Will Silicon batteries be a major game changer?

[peter]

Hydrogen is 15 years behind in spite of a 15+ year head start. So this will tell you a lot about the S curve in the relative performance of these technologies. By the time hydrogen is viable, the performance/cost of Li batteries will be many times better than today.

There are many paths to improvement in Li batteries. On cathode, there are chemistry improvements, the most promising is adding a little manganese to LFP for LMFP batteries. On anode you will see increased silicon content in anode material. There can also be improvements in binders and additives that will provide incremental performance improvements. One of the most promising areas of improvement is the separator material, where new separators are being designed that inhibit dendrite growth, which allows chemistries to be pushed even further. Changes to cell format can also make a difference in cost, like Tesla 4680 battery, or large format prismatic cells like BYD blade. There are improvements at the pack level, like blade battery pack and other cell to pack technologies. Finally, there is a lot that can be gained from new manufacturing process, like Tesla dry coating process or semi solid battery process.

The Li battery industry is still very young. Li batteries were only invented in the 1980s. Compare this to silicon transistor, which was invented in 1950s. Batteries don't have as fast of an improvement rate as transistors, so we will not see a 1000x performance/cost improvement over the next 30 years, but I would bet a 10x improvement is very possible. In the same time, I doubt hydrogen will even have a 2x improvement.

Boy, even more optimistic than I am about lithium batteries, must not work in the industry!

I jest, I jest, I have those 46xx cells (and even larger cells) and large blade cells to play around with and all that new technology is definitely exciting. But 10x improvement? Not going to happen. Hard physics cap, Faraday's constant/Li atomic mass, 13901 coulombs per gram, theoretical cap of 11.6kWh per kg of lithium. That's not factoring the intercalation compounds of the cathodes and the anode, nor is it including the housing, separator films, etc. Graphite as an anode has a theoretical cap of 372 mAh/g, silicon can potentially triple that, but again, once factoring in all the rest of the build of materials, even doubling current leading edge lithium batteries in energy density is going to be extremely challenging. Even that link Arthur posted, there's a lot of marketing fluff in there about their proprietary silicon anode's 3250 mAh/g potential, but their actual stated performance is about 20% better than current lithium batteries and their stated goal is 40% better over the next decade. Even the 4680 cells, it improved energy density on the cell level from 270wh/kg to about 280-290wh/kg. Incremental improvement. BYD blade and CATL qilin, same thing, small incremental improvements, roughly 180wh/kg because it's using LFP for blade, qilin's around 260wh/kg last time I recall. Averaging about 60wh/kg improvement per decade for the past three decades, which is still phenomenal. The bigger shocker is the cost reduction per kwh, went from over $1000 in 2010 to around $80 right now, but talking to sodium and lithium battery manufacturers, the cost reductions hereon out will be incremental, lithium and the other active material costs don't make up as big of a proportion of the total cost and the outlook on long term raw material availability is a bit murky as well with the explosive expansion in cell production capacity.

It's clear lithium batteries is ahead for certain applications, I don't see a hydrogen car being practical or necessary at all. But I don't want to completely disregard the potential of not just hydrogen, but fuels that can be synthesized with hydrogen, such as methanol, ammonia or synfuel. They're incredibly useful feedstock for many industrial processes and practical fuels for heavy machinery, equipment and transportation vehicles, such as bulk cargo carriers, container ships and potentially aircraft, vehicles that lithium batteries realistically have no chance of penetrating in our lifetimes other than very short haul specialty cases. But for me, besides the carbon reduction or carbon neutral aspect, it drastically reduces SOx, NOx and other particulate emissions, stuff that really matters to port cities, seeing as to how bad the air quality is around LA and the bay area, stuff that actually matters to ones health. Sabatier, Haber, Fischer Tropsch processes are all mature on an industrial scale, these gases and fuels can currently be made cheap using fossil fuels, but if we can deploy massive cheap renewables online, far better to use the energy to produce these fuels than just charging up batteries. Hydrogen infrastructure, I'll be the first to admit is too costly outside of centralized production centers, but methanol infrastructure and ammonia infrastructure is quite doable.

Or in my personal use case, I have a 120kWh battery for my house. It can only store 120kWh, and since I made the pack from cells directly procured from China, it was drastically cheaper than any off the shelf ESS. But at the end of the day, it can only hold 120KWh and takes up quite a bit of space. With my home solar setup, it produced a little over 60kWh a day after the winter solstice a few weeks ago, and can produce about twice that in the summer. But my use in the summer is at most 40kWh a day whereas my use in the winter is 50kWh a day. Adding another 120kWh of storage, even at $80/kwh is not exactly cheap, and will only get me 2 more days of winter. About $300/kg for hydrogen tank, 30kg would yield nearly 1000kWh of electricity and would cover the worst weather that I can possibly fathom. I have room, it'll be stationary so don't need highest compression rate or weight saving materials, could be fitted with cheaper compressor/tank, and if I really wanted to say screw it with efficiency, just pipe the hydrogen into a ICE generator and get cheap backup power. Or maybe I'm just being delusional!

 

[count]

10x improvement in cost performance at pack level, not straight performance, and over a period of 30 years.

Performance has a hard cap although there is currently a lot of room for improvement, but the materials cost can be greatly reduced. The manufacturing processing cost can also be greatly reduced.

I actually do work in battery industry.

 

[saimali]

Boy, even more optimistic than I am about lithium batteries, must not work in the industry!

I jest, I jest, I have those 46xx cells (and even larger cells) and large blade cells to play around with and all that new technology is definitely exciting. But 10x improvement? Not going to happen. Hard physics cap, Faraday's constant/Li atomic mass, 13901 coulombs per gram, theoretical cap of 11.6kWh per kg of lithium. That's not factoring the intercalation compounds of the cathodes and the anode, nor is it including the housing, separator films, etc. Graphite as an anode has a theoretical cap of 372 mAh/g, silicon can potentially triple that, but again, once factoring in all the rest of the build of materials, even doubling current leading edge lithium batteries in energy density is going to be extremely challenging. Even that link Arthur posted, there's a lot of marketing fluff in there about their proprietary silicon anode's 3250 mAh/g potential, but their actual stated performance is about 20% better than current lithium batteries and their stated goal is 40% better over the next decade. Even the 4680 cells, it improved energy density on the cell level from 270wh/kg to about 280-290wh/kg. Incremental improvement. BYD blade and CATL qilin, same thing, small incremental improvements, roughly 180wh/kg because it's using LFP for blade, qilin's around 260wh/kg last time I recall. Averaging about 60wh/kg improvement per decade for the past three decades, which is still phenomenal. The bigger shocker is the cost reduction per kwh, went from over $1000 in 2010 to around $80 right now, but talking to sodium and lithium battery manufacturers, the cost reductions hereon out will be incremental, lithium and the other active material costs don't make up as big of a proportion of the total cost and the outlook on long term raw material availability is a bit murky as well with the explosive expansion in cell production capacity.

It's clear lithium batteries is ahead for certain applications, I don't see a hydrogen car being practical or necessary at all. But I don't want to completely disregard the potential of not just hydrogen, but fuels that can be synthesized with hydrogen, such as methanol, ammonia or synfuel. They're incredibly useful feedstock for many industrial processes and practical fuels for heavy machinery, equipment and transportation vehicles, such as bulk cargo carriers, container ships and potentially aircraft, vehicles that lithium batteries realistically have no chance of penetrating in our lifetimes other than very short haul specialty cases. But for me, besides the carbon reduction or carbon neutral aspect, it drastically reduces SOx, NOx and other particulate emissions, stuff that really matters to port cities, seeing as to how bad the air quality is around LA and the bay area, stuff that actually matters to ones health. Sabatier, Haber, Fischer Tropsch processes are all mature on an industrial scale, these gases and fuels can currently be made cheap using fossil fuels, but if we can deploy massive cheap renewables online, far better to use the energy to produce these fuels than just charging up batteries. Hydrogen infrastructure, I'll be the first to admit is too costly outside of centralized production centers, but methanol infrastructure and ammonia infrastructure is quite doable.

Or in my personal use case, I have a 120kWh battery for my house. It can only store 120kWh, and since I made the pack from cells directly procured from China, it was drastically cheaper than any off the shelf ESS. But at the end of the day, it can only hold 120KWh and takes up quite a bit of space. With my home solar setup, it produced a little over 60kWh a day after the winter solstice a few weeks ago, and can produce about twice that in the summer. But my use in the summer is at most 40kWh a day whereas my use in the winter is 50kWh a day. Adding another 120kWh of storage, even at $80/kwh is not exactly cheap, and will only get me 2 more days of winter. About $300/kg for hydrogen tank, 30kg would yield nearly 1000kWh of electricity and would cover the worst weather that I can possibly fathom. I have room, it'll be stationary so don't need highest compression rate or weight saving materials, could be fitted with cheaper compressor/tank, and if I really wanted to say screw it with efficiency, just pipe the hydrogen into a ICE generator and get cheap backup power. Or maybe I'm just being delusional!

 

[peter]

That's still quite an aggressive target, but then again, 30 years is a long time!

 

[count]

That's still quite an aggressive target, but then again, 30 years is a long time!

There is a tendency to overestimate progress in the short term, but underestimate it in the long term. I have no doubt that a 10x improvement in 30 years is achievable. We are only in the 3rd inning when it comes to the development of Li battery technology.

I am directly involved the the development of new manufacturing processes and technologies that we are validating on pilot lines today. As an example, dry coating and semi solid processes will take 40-50% out of the processing cost and, while there are plenty of challenges, I am quite certain that it will be commercialized within a few years.