 Okay, good afternoon everyone Not a good afternoon Anyway, I'm Eckhart Groll. I'm the Perry head of the school of mechanical engineering and I would like to welcome all of you To today's Purdue engineering a distinguished lecture series Very special seminar that I've been looking forward to for quite a while With the strong connections to mechanical engineering and that's why I'm here to kick things off So it's my distinct pleasure as a start of this program to introduce the current interim Dean of engineering that is of course Mark Lanstrom who is also the dawn and Carol Cyphers a distinguished professor of electrical and computer engineering and if you Followed Mark's steps that he was an acting dean a while ago and then Mon came back in then Mon became president. So now he's the interim dean again But he is actually the interim dean for just eight more days and That means I may be the last one to do an introduction of him. I don't know how many events you have left but Couple more. Okay, but it is definitely a distinct planner because I love working with Mark He has been a wonderful boss to me and he said to keep it brief So with that no father I do mark Lanstrom the interim dean of College of Engineering But this is my last time introducing the distinguished lecture series. So and you know, these have been a real treat So good afternoon everyone and welcome to another Purdue engineering distinguished lecture I always look forward to these afternoons in the middle of the busy week It's a chance to hear from a leading expert on an important topic Often outside of our own particular areas of expertise But always thought-provoking and interesting and the panel discussion that follows is also terrific, too So today we're we're fortunate to have with us Professor Esther to go could Taguchi From the Stony Brook University and Brookhaven National Laboratory Professor Taguchi will be talking about a topic of great importance Batteries and the electrochemistry of batteries and of course, we all know how critical batteries are for portable electronic devices or Increasingly for electric vehicles and for use in inherently intermittent power sources such as solar and wind Batteries are complex systems that present many Interesting scientific challenges We'll be hearing about some of those in Professor Taguchi's lecture And then we'll take a very short break So don't go away and then we'll have a panel discussion that follows and the topic of the panel discussion will be what's next in batteries So with that, let me introduce our speaker Dr. Esther Taguchi is a SUNY distinguished professor and the William and Jane Nap chair in energy and the environment at Stony Brook University She also holds an appointment at the Brookhaven National Laboratory as chief scientist and chair of the interdisciplinary science department Dr. Taguchi was previously employed at Great great batch Inc. Where her work was instrumental in developing the lithium silver vanadium oxide battery Which is the power source for implantable cardiac defibrillators. She's a prolific Inventor with more than a hundred and fifty patents Dr. Taguchi is a member of the National Academy of Engineering the National Inventors Hall of Fame the American Academy of Arts and Sciences She is a charter member of the National Academy of Innovation and she was awarded the National Medal of Technology in innovation and many other awards as well Dr. Taguchi received a BA from the University of Pennsylvania with a double major in chemistry and history And a PhD in chemistry from our neighbor in the Midwest the Ohio State University Would you please join me in welcoming dr. Taguchi? So thank you very much for the kind introduction. It's great to be here As many times as have been to various places. I've never had the opportunity to come to produce I'm really delighted to be here today and Not only witness the campus, but the enthusiasm of this the students and faculty alike so I am going to talk about energy storage today and I'm going to put things in a little bit of context One of the things that's facing the world really not just the United States is the whole idea of Decarbonization, how do we get to a cleaner environment? to offset things like carbon change a Climate change excuse me, and there was there was a Study commissioned by the National Academy of Engineering and I participated in that study To look at if we want to achieve net zero by 2050 what has to happen in the short term so what has to happen in the next ten years and This study is available online. So if you want to Google it and find it you can download it free But basically there's four critical things and I'm focused here on more the technology and science things there are certainly Societal things that have to happen as well, but I'm more focused here on the on the technical aspects So we need to electrify almost everything so transportation buildings industry. We need to electrify well in order for that to be It you know productive we need to have carbon-free electricity we need to improve energy efficiency and Generally expand innovation in order to accomplish what we need to accomplish over the next 10 to 20 to 30 years So if we look at the emissions by sector the two biggest sectors have to do with generating electricity and Then also transportation so if you wonder where your missions are coming from that's that's where they're coming from So let me then segue that into advanced batteries So why do we need advanced batteries and what critical roles do they play in our society? One is we certainly are aware of portable electronics. I'm sure Everybody has you know cell phones laptops, you know iPads whatever it is they carry around those for lithium-ion batteries Lithium-ion batteries are actually a fairly new technology. They were introduced by Sony Corporation in 1992 So many of you weren't born then but I was and I remember what an Unbelievable transformation that was to introduce lithium-ion. It was just a huge C change Implantable batteries is where I spent the first part of my career making life saving Devices for people the importance of being able to implant a device fully that needs to be powered It's any break in the skin, you know for wires or other things is a source for infection So we were committed to making medical devices that could allow people to live very Normal lives and extend their life extend their quality of life by providing the batteries that could power these devices so what I'm going to talk about today, however is Transportation and large-scale storage and if you look at the radar plots along the bottom What you notice is that while batteries are important the type of battery and the role the job that the battery has to do is different and So whatever battery is going to win the day is the battery that meets the needs of that application better than any other possible solution So those are my icons, so you'll know what I'm talking about transportation when you'll see the little car and when I'm talking about the grid You'll see the power lines pop up So from a scientific or engineering perspective our strategy was to investigate phenomena over multiple scale lengths Turns out batteries are very complex. You know, we think of them as pretty simple. Oh, well, there's an anode There's a cathode, you know, one releases electrons the other one accepts electrons There's some kind of electrolyte and some kind of membrane that separates everything, but the complexity of batteries is such that Every length scale matters it turns out that at a molecular level the structure matters the particle matters the aggregation meaning the nature of the electrode matters as well as the entire system and Much of the work that I'm going to describe today Was done under our energy frontier research centers. So these are funded by department of energy. These are highly collaborative multi organization Multidisciplinary undertakings I also wanted to point out because we recognize the important of bring Importance of bringing together multiple disciplines that we created an institute to bring together academics National labs as well as industries to really facilitate interaction and hopefully move advanced batteries even further Towards not only invention but commercialization So let me start with a transportation problem One of the things that has impeded Adoption of electric vehicles is this question of range anxiety and also the anxiety of oh it takes me hours and hours and hours to charge My battery So the challenge that we were facing was how do you charge a battery effectively in 10 minutes? So today it takes hours our challenge was 10 minutes Not only does this allow Charging faster, but it saves money because typically today's batteries and cars are over designed They're bigger than they need to be to compensate for the fact that you may need hours to charge And it turns out that in a lithium ion battery the problem limiting Fast charge is that the graphite anode should accept lithium Ions where the ions move back and forth between the anode and the cathode, but instead If you try to charge too fast you drive the potential of the negative electrode below the potential of lithium and You end up plating lithium all over the place And when you play it lithium sometimes that lithium becomes the ineffective and basically the batteries Lose capacity and decline pretty fast if you do repeated fast charge So our strategy was really a very fundamental one, you know fundamental concept and electric chemistry There's a thermodynamic potential, which means the fundamental nature of a material But there's something called over potential and over potential is really critically driven how much past my thermodynamic potential do I need to do go to accomplish something and Our hypothesis was that we could control that lithium deposition over potential than we could influence And minimize lithium deposition, so that's what we set out to do and we studied what materials have unfavorable deposition for lithium and it turns out that certain metals for example copper and nickel have unfavorable deposition and We believe it's because there's a mismatch there's a mismatch in the crystal structure of lithium Versus the metal crystal structure So this means that there's an energy barrier a kinetic barrier to trying to deposit lithium So what we did then was deposited very thin films of either copper or nickel on the surface of the graphite electrodes With the idea that if we can minimize over potential Then well actually in this case what we're we're we're maximizing the over potential for lithium deposition And minimizing the over potential for lithium insertion in the graphite that we might be able to Offset some of the lithium deposition So we did some fundamental studies really looking at lithium deposition and quantifying and we quantified it through x-ray diffraction Scanning electron microscopy measuring the capacity or the coulombs driven below zero Lithium potential and sure enough if we looked at the electrodes that were either copper coated or nickel coated Quantitatively the amount of lithium deposited was much much less Compared to the uncoded graphite. So this was looking quite promising We then moved on to assembling full-scale cells So these now aren't tiny lab cells. These are pouch cells Where we had an nmc cathode which is a typical cathode for electric vehicles We had graphite anodes that we either plated or did not plate with Nickel or copper and in fact Over many many cycles. We've run up to 500 cycles. We get significantly improved capacity retention with our metal coated electrodes And we're excited about this because this is a technology that can be implemented with existing manufacturing processes So Let me move on. So that was kind of a story about the negative electrode now I'm going to move on to the story about the positive electrode Typical as I mentioned a typical cathode materials are nickel manganese cobalt So often called the nmc and they have a number of crystalline structures and The goal was can we exploit this material further? Can we use unknown material and get more capacity out and if not why not? So the amount of energy that you can get out of nmc depends on the lithium content So if you pull more lithium out By charging it to higher voltage you can in fact get higher capacity You can get about 20 percent higher capacity So we cycled batteries At charging to 4.7 versus 4.3 and said well, you know the 4.7 ones Are degrading a lot the capacity is fading and we knew that we had increased impedance We also observe you know particle cracking That's a little bit more exaggerated when the materials are at higher States of deletion So we wanted to understand that more We did a detailed Extra diffraction studies. So in this case, we're using What's called operando extra diffraction. So operando means we have a working battery And we're measuring it while it's working. So we're getting real time data And we looked at charge to 4.3. We looked at charge to 4.7 And what we found out is that the that there's much more expansion of the unit cell So change in volume is significantly exaggerated when you go to 4.7 We wanted to understand this further and we turned really to kind of fundamental thermodynamics If you think about you know at the first law of thermodynamics when there's a change in energy, there's two things There's heat and there's work So if we think about a battery work is the electrochemistry So what's the voltage? What's the current? That's going to define the amount of water hours that we're going to achieve But then there's heat Now battery people often test Extensively the work part right cycle cycle cycle, you know, what's happening But we were interested in the other portion of the equation as well We wanted to measure as a heat To see if we could get insight into what was happening with the batteries So we used a method called isothermal microcalorimetry. So we're keeping the temperature fixed We're measuring the heat dissipation And we analyze the data according to the equation that i'm showing you we determined The heat dissipation due to polarization meaning basically voltage drop We determined the entropic contribution And what we were interested in was the parasitic heat meaning everything we can account for through polarization or entropy And we studied these are again nmc batteries that were charging to 4.7 or 4.3 And no question about it. We looked at five different cycles at five different current levels the batteries that were charged at 4.7 Dispate much more heat. It's about a factor of two higher Compared to the batteries that are charged to 4.3 So for that 20 percent gain in capacity We're dissipating about two times the level of heat So that gives you some sense that there's a lot going on when you change the the the the charge voltage um We looked at what's called the voltage hysteresis and The back and forth Voltage profiles meaning if you charge and discharge and they follow the exact same voltage profile It gives you a better sense that things are reversible and at 4.3 volts. That's the case At 4.7 volts that is no longer the case the trajectory for charge and discharge for the voltage profile Is not the same When we looked at the heat and work Contributions we find out that from a thermodynamic perspective when we charge to 4.3 The system is largely Reversible But when we charge to 4.7 the system is no longer Fundamentally reversible and we plotted to see how much that offset is So what's appealing about this method is that we can get really Important information in as little as five cycles So we don't have to cycle 300 and 500 times to find out that there is a fundamental irreversible irreversibility going on with these batteries So The other thing we were thinking about was Again, if we don't invent a new material, can we improve cell level usable active material content? Today the batteries in lithium are the the electrodes in lithium ion batteries are really very thin They're very high surface here and they're thin and they're thin To maximize transport. We want the ions to be able to move readily. We want the electrons to be able to move readily But if you change how you design the the cell and change how you package it if you make a thick electrode The amount of the inert materials such as separator current collectors decreases substantially and you can increase The energy content of the battery, but the downside is so now the ions have further to go It's fundamentally a transport problem We have to be able to get the the ions to every particle. We have to be able to get the electrons to every particle So we've spent um a number of years actually Investigating the opportunities to design Low tortuosity thick electrodes with tunable features So the opportunity for increasing Cell level energy content can go up and it's a balance between Porosity and energy content because if it's too porous then you're also not effectively using space and we working in conjunction with Some of our modeling colleagues We developed some models where we could Really predict as a function of the discharge rate what the voltage profiles would look like for these various electrode designs And interestingly when we first started this we thought that the models would be fairly specific to a given chemical system But as we started looking more broadly it turned out that the models were pretty broadly applicable That in a general sense independent of the chemical system as long as it's an insertion cathode These models hold up and we can relate the rate capability and the electrode design for almost Any chemical system that's that's relevant. So these are continuum models. I should explain So now Big shift now we're going to grid scale storage. Why is this important? In order to implement solar or wind That are renewable clean forms of energy generation You have to have storage. They're too intermittent To just feed directly into the grid at any significant level the grid Actually can't handle it because today's grid doesn't store anything There's a few places where you know, you have a hydrothermal storage, you know, where they pump water um, not hydrothermal but just you know, um Water storage, you know pump it pumping into a lake and then later go and go through a dam but geographically Not everybody has a waterfall. So it's not not universally applicable So we were interested in storage that would be scalable. We thought about using Water rather than flammable electrolytes and rather than lithium as a negative electrode we turn to Zinc So the first material we looked at is sodium vanadium oxide or nvo for short It's a layered structure. The sodium makes pillars. So we thought that it would be effective in storing zinc First thing we did was actually synthesize the material we use a sol gel method This is an aqueous method. That's readily scalable And we were deliberately controlling the water content Our hypothesis was that the water content between the vanadium oxide layers would be an important contributor to facilitating zinc ion mobility between these layers so With the as prepared material h just means hydrated There's a lot of water present in these layers if you heat it to 300 There's a few percent if we heat it to 500 the material is Close to anhydrous not quite but close to anhydrous. So we have three different materials systems that that we explored It also affects the morphology After heating the material turns into nano rods and at a higher temperature the nano rods become Thicker bigger We started running electrochemistry of our three different materials and saw that um The reversibility in terms of electrochemical reversibility Was different for the three materials and by electrochemical reversibility what i'm really looking at is delta Delta E peak so where is my potential peak and how closely are those peaks spaced For oxidation and reduction If we look at cycling we observe something very interesting the hydrated material starts that so that's the the black series of dots Starts out at very high capacity but fades pretty quickly The green dots are my 500 material It's very stable in terms of fade, but the capacity is also about a third And interestingly the compromise material was the nbo 300 where we were able to Start out with relatively high capacity not as quite as high as the hydrated material But then it would be much more stable than the hydrated material And so we were interested in understanding why that was the case We studied the all materials using something called x-ray absorption spectroscopy X-ray absorption spectroscopy allows us to determine the oxidation state of the materials and this these also were studies So we can watch the evolution of the vanadium oxidation state as the battery is functioning and in fact Vanadium changing an oxidation state is the the reaction that's taking place. So we're basically reducing vanadium as we discharge There are several phases that are formed that I show them here. There's the parent phase then we have zinc hydroxide sulfate Zinc hydroxide sulfate is important because that told us that actually there's a ph change taking place inside the battery What's happening is that there's proton insertion The electrolyte becomes more basic and we precipitate a solid and then zinc vanadium oxide is a zinc insertion material This is a shout-out to one of my collaborators professor. Amy marshall. She's really been a pioneer in developing something called energy dispersive x-ray diffraction So again, we use a working battery We use a small 20 micron x-ray beam move the battery through the beam and then we can Spatially and temporally resolve. Where is the elect? Where is the reaction happening? And these are the x-ray results for the 300 degree material and I won't go through the details here Other than to show you we have the results on the 500 degree material as well And I think it's more apparent here As we charge and discharge we can map Where these various phases form and what's taking place inside the battery? And what we find is that for the 500 degree material We're really only accessing the very surface layers Of the the material itself with limited amount of chs formation With the 300 degree material we're accessing much more of the active material and the active battery So we're getting much more complete utilization And with the porous electrodes that we designed The reactivity throughout the electrode was fairly uniform So this was more a material issue than an electrode issue I will point out that the non annealed material and this is a study that we have ongoing now Just begins to dissolve So it's amorphous enough that it starts to dissolve in electrolyte and that contributes to the fade that we're seeing So let me move on to my last example here. This example has to do with zinc manganese oxide batteries So manganese oxide comes in various forms and the drugstore batteries that you buy, you know alkaline batteries Are zinc manganese oxide. They're a different form of manganese oxide But what we were interested in was is it possible to make zinc manganese oxide batteries rechargeable? Zinc is pretty cheap manganese oxides pretty cheap manganese oxides also fairly environmentally friendly And of course, you know as good researchers we started off looking into the literature And we were intrigued by this two by two tunnel because this two by two tunnel structure of manganese oxide The tunnel is big enough to accommodate a zinc caravan But when we looked further in the literature Well, people have in fact tried to use zinc alpha manganese oxide for rechargeable batteries But there are reports of many many different types of reactions Oh zinc is inserting. Oh, no, it's proton insertion. Oh, actually manganese oxide is turning to something else It's a chemical conversion reaction There were reports that said that a tunnel structure goes to layered structure and goes back to a tunnel structure So we thought This is very odd, you know, the very talented scientists are reporting Seemingly the same experiment with multiple outcomes. So we decided to try to understand this further to understand what was happening So these manganese oxide studies were done by my Collaborator professor Kenneth Takayuchi, and you might guess Kenneth Takayuchi is also my husband Um, he's really very talented very uh synthetic chemist and experimentalist in general So the first thing was making the tunneled material and characterizing very carefully. So we had to phase pure material Next thing was starting the electrochemistry And we observed that the electrochemistry is quite different in cycle one and subsequent cycles So we isolated samples of the electrodes after charge and discharge And we did x-ray absorption studies and if you remember I mentioned before X-ray absorption is very useful in determining oxidation state of transition metals So we determined the oxidation state of the manganese oxide in the charged and discharged condition And then tried to relate it to the electrochemistry And while in the vanadium case The electron count added up we can account for the oxidation state of the vanadium In the manganese oxide case, we could not we're getting more electrochemistry than the oxidation state change of the manganese oxide accounts for So kena had a very clever suggestion and said look what you've got to do is study this operando You've got to look at the cathode But don't look at the cathode in isolation So a very um, this was actually a collaboration between kentakeuchi and david bach of who's a brookhaven scientist To design an operando cell and i'm showing it as a little cylinder and what you can see is that it's stacked So we've got the cathode on top with you know current collector We've got a separator in between And then we've got the zinc anode on the bottom And what we're doing is x-ray fluorescence mapping So that means we're looking for a specific element And if you look at the middle picture Everything that's bright means there's a lot of it present and what we're doing is mapping zinc So the zinc anode is very bright the electrolyte contains dissolved zinc so you can see that's kind of bright yellow Even the cathode is porous enough that there's some electrolyte present meaning some zinc ions present So instead of being dark red, it's kind of you know a little bit orange ish The far right hand map is manganese edge So what we're mapping there is the fresh cell That whole layer is basically the manganese cathode. So that's what we're seeing is a manganese cathode So the next set of experiments was mapping the cell But in an intermittent Electrochemicals in process. So what we're doing is we're discharging the cell then we pause Then we're discharging the cell then we pause and then we keep going. So think of it as applying pulse weight pulse weight pulse weight And we saw something pretty incredible if you look at the maps on the top that bright White yellow spot is you know the sections is the cathode But as we continued with The discharge what we saw Is more and more manganese going into the electrolyte layer So this meant that The manganese was in fact Dissolving into the electrolyte level into the electrolyte And that was part of the electrochemical process So the next step was actually to cycle A battery While we were doing the micro fluorescence maps, and I think unfortunately my video I checked it earlier Doesn't work, but let me describe So what we're able to see is as the battery discharges and charges We could see the manganese intensity in the electrolyte layer Increased during discharge and decreased during charge So this not only said that manganese dissolution Is a key part of the electrochemistry, but deposition is as well So what we wanted to do was quantify this so not just a qualitative observation, but a quantitative observation Of the dissolution deposition So he established a calibration curve Using multiple concentrations of dissolved manganese in the electrolyte and then Tracked and quantified based on the micro fluorescence behavior extra fluorescence behavior The amount of dissolved manganese that's in the electrolyte and compared it to the electrochemistry And what we observed was that if we quantify it The dissolution of manganese and the manganese Concentration the electrolyte Is really the dominant electrochemical mechanism that's taking place So what's happening here is on reduction of the manganese four and manganese three When it's reduced to manganese two The manganese plus two goes into the aqueous electrolyte layer as a hydrated Cat ion And then remains in the electrolyte layer until the charge step Where the manganese two is oxidized and then Deposits on the cathode And it's this mechanism that helps rationalize why there are so many disparate reports in the literature Then in fact it is changing phase it is changing structure And if you look at things in isolation that it's hard If not impossible to see the whole sequence taking place simultaneously So this gives you a picture kind of at the molecular level of what's happening. We start with zinc alpha manganese oxide Upon reduction we form manganese plus two That dissolves in the electrolyte In this case we're forming zinc hydroxy sulfate. This is a precipitation So this also tells us that there has to be associated Proton insertion into the manganese oxide to precipitate CHS On charge the manganese two is oxidized The ch s as the pH becomes more acidic the ch s it dissolves And we end up with two things we end up with a layered zinc manganese oxide as a charge product As well as an alpha manganese oxide Sorry But in this case It no longer has intact tunnels And the material has become a partially layered structure Due to the disintegration of some of the tunnels So a very recent paper That can published took this Challenge one step further in the first experiment if you remember We looked at the isolated solid cathode material In the second experiment what we were doing was Mapping The concentration in the electrolyte but this recent experiment Combined both Where in fact Simultaneously we we were measuring X-ray absorption spectroscopy Of both The solid cathode material As well as the liquid contribution simultaneously And we were able to do multi multi phase fitting Where we could fit The contribution from the solution as well as the contribution from the solid Because really in order to understand the system more fully We needed information both about the solid contribution as well as The liquid contribution In conjunction with our x-ray absorption spectroscopy study We used x-ray diffraction. We used transmission Microscopy selected area electron diffraction and roman And this is just a comment perhaps More to the graduate students and students Than to the faculty because i'm sure the faculty already know this When you're dealing with a very complex system often having multiple characterization methods is necessary Because the multiple characterization methods if they all end up pointing in the same direction Then we have much more confidence Than in fact what we've identified by a single characterization method is representative of what's happening for for the entire system So we found that just the spectroscopy diffraction and microscopy all led us to the same conclusion which was Certainly gratifying So when we look at the combined mechanism what we're seeing overall Is the transformation of the cathode material Into zinc manganese oxide and the precipitated zhs phase On charge we recovered manganese oxide in two different phases Some of the original tunnel structure remains But then we do recover a layered structure as the charge progresses Because much of the the dissolved material doesn't re-deposit In the same phase that it was originally formed it re-deposits in in a new phase structure We tested this mechanism in a series of electrolytes using sulfate Acetate triflate and this general mechanism holds true independent of the anion that's that's present the The anions lead to different levels of cell efficiency But generally the mechanisms were pretty universal across these different electrolyte systems So let me summarize here and actually end on time As you can tell from from the presentation Various size domains really do play a role as simple as energy storage seems These systems are very complex and they do involve a combination of chemistry material science, but also Mechanical factors that end up being very significant in terms of not only the design But the the ability of these systems to continue to function effectively Transport through three through thick three-dimensional electrodes is possible understanding characterization and how to readily Follow the transport mechanisms through operando methods has been something that you know, we believe we've been able to contribute to And in terms of operando studies, particularly the manganese oxide studies The information that we learned was pretty transformational that these were really the first direct observations of this Pollution deposition mechanism that was taking place inside these batteries So let me acknowledge first my colleagues and collaborators Professor Ken Takiyuchi Professor Amy Marshall lock and highlighted in the circles This picture is Just before coven so many of the students In our collective research group Our collective research collaboration have graduated and i've listed Our new members across the bottom We do have students from chemical engineering material science as well as chemistry So we have a very multidisciplinary activity and involve actively Staff scientific staff from brookhaven national lab as well And i'd like to thank the financial support particularly from the department of energy as well as Mercedes Benz new york state and several heart students have graduate research fellowship. So thank you very much for your attention Thank you very much Esther for the wonderful presentation Are there any questions from the audience? Yes, thank you very much for very inspiring lecture. I have one question You mentioned at the very beginning To achieve carbon neutral by 2050 Nearly everything needs to be electrified How do you see hydrogen playing the picture? Oh, what a great question, you know, we've been talking about that all day today My view is that the challenge we have in front of us is so big that that many Forms of technology are going to be important. I'm not sure that any one technology Can solve all of the problems quickly enough So can hydrogen solve everything? Maybe not. Can it play an important role? I believe so, you know, we also talk about Nuclear power. I think nuclear power can also play an important role But it's like it's like anything. I think that the technology That's best suited to the specific application and the location So I used to live near Buffalo, New York And of course in Buffalo We're very privileged because we're close to Niagara Falls So the majority of the power is hydro power. So it's already pretty clear Pretty clean, but now I live near New York City about an hour away. Well, there's no place To build a dam and you know power New York City So New York City likely it's going to be powered by a combination of Wind Offshore wind maybe solar hydrogen may play a role in terms of Storage may play a role in terms of Electricity generation through things like, you know fuel cells, you know Hydrogen can be formed by electrolyzers But there's significant technology challenges there to Hydrogen is a very if you're working in hydrogen, you know, it's a very small molecule that can move through Almost anything Pretty effectively. So but can it play a role? I I think so. Yeah and important. Thanks for the Thanks for the terrific talk. So You showed these beautiful Characterizations on many different length scales. I'm curious about the complimentary synthetic control. That's necessary To take action on these different length scales. Can you comment about where where you think major gaps exist? That's that's also an outstanding question. And that's something we we think about a lot because The challenge was something like for example, transmission transmission electron microscopy is you're typically looking at one particle one segment of a particle And the the risk is Even though the data is beautiful is a representative of anything in the bulk. So we're we're very careful about Synthetic control and I think Can't talk to you who is Really a synthetic inorganic chemist? Pays a lot of attention to developing methods that are highly controllable where we can control Not only The structure until in terms of you know, the molecular arrangement But things like crystallite size more phylogy because all of those end up affecting the electrochemistry So we're also very careful about lot Let's say synthetic lot control And making sure that if we're trying to compare A diversity of techniques particularly if these techniques Give information at multiple length scales that we are in fact looking at representative materials and Your question is on point because that is not easy to do And but if you don't do that if you don't have a common source of materials Then the conclusions you draw can be pretty disparate. So for example In our energy frontier research center One of the materials we were studying was a conversion material magnetite every 304 and we had a consistent group Synthesizing the magnetite for all of the studies across the center because we knew that if somebody used a commercial sample and somebody made their own That comparing the results would be very challenging to know that those results really had anything to do with other results So Absolutely word of the wise you have to have consistent input materials to make sense of your of your data I think i'm not a good moderator. I I should have asked you To please state your name too for our guest, right? So I do that with the next person introduce yourself and you go with the question. Okay Okay, I'm deba. I'm a boosting us and professor of mechanical engineering. So I'm from the heat transfer background Presently all lithium ion batteries, you know, you need thermal management at the same level module battery level Do you in your opinion? Do you see a future where thermal management is not needed and everything is taken care of by electrochemistry You know when we started out that was really our objective What we wanted to do was understand at a fundamental level, what are the sources of heat? And to see if we could design materials and systems to change that balance in other words to have more productive Electrical work and less generated heat I think it is possible to Change the balance depending upon how the what material you pick Um how the electrons are designed how the cell is designed and importantly linking that with how it's utilized But I don't think it's ever going to drop to zero. I I don't think your career is in threat. I think we're In other words managing that heat and managing it really carefully. It's going to continue to be of critical importance moving forward because Uh, you know The batteries degrade, you know when the temperature goes up. I mean it helps transport the degradation is also accelerated So managing that heat is it is going to remain critical There are things that can be done to minimize it, but it's not going to be zero I don't think so, especially not with lithium ion Not going to happen Thank you for the beautiful talk ester and i'm jeff greatly from chemical engineering Um So I was fascinated by the last example with the the zinc manganese oxide And the the transformation that the material goes through is incredibly complex So I guess I I have maybe just a two-part question. The first is You know in retrospect if you had perfect thermodynamic knowledge of this system Is that a transformation that you would have been able to predict? Based on thermodynamics phase diagrams, or is it more of a kinetically controlled process? And I guess if it's kinetically controlled i'm just curious to To get your perspective on whether you think it'll ever be possible to To get some intuition about when to expect those types of dramatic transformations a priori It's a really good question I can tell you what is kinetically controlled for sure because we've seen this in other materials for example, we've seen this in the sodium vanadium oxide case Which is an example of a let me call it more clean insertion mechanism whereas this is complicated by You know initial proton insertion followed by dissolution with the sodium vanadium oxide case The kinetics determine whether it's proton insertion or zinc insertion and If you drive something quickly right try to go to high rate perhaps not surprisingly Proton insertion has definitely favored protons are small they're mobile you can you know jam it between those layers If you go slowly enough there is still some proton insertion that takes place But zinc zinc insertion becomes a more significant process So the the complexity here is that The details of the mechanism Let's put it this way now we know this when we started this we didn't know So in fact the colleague that we talked about Dr. Ping Liu is trying to now back up and look at this More from a thermodynamic perspective and say well If we have this material and we are going to try to do zinc insertion Is that reasonable are we you know if we try to do proton insertion is that reasonable? So This is one case where I think we needed some experiment to help Define the direction to to to look but I think now the theory then will help us guide You know like okay well now we're to the next set of experiments need to go To help you know validate that theory or perhaps give us insight into how to Make these systems more robust or more reversible based on the thermodynamics It's a great question. I will say that for many years I worked My research really focused on lithium and lithium ion and lithium and lithium ion It has its own set of complexities for sure But the one thing you know Is the charge carrier you pretty much know that it's lithium ion right? Once you go to these aqueous systems you no longer even know what the charge carrier is You know it can be zinc it can be proton You know so it it adds another set of complexities that that lithium batteries Don't have Yes Hi. Hello. Thank you for your lecture today. I wanted to like know About your charge characteristics and like solid state batteries And so you mentioned that aqueous batteries are it's really difficult to characterize their charge characteristics I was wondering if we did like solid state batteries. It would be easier to characterize the charge characteristics Yeah, so so great question Um, I just attended a several days symposium last week actually Where many many of the talks dealt with solid state batteries and I think you know Many of the research the researchers have been successful In characterizing the charge carrier. So In some cases they know What's more challenging to understand is The exact role of the interface because the interface between Your active electrode and the solid electrolyte can be highly complex And also the role of not only the mobile ion but the role of Let's say the the surrounding structures, you know that are that are allowing that mobile ion to to move Because the as much as we think they're everything static. It isn't always so I hesitate to say that something's easy because because it never is But I think my point about water was just that It can be two positive charge carriers In most solid state systems the anion can play a role the cation can play a role But it's typically not more than one cat ion. That's the active charge carrier So but I think that's unique to you know, kind of letting maybe sodium systems Okay All right, I got the signal. I'm going to wrap it up. Thank you very much One more time Esther for the wonderful presentation And being available for our question and answers Uh, we're going to take a 15 minute break now five minutes five minute break And then we start with the panel. We just rearrange and go straight into the panel. So thank you and Just stay put more to come