Battery Insiders Reflection - Silicon Anodes

0:00Transcript

0:00Welcome to Battery Insiders, your podcast providing you insights in the fascinating world of batteries. Hosted by Bhavya Jha and Simon Engelke. And we're back. Welcome back, everybody. We're glad to have you back with us here. Today, Simon and I are going to talk about silicon anodes. That was the conversation we just wrapped up with our friends over on Clubhouse. Hey, Simon, how's it going? Doing well, doing well. Yeah, it's an exciting topic. It's a bit of a nerdy one, but I think we appreciate a bit of a nerd talk sometimes. And yeah, I had a good session. Super nerdy one. So I'm going to let you take the reins on this one. I'm a resident nerd. No, I'm kidding. What did you think about the conversation? What are your thoughts on silicon anodes? Yeah, I think it's an interesting topic, you know, I think from a bit of a history, or not too much history, but silicon, you know, is one of the materials people want to use for the anodes, for one of the electrodes of the battery.

1:09And the idea is really to increase your capacity by quite a bit of a significant way by having this material instead of graphite, which is the most common, I would say, anode material right now. And the idea is with silicon, you can increase the capacity maybe about four times or so. But the issue is actually that the way you do that is you store the lithium inside the silicon and it kind of expands quite a lot. So there's a lot of expansion going, which you can imagine. In graphite, you have like, you know, layers of graphene, layers of carbon, and you like store, intercalated lithium in between these layers. So there's not too much like swelling or so much movement happening. But on silicon, on the other hand, as an alloy, you actually have a lot of increase, a lot of movement, morphological changes. And on the one hand, so people want to use silicon, people are using silicon, you know, the reports that, I mean, all kinds of companies are using silicon, you know, including Tesla and Apple and others.

2:09But at the moment, people use quite a low amount of silicon. So they only use a few percent or so. They try to increase it all the time. And there are, of course, quite a few startups and companies try to do it as well. But it's quite challenging. And the holy grail, right, for many people has been to actually have like a pure silicon anode. So only have silicon instead of graphite. But that, again, is very challenging. So, but that's, for example, one thing, Christian Rood, one of our conversation started for the session, his startup is working on, yeah, creating this full, you know, full silicon anodes and there's a few others as well. So it was just, I think, interesting to hear from his side, you know, some of the work they're doing. Of course, also the challenges, you know, with an interesting discussion about that. And I think it's also interesting just as a deep tech startup, you know, I think, I think it's something very brave to do.

3:01It's a very challenging, batteries are very tricky. And to change one of these chemistries can be quite challenging. So I think it's cool that they're doing this work. But I think, you know, there's so much to be done for, until you actually get a real commercial sell, right? I think we can see that. But, you know, people trying to push the, to push the envelope. So that's always exciting. What do you think, Bavi, about this? Yeah, absolutely. I guess it was interesting to hear that this is already something that's being done by, or at least kind of in a trial period. Um, I guess from kind of looking at the economics of it, like, are there supply chain risks? Where is it? Where is most of the silicon being sourced from? These are some questions that, um, definitely I've come, I've been thinking about. Um, and yeah, you know, me and my standardization, but I just, what is, how does that affect end of life?

3:57But I think that's, I mean, a little bit of a far off question. It seems like it's still a pretty like novel idea. Um, but one that clearly people like Christian and others are, um, are exploring. So I'm a bit curious about a few aspects of it. Um, it's nice to, always good to hear about, you know, increased performance and whatnot, but yeah, that, those are some of my thoughts. I think there's actually two very important points you just put up, one from a supply chain perspective. And, you know, I think one thing is, I mean, silicon in some way, it's sand, right? You can get a sort of silicon, but of course, all our transistors and chips, et cetera, also, you know, based on silicon. And, you know, we are, we're quite grateful for that. At the same time, you know, silicon is not always the same, right? There's door pins and things like that. And actually, for silicons like this, there's also a lot of different procedures, you know, techniques, how you can use it.

4:49You can do, you know, like plasma treatments and all kinds of fun ways. And so yeah, silicon is not always the same. So actually getting the good silicon or the silicon you need, which is also consistent, is not always that trivial. So I spoke to some other startups in this space as well. They definitely had some challenges on that. And the second thing, but that's the same, of course, with graphite, et cetera, as well, especially if you take natural graphite, right? I mean, anything natural, there's some variance in there. So you have to take this into account. And then I think the second thing you mentioned was, you know, lifetimes and things like this and second life and all these other topics and realization. That's another really big point, right? I think back to our battery day, which was one of our previous podcasts. And we also had a session there. And I really liked the quote of one of our panelists, Claudius Gieler, from Politica Diagnostics.

5:34And he was talking about, you know, how costs are going down. I think, you know, range are going up, but lifetimes are going down. And so there's two improvements, but one, you know, it's quite tricky to improve it all. And it's one of these things that's more meant for, I think, the cathodes he was talking about, some of the higher nickel cathodes, but same with silicon, right? I think you can increase your capacity, but because of the swelling I mentioned, actually, it's quite tricky to get like a stable configuration. And actually, I've seen some silicon anodes. I mean, I spent a bit of time on this in my PhD as well. And you get like this mushy material, just like, you know, all over the place. And that's a big challenge, right? So you maybe can create a nice battery, right? Which lasts much longer, but then, sorry, like, you know, it lasts much longer at a single use, but then over the lifetime, it's shorter.

6:23But then again, you know, I think you have to take into account what you're using it for, right? If you think about things like, you know, your smartphone, you know how many charges you have. There's other devices. There's some other devices where you care much more about, you know, that it lasts. You have a single charge, which is super long, but you might not charge it often. Let's think of, I don't know, it doesn't make too much sense maybe, but let's think about an electric vacuum, right? You have an electric vacuum with a battery. I maybe charge it, I don't know. How often do I use it? You know, let's pretend every week, every two days. I don't know. But it's not the same maybe as your phone, right? Which you would use at the same time, for example, an electric car. You might not charge so often, but you want to use it much longer than a phone, right? A smartphone you might use for two years or a few more, and ideally as long as possible.

7:08But an electric car, right? We're talking about eight years, 10, 20, maybe not even 30. Who knows? So taking these things into account, this is, of course, important as well. And yeah, I think the big challenge of batteries is you can never take it in isolation. So we change one thing, but it's going to affect other components of the battery, but then also all the ecosystem, things like you mentioned, supply chains and lifetimes, et cetera. Yep, the entire ecosystem. Well, this has been really helpful. I think hopefully our listeners have gotten some more perspective on Silicon Anos, especially as they gain traction in industry. But I think we'll have to continue the conversation next time. This has been really nice. Thanks so much, Simon. Thanks, Bavia, and see you next week. Bye-bye. See you. Bye-bye.