Cheap, abundant sulfur has been posited as the highest-energy, lowest-cost material that could potentially be incorporated into a viable lithium-ion battery. In this episode, Charlotte Hamilton, CEO of Conamix, talks about her company’s aim to tackle the challenges of commercializing lithium-sulfur batteries, and the exciting implications if they succeed.
Text transcript:
David Roberts
When I was working on my series about lithium-ion batteries (LIBs), one thing I heard from several experts stuck in my head: As production of LIBs scales up and costs continue coming down, eventually the cost of batteries will fall to near the cost of the materials that compose them. That means that the long-term winner of the LIB race will be the battery chemistry composed of the cheapest materials that can perform adequately.
However, as Keynes reminded us, in the long run we are all dead. In between now and that nebulous future are many challenges and uncertainties.
Currently, the leading battery chemistries involve cobalt, nickel, manganese, and lithium itself. All of those minerals are currently mined and processed in socially, economically, and environmentally harmful ways, and with demand rapidly expanding, supply chain shortages loom in the short- to mid-term.
There is one alternative that's coming on strong lately, particularly in China — lithium-iron-phosphate (LFP) batteries, which use iron. However, LFP batteries lack the energy density of their competitors and are not suitable for the high-end electric vehicles that comprise most of the US market today.
The true holy grail for LIBs is sulfur. As Purdue University’s Rebecca Ciez told me for my battery story, “the true least-cost system for a lithium-based, rechargeable battery is lithium metal [as the anode] and a sulfur cathode.” Sulfur is cheap, ubiquitous, abundant, and already produced to the tune of 77 million tons a year. The US is the world’s second largest producer.
What’s more, sulfur’s “specific capacity” (energy it can hold per unit of weight) is higher than its competitors’, so in theory it could compete with or even best other LIBs in energy density. Of course, this has been well known for a while, and people have been pursuing it, but the engineering challenges remain substantial. Lithium-sulfur batteries have not reached the market in any appreciable numbers. Is there a pot of gold at the end of this rainbow?
Today I'm talking with someone who believes that there is. Charlotte Hamilton is the CEO of Conamix, a company that is working to commercialize lithium batteries with sulfur cathodes. The company was founded in 2014 using technology from Cornell, Stanford, Berkeley Lab, and elsewhere; last year it emerged from stealth, closed a B round of funding, and secured an $8.6 million dollar contract from the federal Intelligence Advanced Research Projects Activity.
I'm excited to talk to Hamilton about why lithium-sulfur batteries are needed, how close they are to commercialization, how easily they could fit into current LIB production infrastructure, and what kinds of technological advances they could bring in their wake.
So without any further ado, Charlotte Hamilton, welcome to Volts. Thanks for coming.
Charlotte Hamilton
Yeah. Thanks, David. That's a great introduction, you've clearly been following the space.
David Roberts
I'm immersed in batteries, if nothing else. My children mock me for it.
Charlotte Hamilton
It's a crowded world out there, and there's a lot of new technologies.
David Roberts
Yes, there's a lot going on. There's a lot going on. So, yeah, before we get into the sort of specifics of sulfur, just a couple of background questions. I know that you are a little bit more bearish on the expansion of EV markets than a lot of analysts. There's a lot of very bullish EV analysis out there. You have sounded a note of caution. So why is that? Why are you less gung ho about the growth of EV markets than some people?
Charlotte Hamilton
Yeah, well, I very much believe in a full electrification future of all personal transportation for cars. It will happen. And I think the government mandates are there, the market drive is there, the broader push to reduce greenhouse gas emissions is there. There's, I think, a misunderstanding that it's going to be kind of a smooth curve up and to the right. And we'll all have 100% of all new vehicles will be electric by 2035. That's the recent date that EU, California and some other US States have put out. I think we will get there. We will get to a full 100% of new cars being electric.
It's just not going to be a smooth ride. The materials that are currently out there are, as you mentioned, in limited supply. They're getting more expensive by the day. And the chemistries don't really exist in the broader auto market, in the way that they should, to really drive that full electrification.
David Roberts
And you have been, I think, also a little skeptical of some of the kind of extravagant promises that are being made on behalf of current chemistries. Why do you see them as sort of limited?
Charlotte Hamilton
It's interesting because I am an entrepreneur, and I move innovation into the market. It's what I've done for my career. Now, this is my third company, and it takes a very, very long time to move a new innovation from an academic discovery, makes a really great paper in science or nature, and turning that into something that is in a car that my daughter can drive around, that takes a really long time. Batteries themselves are a very complex system. It's often described as a holistic system, because there's so many things that have to work together to actually make a battery successful, particularly, for what's really a crucible for battery performance, which is electric vehicles.
Electric vehicle batteries need to have a high energy density. They've got to have long range. They've got to get the energy out very quickly. They've got to have good power, so you can accelerate, and so you can recharge the battery when you're breaking the vehicle, decelerating. And they need really great cycle life. So they need to be able to be charged and recharged hundreds of times and still maintain a really good charge. So you've got good range in your EV. And the critical piece, they've got to be inexpensive enough that the automakers can make a profit and that the broader market can actually get those EVs, rather than just being kind of like, the halo products for every automaker out there.
David Roberts
And do you think they're serving as halo products right now as you think that's the current state of things?
Charlotte Hamilton
In terms of what's actually launched, like that I can buy at a dealer?
David Roberts
Right.
Charlotte Hamilton
Yeah, I think they are. There are some lower-cost EVs, a couple spring to mind, and they are, typically, heavily subsidized by the automaker themselves. They're sold at a lower profit margin by the automaker. The idea that a huge automaker can move 100% of their vehicles to EVs and that, say, a single mom just graduating from college can buy themselves an EV as a first vehicle at a competitive price compared to an internal combustion engine car, that is not on the market yet. And I don't think it can really be on the market with the existing chemistries that are in play at the moment.
David Roberts
Given existing chemistries in two big buckets for the cobalt magnesium nickel batteries, which are most, I think, of car batteries today, and then the LFP that we're talking about, the lithium, sort of iron batteries.
Charlotte Hamilton
Lithium iron phosphate. Yeah.
David Roberts
You don't think either of those can ever be cheap enough to sort of, sustain a sort of mass EV market?
Charlotte Hamilton
You, I think, hit the nail on the head in your introduction saying that they can't ever really be lower than the cost of the materials themselves. What in the industry, we would call the bill of materials cost. For nickel cobalt aluminum batteries, even if you have a low cobalt battery, so there are different flavors of nickel, cobalt, aluminum, there's different ratios, and we could throw out numbers and acronyms. But, even if you have a low cobalt battery, if you're using cobalt and nickel in the system, the best you can kind of do is around $100/kWh, maybe a little bit less than that, in the $90/kWh range.
And what that does is it translates into a high cost for the overall battery, where the battery ends up being a significant cost of the vehicle itself. And even at broader scale, you can build as many gigafactories as you want, you really can't produce that battery for any cheaper than the materials that went into it. Lithium is an interesting case. Lithium has increased in price recently, but the market is responding to that. The producers of lithium are actually expanding production at current existing mines and finding new and better ways to actually extract more lithium from brine and other things.
So lithium, I think, as a price, will stabilize, potentially even come down in price. But high purity nickel, which is what you need, and cobalt, are harder to address from a price perspective.
David Roberts
I think none of these minerals are truly rare. So you don't think, like, cobalt and nickel mining could eventually, I don't know, expand and find safer ways of doing things such that they bring their costs down substantially?
Charlotte Hamilton
Not substantially. I think that's the key word. The cobalt in the world is predominantly mined in the DRC in Africa and also in China. There is some production in Australia, and a few other places, but it is, of those materials that we're talking about, the most rare of them. It's been something that the world has been tilting at the windmills of electric cars here for a long time. And nickel cobalt aluminum has been known to be the high energy material for the cathode side of the battery for quite a long time. And if it was going to get any cheaper and drive that price much below, say, $90/kWh, it would have happened already.
The world keeps building more and more gigafactories, and more and more governments keep announcing mandates to move to 100% electric vehicles, and that price has not been dropping significantly. If anything, it's going in the other direction. So I think a real step change in the chemistry is what's needed. That, unfortunately, is a very difficult problem.
David Roberts
Well, before we get to that step change, the one other thing I wanted to touch on is the environmental justice angle. So this is, in a sense, kind of a parallel question. Right now, we know that these minerals are, especially in the Democratic Republic of Congo, you've got small owner mines where children are working. It's pretty horrible how these things are produced currently. So we have sort of the same question, like, is that something that could be overcome in the long term? Or how do you think about those, kind of the social justice angle?
Charlotte Hamilton
The social justice angle is a big reason I started the company to find lower-cost materials to improve the adoption of electric vehicles, and to reduce the dependence on these types of materials. But that's not what's going to drive adoption. Driving adoption requires performance and price. We can talk all about that in a second, but I don't want to kind of dodge the question that you asked. I think the social and kind of ethical issues are really fraught in the current market for these cobalt based batteries, in that the countries that didn't create the problem of global warming are the ones bearing the brunt of the environmental and social challenges of extracting the expensive material that gets put in very expensive automobiles, that are then very, very heavy, and driven by people who have a lot of money to buy an expensive electric automobile.
And it does seem ethically fraught. I think it's the nicest word I can say.
David Roberts
It sort of reprieves the power imbalance of climate itself. Right?
Charlotte Hamilton
Yeah. The West and the industrialized countries created this problem by burning hydrocarbons and by creating a culture in a society that requires us to commute to work in an individualized mode of transportation, because, that's a lot bigger issue for another podcast. But, we kind of created the problem. And one of the solutions is, okay, let's not burn as much gasoline when we drive around, let's use electric vehicles. Okay, well, the highest energy way to do that currently on the market, is to use a high cobalt battery. Now, you can reduce the amount of cobalt, but you're still taking an ethically fraught material from a non-industrialized country to contribute to solving a problem, being the first step in the path of solving a problem for industrialized countries. It is ethically challenging. And I'd like to get away from that. But my pause here is that the ethical challenge is not what's going to drive wide adoption. It's not good enough to have something that's just an ethically better material, or an environmentally better material. That's important, it's been a huge part of my career, but it's not what's really going to drive global adoption.
To get it adopted in the engineering rooms that are making the decisions about the materials, and the boardrooms that are making the decisions about how to move to electric vehicles, how to make these global companies profitable. What will drive adoption is something that is high energy, good power, good cycle life, and very, very inexpensive. That it's better ethically is a bonus. It's an important bonus.
David Roberts
You can imagine that having an effect at the margins. The whole social campaign against sweatshops and stuff like that. It does nudge things at the margin, but a better product will.
Charlotte Hamilton
Yeah, I mean, here we are talking about it, right? The world is interested in solving this problem. And I talk to folks all the time, they're like, "oh, you're the CEO of a battery materials company. I don't want to buy an electric car. It's got all this horrible chemicals in it". And I'm working on trying to replace that with a material that's much more abundant. And hopefully Conamix is a part of the solution that is sparked by these ethical questions. So I'm all for the ethical questions, I guess, to use your term, I'm a little bearish on whether or not these ethical questions are going to drive real global economic change, because do they attract attention? But not like a product that can do the same thing as a $90 product that only costs $50.
David Roberts
Right. In that case, let's then turn to sulfur. This is the material that you're working to use to replace the cobalt, and the nickel, and the magnesium in the batteries. So what is so special about sulfur?
Charlotte Hamilton
Yeah, it's been described as the holy grail of battery materials, on the cathode side. It's the highest energy material, that's the lowest cost, that can make a viable battery. People talk about lithium-air batteries sometimes on the cathode.
David Roberts
Right, yeah.
Charlotte Hamilton
Yeah, that's-that's why I just put in that "viable" word there.
David Roberts
It's not cheaper than air.
Charlotte Hamilton
It's not cheaper than air. There's an argument you can make a higher energy density battery with a lithium-air battery. The problem is that's not actually viable, because then you've got to carry around a huge pressurized tank of oxygen and run a compressed system, and all different kinds of things. Lithium-air battery is actually a lithium-oxygen battery, which is a little bit difficult to engineer. That's a bit of an understatement. But lithium-sulfur has been identified, as you said, for a long, long time. And that's because it holds a whole lot of energy. It does that in a slightly different way than the nickel cobalt aluminum batteries that currently dominate the market.
It does that through a chemical reaction rather than by holding it in a crystal structure. So, I often describe this in person using my hands, and now I'm on a podcast, so it's going to be a challenge here. But a lithium-ion battery is like a sandwich. One piece of bread is the anode, and the other piece of bread is the cathode. And going back and forth is the lithium between these two pieces of bread.
David Roberts
Right.
Charlotte Hamilton
So the lithium is what it stores the energy on. You got to store a lot of it on one side, and then you got to store a lot of it on the other.
And the way a nickel cobalt aluminum battery, in its cathode, it's going to hold that, it's going to create a crystal structure. And the lithium is going to go into that crystal structure, and it's going to come back out again. That allows you to hold a lot of lithium. It's also easier to make that system work because you're not actually doing as much chemistry on that cathode side of the battery. A sulfur battery does something more complicated than that. It actually does a chemical reaction. When the lithium hits the cathode, it's actually going to combine with the sulfur and create what are called polysulfides.
For the sake of kind of simplicity, I just say byproducts. But it creates these byproducts that can then run a muck in the battery system. They basically lose contact with that side of the battery, they interfere with the separators that are in between, they will react with your anode side on the other side of the battery. So controlling those polysulfides, those byproducts of that chemical reaction, become very important. That's what's actually very hard to do in order to make it work.
David Roberts
I'm going to ask some scientifically illiterate questions, if you don't mind.
Charlotte Hamilton
That's fine. I'll do my best.
David Roberts
I'm going to put my English degree to work on this.
Charlotte Hamilton
Sure, no problem.
David Roberts
So if I'm envisioning the cathode, the nickel cobalt aluminum, I sort of envision it like a sort of three dimensional cage. And the ions, the lithium ions, go into that cage, and they're sort of trapped in the cage, and then you can sort of nudge it and let the ions out of the cage.
Charlotte Hamilton
Yeah, that's not bad.
David Roberts
That seems simple enough. But when the lithium ion goes and reacts with the sulfur and becomes something else, that you're calling a byproduct, where are you getting the lithium back out, or how are you getting the lithium back out? Which is, of course, the whole.
Yeah, you basically reverse the reaction. You start with sulfur S 8, and you turn it into Li2S. But it actually goes through a series of steps in between where the sulfur part of that material is longer. So it goes to Li2S6, then Li2S4, eventually getting to Li2S. So that step where, each time it does that conversion, is storing that energy. So then when you reverse that, you move the other direction. Think of it like a stair step. You're going to go down the stairs, and then you're going to go back up the stairs.
Charlotte Hamilton
And that conversion stores a whole lot of energy. The theoretical capacity is really, really high. The problem is you can't access all of that sulfur to actually do that reaction without having these byproducts, the other stairs on the step, so to speak.
David Roberts
So I've got the reaction I care about: shortening the sulfur and then re-letting it go. And as that's happening, it's creating, effectively, waste byproducts?
Not really waste, they're the other pieces of that exchange. It's just, you store the energy or you release the energy, depending on which way you're going on those steps. You can think of it compared to your lattice structure. So your English degree description is actually really great. So the lattice itself doesn't change. You get an ion in, you get the ion back out again.
Charlotte Hamilton
Right. In a lithium-sulfur system, you get the ion in, it goes down a bunch of steps, you get the ion back out again. Then you got to go back up those steps, and maybe you don't convert all of it exactly right. And you're not really creating other things. It's these polysulfides that don't fully complete the conversion. And no matter what, it's going to happen, they're going to be polysulfides loose in the system.
David Roberts
So they don't get reabsorbed when you reverse the reaction. They don't get sort of reincorporated.
Charlotte Hamilton
Yeah, they do, but they don't get fully reincorporated. And it's done, you have to make it work in a liquid system, because you've actually got to have the liquid to make your lithium ions react with the sulfur. So people talk a lot about solid state batteries, and we can talk all about that if you want, but what Conamix does is actually works on a liquid sulfur system. So you've got liquid in that system, and.
David Roberts
Is that the electrolyte that we're talking about? The liquid electrolyte, and that's between the return to the sandwich. That's between the two pieces of bread.
Charlotte Hamilton
It's between the two pieces of bread. And on our side, what makes our system unique is that we very precisely control the amount of liquid that's in that system. So you can't have too much liquid, which is kind of what's often done in the academic literature. When people were first discovering lithium-sulfur batteries, they would put a whole lot of liquid in there so that they could get access to all that great stairstep conversion. And then they'd publish a result. I got all this, my theoretical capacity, I got really high, and it's great. But that doesn't make an automotive battery because you can't have a big, huge battery filled with liquid.
David Roberts
Right. Pretty heavy.
Charlotte Hamilton
Not in your Mercedes S Class, where you've got to fit a whole bunch of luggage in the back and things like that. You've got to have a smaller battery. It's called volumetric energy density has to be high enough.
David Roberts
So you're trying to get more conversion with less liquid. Does the composition of the liquid electrolyte? Is that a big piece of the puzzle here?
Charlotte Hamilton
Yeah, you're kind of serving me softballs here, scientifically, which I appreciate. But yeah, you got to really do a couple of things. So my sandwich analogy, I guess I'm running on a soggy piece of bread. This is what happens when I'm forced to do this on the radio. But you've got liquid all the way through the cathode system, and you got to very precisely control the porosity of that cathode system. So you only have a very small amount of electrolyte, so that you can have a high energy density battery. When you do that, with a kind of traditional approach to lithium-sulfur, you end up losing control of those polysulfides, the other stairs on the step, and you can't get enough access to the sulfur itself.
So what we do at Conamix is, we have additive materials. We have innovations on the electrolyte that allow it to work with a very tight electrolyte system. So we have proprietary, unique, protected electrolytes that we use and have developed lower cost. That's another way we drive the cost down. But we also have additives in what we call a sulfur stack. So we have a stack of materials that everything in that piece of bread is going to do more than one thing. So you've got to have conductive binders that hold that sulfur together. You've got to have an additive that also does a little own kind of sneaky electrochemistry.
So we have a combination of things that allow our cathode to actually perform in very low electrolyte numbers in order to actually get, for the first time, I think, really truly automotive level performance out of a lithium-sulfur cathode.
David Roberts
I think I've read that one of, that the big challenge with lithium-sulfur is that they have really high energy density, et cetera, et cetera, but they fall apart. They literally physically decompose.
Charlotte Hamilton
Yeah.
David Roberts
What is that referring to?
Charlotte Hamilton
It's referring to those polysulfides, those other steps on the stairs. My stair step analogy is falling apart a little bit, but the other.
David Roberts
You got a sandwich on the stairs.
Charlotte Hamilton
We got a sandwich on the stairs. And some of those stairs, they don't stay where they're supposed to. They're wayward stairs. All the scientists in the company are going to listen to this and make a meme about the CEO.
David Roberts
So a big part of the engineering challenge here is controlling those byproducts so that they don't wreak havoc on the rest of them.
Charlotte Hamilton
Yes. So we have specific binders that hold everything together that also hold those polysulfides in the right place. So they kind of pin the polysulfides where they're supposed to be. We also have additives that allow the lithium to react in a very tight liquid environment. So you have to have materials that accomplish that. And then some of those materials can do more than just kind of catalyze that reaction. They can also have their own electrochemical storage benefit. So we have a suite of materials that we originally started developing based on that technology from Cornell, originally, Stanford, Berkeley, and then Waterloo University in Canada, we work with Linda Nazar up there, who's great. And all of these different technologies allow us to do, in a very small space, very high energy, while also preventing the cycle life loss. So that's what you're talking about, about them kind of falling apart. They work really great first four or five times you use them, but if you don't, you can't just drive your car five times. It's got to work hundreds of times. That is the challenge.
David Roberts
So then, if I'm looking at the, because as I mentioned in the intro, this is not a secret that sulfur has these qualities. And there have been people, I feel like I've sort of been reading references to the kind of pursuit of sulfur batteries for many, many years. So if you were describing what sets your system apart from these previous efforts, it's not one thing. It's just all these tweaks in your materials. It's mostly a materials science kind of thing.
Charlotte Hamilton
I think it's a material science approach. We often call it a series of band-aids. We're proud to say we, I think, know more about breaking a lithium-sulfur battery than most folks. We drive them to very tight performance levels. We're a commercial development facility. So the data scientist keeps writing this number. We've got nine and a half billion data points at this point. We've been cycling 300 plus batteries, 24 hours a day, for years and years. We beat the heck out of these batteries. And when you do that, you realize why they're not hitting the energy density that you need.
You realize why they're not hitting the cycle life that you need. Every time you run into a problem, you fix it. And that is a material science innovation that gets you closer and closer to that holy grail battery. Now, I'm very quick to say that we are not there yet. I think Conamix, we make the very best lithium-sulfur batteries in the world. I think we're the clear technical leaders in the space, and our technology and our technical partners have kind of backed that up. However, it is not good enough yet for an automobile. And we can go into kind of exactly why, but it comes to that other side of the battery. On the lithium metal side of the battery.
David Roberts
Why is that? On what performance metric is it currently falling short?
Charlotte Hamilton
Yeah, we fall short on cycle life.
David Roberts
So the falling apart thing is still the main problem.
Charlotte Hamilton
Yeah, but if you'll forgive the simplicity and to the scientific team at Conamix, who may or may not find this podcast later, I apologize. It falls apart in different ways. So very early in our development, we were actually doing a job where we were trapping those polysulfides really well, and we might get good cycle life, but we'd get very low energy. Because we didn't have access to that sulfur. Basically, if you trap those things too well, you don't have good energy because you can't access them anymore. And that, I think, comes to a point that you made earlier, about other approaches and the battery world kind of being filled with breathless claims from everybody in their sister's battery company. And it's a complex system, so you end up making something that works well in one way, but not in another. So we have to break them. We have to make them get the right volumetric, energy density. How small can you make the battery? You've got to get the right gravametric energy density. How light can you make the battery? And still you got to be able to charge it fast enough, and you've got to get cycle life.
So right now, the cycle life is a challenge for us. We're working on integrating our technology against multiple different anode technologies. And as we make those innovations, as we integrate with some of our partners, we know that our cathode material will do what it needs to do. We have to solve the integration challenge between our cathode material and existing and new technologies on the anode side of the battery.
David Roberts
Got it. So on the anode side, and I don't want to talk about engineering the whole time, although I could, I find it all fascinating. On the anode side, this is what you need to perfect to get your cycle life up. So you're currently aiming for, or already using lithium metal. Just for listeners, I guess the listeners who read my battery series will recognize this too, but on the anode also, you can either have one of these kind of lattice structures where the ions embed, which are graphite, usually, right? And relatively speaking, bulky. And the idea that you're going for, is just to use a lithium metal plate, and instead of the ions getting trapped in some lattice structure, they just attach. They attach to the plate. So there's less material, you lose some weight, you, I assume, gain other things. So briefly, tell us what's so great about a lithium metal anode and how does it work better?
Charlotte Hamilton
Well, I think just like lithium-sulfur is really the end game material on the cathode side. Lithium metal is very much the end game material on the anode side. It's because it has the highest voltage difference from sulfur, so you're going to get the most power out of it. And it's ultimately, just like you said, it can be the most dense material and it doesn't have anything else there. So you're not paying for graphite, although graphite is not particularly expensive, but you're not paying for 3D structured graphite, which some people do to improve energy density. You're not paying for 3D structured silicon, which is something that lots of folks have been working on, holds more than graphite.
But what we started out to do when we actually started, the company started, Conamix started, we were working on silicon anodes. So we actually know quite a lot about making silicon nanowires. But we switched to sulfur because we thought that, okay, well, no one's really working in a super focused industrialized way on solving this problem. On the cathode side. Let's work on this, and by the time we're done, by the time we've made this soggy bread work the way we want it to work, again, forgive me scientifically. But by the time we've made that work at the energy densities that we need, at the power that we need, the world will have solved the lithium metal problem on the other side of the battery.
David Roberts
Right. Because it's not just sold for batteries that would benefit from lithium metal anodes. I mean, they would be awesome for lots of different reasons.
Charlotte Hamilton
Yeah. So we, from the start, have been using, like most folks who work in the academic literature and other practitioners, I believe, in the field, we start in the development side. We use lithium metal foil on one side of a battery. So we can do that. But just like anyone else that just uses bare lithium, you've got a problem in there in a couple of different ways. So just using bare lithium is not going to create a good cycle life battery for two primary reasons. The first is that you'll form what are called dendrites.
David Roberts
Yeah.
Charlotte Hamilton
So you'll form these very small, they're very kind of beautiful and cross section, they look like little trees. It'll grow up. It's basically lithium will deposit and form this treelike structure from one side of the battery to the other. And you don't want to do that because it's going to short the battery. If you have enough battery short, you'll start a fire, and you definitely don't want to do that. So you have to protect the lithium metal in a way that prevents these dendrites from growing. That's been a challenge for battery researchers, for a long, long time, and there are several startups that work on it.
Several hundred million dollars plus has been invested in solving that problem. Folks have been working on it on the academic side for quite a long time. Our approach, we said in 2016, well, we'll just work on the cathode, and by the time we're done, we'll just merge onto this highway of lithium metal protection, and we'll drive off into the sunset with the perfect battery. Didn't quite work that way, because the lithium metal side, like all material science, is challenging, and it hasn't quite worked to the point where I can just go to "Anodes R Us" and buy myself a great protected lithium metal anode.
David Roberts
Are you now in the game also of doing material science on lithium metal anodes, or are you researching that alongside all the others who are researching it?
Charlotte Hamilton
By necessity, we are. Specifically about making it work with a lithium-sulfur system, and we have been for a number of years. So the other piece, and I spoke publicly about this at a conference I did about this time last year at University of Binghamton, actually. I did a technical talk about this failure mode, so folks are interested. Our website, conamix.com, I think you can still find me talking about science there. The other failure mode is the consumption of that electrolyte at the anodes itself. So the electrolyte, that liquid that makes the whole thing work, if you don't protect the anode in a very specific way, it'll react with the lithium metal anode. You'll dry up, the battery won't work anymore. So that's the second primary failure mode for a lithium metal anode in a sulfur system. You've got to prevent the dendrites, and you've got to prevent the consumption of electrolyte. To do that, you've got to protect it. So, yes, by necessity, we've been working on solving that problem as well and making some really interesting advances, along with a lot of others.
David Roberts
I know that science does not unfold in a predictable way. Would that it did. But are you close enough now that you feel like you can predict when you're going to enter the market?
Charlotte Hamilton
Great question. And no, the answer is no, I can't predict exactly when we'll enter the market. Material science, this kind of innovation, it's more something that you can plan that you will be able to solve the problem. It's very difficult to say when you'll solve the problem.
David Roberts
Yeah, that was my other question. Are you close enough now that you are confident that it is a solvable problem?
Charlotte Hamilton
It is absolutely a solvable problem. We have alternative systems that work that allow us to test much higher cycle life, allow us to develop even cheaper materials to drive that cost even lower, develop some nice patents around those, which is always great. And we've been making innovations with multiple partners. We have probably three that we're very actively working with on the anode side, of these systems, along with our own team here, working on this. So we have been making some very interesting innovations that point us in the direction of this is a solvable problem. Am I going to solve it on the 7th March of next year?
Well, I can say for sure, Charlotte Hamilton, I'm not going to solve it. It may be a member of our team. It could be Amber, or Nick, or Dice, or somebody else on our team that assembles a battery, or comes up with a new way to protect the anode in a lithium-sulfur system. It could be one of our partners that sends us something that they took some direction from us and some direction from themselves, and they said, "okay, we can protect it in this way", and they ship us something and, eureka, that works for us.
David Roberts
But you are 100% confident that a EV quality lithium-sulfur battery is on the horizon? Is doable, is going to happen?
Charlotte Hamilton
Yes. And that's something I hesitated to say, because 100% confidence is a heck of a number.
David Roberts
Not something you say a lot in science.
Charlotte Hamilton
Yeah, I guess that's why I'm the CEO, right? I have to be the "Chief Optimism Officer" for the company. I would say to anyone that was interested in working with us or investing in us that it will happen. Lithium-sulfur batteries will dominate the market because of the cost advantages and the energy density advantages. I can make something now that meets the energy density performance metrics in all regards on the cathode side. I cannot make it integrated in a complete system. It will work in an automobile eventually, and I think that solution will come through Conamix and the technology that our team has developed over the last several years.
But is it 100% certain? Oh, wow.
David Roberts
Nothing is.
Charlotte Hamilton
It's 100% certain that it will eventually work in an automobile. It's just when it will actually work there. If the team came and told me, "Charlotte, there's a thermodynamic problem, this is never going to work. We're disobeying the laws of physics. It's just not going to work. We've run into a problem that can't be solved without some extremely expensive material". My door is open and nobody told me that. So I do not think there are any showstoppers for lithium-sulfur, but it is a long road. I think next year we should be able to have a really nice announcement about integrated performance that can have additional third party testing.
We should be able to hopefully announce some of these partnerships that we've been working on. The year after that, I hope that we can announce a partnership with a major automaker that wants to work with us to test these materials and test these cells that we're making. We work with some of the largest automakers in the world now. In terms of setting our targets.
David Roberts
That raises the question I've been actually, it's been on my mind this whole time I've been reading about this. Another thing you often hear from lithium battery experts, or that I heard a lot when I was researching it, is that even a much better chemistry is not going to be able to basically catch up with existing chemistries because of the extent of the build out of production. Like the infrastructure for producing the current form of batteries is so elaborate now and has come down and cost so much that you're basically chasing a receding target, unless you can slip stream your product into those existing factories and production facilities.
So, just to clarify, you don't need to build new bespoke factories to build these things, do you?
Charlotte Hamilton
No, we don't. It's been in our DNA from the beginning that everything we do needs to be fully scalable, easy to make and drop-in ready to existing methods of manufacture. We're not doing anything that can't be sold as a powder and slurry-coated onto a cathode in the world's largest battery gigafactories.
David Roberts
So once these things are ready to go, like existing gigafactories could start cranking them out.
Charlotte Hamilton
That's a simplification for radio, but there's teams of engineers can make that happen over a length of time. But yes, you can use existing facilities. You don't have to do any complex vapor deposition under pressure. You don't have to make them one by one in a chip fab at high temperature. You can take a barrel of cathode material, slurry-coat it onto a line and make it roll-to-roll in existing battery manufacturing methods. If it wasn't that way, we wouldn't have been moving forward with this technology.
David Roberts
When you set out to make an electric car battery, you are in a sense playing the battery game at the highest level of difficulty. You've put yourself on hard mode in this game. Why not start by making batteries for applications that don't have these insanely tight performance parameters, where maybe you don't have to worry about cycle life as much, or you don't have to worry about energy density as much. There's a lot of other battery chemistries out there and they all have their own sort of niches. Why not start with a different niche and try to kind of grow up and out from there?
Charlotte Hamilton
Yeah, well, it's a good question. And in 2016, my entire board of directors was asking me "Should we be a drone battery company?"
David Roberts
Yeah.
Charlotte Hamilton
Should we make batteries for e-bikes?
David Roberts
Yeah.
Charlotte Hamilton
The thing is, and lithium-sulfur has some really pretty nice advantages for drones, actually, because you could make a very light battery. And that market is nice. It's just the largest market in the world for batteries is electric vehicles. It's over a trillion dollars at full electrification of the world's independent transportation like that. And it's not just a market size piece. I think those niche markets, your e-bikes or your drones, the performance of the existing systems was enough for those systems currently. I could get into some numbers about watt hours per kilogram.
But basically you can put some silicon in your cathode, you can push those batteries and you can make a high enough energy density battery to make a drone using existing cobalt and nickel systems. And they're not particularly price sensitive.
David Roberts
Right.
Charlotte Hamilton
Also, likewise, like the batteries that go into your $1,000 iPhone, that's not really a price sensitive market. Particularly, you want high performance in a very small space. So I think chasing those, had I made that switch in 2016, and many, many battery companies did, that was a point one of my board members made it's like, well, everybody has a drone battery start up already.
And I kept my eye on the prize of the largest market because it's got the biggest advantage for lithium-sulfur's particular use case. So what I mean by that is that the price matters.
David Roberts
Right.
Charlotte Hamilton
Volume matters. We looked at the system of the world's vehicle electrification and we said, "we're going to have a problem with cobalt." And we do currently have a problem with cobalt. We're not going to be able to get below kind of this asymptotic price of $90 or so a kilowatt hour for existing cobalt batteries because the materials themselves cost too much. So if you have a lower-cost material, and I'm talking like quite a bit lower, then you have the market pull into the largest market in the world for batteries.
So it's a classic startup approach. I'm going to aim big and keep the main thing, the main thing, we stay focused as much as we could on lithium-ion for automobiles. And I think it's the right strategy. It's been a long road. I think we would have distracted ourselves by going after some of those other markets.
David Roberts
Do you think if you get this working for cars, on an appreciable scale, that batteries for e-bikes and drones will fall out of that? Do you think sulfur will make its way down to those other applications?
Charlotte Hamilton
It might make its way up in the case of drones, I suppose. Yeah, absolutely. If you can get ubiquitous batteries for electric vehicles, where truly 100% of electric vehicles all across the price range, not just these halo products, all across the price range can be electric, you're going to be able to have increased car-to-grid storage where batteries are actually serving to do load balancing. Car batteries are doing software load balanced between households to do kind of peak shaving and grid storage. You'll get the recycling of these batteries and they'll be able to be down cycled into second uses, once they're not good enough for the automobiles, or the automobile falls apart around the battery. You could absolutely see the chemistry.
Maybe there'll be a spin out company and my daughter will run it to make high energy lithium-sulfur Conamix batteries for drones. I'd love to do that. But the existing technologies were good enough. The price advantage that I brought to the table, coupled with the length of the runway to prove that it works, just didn't make it a viable business choice for Conamix.
David Roberts
Right. So the electric vehicle market is kind of like, if you're a singer, you go to New York. If you can make it here, you're you can make it anywhere, right?
Charlotte Hamilton
Yeah, it's hard. It's the very hardest market, I think. And the requirements are extremely strict. And we've talked to the largest automakers in the world about what their requirements are, and they're tracking our progress. And I think if I showed them really great third party test results with a partner working on the other side of the battery, or a partner manufacturing them with our Conamix technology, I would absolutely have the ear of the automakers that are necessary to get this pulled into the market.
David Roberts
I'm about to do a pod on battery recycling, and this is another huge, looming issue.
Charlotte Hamilton
Sure.
David Roberts
Does lithium-sulfur give you advantages on the end of life side?
Charlotte Hamilton
No, it's not particularly better for recycling. The materials themselves are not as valuable. So some of the market drive to recycle is not there as much because you're not going to get cobalt out of the system, because there's no cobalt in the system.
David Roberts
Right.
Charlotte Hamilton
So, end of life use, you'll have lithium in the system, you'll have sulfur. There are some other metals involved. There will be value, and I think an industry will be born and take shape in the recycling of batteries. If you take an entire world and you move it from internal combustion engines to chemical storage, it's very similar to the switch from whale oil to rock oil. It's a dramatic, huge shift in a global industry. Entire industries will be born as subsets of that. There's no particular barrier to recycling a lithium-sulfur cell, but I'm focusing on the front end of the equation.
Let's get a lower-cost battery widely adopted, and I'm excited to see what happens with grid storage software, or broader recycling, or second-use batteries. It's an exciting time to be in the battery business,.
David Roberts
Truly. Just a couple of final questions. Do you think that these, there's been a lot of talk about short duration versus long duration batteries and the extent to which long duration batteries will be required in the grid, and the extent to which lithium-ion batteries will ever be able to, sort of, inch their way up and provide longer duration storage. Is there any reason to think sulfur batteries will be particularly good in that market? Will we get cheap enough that we can use these for long duration storage? Or have you thought about that?
Charlotte Hamilton
Yeah, no, we think about it a lot. Around the same time that people were asking me if I wanted to be a drone company, they were asking if I wanted to be a good mortgage company. It is an opportunity.
David Roberts
Much smaller market, obviously.
Charlotte Hamilton
Yeah. Well, huge market, though. I mean, as an entrepreneur. Yeah, you love a market like that. It's just, again, the use case for lithium-sulfur. Right? I said earlier, cycle life is where we're not currently.
David Roberts
Right.
Charlotte Hamilton
Grid storage is all about cost and cycle life. So if you can make that electrolyte even cheaper, if you can drive the price of that battery down even more, yeah, I think there is room for some of Conamix's technology to be useful in grid storage, but I think it's a second or a third market, maybe one of my other kids.
David Roberts
You're going to have an empire, a battery empire.
Charlotte Hamilton
Not really the way capitalism works, but it's not a dynasty here. We're owned by the shareholders of the company. But I've got pictures of my kids here next to me on my desk. But yeah, grid storage. I've actually made the case that what I mentioned earlier is actually a really great idea about what's called vehicle-to-grid storage. Yeah, you probably researched this, but I think if I'm successful with Conamix and the team here makes the innovations that we need to make, we can be part of that future where 100% of the cars are truly electric.
If you have 100% of the cars in the US are electric, you can hook those all up with software and you've got grid storage right there.
David Roberts
It is the world's largest distributed battery.
Charlotte Hamilton
Yeah.
David Roberts
I'm not sure people understand that the amount of batteries on all the cars put together is just going to dwarf anything you could do with freestanding batteries.
Charlotte Hamilton
It's a huge amount of batteries. And then what about when they're not good enough for the cars anymore? Whether they're making fault for batteries or some other technology. Eventually the car is going to rust out from under the battery or the battery is just not going to be good enough for the car anymore. So you've got, well, a whole bunch of energy storage. Maybe you've got 60% of the energy storage left in that battery still. There is value in that. And so, if you're living in a world where second-use batteries are widely available, then I think that will eventually dominate the grid storage market as well.
Again, I think automotive, because it is the elephant in the room, there are just so many batteries involved with cars that I think it makes sense to focus on that. And if you're doing a heavy lift on a new material, you might as well aim big.
David Roberts
Yeah, because I've heard the argument made several times and I find it pretty convincing, that whatever you end up using for automotive batteries is going to enjoy such scale, that it's going to get so cheap that it's going to end up being used for all the other stuff. Even if it's not like the ideal chemistry for other stuff, it's just going to end up so cheap, you're going to end up using sort of car batteries for almost everything.
Charlotte Hamilton
Yeah, and I think that's true. But there is a floor to that cost based on the material cost that goes into that battery. Cobalt, high-purity nickel, lithium itself, there is a floor to that cost. So there's room in a new world for lots of different battery chemistries. There's room for lots of different ways to store energy. But for automobiles, for something that makes an electric vehicle broadly adaptable, lithium-sulfur, I think, really is the end game on the battery side. It's just not an easy road to get to that end game.
David Roberts
Right. So final question, then, about that end game. And this requires, I guess, a little sci-fi looking into the future speculation, but do you think sulfur is the end of the line, or are there theoretical future advances in chemistry that could be another step change forward? And I'm not even scientifically literate enough to speculate what those might be, but do you see sulfur as sort of like the true end of the line, especially in terms of vehicles?
Charlotte Hamilton
Yeah, I think in terms of vehicles, if you're using chemical energy storage.
David Roberts
Right.
Charlotte Hamilton
If you're using a lithium-ion, sulfur is the end of the line on the cathode side. And I think lithium metal is the end of the line on the anode side, and lithium-ion is the end of the line on chemical energy storage, meaning batteries. There are some very interesting technologies, of course, in other methods to store energy, and there's a whole revolution going on in the production of hydrogen and all kinds of different materials as the world moves away from internal combustion.
It's a great problem to have. You've got a whole bunch of cool technologies, right? Batteries are really great. They store a ton of energy, and you can recharge them. And the vehicle infrastructure already exists, and the battery manufacturing already exists, you know? There's dozens of gigafactories all around the world now. And, yeah, the work of Conamix is difficult. The prize is huge, and the walls between us and the prize are difficult. But we've got our best people on it, as we say, and we're excited about the future. Partners that want to work with us, others that believe in material science approaches to really make these step changes. We're interested to hear from them.
David Roberts
Okay. Well, I've taken so much of your time, I guess I just wanted to conclude by saying I know you came out as a trans woman last year, and I didn't want to focus on that because the battery stuff, I'm sure you agree that the battery stuff is more interesting. But it's a nasty political climate out there right now. Just a nasty climate in general out there right now. So I guess I just wanted to say, and I know I speak for my subscribers too, that we are glad you exist, and we're glad you are who you are, and we're glad you took all this time to share with us. So thank you.
Charlotte Hamilton
Yeah, that's very nice of you to say. I appreciate the support from you and your listeners. Being transgender is not something I hide from, but, yeah, I'm more excited to talk about battery chemistry.
David Roberts
Soggy sandwiches.
Charlotte Hamilton
Soggy sandwiches. And I'm more concerned about the scientists on the team hearing this podcast. But that's fine, maybe I won't tell them.
David Roberts
Yes, forgive us, scientists. We're trying to talk in language I can understand, which means you have to go down several levels.
Charlotte Hamilton
Yeah, my job is to explain this technology, is to find the partners and hire the team that can solve these problems. And being a particular kind of diversity helps me in the world, attract a diverse workforce, and I am who I am like anyone else in the world. So I really appreciate the support, and thanks for your time today.
David Roberts
Thank you for listening to the Volts podcast. It is ad-free, powered entirely by listeners like you. If you value conversations like this, please consider becoming a paid Volts subscriber at volts.wtf. Yes, that's volts.wtf, so that I can continue doing this work. Thank you so much, and I'll see you next time.
Working on the cheapest possible lithium-ion battery