Will battery recyclers have enough used batteries to sustainably feed their operations?
The lithium-ion battery business is taking off, and the battery recycling business is close behind. Financiers are pouring over a billion dollars into recycling companies like Redwood Materials, Ascend Elements, and Li-Cycle. But success depends on a steady supply of used batteries, and with batteries lasting longer than expected — and the battery market still in its infancy — there just aren’t enough dying batteries to go around.
As a result, a significant portion of recyclers’ feedstock is coming from manufacturer scrap, i.e. the waste that companies like SK On and Panasonic don’t turn into cells at the factory. But these battery makers are incentivized to minimize waste, which raises big questions about whether recyclers will be able to get enough used batteries to sustainably feed their operations.
So which technologies and business models will succeed in this chapter of the battery industry?
In this episode, Shayle talks to Dan Steingart, chair of the earth and environmental engineering department at Columbia University. (Steingart’s lab gets funding from battery manufacturer Northvolt.) Shayle and Dan cover topics like:
Announcer: Latitude Media, podcast at the frontier of climate technology.
Shayle Kann: I'm Shayle Kann, and this is Catalyst.
Dan Steingart: All of these companies, by the way, are starting with scrap because there's just not enough. And what I mean that's scrap coming off of manufacturing lines for batteries. There's not enough batteries entering the recycling ecosystem at end of life yet we hope scrap rates go down because they're wasteful. But we also hope batteries last a long time, so there's going to be a bit of a lean period before they can be fully engaged in recycling.
Shayle Kann: Give us your poor, your degraded, your end-of-life batteries yearning to be recycled.
I'm Shayle Kann. I invest in revolutionary climate technologies at Energy Impact Partners. Welcome. All right, so a few weeks ago in one of my World Decarbonization Tour episodes that I did with Nat Bullard, we briefly discussed battery recycling and specifically talked about how it appears there's going to be a pretty huge oversupply of recycling capacity relative to the number of recyclable batteries in coming years. In other words, not a great time to be a battery recycling company and especially challenging to be a subscale one, but a bunch of you reached out to point out something correct, which is that not all battery recycling capacity is equal and some of that capacity might have more real legs than others. And fair enough, I realized actually we've never really talked about the technology of battery recycling here, so let's rectify that.
For this one I brought on Dr. Dan Steingart. Dan is the chair of the Earth Environmental Engineering Department at Columbia, and as you'll hear, has thought a lot about battery recycling from a process engineering standpoint as well as from a business standpoint. Here's Dan.
Dan, welcome.
Dan Steingart: Thanks for having me.
Shayle Kann: Let's talk about battery recycling, starting with the basics. So there's an end of life battery, whatever kind of battery, it's an EV battery, it's a battery from some tool, whatever it is. Could you just walk us through the steps in the process to recycle its components?
Dan Steingart: Sure thing. There's already differentiation when the cell is delivered to wherever it's going to be recycled. The first thing the recycler has to ask itself is, "Does it need to discharge the cell or not?" When cells come in, they may be charged, they may be discharged, they're likely somewhere in between zero and 100. Importantly, there's still flammable components in some degree of energization inside of it. A big concern that we've seen in my lab is what's called dead lithium, or I like to call it zombie lithium because it comes back and bites you in moments that you didn't expect. And this is lithium metal that's deposited inappropriately in a lithium ion battery. And what that means is in the lithium ion battery, there's not supposed to be any lithium metal.
As cells degrade, as cells get older, particularly as we ask them to charge faster, there's more of this stuff. And so recyclers have to contend with what the latent energy is or the remaining active chemical energy that's in the cell. Ideally, they would just like to chew up the cell and turn it into what we call a black mass. So let's assume that they, one way or the other, either discharge the cell or allow for a little bit of a combustion in their consumption process and they will typically just take the cells and shred them completely.
Shayle Kann: And I guess before we get... You're starting at the sort of like what do you do with the cell, but there's a step before the cell, right? There's a disassembly component as well.
Dan Steingart: Yeah, no, excellent point. Cells come in typically welded packs and each pack has its own design, and so the recycler has to have an understanding of where the cells sit, how the cells sit in the pack, and a means to un-weld or mechanically remove the cells from that pack without breaking or reducing the integrity of the cell itself. In this mechanical disassembly process, you don't want to have something that eats into the cell itself. And so the way to think about this is most of your listeners probably know that a Tesla has something like 8,000 plus cells inside of it. When that pack would be disassembled, you don't want to break the integrity of the individual unit as you take it apart. And so these cells have to be taken out and separated from the rest of the pack and module assembly. The degree to which these cells are then checked and sorted for remaining life I think is questionable.
There is some interest, with good intention, to have a second life for some of these cells. Maybe some of them are still good, maybe some of them are still useful. It's typically pretty difficult to justify the cost of grading these cells and estimating their second life. We do a fair bit of that in my lab, and I have to say to date, I think that it's probably not a bankable effort yet. I'm not sure that even if we had perfect metrology to understand the second life of cells, we would actually want to put them into that application. So once the cells are removed from the pack, they're then put directly into this digestion process.
Shayle Kann: So they're put into this digestion process. How, then, do you get from there to extracting the valuable components of the cell?
Dan Steingart: There's two processes and they're identical to the ancestor processes in mining in the same way we would act on an ore, and so at a very high level, the very cheap but very dirty method is called pyrometallurgy where you just start to burn things and let whatever nasty gasses evolve that will evolve and typically in 2024, so we have to use fossil fuels to heat the pyrometallurgical process, although there could be some exothermic combinations from just heating the cell itself. But the off-gassing is so nasty that in the United States we basically don't want to do any pyrometallurgy anymore.
It's not to say that there isn't a lot of pyrometallurgy, there's plenty in China and India and other parts of the world, but basically you heat the cell components up. It's again a homogenized mass. This is called a black mass, and then you go into a process by which you begin to separate the components out and it's identical to the processes one would use in mining, you would use physical separation and flotation methods as much as possible as those are cheapest, and then where you need to put in alloys and fluxes to get out specific chemicals, you would do this in a molten state.
Shayle Kann: Okay, so that's a pyrometallurgical process. And so yeah, in virgin ore mining you do concentration and flotation, you get an ore concentrate and then you smelt it, which is the burned fossil fuels, super high degree temperature, lots of off gasses, lots of problems. We don't really build any new smelters in the United States, as you said, across the board, including for battery recycling, but they do in some other parts of the world, and so that's how a lot of ore ultimately gets processed. You said that's the cheap but dirty version. My understanding is it may be overall cheap, but it's pretty capital intensive like smelters concentration and smelting are both really high CapEx. We're the billions of dollars of CapEx per unit.
Dan Steingart: They are, but they give you a guaranteed result and it is generally cheaper than the cousin that I like more, which is hydrometallurgy in my experience, or at least in my conversations with Chinese recyclers in China where there are fewer local restrictions on having pyro in certain provinces. Pyro is, as I understand it now, the majority of recycling methods.
Shayle Kann: Okay, let's talk about the other then, which is hydrometallurgy.
Dan Steingart: So in hydrometallurgy, and I'm a big fan of hydrometallurgy, rather than take things to high temperature, you basically take the black mass and digest it in a series of acids and what acid you digest the black mass in is a bit different from traditional mining. In mining it's typically sulfuric acid. Every once in a while it's hydrochloric acid. And in mining this is the most environmentally damaging part of the process because you build up these massive piles and you soak them in sulfuric acid for months at a time. The residence time, for example of a copper leach pile is on the order of three months. The capital intensity, to your point, Shayle, of doing that for batteries would be way high. And so what most recyclers use now for hydro-met digestion is a combination of sulfuric acid with hydrogen peroxide for a bit of H2O2, and this is really nasty stuff.
It's called piranha because it eats through anything and it reduces the residence time from about 90 days to just a few hours. But handling the piranha is a significant challenge, but it allows the process to be far more portable than it would be in a standard hydrometallurgical process. So rather than need to have this big leach pit that takes up huge amount of space and creates local environmental contamination, you can do it in a closed reactor vessel in a warehouse and no one outside would be the wiser assuming that the waste is handled properly. After this point, you either do a series of pH swings where you understand what metals are in your mix and swing the pH up. So we're starting with an acid, so at a very low pH, we add sodium hydroxide to this carefully so that we precipitate out certain metals in a certain order.
Every metal has a different point at which it wants to precipitate as we swing up and we can take advantage of this process to get it out. This is imperfect, this is the cheapest way of doing things, but this is imperfect as metals. Speciate means they mix in solution in different quantities. A process that in the minority I think in the field, but I think is something that needs further work. Because I think it's a beautiful process is solvent extraction where organic ligands are designed to specifically target certain metals and you can create complex circuits that target certain metals in a certain order to extract concentrate and then refine sulfate solutions that can then be valorized later on. SAX processes are typically used in copper extraction. In the mining industry, that's where most of them were developed, but now there's a lot of value in using them in nickel and gold and anything basically more valuable than copper on the London Metals Exchange for metals like zinc precipitation is still dominant, but there's a lot of academic work trying to make solvent extraction work for that as well.
What's nice about solvent extraction and why I'm a big fan of it, and you can do this in precipitation as well, so what you're left with is a metal sulfate. And this is exactly what battery companies want for recreating in particular cathode material. So you to get to a sulfate anyway when you're making the chemical through pyro. And so I think it's disadvantaged there. In the United States and most western countries, the recycling efforts you see are rooted in a hydrometallurgical stance. Different companies process it in different ways. In general, to your earlier point, to reduce CapEx, you want to use as much of a precipitation process in 2024 as possible because you just need fewer reactors and fewer reagents and less complex loops. In my experience though, and I invite any of your listeners to come at me with knives, I think that running steady state solvent extraction has much lower OpEx.
I've been to a few copper plants and 20 years ago there was a lot of maintenance and a lot of folks walking up and down the miles and miles of solvent extraction lines or extraction loops, making sure they were working. I visited a mine in Morenci, Arizona a couple of years ago, same one I'd visited 20 years ago, and there was almost nobody having to walk up and down the process. It just ran by itself with maybe daily checks to make sure that pHs were in the right place. So very, very long story here, but I think that within the world of hydrometallurgy, there is a lot of blue ocean for solvent extraction.
Shayle Kann: I've spent a bunch of time on copper as well, and similarly solvent extraction now is, I think of it as mostly a solved problem. It's like it works really well and that's part of what has made the hydrometallurgical path for copper refining more attractive over time. So we have these two high level paths, pyro and hydrometallurgy, trade-offs amongst them and some nuances within each category. Let's just talk about the landscape that exists today. Who are the big battery recyclers and where are they and which path are they taking?
Dan Steingart: Right, so I'm going to focus on three that I have some familiarity with because I've looked at their flow sheets and their patents. There are many out there and many I don't know. So I just want to be clear to your listeners that it's a pretty competitive space. In China, there's probably 50. 50 to 100, easy, at different points in the tech stack. But the three we can talk about today because I think they represent three interesting shades of hydrometallurgy upstream and downstream are Redwood Materials, Ascend Elements and Li-Cycle. They've all capitalized to significant extents in the United States. I would say that Redwood, in both its design and its aspirations, wants to be the mind of the future. They really see that the main value of recycling is not the process but the input material. You can control the value of the output, the downstream material as much as you'd like, but you're going to have massive margin pressure from all the battery suppliers who are facing massive margin pressure from their OEMs.
I think that Redwood is taking an approach where it is trying to consolidate as much of the recycled material at a commodity level as possible. And so, as I understand it, starting with... All of these companies, by the way, are starting with scrap. There's just not enough. And what I mean that's scrap coming off of manufacturing lines for batteries. There's not enough batteries entering the recycling ecosystem at end of life yet. So these problems of digestion that we started the conversation with are problems that will be at scale in the future. Currently, all three of these companies are living off of gigafactory scrap, which is exceptionally high over 20%, as I understand it. I worry about the business case here because the gigafactories have every incentive in the world to minimize this amount of scrap. And so at the same time, we don't want batteries to die, so every recycler is going to have a lean period as scrap rates go down.
We hope scrap rates go down because they're wasteful, but we also hope batteries last a long time, so there's going to be a bit of a lean period before they can be fully engaged in recycling. I think Redwood is establishing itself as the place where batteries go to die so they can be reprocessed. They are using a fairly traditional hydromet stack as far as I can tell. On the opposite end, in terms of innovating a well-understood process, Ascend Elements has something they call Hydro-to-Cathode. That's a process in which they cleverly don't use solvent extraction because they say, "Hey, most of what the battery looks like, the material that we need to have looks a lot like what the battery coming in has."
So why go through this process of separating out all of the metals once we've cleaned things out. In particular, these cathodes have nickel, manganese, and cobalt. The ratio of nickel to manganese to cobalt is changing, and so a little bit of nickel makeup or a lot of nickel makeup has to be added, but a sense sees a pathway where they're focusing downstream and produces actual precursor for cathode and then eventually cathode material because the value of cathode materials is the highest of it all.
Shayle Kann: For what it's worth, I believe Redwood is also going that far downstream, but you're saying through a different process?
Dan Steingart: I think so. I don't know. Ascend has IP around this direct Hydro-to-Cathode process. And to be clear, yes, it's my understanding that Redwood wants to cut out the middleman cathode manufacturer and go straight to cathode manufacturing as well. I think that Ascend has spent, at least in terms of their marketing, and I think in terms of their tech stack, more time focusing on how one valorizes the input stream faster and more efficiently.
Shayle Kann: Okay. So you're saying all things equal, Redwood is sort of really focused on this getting feedstock and winning the feedstock battle, which for what it's worth, I think is probably a smart thing to do because-
Dan Steingart: I agree. Absolutely, yeah.
Shayle Kann: Yeah. You're saying Ascend has spent a lot of time focused on this Hydro-to-Cathode bit. What about Li-Cycle?
Dan Steingart: Li-Cycle is the realpolitik of the three. Li-Cycle is born from Hatch DNA. Hatch has been making primary extraction, electro winning equipment for a very long time, and Li-Cycle says the world wants metal sulfates as a commodity, and we should focus on the best possible processes to create the digesters to focus on the battery inputs as they are. So, what I mean by realpolitik is they're not trying to necessarily disrupt the way the battery industry works, but rather make a product that the cathode manufacturers already know how to deal with. So they have the product as possible customer base and use their mining routes to digest the ore in a reasonable fashion as I understand it, using a mixture of precipitation processes and solvent extraction. So they are the... Conservative I think is not fair to them. I think they're taking the world as it is as opposed to as they want it to be.
Shayle Kann: Let's talk for a minute. Stepping back from just these three players about the unit economics of battery recycling. What are the things that really drive the value? If you're a recycler, obviously what you're getting out is the materials from the battery, what relatively speaking drives your profitability or lack thereof. For example, you mentioned a lot of these, the cathodes that are being recycled right now are mostly NMC, nickel is a big portion of that value, and of course nickel prices have crashed and the nickel market is struggling at the moment. So how much does that, for example, affect the unit economics, the battery recycling, and what has to be true about the cost of your input or the cost of your process to make this profitable?
Dan Steingart: Well, you've hit on it exactly right, and I agree with this 100%. You have to beat the LMX on your eventual price of a sulfate to be competitive for Alibaba or whatever your benchmark price is. Nickel drove most of the deal flow in '21, '22, '23, and as you said, nickel prices have crashed. Look, we've seen this story before, even before recycling was a challenge. When I started my academic career in '09 and '10, the nickel prices were pushing the world to LFP once before and then nickel prices crashed in the early teens, and we had all this wonderful NMC coming online and then the world saw nickel prices spike, and so LFP swung back and now LFP is safer and easier to source. So LFP seems to be here to stay for a little bit, but nickel once again is cheap. And so what does that ultimately mean for recycling?
I think the brutal truth is that it's a cost center and that recycled inputs are ultimately a tolling operation unless Redwood can pull off owning the supply. Because if Redwood can pull off owning the supply, then it owns the mine of the future, which are these terawatt hours of spent batteries, how a Redwood or any one of these three can begin to capitalize towards having battery warehouses for spent batteries. But Tesla already controls the end result in many ways of its batteries. When GM and Ford and Stellantis, when it becomes more of their output, they're going to want to control this as well. And so what entitlements recyclers have to controlling that upstream feedstock is going to be a bit brutal. And at the same time, all recyclers then at the end of history are in a very tight position because their customer is also their supplier.
And so they're ultimately tollers and they're forced to win on the efficiency of their process. And we've seen this game before in all process metallurgy. Once the winner shakes out, then margin pressure on these folks will be enormous. Ultimately, recyclers are going to have to be built in as either a partner toller where they're just guaranteed feedstock to live and they just have to make sure they're processing at an optimum ways for as long as possible, or they become part of the manufacturing chain as well. And so Northvolt has a lot of interesting IP on recycling. I think they call their recycling effort Revolt, and I want to point out that my lab has some funding to Northvolt, so we're very thankful for that. But Northvolt sees a future where recycling is part of the manufacturing process to begin with. So this is a long and winding answer to your question of where is the value? The value is on guaranteeing input for the batteries that you need independent of the vagaries of the metals markets and your input markets when you're needing kilowatt hours worth of energy stored.
Shayle Kann: What about LFP? As you mentioned, the world has turned toward and back from LFP, but it is a significant portion of batteries these days. We have fewer of them getting recycled because LFP hasn't been around in large volume for a long time, but it will be clearly, and just as a reminder, NMC is nickel, manganese, cobalt, LFP is lithium iron phosphate. And it's not hard to understand why LFP is generally cheaper because that list of things is generally lower cost than the list of things that goes into NMC. That's the value of LFP, right? It comes at an energy density cost. However, the decision has been made in some applications that's worth it. But from a battery recycling perspective, strikes me that that makes it an even bigger challenge because where on the NMC side, the value of your output, whether it is the sulfates or you're going all the way to PCAM or cathode-active materials themselves contains high value things. Nickel prices are down, but they're still orders of magnitude above iron, for example. So what does it look like to recycle LFP?
Dan Steingart: So, using any of the methods we spoke of to date, it doesn't make a whole lot of sense. The lithium is the most valuable thing followed by the phosphorus. And the phosphorus is really valuable looking forward to future of phosphates given how an environmentally nasty phosphorus extraction is. But on a recycle market now recycling phosphorus doesn't have a ton of value. So it's brutal. And I point your listeners to a great paper written by a former colleague, Professor Rebecca Ciez and Professor Jay Witacre. When Rebecca was a PhD student, his group that went through these unit economics in painful detail. And this was prescient because this was written in like 2016. So the value of standard recycling of LFP is real hard, but there's a silver lining LFP, one of its saving graces, it's really robust stuff. It doesn't change its molecular composition all that much as it cycles.
And so now, a very low TRL but exciting technology comes into play called direct recycling. And direct recycling says, "Why do we have to take this cathode and digest it to its core components? Why can't we just refurbish the cathode or rejuvenate it?" And so I think if LFP recycling is going to have a shot, it's going to be on a direct recycling route. And for those that know me and get a beer with me after conferences, they're probably doing a spit take because I'm pretty skeptical of direct recycling in a lot of ways. I think that for nickel, for NMC compounds, it's really difficult and it's just cheaper and safer ultimately for guaranteed lifetime to break it down to sulfate or something similar or in a mixed hydroxide precursor and build it back up. But I think for LFP to be economically viable, direct recycling likely has to be the option where the cathode comes in and instead of being digested, it is thermally treated in similar processes to making the cathode material to begin with.
Shayle Kann: So far as we've been talking about the unit economics and the technical pathways, actually, I think we've mostly been talking about recycling cathode materials and cathodes themselves. We haven't really talked about the anode, which is where you have graphite or maybe some silicon or lithium if it's a lithium metal battery or something like that. What are the similarities and differences on the anode side?
Dan Steingart: This is a hard question. The carbon is pretty robust stuff, but it's not as, I'm going to use a fancy word here, immutable, right? I'm a professor of metallurgy and I studied metals my whole life because you can always screw up with metals and start over. You can always break something that has metallic ion or a metal in it, a metal element in it. You can break it down through any of the methods we spoke about and build it back up. And it's very easy to do so. It's much harder to recreate the right structure out of carbon even if you have a lot of carbon. So we're seeing this play out. The prequel to the story on graphite recycling is just in where we're going to source graphite to begin with for first use. Not all graphites are created equal, and there can be a whole other podcast on the history of different graphites in the lithium ion battery.
The small differences in composition in starter material have a big impact on how the performance plays out. Long story short, graphite recycling is in its infancy and it's pretty difficult to justify from a purity and homogeneity basis. And frankly, there's plenty of graphite in the ground. So it's hard to justify from an economic basis recycling of graphite. We've certainly want to do it from an environmental basis. We want to be able to recycle all of the components. Silicon is a bit easier to process and refine, but that silicon is mixed with significant amounts of carbon to begin with. And silicon is, I think the most abundant solid on the Earth's surface. So there's plenty of it. There's is a duality in thinking about silicon anodes. In 2024, the best performing, or at least the fanciest silicon anodes come from a process called chemical-vapor deposition where you need to start with silane anyway.
Taking spent silicon batteries and processing them back to silane is something that is doable and it's a pretty good source of silicon for that process. But again, starting with silica, there's not a big shortage of that. And it's the making of the silane which is the expensive part. And most of that is done in China and Korea except for a couple of facilities in the very Northwest corner of the country. With lithium metal... Well, the lithium metal is the same lithium that's in the rest of the battery. And this can be extracted and refined using all of the processes that we've discussed previously. And there are a lot of clever ways of getting lithium out in both hydrometallurgical and parametallurgical processes. So, as far as those three anode choices go, carbon most likely won't be recycled anytime soon. Silicon has some merit being recycled and all of the lithium that's in cells should be recycled to nearly 100%.
Shayle Kann: All right, so I guess final question, the sense that I'm picking up from all this discussion is that you think... You're pro-battery recycling, certainly think that there are fairly well-known and well-trodden pathways to do it, but you have a healthy dose of skepticism around the business of battery recycling. Am I picking that up right? And give me your high-level take on what the battery recycling business looks like in five or 10 years.
Dan Steingart: I think that's exactly right. I think we're at a market inefficiency now with battery recycling, and I am a process engineer by training like I'm a professor, so those who can't do, those who can't teach. So I'm very much someone who has not had to be responsible for making this material. And so I don't want to be seen as underappreciating or nagging on the difficulty of battery recycling. But the truth of it is that these primary processes are a cost center. And to your earlier comment, they're high CapEx and low margin. And battery recycling is no different. When I started looking at battery recycling a few years ago, I asked myself, "Why aren't the big mining companies talking about this in a significant way? Why isn't Rio or FMI or Vale," they have some text on their websites about this, but they're not in the conversation of developing technologies in a significant way.
And it's for a really simple reason. The value of these companies, the big assets these companies have are in the ground. Their real estate efforts and their processing operations are to valorize what they already own. And their process operations are a satisfaction condition. So in terms of their unit economics, it doesn't make any sense for a mining company to involve itself in recycling in a big way in 2024, both because all the recycling material coming in, or most of it is scrap and what's not scrap is a product owned by somebody else.
So as difficult as battery recycling is, and we spoke about all of the complexities that one has to think about when we go through it, it's ultimately something where it's squeezed from the upstream and downstream, and there's very little margin allowed on either end. So in a perfectly efficient market, recycling is just a tolling operation where it will exist to an extent that it can keep its costs neutral, and every time there's an advance that lowers the cost of recycling, there will be a year or two where that provider gets to benefit from that extra profit, but then the market will expect lower prices going forward, particularly as we need cheaper and cheaper batteries.
Shayle Kann: Well, Dan, thanks so much for walking me through all the ways to recycle batteries and all the reasons it's going to be difficult to turn it into a good business. We'll keep you posted and have you back on when direct recycling becomes the state of the art.
Dan Steingart: I would love to be proven wrong on the economics of the process. I think recycling has to happen, and if the economics were rosier, I think it would happen faster. And so I would love to be wrong about this.
Shayle Kann: Thanks for your time.
Dan Steingart: Thanks much for having me.
Shayle Kann: Dan Steingart is the chair of the Earth and Environmental Engineering Department at Columbia University. This show is a production of Latitude Media. You can head over to Latitudemedia.com for links to today's topics. Latitude is supported by Prelude Ventures. Prelude backs visionaries accelerating climate innovation that will reshape the global economy for the betterment of people and planet. Learn more at Preludeventures.com. This episode was produced by Daniel Waldorf, mixing by Roy Campanella and Sean Marquand, theme song by Sean Marquand. I'm Shayle Kann, and this is Catalyst.