Sila Nanotechnologies has harnessed the chemical properties of silicon to pioneer lighter, faster-charging silicon anodes with greater storage density available as drop-in replacements for graphite components in pre-existing renewable batteries.
Can you explain Titan Silicon anodes and how they work as drop-in replacements for graphite in lithium-ion batteries?
Lithium-ion batteries have been around for 35 years, and inside every battery there are four critical components. The two most important are the anode and the cathode. The anode stores lithium when the battery is charged and the cathode stores lithium when the battery is discharged. The more lithium these hosts can store per unit volume, the better battery one can assemble from them. So the Panasonics, the Samsungs, the CATLs and the LGs of the world assemble their batteries from components they buy from anode and cathode producers. We happen to be an anode producer.
Pretty much every lithium-ion battery anode in the world has used graphite, whether in EVs, grid storage, drones, satellites, phones or laptops. What we set out to do 15 years ago was invent a much better material. Titan Silicon™ is our brand name for silicon-carbon anodes, often abbreviated SI/C or SI-C. This is the first fundamentally new anode chemistry, designed as a drop-in replacement, meaning any lithium-ion battery using graphite today can switch to silicon without different assembly. The technology also works with the same electrolytes used today, so temperature performance, governed by this component in batteries which we are also exploring new chemistries to improve, is very similar to that of graphite-based batteries. You still cannot leave batteries on the dashboard of a hot car in the desert, and they will still freeze if you have them at minus 20 degrees Celsius. But silicon anodes can recharge about twice as fast as conventional graphite batteries while also reducing size and weight. The real advantages are that drones or other devices can carry much heavier cameras, fly longer and recharge much faster.
How did you solve silicon’s swelling problem inside batteries?
Silicon was always theoretically known to be much better because it stores far more lithium and is five times lighter and two times smaller than graphite, so batteries can become 20% to 40% smaller and lighter. However, silicon is too good at storing lithium. In graphite, six carbon atoms hold one lithium atom. In silicon, one silicon atom bonds with four lithium atoms. This gives silicon a massive atomic advantage but also causes expansion problems when charged.
We created a carbon scaffold filled with tiny nanometer-sized pores. Through a gas chemical reaction, silicon deposits into those pores, creating nanometer-sized nodes of silicon inside a larger carbon particle. When the silicon expands and contracts, it does so in very localized areas without damaging the surrounding structure. Imagine leaving a little extra space so the silicon has somewhere to expand into, and the scaffold is able to stretch and come back together as the little silicon nodes contract. If you have a large silicon particle, it breaks apart. But if you synthesize it into these tiny nanometer-sized features inside a stretchy micro scaffold, you can get around the swelling problem.
Have you found any opportunities for optimization and sustainability in manufacturing?
Graphite production requires very high temperatures for long periods of time. Our preliminary estimates show about a 70% reduction in footprint and CO₂ compared to graphite materials, partly because we simply use far less material. Our factory is located off the Columbia River and uses hydropower. We do not rely on rare materials or catalysts, and the process is relatively clean.
The best way to reduce environmental footprint is not necessarily through recycling but by using less material overall, and that five-times reduction in anode tonnage is a major advantage.
We buy our raw inputs, mined materials and somewhat processed commodities from further upstream. Our materials are primarily carbon and silicon from quartz. We have no dependence on rare earths or the China supply chain. Most of our equipment and input materials are sourced from the U.S., with some coming from other allied countries. The beauty of this technology is that it relies on abundant materials, which keeps the supply chain relatively simple as we continue scaling.
What progress have you made scaling up and approaching commercial shipments?
Inventing is very hard and manufacturing is very, very hard. After inventing the technology it took the last seven or eight years to scale it up from about a gram of material per day to about a ton per day in our Washington state factory. We completed phase one of the new Moses Lake plant there late last year and started operating it. We also received a $100 million award from the U.S. Department of Energy to support the buildout. In the very near future, we will begin announcing first customer shipments from that facility. We are currently producing a couple of gigawatt-hours worth of material, but the world uses a couple of thousand gigawatt-hours of batteries today. The next step is expanding the plant to produce as much as 200 gigawatt-hours over the next three to five years.
We will expand the Moses Lake facility by about 20 times in the next phase and continue to scale in the U.S. We are currently on track for our technology to be in electric vehicles next year. Some of the first shipments will go out in the third quarter of this year, and then we will finish qualification. The technology to drop into is already in millions of consumer devices today, so we are also launching into more applications this year, including drones, satellites, robotics, power tools and data centers. Really, silicon anodes will start to diffuse across the board to many industries.
