Why we're not seeing solid-state batteries right now - Prof. Rupp | Battery Podcast

foreign welcome back to battery generation your podcast on electromobility and European battery research today we finally have the chance to talk to a leading expert on solid-state batteries hello Professor Jennifer Rupp from Munich Germany nice to have you here hi Mr Rosen very nice to have me invited let me introduce you to our audience Professor hope you are a professor at the Technical University of Munich a visiting professor at the Massachusetts Institute of Technology and chief technology officer for battery research at tomb International Energy Research solid state batteries have been announced multiple times already for lots of researchers solid-state batteries are the Holy Grail since they promise an outstanding energy density but lately honestly we get the impression that the current Lithium-ion batteries with liquid electrolytes are being developed at a much faster Pace than solid-state batteries we might be wrong on this but we ask ourselves will we even need solid-state batteries after all and will we probably never see them Professor hope thank you so much um Patrick this is a very valid question right um so overall I can't think we can say that the lithium-ion battery Market is uh progressing however there is certain limitations and the energy density that you have overall where a solid state battery could give you the 30 percent higher increase in energy density and if we look at the market prices that's a very important thing to compare right then you would find the lithium-ion battery at being at around like 700 watt hour per liter was 120 per kilowatt going down to 90 roughly in the next five years and this will say battery currently being higher in price tag right so this is right so you're about like a factor of three higher however this is supposedly going down and the increase in energy density is so high was 30 percent that I think there's a very high likelihood on your question that we will see solid state batteries or that components thereof will be integrated later for hybrid batteries in various forms so I think this is a very Crystal Clear future that this is going to happen and impacting I think as well hybrid and possibly full solid state batteries well then let's take a look uh back on a 2008 until 2020 the volumetric energy density of Lithium-ion batteries increased more than eight volt between these years and again what do we need solid state batteries for if this trend continues I mean wouldn't you compare these two technologies with another after all um I think it's a trend is pretty good not to continue it's going in a stuck Nation so if you look in Lithium-ion batteries then the roughly yeah I think about 300 watt hour per kilogram um 750 watt hour per liter this will increase maybe a little bit but more like in the maybe like 10 20 range and that's it whereas in solid state batteries just by a switch of materials and enabling uh with lithium an athletes is much higher energy density you have the perspective to reach double of the gravimetric energy density and actually 30 plus of volumetric energy and this is actually I think a very steep curve so um currently I would say that it is not to be expected that the growth rate that has been seen in the volumetric energy density of lithium-ion battery is continuing the same slope it's not that's very interesting to hear of course we get these announcements from citl and amprios they recently announced a condensed battery with an energy density of 500 watt hours per kilogram um and I asked myself are we there yet are these solid-state batteries by definition or is that slightly something else I would think it's likely that it's having some solid state battery components that are still asking to be confirmed and to be seen but it's I think a good sign it means that leading companies are actually going in this way right and are facilitating technology that is relevant from solid state battery materials I think in parts of their battery designs so I think it looks very very promising actually yeah I have read something that was already four years ago about these blue cars in France balori I think was the name um I asked myself by then why have these uh batteries not been developed further developed up until now yeah so I think it has to do techno historically as with the fact when you look back how are some of the you know most prominental State lithium conductors may be in sulfide or an oxide it doesn't matter when I've say been proposed and then how long did it takes the fear to optimize those materials and you can clearly say this is the development of the last 10 years right and it needs a certain traction for many scientists and Engineers to jump on this topic and that is how things developments that we're currently in into integrating that into products bringing and spinning that out to the market so um that is I think currently is a development but I would say like um you know 10 years ago there has been not even as thick enough processing know-how how to make for instance materials and really good layers Define good interfaces to actually later have a good um energy storage and exchange actually here yeah well then let's jump into the cell chemistry would you please at first distinguish between these terms all solid state battery and almost solid-state battery what is a solid state battery in by definition so I think these different types so in all solid state battery you can Define of having no liquids ideally inside so it has all the components being a solid state and well classically defined is that you have a lithium-based anode a solid-state electrolytes that can have lithium ions migrating over defects or over random walk and the material and then you have a cathode based component so it forms like a solid solid solid anode electrolytic acid interface and in this also safe battery I think what is a huge Advantage is because you have you know liquids inside um you can use actually sort of say battery elect light which large electrochemical Windows which allow you um to really profit from these high energy densities towards pulisium now in a normal solid state battery you could say you use a little bit The Best of Both Worlds right in a classic lithium ion battery you have up to 25 of a liquid and the sort of set battery is zero now the owners will say battery I would Define as such as having lithium associate battery electrolyte and then a cathode where you have for instance partially wetted interfaces that help later insulation diffusion over the interface so that one you would have maybe something like five to ten weight percent of a fluid yeah to just facilitate the transfer but use the benefit of having pulisium enabled by the solid state the stable battery electrolytes that you have inside and can you also distinguish between these types of electrolytes I've heard about Ceramics I've heard about polymers and even sulfur-based electrolytes is there huge differences technically you can say that as the world of Ceramics which would entail oxide base solid state battery electrolytes and also cyphoid based so State Battery electrolyte so ceramic is defined as an inorganic chemistry right so it's it can be both right and within this chair of Ceramics what they have in common is that their solid state compounds that you try to densify as a layer now between oxide and sulfides there's still some differences like for instance a changing electrochemical stability window which is for some of the oxides much larger than for the sulfides but then on the Sci-Fi you may have a faster diffusion it's a solid state case in a polymer based material you have polymer chains that form kind of like a polymer coating that you have and they're very often you have actually the lithium going through and when them walk so it's a very different migration work and also the electrochemical stability window and the overall listing production may change and if you reflect first as a obviously also differ in their mechanical stability and in making good interfaces yeah towards the cathode and the lithium where they have different wetting abilities between the Ceramics and the polymer yeah we have often talked about these solid state electrolyte interface in current Lithium-ion batteries in this podcast uh could you please uh explain to our listeners how that works in solid state batteries in general is there something like an SEI even I think that it's quite common when you bring two solid state materials together let's exemplate if I you have a composite Castle so this would mean you have a part which is a castle face which could be lithium carbide oxide in this example and you have an electrolyte phase which could be lithium Garnet just for the heck of the example now if you bring them together these two phases may have very different um positive effects actually that you want to join in and so what have you want to have let's say some electronic conduction and you want to have a huge filling in the cathode of the active cathode phase but you need also some ionic conduction now if you bring those materials together you need first to find a way that the adherence is very good that you have good mechanical stability and the castles it start to swell yeah so it's not a static material you bring in whereas the electrolyte is more not swelling but it can be a good support structure and if you think about the charged mass transport that has several implications as of you know in a liquid phase you would have covering all over if it's sort of State it's just the contact points that you have and so let's hear as it migrates over defects often is a little bit more inhibited to do so so you need a certain activation for this to happen at the interface and that is I think some of the Holy Grails Grace of finding the best optimization between good Transportation interface as a form some form of a little capacity at the interface which they shouldn't ideally but in real life they do yeah and then also kind of like having as much of the skin transfers through that um and overall having a very low um kind of like interfacial resistance that's that's what you want that's what you optimize for as an engineer yeah [Music] there is one huge difference in one uh um variant so to say of solid state battery we have heard about an anode free cell how does that work our listeners are very used to the traditional function and setup of a battery with an anode a cathode separator and electrolyte how does a cell without an anode look like yeah it's it's it sounds kind of like odd I may admit that and maybe their terms are also kind of like not very well placed but that's how it's named right now so in this other tree design what you would have um is once as a metal Grid or you could take a copper grid for instance right and you could use the ability of the solid state battery like lines of Casa to just internally kind of like have lithium transverse electrolyte plate and go back actually and in doing that you don't have so to speak an active anode yeah you kind of like form and deform it all the times and that has of course obviously several advantage and disadvantages later on the cell life yeah but it is an option uh to operate like that that is currently under discussion in hybrid and also in solid state battery designs really interesting um at this point let's talk about mass production uh we'll talk about the stability and safety of solid-state batteries in a while I picture a production site um the let's say the the part of assembling the cell pretty um well uh difficult when filling in the electrolyte the liquid electrolyte isn't that much easier with solid-state batteries to produce to mass produce these cells or am I mistaken the answer is yes and no so here's a digested answer and what I will say I would say um a thing says very good industry standards and the feed has come extremely far in making liquid base electrolyte Lithium-ion batteries right and there's a certain sequence of a salmon it's actually quite beautiful process because you have a polymer separator and you just can a sample by density Cascade urine powder and your liquid type electrolyte or a salt so it's actually quite straightforward in putting that in a small capillary now in a small battery what seems on the first side to be very easy is everything is a solid right so that's beautiful you have zero liquid in it and you could say well you just assemble your cathode your electrolyte and your anode right however here's the trick uh so too later and that's something we should remind ourselves an electric vehicle you need a 30 by 10 square centimeter area that has to be Crack free and homogenously coated yep 10 by 30 square centimeter and this is for any ceramic if I take that as an example still quite a challenge yeah because um to make tapes for instance in the size that are crack free or to make also like towards pressure homogenous sulfide electrolyte Coatings isn't as easy as it seems and it needs us a certain pressure for the latter for instance during operation these are things that you don't have in the initial assembly of a typical liquid type so it's safe battery and you can say there is you know if you go on Sapphire it's a challenge that's really to maintain the pressure to really make sure that on this footprint of the area this is maintained and that you have a suitable um kind of like array actually here of your analect like Castle layers and I would say on the oxide based um um kind of like designs that you have the challenge is to get a crack-free center or otherwise produced uh electrolytes that it has a good contact later with castledence res you need less pressure but that is your challenge and I would say that these are manufacturing wise currently the largest challenges and there is there is a balance between how you process that and your costs that you are allowed later to cost So currently when you look for instance what a classical lithium-ion battery electrolyte costs based on a separate and polymer it's about 1.5 dollar per square meter most of the solid state battery electrolytes are more like four to six dollar per square meter and this means also that we have to really examine very carefully what is the best way of processing that which processes to take what to ditch literally um to make that work for the sort of State battery is but that's roughly where Lithium-ion batteries have been a decade ago right and that's fair that's just only fair and it will go down I'm very convinced about this I was hoping for an easier answer but uh that kind of get the I get the impression that uh the nowadays sites for building the current Lithium-ion batteries can partly not be used for future solid-state batteries could you talk on pricing and costs once more these first solid state batteries will they be at a high very cost level pricing level currently I would say they are realistically so they are a factor of two to three higher than the lithium-ion battery if it just takes electrolyte it's four to six dollar per square meter for the soil State Battery electrolyte versus 1.5 to 2 dollar per square meter for any elect flight you take right now that you have in your semi and battery so so this is the difference but then on the other hand you have to say you are allowed to be higher this will say battery Electro if I just exemplify that by 30 because you gain that energy density still it means that overall this has to come down what's driving those factors is things like um material assembly like processing 75 of this cost is just processing it's not the raw material so anything that we scientists and chemists and Engineers can do to reduce the share of processing costs like pressure temperature all of those is gonna reduce later the price in the end and I think that's the Avenues to be explored I thought the lithium the more lithium you use in the solid-state battery uh the higher the price but let's uh talk about something else first um about the applications um solid state batteries will be used for um in the first place so do you think electric vehicles is something to be equipped with uh solid state batteries or maybe are we talking airplanes are we talking Long Haul trucks or maybe vessels yeah I think that's um that is a great question and um I would say for now that solid state batteries are considered by several manufacturers as well as hybrid batteries uh using a solid state battery electrolyte but then with a little share of liquids are considered in electric vehicles and are pursued which is exciting this is very important to give you an example even a classic combustion engine car just if you think about the carbon dioxide footprint has a 40 higher carbon dioxide Footprints in any electric vehicle if I can increase the range of the car to drive by having a solid state component in by 30 that's an argument and I reduce my personal carbon dioxide footprint by 60 so even the dirtiest battery it has the dirtiest that I put in is fantastic because my personal footprint is so much more improved in doing that in carbon dioxide now will it go in a truck and airplanes uh yes I think it's very high perspective right now it depends always um whether you're looking you know for how much the specific energy is also going to be how much weight you can carry with yourself these are concentrations and then what is the range that you have for your application and within the Spectrum I would say it's okay means a portable sector various solutions that can range from is it better to take a full source State a hybrid battery with some liquid in it as well or even Elysium ion battery or another energy conversion or storage scheme and to have on this a precise answer we're just gonna have to wait a little bit I think definitely nevertheless um citl from China they have announced to soon work with um Aviation companies with airplane manufacturers for the condensed battery I'll give you three other manufacturer names that is quantum scape a Volkswagen investment prologium from Mercedes or Mercedes partner and then finally solid power that is working with uh BMW in Munich together with you guys at the Technical University in Munich so every German OEM car manufacturer already have an investment for solid state batteries what can you tell us um about the developments and activities of these three solid-state manufacturers yeah so I think one one can say is that what is exciting as they sat on very different materials and Technologies yeah so if you think about solid powers and then I think it is public that it's more considering Cipher based um materials for the electrolyte looking into this direction where the positive part is you can process that all at very low temperature the challenge is you have to equalize later and maintain the pressure up in the cells that's for sure what is currently a Hot Topic there in the field if you think about sci-fi polarium is again another set of material they are looking into oxide polymers operators and in those they're kind of like looking more at you know trying to combine the best of both words uh so to speak right having a soft matter with uh you know later like um oxide based compounds uh in in assembling the whole cell so it's kind of like quite flexible right so it can be good and difficult to apply later the pressure maybe a bit of a Down pit on the electrochemical stability window but I think there is for each of those in this diversity of various battery designs very different pros and cons and it represents at the very best that the field is divided up to unclear who wins and I would say maybe that doesn't need to be a winner it is allowed to have very different concepts that will later lead to different product lines and for different applications the one on the other may actually do better the trick so I think it's very positive that a diverse landscape with these three names exists in providing products all right this is already a very important takeaway message a solid state battery is just a term which combines lots of different approaches but what do you expect from um lifespan of the first solid-state batteries will they last for longer as the current Lithium-ion batteries with fluid electrolytes I think some of the solid state batteries have incredible lifespans like 10 000 Cycles if you think about life one yeah a material we don't hear so much but actually was one of the first solid state battery electrolytes seriously put into solid state batteries and tacit really over long lifespans is remarkable it has ten thousand seconds so that's great right the question is how to compete with that and because it has a stable interface there has some been some preparators but not too many from a material perspective yeah now um towards I think liquid iron this is very promising it shows you some of the Benchmark of where that can go um and I think understanding this interface and how to engineer stabilize them is key that's what one is on but it shows you I think one end of The Benchmark which is very promising towards the semi yeah foreign topic we have to talk about safety of these first solid-state batteries of course everyone is talking about the um higher safety apparently about these cells but again they store much more energy in these cells so I don't really get this as a non-scientist there's absolutely no way these cells can explode can catch fire that can't be true right pattern gets so smart I think absolutely right I mean if you take a big hammer out you can kind of like throw it on anything and it will crack right at some point eventually the same as a battery right if I were to really do that and put it in the most extreme condition it will sure but on the other hand I think remarkable remains you can tag for instance knocks at base so stay lithium electrolyte and I can have it openly in air right and it's not gonna inflame because Elysium is stored in some positions within the material and is later kind of like stored on these defect positions quite safely so I I would say that compared to the classic lithium-ion battery the more you reduce the fluid content the safer you are yeah and if it's more oxide you have very high temperatures whether it was assembled is probably going to be fine right and I I think there's some boundaries in it and one can always critique it but I think overall it is safe to say that the solid state battery is safer than the museum I'm battery I think of all in terms of the materials that you put in I'm asking that actually um for my colleague who uh as well as me um followed these announcements from catl trying to work with Aviation companies to sit in an airplane that is powered by solid-state batteries um of course the batteries must be a million percent sure to not catch on fire so that's uh probably the case where safety is definitely the most important thing for these cells right yes let's talk about sustainability of solid-state batteries of course every cell Innovation nowadays has to be a sustainable more sustainable than um we see nowadays the lithium content is sometimes up to 80 times higher in solid-state batteries with a lithium anode for example compared to nowadays Lithium-ion batteries and we're already seeing shortages of lithium in Europe and elsewhere so my question is shouldn't we switch to solid-state sodium batteries right away is that possible yeah so um I think there is a factor of 10 more sodium than lithium available or knowledgeable by what to say as a mining resource so this is quite comforting in terms of availability and if you have a little bit of a look on the stock market price I think the lithium price went up a factor of four or something uh over the last I think three years so it's actually quite remarkable it's uh it's raising yeah so this would be strong motivated going to sodium so um here is where I think there is also a little bit of a reservation in the field as well uh so for sodium you know there is still on a cell level um some of the voltage window which is not equivalently achieved so let's say an energy density um there is great work currently being undertaken but I think that's something that needs to be worked on further yeah and we will see where that goes and I think it's very promising to us we look into sodium but also currently realistically working and looking also with lithium there's so many more aspects of sustainability of course within materials we don't have the time to talk about this but one thing I really need to point out the recycling of solid state batteries so the question would be will the solid components make recycling easier compared to the nowadays Lithium-ion batteries no they won't it's a very simple answer um so I think so if you think about it in in a solid state battery you have fusioned interfaces that have seen a certain temperature way to be able to make a connection in a solid state battery if I just take from an oxide-based Castle acride interface I need quite high temperatures to bring it together and I think to kind of like re-separates that and go to the component certificate what you do normally is you just Shredder the whole battery and create a black mass and then later you give this in recycling and you do reverse mining so you mine back the elements that have been parts of it and it has perspective so let's if I take Elysium ion battery as an example this would be easier because I can easily strip my separator and I have kind of like my castle on my anode side and go with that right so it's it's a little bit different in terms of the elements you have and also the castle and the electrolyte elements are a bit more alike yeah in terms of you know density you know whether the periodic table of elements or closer yeah compared to what you find if you compare the electrolyte itself with the castle and the anode for instance in a classic lithium-ion battery the other thing that I will say here and I think it's very important because that's something that is not discussed enough in the field currently it is very important for recycling to find better ways to do low temperature assembly and low temperature disassembly of any oxide and sulfide based compounds if that is mastered it allows you to have less energy in the separation later when you do the reverse mining so I think it's it's really helpful to consider how these batteries are made and that will affect I think overall in the recycling how the refining regaining of of those component works yeah I'm very happy that researchers are aware of that field even five years ago that probably wasn't uh so much the case so I'm actually very happy that there's something happening there on the other hand you said it's quite complicated even within solid state batteries thank you very much that was Professor Jennifer rope from the Technical University in Munich thank you so much for your time and expertise dear listeners are you convinced of solid state batteries yet or do you remain skeptical send us an email at hello batterygeneration.com or just comment below this podcast that's it for today thank you so much for listening take care see you next time bye-bye thank you so much thank you Patrick it was fantastic really enjoyed to be on your show thank you foreign [Music]

Channel: Battery Generation Podcast

Views: 105,415

Keywords: Almost Solid State Batteries, Battery, Batteries, Lithium ion Batteries, Solid State, Condensed Battery, Amprius, QuantumScape, Toyota Solid State, Cells, ProLogium Mercedes, SolidPower BMW Ford, Solid Power, CATL Condensed Battery, Jennifer Rupp TUM, Prof. Rupp TUM München, Jennifer Rupp, Prof. Jennifer Rupp, TUM Energy, Battery Research, Electrochemical Energy Storage, Polymer, Oxides, Lithium, Ceramics, Sulfur, Electrolyte, Anode, Cathode, anode-less, anodefree

Id: lr7-PzSr5SU

Length: 30min 17sec (1817 seconds)

Published: Sun Jul 30 2023