sodium poor and very stable materials then you need to get your sodium from elsewhere either you already have it in the anode side or you put it into some other material and uh research has been going on to put it into all sorts of things uh the binder that keeps all the all the powder together uh the separator that separates the anode and the cathode um even the the conductive carbon uh people try to put some sulfur in the conductive carbon and combine it with sodium so the sodium could be released uh and so on so there's um there's a lot of development going on there to to use that the other way is um you have a sodium rich structure that is somewhat more unstable only lasts for a few hundred cycles but what you can do is you can get a structure that is kind of in between and where you get at least a bit more than 500 watt hours per kilogram and that is um that has been demonstrated already and faradion which is in great britain they have demonstrated a material like that for with about 500 watt hours per kilogram um their batteries are also uh uh very safe um the safety of sodium ion batteries is in general much better um than lithium ion batteries um because the sodium salts um this integrate at higher temperatures um the sodium salts are like the first um the first thing that's starting to disintegrate when you heat up a battery and uh the problem with that is there's fluorine in these uh in these salts and the fluorine starts to react with the electrolyte around it and it starts to get it starts to um increase the temperature of the battery even a little bit more and a little bit more and a little bit more and at some point you reach the point where the cathode material itself starts to disintegrate and release oxygen or uh some other volatile components and the entire thing starts to heat up and essentially combust um that's a big problem with the nmc materials nickel manganese carbonate for nickel manganese cobalt for lithium ion batteries which can be very flammable um it's much less a problem with other materials um one of the other advantages is that you can use propylene carbonate which is liquid at low temperatures um in uh lithium ion batteries you have to be used at today in carbonate which has a much higher melting point only gets liquid at around 30 degrees uh so in a very warm summer day it would be liquid otherwise it's solid and you need to mix it with other components that are very volatile that have uh and uh um yeah turn into gas very easily and very flammable and uh so that's one of the main reasons why the thermion batteries uh can turn into fireballs very quickly uh and you don't need those at those additives here to reduce the the melting point because melting point's already very low um yeah so that's why the flammability is not quite so bad um the other point in safety is you can discharge a battery a sodium ion battery to zero volts because there's no copper in the current collector um the copper would normally dissolve into the electrolyte and then uh next time you start charging it after you've fully discharged it um you would get copper somewhere in the battery and that somewhere could be absolutely anywhere and you can get short cuts and you can absolutely destroy the battery like that that's why lithium ion batteries must never be completely discharged it's very dangerous actually uh there's no problem with that in sodium ion batteries and that means you can work on it you can completely discharge a battery and work on it without having it at 400 or 500 volts or something like that and get shocked by that um so everybody can can work on a fully discharged battery no problem um very big benefit in terms of safety um of course uh energy density is very important and a lot of people think that sodium ion batteries because they're not the highest energy density um will not quite be enough and they would like to have higher energy density so there's a there's a possibility and CATL in their presentation already used this and showed that they are going to develop this is to simply use both kinds of batteries in one car in one battery pack um so you use both sodium and lithium ion battery cells uh so you can use some cheaper cells the cheaper sodium ion cells along with the lithium ion battery cells and uh you can get the best of both worlds especially when it comes to the cold temperature performance uh the sodium ion batteries can you can start driving your car with the sodium ion battery cars uh batteries while you heat up the lithium ion batteries especially with lithium ion phosphate which is a technology that is very sensitive to cold temperatures and when you use both of them together uh you have a much better battery pack overall and uh in terms of energy density uh you can really choose what you want depending on and i've done it here with uh what else per kilogram but it works the same with what else per liter depending on whether you your problem is depending on getting uh small volume or small mass uh whatever you want and uh so if you if you choose 75 sodium uh you can get a slightly a slight increase in energy density um if you just want to uh if you just give up on 10 uh what else per kilogram so you go from 170 what else per kilogram to 160 uh you can save 25 percent of the lithium in the battery pack uh it's uh it's absolutely possible to save a lot of lithium that way and especially when you're in the lithium supply is tight uh this can be very important um the materials used especially this is again for the CATL battery is aluminum iron carbon nitrogen carbon hydrocarbon uh and some phosphorus and fluorine and that's it um those are very common elements and this is from the wikipedia article of the crustal abundance of elements and you can find them all here at the top of the list uh lithium would be at place 33 i think along with nickel something like that um as you can see a lot of these elements are very high up also look at place 12 there is manganese and manganese is a very popular choice for the layered oxides in sodium iron batteries in the cathodes here uh cost can be much cheaper especially because the raw materials are so cheap but it's not just the raw materials uh the synthesis is also much cheaper because um the layered oxides are ceramics um and if you know how to make ceramics um you know that you have to fire it at very high temperatures and uh if you have a cup like this the ceramic would have to be heated up at uh almost a thousand degrees Celsius um to make this into a ceramic um but for the prussian blue the temperatures you need is no more than the hot tea that i have here in the cup and that i really need now um the the cost is very low um the material cost is like a dollar or something like that is very very low and for the completed material it's just a few dollars per kilowatt hour in most batteries the cathode is the most expensive part of the battery in sodium iron batteries uh it's uh well it's not the cheapest part but it's among the cheap parts um so uh the the manufacturing is much more important so if you can scale up your your manufacturing plants to be very big and very cheap uh then the batteries themselves can be very cheap and that's how it's here the L uh wants to achieve like 30 or 45 dollars per kilowatt hour and that's quite possible especially because the salts that you need and the electrolyte is much cheaper and you don't need copper for the foils and because the electrolyte is much more resistant to high temperatures you can use higher temperatures for the drying process after you have coated the uh after you have coated the uh foils with uh with your cathode and your anode material and then it's wet and you have to dry it out and you do that in long ovens and the higher the temperature you can use uh the shorter time is required and the shorter and smaller your ovens can be an important thing that uh strangely enough was brought up time and again by a lot of people who doubted uh this development is that yeah we have seen so many startups uh promising new technology well CATL is not a startup it's it's the largest battery manufacturer in the world i i don't i don't know how these these arguments uh even started it's very strange they have years of experience uh they have support by the chinese government officially and uh they will not suddenly start lying about what they can do with their technology especially because we know this technology it has been developed years ago uh we all know it's possible at least if you if you read in the in the literature and if you followed uh the old developments um you will have to get used to the idea that this is actually going to happen it's not going to happen on a small scale it's going to happen on a big scale because it's the biggest uh battery manufacturer in the world um so so here my batteries will come and they will come in two years and you better be prepared um not like the people who are surprised by uh the my own phosphate these days okay two slides um what's next uh next is the second generation that was announced uh will be about 200 watt hours per kilogram similar to lfp um this is a similar performance to what faradion is already demonstrating using their oxides but uh if you just uh exchange the uh the faradion's own anode materials with what what CATL has announced you already get to 200 watt hours per kilogram so this is kind of quite realistic um the big question is uh what kind of layered oxide will CATL use and they have said absolutely nothing on that uh if there's nickel inside or not uh nickel would be a bit more expensive uh most materials are dominated by manganese though so they should be quite cheap but they are ceramics so they need higher temperatures and processing costs quite a bit more um okay and after that um because uh i think the the rumors are that CATL will announce the second generation this coming year in 2022 um we will see it's certainly quite realistic the the technology is not that far away um because layered oxides have been demonstrated to be uh possible and uh CATL has all the rest of it um so after that uh what we will probably see is anode materials using pre-sodiation that can achieve uh higher capacity and also fewer losses in the first cycle uh first cycle typically about 10 and if you can uh just uh reduce these losses by just putting more more sodium in in the first place uh that would be great uh and then you could also use these layered these layered oxide materials uh that don't have enough sodium in the layered oxides at the beginning in doing construction of the battery and then you could reach uh energy densities between 200 and 250 watt hours per kilogram and uh that would be very similar to what lithium ion batteries have now and of course you can do solid state batteries with lithium with a lithium anode uh just pure pure lithium anodes but you need different separators you can do the same with sodium and pure sodium anodes pure sodium metal and would be much better you would get much higher energy density but um with sodium it should be actually easier to achieve that uh the problem is it's harder to achieve there if you don't get money to do it and right now all the money goes into lithium ion batteries um so it's from from a practical point of view it's much harder even though from a physical point of view it may even be easier um and in in the future we might see prussian flu batteries with 250 watt hours per kilogram which is granted not that great it's as good as uh some average lithium ion batteries these days but it could be extremely cheap um yeah maybe that's a bit these two slides were a bit of speculation okay thank you and i hand over to the q and a okay i'll thank you very much for the nice talk frank uh thanks there a couple of time was very short again yeah i realized that um someone is wondering is the biggest problem with sodium batteries um their weight and if so isn't that irrelevant for um uh stationary batteries such as used in grid scales yes exactly um that is in fact one of the reasons why a lot of people said sodium ion batteries will only be used for um for stationary storage uh and that has become a bit of a meme actually and uh because people kept saying okay it's just for stationary storage and maybe some light duty vehicles low vehicles um people just kept repeating on kept repeating that and saying that and nobody ever looked at the numbers and at some point you ended up with a situation where um yeah the numbers are in fact just as good as the tesla model three and people still didn't realize it but kept repeating the meme that uh that sodium is not good enough for cars and yeah um yes of course stationary storage absolutely um and uh in a few years people will look at lithium ion batteries used for stationary storage as a bit of a waste all right thank you um are you aware of batteries with a lower densities than water um lower densities than water i wouldn't know because that's kind of hard to do um because you always need um i mean lithium has half the density of water okay but you need to react with something and that that something you want to react with um that is kind of hard um you can of course always build a battery that's much lighter than water by putting a few battery cells into a container and make it airtight and it's uh it has an average density that is lower than that of water um so yeah um there are cathode materials that are made up of polymers but you cannot uh you don't have any sodium in those material you can put sodium in and have the reaction and so on but um uh yeah uh those are polymeric polymer materials uh that are in research might be quite cheap but they have other challenges in using them thanks uh someone is wondering where to start when planning to recycle electronic stuff and trying to bring the materials back to whoever needs it or is there some kind of a bay for materials uh i'm sorry i didn't quite get that um what was the last bit is there some kind of bay for materials so some place where you could bring these uh okay um right now right now it's not um the problem with recycling of batteries right now especially lithium ion batteries in electric cars uh is simply that they are too good um they they just um unless you crash the car the battery will usually last until uh well as long as the car is running and most of the lithium ion batteries and cars are just so working there in the cars some have been recycled but it's a minority of the entire of the entire thing so there are a lot of recycling companies that have been uh that they didn't quite get into business because um their business model said that there would be a lot more uh defective lithium ion batteries than there actually are these days and they they they want to recycle them that but they just can't find enough and uh it will take a bit more time uh to get recycling and will be similar with sodium ion batteries um as soon as those batteries are actually available as soon as the waste batteries are actually available you will get to see uh some recycling going on of course thank you and one galactic life form um is wandering um and edit this is a bit far-fetched but if that life form is remembering correctly there was research on liquid batteries um and probably there's a better term for that um did anything happen in that department um i i did read about this about 10 years ago so uh i'm sure that something must have happened in that department but uh nothing that was uh nothing that ended up being commercially relevant uh or oh i'm i'm just thinking about which what kind of what kind of battery they meant um there there are two kinds of liquid batteries uh one where you had just two liquids on top of each other and then just that just formed a battery and you had to separate in between in between the two liquids more or less um that's what i meant the other is of course redox flow batteries uh like uh most popular is vanadium redox flow and the problem with vanadium redox flow is that it has a low voltage and that means you need a lot of vanadium to store a given amount of energy and it's just not very competitive in terms of in terms of the price per kilowatt hour um but there are some other developments also using sodium uh also using other compounds uh in that direction um whether or not they will be competitive uh we have to see um i don't think that vanadium redox flow is competitive even though some some demonstrations have been built but they're usually very small and it's it's really just um because they can get subsidies from it all right thank you and last question for this talk which batteries are better suited for bi-directional flows um well these are actually quite uh they work in both directions uh quite well also at high power um usually this charge is a bit better than charging a battery um because when you charge a battery uh you have to take care that you don't form uh from pure metal and get metal dendrites that might penetrate your your uh separator especially if you don't have a separate a separator material that is resistant to these dendrites which uh normally it's just like a piece of plastic uh porous plastic uh um like poly poly alterine like you know like you're shopping back or something just much much thinner and porous um and that can easily be penetrated and you don't want that so you have to be uh you have to limit your your charging speed especially at low temperatures when this can happen quite easily um but other than that it's uh it's pretty much uh yeah it's just fine you can you can use them both direction at very similar powers thank you