George Crabtree Interview Transcript

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Bruce McCabe: All right. Let me start off by thanking you again, Dr. George Crabtree, the Director of the Joint Center for Energy Storage Research here at Argonne. Have I got that right?

Dr. George Crabtree: Correct.

BM: Fantastic. And I was looking your bio beforehand and it is miles long. So I'm going to put a little link to that on my website with all the awards you've won. And I wanted to start with you, this conversation, because I noticed a few interesting things in that bio. In particular, high temperature superconductors, I believe, are an area of passion for you. So, everywhere I go, I keep hearing about the importance of that stuff. I've met with Paul Chu down at Texas.

GC: Of course. My friend, Paul right.

BM: A friend of yours. There you go. And a guy who's dedicated his life to just that area. Raising the temperature.

GC: And, of course, he was one of the pioneers, an outstanding guy, and you know leading the field. He was the first one who said it really is a high temperature superconductor.

BM: Just amazing. And such a lovely person. Very, very positive and vibrant. And recently, Jane and I, we were in France and we went to ITER to have a look at the fusion power plant. And I've been monitoring, over in Massachusetts, Commonwealth Fusion Systems. High temperature superconductors. And the better they get, the closer we get to doing fusion, right?

GC: Yeah, absolutely. And this is one of the things that only happened in, what, the last few years?

BM: Yeah. So exciting.

GC: So we all thought high temperature superconductors, maybe they would be deployed in the grid. Maybe they would be in substations in various places. But this is, by far, the biggest use.

BM: Yeah. How exciting. Yeah. So just going back, was there a catalyst for you ending up in energy? Did you start, before the PhD that I see on the bio, did something inspire you before that? Or did you arrive organically at this place, in energy being the center of your universe?

GC: So to a certain extent, it's a journey down the yellow brick road. I'm not quite sure what's going to come next. But what you're doing right now, in my case, always very, very interesting. So I started out as a basic scientist. I always wondered what makes the world go round? Why does it work the way it does? What are the natural laws? And actually, I went to school at Northwestern, undergraduate, as an engineer, and I realized two years in that I was much more interested in ‘why?’ rather than ‘how can I make it work?’ So I switched, although I kept my engineering curriculum, it was possible to do that. But I switched, basically, to physics, which was my interest at the time.

BM: You wanted to get more into the fundamentals.

GC: Fundamentals. Right. Absolutely. So I did that. And I was perfectly happy. I came to Argonne National Lab, actually, as an undergraduate intern.

BM: Oh, wow.

GC: Way back when. Yeah. From Northwestern, which is down the road, so to speak, in Evanston. And followed my nose. And there was so much to learn. There was no problem. I was a curious guy. So I just kept learning and learning and learning, and worked with my colleagues here to do research. High temperature superconductivity was maybe the third or fourth thing that I did. And then it became clear, in those days, we weren't quite sure if we were in a period of global warming or stable climate or global cooling. After all, you might expect, well, the next ice age is right around the corner. And during that time, it became clear that it was global warming. And it became clear how serious that was. So when the opportunity came to take on the Joint Center for Energy Storage Research, I was eager for it. It was a surprise to me. I hadn't planned it. I said, "Yes, I think I will do that." It's doing ... as we were saying earlier, solving a major problem that needs to be solved.

BM: Yeah, a problem that matters.

GC: Problem that matters. Thank you.

BM: Really, there's no other problem that matters more if we take it from the point of view of global energy and carbon. And if we then subdivide that, there's almost no subproblem that matters more than building better batteries and energy storage right now, in terms of an unsolved problem or an unmet need for better batteries. So, no pressure, George, but what you're doing is about saving the planet so... [laughter]

GC: We should get busy. [laughter]

BM: Exactly. Thanks for taking time out to talk to me instead of saving the planet. But you know it really is that sort of a scale of problem. Everything you do here, any breakthrough here, impacts everything. It impacts everything in transportation, everything in the way we distribute and store energy on the grid, potentially. It impacts all industry, potentially. It impacts everything. So it really does matter what you're doing here. So let's get into it. If I start with lithium-ion as the base that everyone understands and uses today, and it's very ubiquitous, and I believe we continue to improve it, but I'm not sure how much more headroom there is.

GC: Good question.

BM: That's one thing I want to tackle, yeah. The big question today is what lies beyond lithium-ion? What do those pathways look like? What holds promise, I guess. I don't want to be dishonest with people in this. I want to be honest about, well, this holds promise and maybe we won't get there, maybe we will, but here's what George Crabtree is excited about now. I'd like to get into that and then maybe build up from there to some of the grid scale batteries and talk about, I hear with lithium-ion replacements, I hear every metal on the periodic table as potential replacement. It's impossible to discern what has meaning and what hasn't. There's lots of people out there launching companies and saying, "We've got the answer." And you hear about solid state and all that. So if we can carve a little path through that, just in terms of understanding it, that'd be great. And then maybe move into the grid scale stuff as well.

GC: Yeah. Great, great points and great topics so I...

BM: And huge. [laughter]

GC: And huge, right. Suitably huge, yeah. I mean, one comment I would make right off the bat is that lithium-ion is the best battery we have ever had, without a doubt. Highest energy density. Recharge it. It's like round-trip efficiency, as we say, something like 95% of the electricity you put in, you get out. Wow.

BM: Yeah. So 5% loss in that yeah.

GC: It's fantastic. And it does so much. Of course, it came out for personal electronics. You may know the history. In 1991, Sony had a camcorder, and they wanted it to be a portable camcorder. But the battery was too heavy. So it was very awkward to carry around. They said, "Well." At that time, lithium-ion had just sort of come on the scene. They said, "Let's develop it into a product. We'll use it in our camcorder." Well, it worked fine. It was half the weight of best previous battery for the same energy. And it made the camcorder a big success. Nobody understood at that time that personal electronics was going to bloom like it did.

BM: Yeah. Yeah.

GC: But now we have, of course...

BM: There's one device.

GC: Yeah. And we've probably got two or three lithium-ions on our person most of the time. Cell phone, laptop, whatever, Kindle, whatever else you're doing. And it has been perfect for the personal electronics industry. Why? Because it's tiny. You don't need much of a battery. So although the battery is expensive, it's not a big part of the cell phone cost. You can recharge it as you're using it. So you don't have to fast charge. The battery doesn't have to last a long time because you're going to throw away that personal electronics and upgrade in three years. So lifetime doesn't matter. Safety, there are some safety problems with lithium-ion. But in a little cell phone, what happens is if the battery for any reason happens to get above 150 degrees centigrade, what's called a thermal runaway reaction occurs between the cathode and the electrolyte, and that releases heat, so it warms up even more, so it goes even faster. But if it's your cell phone, you'll realize, "Hey, this is getting hot." You can throw it over on the floor and it might scorch the carpet, but probably nobody will get hurt and you can clean the carpet and so on. It's different if you've got an EV.

BM: Yeah, different as we push it beyond the boundaries it was initially intended for.

GC: I think this is a very good way to say it. So it will continue to be the battery of choice for personal electronics. I think there's no doubt about that. But when you say, "Well... " – and by the way, this is the attitude now – "What battery do we have? Lithium-ion. What applications do we have? Well, we've got EVs, we've got heavy duty transportation, we've got the grids, we've got...”

BM: Aircraft.

GC: Yes, aircraft...

BM: We've got to talk about that at some point.

GC: Yeah. “And let's use lithium-ion for it.” Well, it doesn't match quite as well. So it works... Will work and there's no doubt that this will be the path forward for passenger EVs. It's a light duty vehicle. 10 years ago, maybe it wasn't clear. It's clear now. It will work. You can drive 200 miles, 300 miles. That's enough. You can deal with the safety issues, although I think they're more serious than they are for personal electronics. You'd like it to charge a little faster. Maybe it takes 20 minutes, you know, minimum time, to get 60% or 70% charge. But you can fill your tank up in five minutes. Plus the cost. So you buy an EV, 30% of the cost is the battery...

BM: The battery yeah. But we can hot swap them as well, potentially.

GC: It's another opportunity, absolutely. Yeah.

BM: Yeah. Okay. It sounds quite like you're quite definitive though in saying it's pretty much it for EVs. So for the next decade, you don't see that changing.

GC: No. And one reason is...

BM: That's an interesting statement.

GC: I think it's an interesting statement too. And I would say one reason for it is that the car companies have gotten on board. They have, I believe, seen the handwriting on the wall. They know where the future is.

BM: I think so now. [chuckle]

GC: Yeah. And they've now, with virtually no government incentives or what's the other … penalties I would say, they've made the choice to switch. So a lot of companies have said, "By 2035, we're not going to be making any more gasoline cars." And that's a wonderful thing for the climate. Of course, 2035 is what you need, because if you want to decarbonize by 2050, you'd like all the gasoline cars off the road. Car lasts about 16 years. So by 2035, if you're selling mostly electric, that would happen. But it's not perfect. And when you go to heavy duty transportation, which we were talking earlier about, so what is that? Well, long haul trucks, rail, marine shipping, aviation.

BM: Yes, shipping comes up a bit now yeah. And aviation.

GC: And the batteries just don't work for that. They're too heavy, honestly.

BM: They have too much of a penalty in the freight cost of the battery itself, and the real estate taken up by the battery to do it. And I guess you're asking too much of them. The duty cycle is probably just too heavy as well, perhaps?

GC: Well, they don't run 24/7, but nearly so. If it's a long haul truck, you want that truck driving, you don't want it sitting somewhere, i.e. charging. And that's a challenge. But if it's a fleet, you know, you can probably take care of that.

BM: And again, with hot swap ability, maybe. There are some truck companies, long-haul freight companies, experimenting with hot swappable modules at points along the long-distance route.

GC: Yeah. Just take it out, put the next one in.

BM: Yeah, which seems to be a partial improvement anyway.

GC: Sure.

BM: But just going back just to the EVs for passenger use, I regularly get asked about the mineral side of it with lithium-ion, cobalt and shortages and... Now, I'm hearing mixed messages on that now. I'm hearing quite a lot of messages out of the auto industry that they're not worried about the shortages so much. I'd really rather hear it from you as to what your take is. Because recycling is part of that. Can we do more closed loop stuff with these lithium-ion batteries? Or do you see some cliffs coming, in terms of supply?

GC: There's huge challenges coming. And I think, we haven't mentioned this yet, but the supply chain, well, we did mention it. The supply chain of lithium-ion, it's expensive. It's earth-limited, some of it, and it's highly international. And sometimes international means, well, there might be some partners that are not so reliable. So I think every country is thinking now how can we ensure that we have the minerals and the critical materials that we need for lithium-ion. Why? Because EVs are going to take off. Most of the estimates are that by 2030, the market and the sales of EVs will go up by a factor of 10, which is huge, and so the question is how can you make enough batteries to satisfy that market? So we were talking earlier, well, is that something to worry about or not? In some cases, it is. And lithium maybe is a good example. So all experts agree there is enough lithium in the earth's crust to handle a global exclusive EV market. The question is can you get it out fast enough? So if demand goes up by a factor of 10 in 10 years, you can't ramp up the lithium supply that fast. So there will always be a shortage. It means the price will go up for sure, inevitably. And where are you going to get it? So you could get it from hard rock mining. That would be mostly Australia and a few other places. You probably know about this. Or you can get it from brines, which are usually underground, but saturated with lithium. Two very different ways to extract. Hard rock mining, it's traditional mining. The brines, you want to pump it up to the surface and put it in an evaporation pond for maybe two to three years. And just let the sun evaporate the water, and what's left is rich in lithium. But that means there's a timescale. You can't ramp actually either one of those up instantly. So we're going to have some supply challenges.

BM: And the heavy metals and the cobalt, and there's similar things there. But there's enough supply theoretically?

GC: Well, the others, besides lithium, some things are difficult. Graphite is the anode of lithium-ion and there's plenty of graphite in the world. It's just carbon. However, it's not any kind of carbon. It's a specialized kind of carbon. And most of the refining of that carbon is done in China. And I think for the last 10 years, China has very strategically and intentionally ensured a market, well, ensured a supply chain for the ingredients of lithium-ion, including graphite. So although graphite is pretty common and there's no earthly shortage of that, the refining could be a problem. But that is true. And you mentioned, of course, cobalt. Belgian Congo. It's not Belgian anymore. The Congo. And I think kind of a potentially unreliable partner. There's a lot of corruption there, a lot of child labor abuse and other things ...

BM: I hear different messages. I hear, you know, we can extract from seawater. There's cobalt there. I hear there's other sources. And just from a pure science point of view rather than a geopolitical point of view, that if things go right and we get the right, that we shouldn't be concerned about that as a ‘brick wall’ for lithium-ion in the vehicle. Is that fair?

GC: I guess I would say that I would agree with that optimism. We'll have to see what plays out. So it's a question of how fast can you ramp up and...

BM: Which is a tough challenge.

GC: It's a tough challenge. But once I think the incentives are there and everybody makes up their mind to do it, well, maybe it's not as hard as you thought. And it will certainly take some time.

BM: Okay. So as we get into the big heavy stuff, long haul trucks, aircraft. Aircraft fascinate me because I've actually gone and looked at an electric aircraft.

GC: Oh. Wonderful!

BM: And they are gorgeous. And then we look at this new... Alice, for example, that Eviation is putting out, nine passengers. They're pushing, very much pushing the boundaries of what you could do with lithium-ion. And the issue is range, of course, with the weight. But the plus side in terms of reduced complexity is enormous. The reduced maintenance overheads are massive. So I get very excited about it. Now, if you can give me a 2x improvement even, you know, it doesn't have to be 5X. [laughter] If we just get a doubling of the energy density, we can do all that at short range aviation. Can we do it?

GC: Yeah. Absolutely.

BM: When are we going to do it? [laughter]

GC: Well, I think the airlines actually, it suits their business plan. It's cheaper to fly as it is cheaper to drive on electricity than it is on gasoline or jet fuel. So they will save money. This is great. They want those planes in the air at all times. So the idea is you land long enough to unload and load and then you take off again. And you could do that. That's enough time. It takes about an hour to charge any lithium-ion battery from zero to 100%. Well, when you're unloading and loading, there's an hour.

BM: Absolutely fine. They don't have a problem there.

GC: And you would have this fast charging installed, of course, at the airport on steroids. But you could do that. We have the electricity.

BM: Yeah. And we're seeing the first rollouts of those for small electric two-passenger aircrafts now.

GC: Yes. Which are the precursors, of course. [chuckle] So the problem is to get the energy density up. And if you talk to, there are various numbers floating around. But one of the numbers that seems to be pretty reliable is that if you want regional air travel on batteries, you need about five times the energy density.

BM: Five times?

GC: I'm sorry, three times.

BM: Oh, three times.

GC: I'm wrong. Three times the energy density of lithium-ion. And it's very clear that lithium-ion is not going to do it. No matter, put in a solid-state electrolyte, put in a lithium anode, drive it to the limit, it'll be very hard to get three times, let alone five, which is what you might like to have. But that would enable 600 miles of, let's say, regional travel, air travel. And it turns out that's a huge percentage of how much air travel is really out there.

BM: More than half, I think.

GC: Oh yeah, for sure. And I don't know the number, but I think it is more than half. But you think sort of romantically about, "Oh, let's go over the ocean. Let's go to Europe or even around the world and so on." We do that, of course, routinely, but it is not ‘most.’ So it would be a big step forward if we could achieve this three times.

BM: Sure, sure. But the 3x you're talking about is for longer than 600 miles or is to achieve the 600 miles?

GC: It's to achieve the 600.

BM: Okay. So there's a lot of work to be done there. Are there candidates out there that you think might produce that?

GC: That’s, I think it's an open... let me start out with another statement and then come to that one.

BM: We can roll it back and then roll it forward.

GC: So what we have commercially right now, which is mostly lithium-ion, solves about half the applications gaps that we need to decarbonize. Aviation is one of them, but so are the other heavy-duty transportation. So it's like long haul trucking, rail, marine shipping, aviation. What's around  that could fill that need? Well, as you were saying earlier, almost every element in the periodic table can be the active material for a battery. And I think many people don't realize this. There's a paper that was published when? Probably about 10 years ago, that listed what is the energy density, theoretical energy density that you could get from, let's say, all the candidates that make sense. And it's a long list, very long list. Top of the list is lithium oxygen. And people have been pursuing lithium oxygen for, I don't know, 40 years, maybe.

BM: Really? 40 years?

GC: Well, we've known that that was the top one. And, of course, you start with the top. You kind of say, "Well, that won't work. Let's go down one notch." And it's pretty clear what the challenges are with lithium oxygen. And I can name them for you in a minute. But what else is out there? So lithium oxygen is an example of a metal air battery. Just to back up one second, with lithium-ion, we have a graphite anode. The lithium goes in between the layers of the graphite when it's stored there. That's when you're charging the battery. You can get one lithium for every six carbons in graphite. So that means one seventh of all the atoms are actually storing and releasing energy for you. If you could put a pure lithium metal anode, so no graphite, no carbon at all, all of the atoms would be storing and releasing energy. So you would get a big increase in the energy density. Might be a factor of two. Might be some other number. Since we haven't done that, we don't really know.

BM: Yeah, but it's not 5%. It's a big jump.

GC: No, it's not 5%. Yeah, it's a big jump. And so that, in fact, if you go back in the history of lithium-ion, that's what everybody in the '70s was working on. And '80s. A lithium metal anode. Lithium was clearly the best anode material, just as oxygen is, "the best cathode material". So why wouldn't you go with those? Well, it turned out it was very hard to make the lithium metal anode work, for maybe two or three reasons. One is the following: if you strip off lithium from the surface of the anode and send it over to the cathode to discharge the battery, then when you charge, you bring it back and it has to replate. It doesn't replate smoothly. It gets rough. The surface gets rough. And it turns out the high points on that rough surface take lithium faster than the low points. So little pinnacles start to grow. And they will eventually, they're called sometimes dendrites.

BM: They'll short out, I guess.

GC: Yeah, they’ll grow across the electrolyte, short out the cathode, your battery's done. We have not been able to solve that problem. Yet. But back in, say, the '80s when people were working on this, the tools were much more limited than they are now. So I don't have any doubt that we will eventually solve that problem. And there are many start-ups out there who say we are solving it.

BM: So there's another big statement. You don't have doubt. Okay, great.

GC: Yeah, this is not going to get you three times energy. But it'll get you there.

BM: No, no. There's a big step coming, once we solve those problems. And from a science perspective, you see, you feel there's pathways to do it?

GC: Oh, I think there's no doubt.

BM: Even if we can't identify all the steps?

GC: Yeah.

BM: That's wonderful.

GC: Well, and one reason for the optimism is there's so many start-ups out there now working on a lithium metal anode of some kind. And they're all pretty quiet about how they do it. But they all claim, yes, look at our performance records. Here's a graph. And you got to believe that there's paydirt there. So that could happen. When? I'm not a fortune teller.

BM: Sure. Of course. It's tough.

GC: But it might be 5 or 10 years.

BM: But the fact that there are pathways there, and you feel confident about them, is important and positive enough to hear. Yeah. Interesting. Okay. So that will be ... There are good prospects for the aviation sector as we solve those problems?

GC: Yeah, I think that's the case.

BM: The economics certainly are beautiful. I mean, it wasn't the fuel costs, it was the maintenance costs. Harbor Air who retrofitted this a Havilland Beaver with an engine—a motor from MagniX, put batteries on it, saying it's 1/20th the maintenance cost. And I can believe it. Because anyone I know that flies privately, when you do an overhaul of a Cessna engine...

GC: It's going to cost you [laughter].

BM: It costs a lot of money. So if you're running commercial aviation and 1/20th of the powertrain maintenance cost, wow. It's a game changer.

GC: Well, it's pretty simple, isn't it? I mean, there's a moving part, the motor and the propeller. That's about it.

BM: And every Tesla owner will tell you the same thing [laughter]

GC: Yes. That's right.

BM: "Oh my God. A million kilometres and this thing is still going!" Okay. So as we move upscale, the grid, it's really important to look at storage on the grid. We had a very spectacular example of pushing the boundaries of lithium-ion in Australia. There was a famous bet taken. I don't know if you're aware of this, but we had blackouts in one of our states. It was highly politicized, unfortunately. This is all due to renewables, wind and solar. It was in South Australia. And a bet was made publicly with Elon Musk, whatever you think of him, but he accepted this bet that I will solve that problem with a 100-megawatt battery in 100 days or it's free. So that took the politics out of the equation, which was quite sweet to watch. They put it in, solved all the intermittency issues, bang! Straight up!. The thing is highly profitable. Every state in my country, where I'm from in Australia, is building or has built another battery in exactly the same way. Now that's just lithium-ion though. There's nothing extraordinary there, except the cost is high for what you're doing. And maybe it's not a good application when we need it for transport or more portable functions. I'm hearing about sulfur flow, iron flow batteries. I'm hearing, again, an encyclopedia of options. Where do you see that headed, these sort of grid-scale batteries?

GC: Well, first of all, that story about Tesla providing a battery in 100 days or it's free is very well known. And I think that was the turning point. So, before that time, at the moment that was done, that was the biggest battery on the grid by far. Others were small and can't do much harm or much good, but I think everybody watched that. Will it be delivered? was one question. And after a year, how well did it work? And the answer to both was extremely positive. Oh yes, all the way around. And that encouraged, I think, everybody else in the industry to say, "Yeah, let's start buying these batteries." So now you may know it's a pretty small battery? 100 megawatts? Don't even talk to me about that. I want something much bigger. There's one in Moss Landing in California, 1,600 megawatts.

BM: Wow. All lithium-ion?

GC: Yeah, it's all lithium-ion. You bring them in shipping containers and you stack them one next to each other, and pretty soon it's a pretty big footprint. But that's okay. And they really work remarkably well. So I mean, this was a huge, I think, inflection point in both people's thinking and their actions. It just took off. And well, it should. I mean, again, well, here's an interesting comparison for you. The battery in your cell phone or your laptop, you know the size of it. Battery for an EV has to be 10,000 times bigger. That already helps you to visualize. It's not the little battery under the hood that starts your car.

BM: 10,000 times.

GC: No. And typically in EVs, they're built on the chassis beneath the seats.

BM: Yes, the lowest possible center of gravity, all that stuff.

GC: Yeah, right. So you don't notice it, but it's there. For the grid, you want a battery that's 1,000 times and maybe 10,000 times bigger than for the EV. So this is a huge battery. And you need a lot of space. And fortunately, if you're not in a city, you can put them next to the wind farm, which is usually out in the rural areas. And that's what people are doing. So the typical installation now of a solar farm is a solar-plus-storage farm. And because you got to... Why? Because you have to sort of, as they call it, firm up the variable, if it's wind or solar. Cloud goes over, solar panel puts out 70% less. Better have a battery for that.

BM: And we want to store that excess anyway, if we've got excess.

GC: Yes. If we happen to have excess, let's take it. Yeah, we'll store it overnight and tomorrow we'll use it.

BM: Yeah, so it's intermittency, it's zero waste, more efficiency out of the assets, all that good stuff.

GC: The one downside is that per kilowatt hour, a lithium-ion battery costs about four times what a solar panel or a wind turbine costs, so it's still the most expensive part of the system, a little bit like the EV. And for that reason alone, you'd like to have a lower cost battery if you could. So, yeah ...

BM: Keep going, because I've got lots of questions on this [laughter]

GC: So where is it going to go? Well, I think everybody would like to have a cheaper battery for the grid, one that has a much more simplified supply chain, i.e. Inexpensive, earth-abundant, and let's say everywhere available. Which means in whatever country you're talking about, just get it. And if that were to happen, it would probably replace a lot of the lithium-ion batteries that are now common use. So it might replace what's in an EV if it's small enough. Maybe it wouldn't be for the grid, you don't need that. But if it were small enough, it would. And I think that's something we haven't given enough thought to. So just the applications that we think of now for lithium-ion might be replaced by just next generation better battery. That's lots of requirements on it. Cheaper, good supply chain, safer and longer lasting and faster charging.

BM: And again, do you think lithium oxygen is the main pathway?

GC: Well, there's challenges with lithium oxygen. So what are the challenges? One is the discharge product. Lithium with oxygen turns out to be an insulator. So it's a little hard to recharge, because you can't get electronic access to it. It doesn't conduct electricity. So solution to that, make the discharge product in tiny, nanoscale particles, mostly surface. You could always contact the surface. And if you wait long enough, you will contact the interior, all the way to the interior. And if the particle is small enough, that, in principle, at least, would not be, let's say, the main barrier anymore. That's possible to do. So that could work. The cathode of the lithium-ion battery is just like the anode in that it's layered. The lithium goes in between the layers. And again, most of the cathode is not storing or releasing energy. It's just housing the lithium atoms. And like the anode, you get one lithium for every six carbons. Might be a little better in the cathode. But still, most of it is not doing you much good for energy storage. So with lithium oxygen, of course, oxygen is not a layered material at all. It's a gas. It reacts directly with the lithium. So it's a molecule. It's a lithium oxygen molecule. And it has to build up somewhere. You're not storing it in between the layers of anything. So you have to leave space for that. Bit of a challenge. That, in technical terms, that's called a conversion electrode. But in principle, because you have a lithium metal anode and a lithium oxygen cathode, you can make the energy density a lot higher. So this is the appeal. But where do you need a catalyst? Because the lithium oxygen reaction just doesn't go very fast. Everyone knows this. And there are some catalysts around. But you have to develop this new architecture, a new way of storing energy that is so unlike lithium-ion, it's going to take some time. So yeah, I would be optimistic. But I wouldn't want to put a timescale on it. That's hard to know.

BM: When I look at the grid, there seems to be like a hierarchy of storage, a bit like the hierarchy of storage in a computer. There's the fast response and then there's the slow but long duration storage. And on the grid, we've got, at that end, the base of the pyramid if you like, pumped hydro. We've got some very basic things that … they work. But then we want lithium-ion at the very rapid switchover, for intermittency and something good like that. But in the middle, people are talking about iron flow. I don't know if it's realistic or not. They also talk about using just traditional chemical batteries, lead-acid type batteries. So at a suburban scale, for example, or a precinct, an industrial precinct … realistic? Important? Not so important? Where do you put these middle ones? I mean, sulfur-flow is the other one that comes up. [chuckle]

GC: Yeah, there are lots of flow batteries. And they've been around for a long time too. And the advantage of a flow battery, so instead of a solid anode and cathode, instead of electrodes that are solids, they're liquids. They're stored in a tank. You can make the tank as big as you want.

BM: Yeah. So real estate is... So presuming real estate is not an issue? That's okay?

GC: Yeah. You can make the battery... And it's just linear scaling. I mean, it's very simple. So it does have a lot of appeal, especially for the grid. There is a commercial one out there, vanadium flow battery, which is based on water as the electrolyte. So there's one easily available supply chain.

BM: Yeah, big plus [laughter].

GC: Right. Exactly. The downside is it's very expensive, vanadium, just to buy vanadium. So it's been around for decades, I guess, but hasn't really caught on commercially. What would you like instead? Well, a vanadium atom is kind of confined in what it can do. It's an atom. It can change its charge state by four, which is quite unusual. So that's a big plus. But it's expensive and it's pretty limited in versatility. What would you like to have? You'd like to have an organic molecule. So imagin – and you might have this or might not – a carbon ring, benzene ring, if you remember your high school chemistry. And you can hang off each one of those six carbon atoms anything you like. It doesn't have to be the same thing for every one. And that gives you enormous flexibility in designing the molecule, unlike vanadium [where] you're stuck with what nature gave you. And you can make molecules, organic molecules that exchange, let's say, two electrons or even three or four. There's no limit there. You could go higher. And two is, I wouldn't say common, but there are many examples where the reaction involves two electrons. You can make them long lasting. You can make them high solubility because you've got this liquid tank and you want to put as much of the active material in there as you can. You would like to make them cheap. And in principle, the materials cost is almost nothing – it's hydrogen, nitrogen, oxygen, just stuff, real common elements. The cost is in making the molecule.

BM: In designing it up front?

GC: But you could overcome that. And, of course, once that's done and you've got the cost down, you're set. So I think that's the appeal.

BM: That's interesting.

GC: And there are, this is one thing that JCESR is working on, flow batteries. But in particular, self-repairing flow batteries. So you could imagine a short polymer, maybe a backbone with eight or nine slots in it. And you put the active material molecules on each one of those slots and you hang this thing and there you have it. Well, it's going to degrade. And the active material in each one of those eight slots is going to start to fail. You could make it signal that it's starting to fail with a light beam. And depending on what reflection you get back, it's healthy, that molecule is healthy, or it's on its way out or it's gone.

BM: Interesting.

GC: And then you come along, again chemically, cut the bond between that failed molecule and the backbone and replace it with a fresh one. So how far have we gotten on that? We can now make the backbone. We can now send in – it gets infrared light – and get a signal back that says good or bad for each one of the molecules in this slot. Replacing them would be the next step. We know how to slit it. But to do this in a way that you could actually do commercially is, I think, still beyond us. But it's an idea. An interesting idea.

BM: And it is interesting. And it parallels, I guess, what's happening in biosciences elsewhere. The tool set to do molecular design has just become exponentially better and more capable. So there's new openings to explore this.

GC: And you can borrow from drug design, by the way. That's the economic driver for it. And the drug companies have really taken it to a high level. So why shouldn't we battery people learn to do that? We would learn from them.

BM: Yeah, absolutely. Looking at the generative AI tools in drug design, it's astonishing! Even the last 12 months, it's astonishing what's happened.

GC: Well, and you mentioned the AI. I think that's another thing that is absolutely going to take off. So when you think about vanadium, it is what it is. Think about organic molecules, it could be lots of things. What could it be? Well, you tell me what you'd like. I'll tell you, Yeah, I can do that. How will I do it? Well, there's a whole vast array, I'm going to call it white space, of molecules out there that have not been explored. How can you possibly survey that white space? It's beyond what a human mind can hold. So you use artificial intelligence. And you have a training set of known molecules, and you realize that, "Oh, if I want two electrons per molecule to be transferred, it has to have this structure, it correlates with this structure. If I want it to be highly soluble, it correlates with some other structure." And you have these... First of all, you need a huge database, which I think we don't have yet. But you need a huge database of known molecules. And then you turn the AI machine learning loose. It says, here's the correlation, machine talking. I don't know why it works. But it works. So we can use that to extrapolate, well, what are some other examples that you might find in that white space that you could then use? And that, it, first of all, because it doesn't have to simulate every molecule on earth, only it's defined data set. Of course, it knows that structure. But then it extrapolates from that, well, here's some other good ideas. That cuts the computational burden down by a factor of 100 or more. So you can start to sample a huge fraction of that white space that you just couldn't have done before. And that's going to revolutionize not only batteries, but again, it's worked in the drug industry. Why don't the rest of us learn from that? And that's what's happening now, maybe the last five years.

BM: Very exciting times!

GC: Yeah.

BM: Now, just a quick time check, we've still got a little bit of time on the clock.

GC: I'm sorry. I'm rambling away here [laughter]

BM: No, not at all! Because I just have a couple of things I want to get at...

GC: Yeah, please.

Speaker 3: 15 minutes, a little over 15 minutes.

BM: All right. Good. Thank you. Thank you. Hydrogen comes up again and again as a storage, a battery if you like, but a storage mechanism. I wanted to do a sanity test, my thinking on this, because I look at hydrogen and there's an awful lot of wastage in terms of energy losses from both the electrolysis to the compression and transportation. And I've never been excited about it from the complexity point of view as well in transportation, because you're now got two systems. You've got your fuelling system and everything that goes with that, plus your electrical system. And I look at hydrogen aircraft and great, we can make them work, but now you've got an energy density issue, which is terrible. It takes up so much space in an aircraft.

GC: Yeah.

BM: So I look at it and say, hydrogen is going to be wonderful for steel-making and things like that. We need it. And some heavy industry. But I feel like it's really overstated at the moment in the world. There's a lot of over-expectation of what hydrogen will do and how big the hydrogen economy will be. I feel it's going to be much more specialized and centralized and certainly not in the transportation sector. What do you think?

GC: Boy, that's a wonderful, let's say, $64 question?

BM: Yeah.

GC: And I don't know, a couple of comments. One is, we never thought about hydrogen until maybe five years ago or ten.

BM: Okay. [laughter]

GC: Seriously, except for the things that it does, refining and so on. And it's kind of a small industry now, but refining is big. But on a global scale, it's, I would say, not dominant. But the reason we're thinking about it is hydrogen as an energy storage carrier is climate change. Fossil fuels have been around for more than 150 years or more, if you count coal. And they're cheap. You find them, you dig them out of the ground. They're ready to use. Maybe they have to be refined. Extremely versatile. They're all hydrocarbon chains. It's basically CH2 strung together as long as you like. And the length of that chain is really important. And you can make it, you can design it for the application you want. So you have methane, which is gas, used for heating, cooking. Propane, still a gas, but you can pressurize it, maybe turn it into a liquid, butane, gasoline, liquid, diesel, jet fuel. All these things come from fossil fuels as a chemical energy carrier, and boy, are they cheap and versatile. So why would you want anything else? Climate change. So if you want to replace fossil fuels, what have you got? Well, you've got hydrogen. And you could make it in a green way, of course. Electrolysis. But it's not as versatile. So it's this little molecule with two hydrogens. It's actually very tiny. It leaks through cracks in pipes that methane won't leak through, or anything bigger. It embrittles pipes that are made for natural gas so you can't really use the natural gas pipelines for hydrogen. You need a special pipeline. And it's not versatile. It's hydrogen. It's a little bit like vanadium. You get what you get. So its … I'm going to call it, and I'm being maybe a little extreme here, but it's a poor substitute for fossil fuels.

BM: Yeah, yeah.

GC: Although there's a lot of excitement now about it. And boy, can it do a lot, as you mentioned, steel and lots of other things. So it maybe could revolutionize that. But it isn't quite a fossil fuel.

BM: No.

GC: So that's the limitation, I think. The other one you hear about is ammonia, NH3.

BM: Yeah, especially in shipping now. There's a lot of discussion about ammonia. Oh, my goodness. Yeah.

GC: Yeah. Well, it's a liquid, at least, or it can be made a liquid. You pressurize it a little bit. So you can send it through pipelines, and it doesn't have the energy density problem that hydrogen has. So it's a liquid. But it's toxic. And if you burn it, you're going to get a lot of nitrogen oxides, which have their own issues, some of which are toxic and some of which are greenhouse gases. So, and again, it's not versatile. It's NH3. It's pretty stable as NH3. It's hard to imagine you would get much else out of it. So my view is that we have not yet found the chemical energy carrier that we need.

BM: Okay.

GC: And if you say, let's replace fossil fuels, it's probably not either hydrogen or NH3. It's going to have to be something more.

BM: And that is exactly how some people are thinking of it. They're talking about, we'll replace the natural gas industry with a hydrogen industry. And to me, that's crazy. It doesn’t … it just doesn't map.

GC: Well so I would tend to agree with you. But I would, as a caution, say, let's try it. And we need some demonstration projects somewhere where we can see, how does it really work? Because you can do it on paper and have an opinion. But try it in reality. See what works.

BM: I have one last little question. It's one that comes up that I see. And I get excited about it. Because it's physical storage of energy with ultra-capacitors. I look at them. Now, capacitors leak and can’t store energy for a long time. But they're quick to charge. And I've seen buses running around in China and Serbia that fast charge on a capacitor. And they're not heavy. They're graphene based. Do they play a role, do you think, beyond these little pilot things we've seen? I mean I could see every Tesla, for example, having a layer of storage which is fast charge and discharge. But maybe I'm wrong in my over simplistic question.

GC: No, I think that's a wonderful question. And it hasn't gotten the attention that it deserves. It's really fast, as you said. And I think one of the problems with batteries is they're slow chargers, sometimes slow dischargers as well. There's limits. So if you had a hybrid of a battery and a capacitor, you, in principle, could cover all bases. And maybe that's something that we ought to look at.

BM: Okay.

GC: I mean so far we actually, in our conversation, we haven't really talked about hybrid solutions, but barring the ideal replacement for fossil fuels, let's say, it might depend on two or three different approaches that you would combine in a hybrid. I think Tesla was really smart in not going the hybrid route, hybrid EV route. Why? Because you need both the battery system and the gasoline system. And why do you want two systems on one car?

BM: No way do you want two systems. All that complexity and more!

GC: So, but if you're talking industrial-scale things where it's not consumers making decisions or paying the bills, there may be a way to make hybrids, let's say, a little bit more appealing.

BM: Yeah, interesting.

GC: But that just has not gotten the attention.

BM: Yeah yeah … Thank you so much for the time, George.

GC: Oh, you're welcome!

BM: This has been an honor for me because you really, as I said at the very beginning, you really are changing the world. What you're working on matters more than just about anything. So, as I said, no pressure. I'm going to let you be back to saving the planet.

GC: [laughter]

BM: But thank you for spending almost an hour with me to talk about this stuff. And I wish you and your colleagues well. And I want to follow all the developments here as closely as possible. So send me anything that comes out that's published. Yeah, thank you again, George.

GC: Thanks so much. My pleasure. Who doesn't like talking to an intelligent guy and having a conversation? What's wrong with that? [laughter]

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