Sila Battery Substitutes Silicon Powder For Graphite In Quest For 1000 Watt-Hour Per Liter Batteries
Gene Berdichevsky was the seventh person hired by Tesla in 2004 and was the leader of the battery team for the Roadster battery system. In 2011, he left Tesla to co-found Sila with Tesla colleague Alex Jacobs and Gleb Yushin, a materials science professor at Georgia Tech.
Sila is planning to supply its Titan silicon powder to battery makers like Panasonic that will replace all or part of the graphite used for the anodes in traditional lithium ion batteries. The silicon powder has several advantages. With it, EVs could soon be able to travel up to 500 miles without stopping to charge. When the need does arise to recharge, the Sila batteries could do so in about 10 minutes. Best of all, using silicon powder from Sila does not require new manufacturing techniques and bypasses China, which currently supplies 96% of the purified graphite used by the world’s battery makers.
Panasonic produces about 10 percent of all EV batteries and its primary customer in the US is Tesla. This week Panasonic said it will use US made silicon powder from Sila in some of the lithium ion batteries it manufactures. Last year, Sila signed a supply agreement with Mercedes-Benz for its new long range G Class electric SUV which is expected to debut in 2025. Mercedes led the Series E funding round for Sila in 2019.
The Sila Silicon Powder Anode
According to Wired, Sila’s Titan Silicon anode powder consists of tiny particles of nano-structured silicon that replaces graphite in traditional lithium ion batteries. “It took us 12 years and 80,000 iterations to get to this point. It’s sophisticated science,” Berdichevsky says. Compared to graphite, silicon stores up to 10 times more energy, so using it instead of graphite for anodes — which release electrons when a battery discharges — can significantly improve a battery’s energy density.
However, the material swells during repeated charging, with the resulting cracks radically reducing battery life. The Sila technology allows for this expansion by using nano-scale carbon “scaffolding” to keep the silicon in check. “Titan Silicon is a nano-composite material,” says Berdichevsky. “It’s like raisin bread, where the raisins are the silicon, and there’s the squishy matrix around the raisins with a big outer rind on the particle itself. The rind holds the space, and the bread moves aside when the raisins expand. The scaffold is not holding the silicon, it’s accommodating the expansion.”
The patented scaffolding process involves silicon-derived silane gas infiltrating custom carbon lattices. The resulting micron scale powder is then shipped to battery makers. “We can replace anywhere from 50 to 100 percent of the graphite in lithium-ion batteries,” Berdichevsky claims. A full replacement could deliver a 40 percent increase in mileage for a typical EV and reduce the time it takes to get to an 80 percent charge to about ten minutes.
Sila says that Titan Silicon is about five times lighter than graphite and takes up about half the space when fully charged. In a press release announcing the agreement with Sila, Panasonic said it has a goal of increasing the volumetric energy density of its batteries to 1,000 watt-hours per liter by 2030.
“That’s a very high metric,” says Berdichevsky. “The best batteries in the world today are right around 740 watt-hours per liter, and those are the same numbers that solid-state battery developers claim that they can reach. We’re saying we can soon reach those levels with technology [that] is here now.”
Graphite is the world’s default anode material, present in almost every lithium-ion battery and consisting of up to 60 percent of a battery’s volume. According to the International Energy Agency, about three-quarters of all EV batteries are currently made in China. Mining consultancy Benchmark Mineral Intelligence estimates that China produces 61 percent of the world’s naturally occurring graphite and refines 98 percent of finished graphite material.
Sila Scaling Up Silicon Powder Production
Since 2017, Sila’s anode powder destined for consumer electronics has been made in a pilot facility at the company headquarters in Alameda, California. In order to produce silicon powder in the quantities needed to make EV batteries at scale, the company is now configuring a 600,000-square foot former fiberglass factory in Moses Lake, Washington.
That area has an abundance of hydroelectric power available. Berdichevsky says European customers want battery materials that are manufactured using renewable energy. The EU now requires every EV battery destined for use in Europe to have a “battery passport” — a label that declares its carbon footprint. Such “battery passports” digitally track batteries and their materials through the supply chain.
There are also supply chain requirements in the Inflation Reduction Act of 2022. To qualify for EV subsidies, battery minerals must be sourced domestically or from allies. The IRA mandates that 40 percent of battery materials be sourced from the US or approved countries starting this year, rising to 80 percent from 2027 onward.
The IRA also prohibits using critical minerals, battery materials, and other components from “foreign entities of concern.” “If you use any material that comes from China in your batteries, then your customers will miss out on a $7,500 tax credit,” says Berdichevsky.
The access to hydro power has attracted other battery companies to Moses Lake. Just a mile from the Sila factory, Group14 Technologies has broken ground on a new factory that will make a similar silicone powder for Porsche, which led a $614 million funding round in Group14 last year. That factory is expected to begin operations in 2024 and produce enough of its SCC55 anode powder to make batteries for 200,000 EVs annually.
“There are companies that have partnerships and collaborations, but they’re all still in development,” claims Berdichevsky, “while we’re ready for scale production manufacturing.”
Jay Turner, an environmental studies professor at Wellesley College, tells Wired large scale domestic manufacturing of new EV battery technologies is an important development. “It marks an important break with history. In the past, the US has been a leader in advanced battery research but much of the actual manufacturing has taken place abroad. It is exciting to see US-developed research being scaled at US factories. Sila and Group14 both look well positioned to scale.”
It’s hard to be King Of The Mountain. China may have a stranglehold on graphite production today but how long will it be able to hold onto that position? The simple answer is to stop using graphene and start using something else — like silicon powder. That’s not easy, as the research by Sila shows, but it is possible.
We reported recently on a company that plans to make battery grade graphite from wood chips. There are thousands of researchers in hundreds of labs working on making better, more powerful, less expensive batteries. As we say around the fusion powered fire pit at CleanTechnica, the batteries that will power our electric cars and trucks in 2030 haven’t been invented yet.
China may dominate the industry today, but that is changing rapidly thanks to policy initiatives in Europe and the US. Relax, people. Everything will be fine.
Hat Tip To Dan Allard
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