Sila, a Californian company cofounded in 2011 by Tesla’s seventh staffer, is going to supply Panasonic with a US-made silicon powder for EV batteries that could banish range anxiety, slash charge times, and even reduce reliance on China.
Panasonic’s main US customer is Tesla, and produces around 10 percent of EV batteries globally. Last year, Sila signed a supply agreement with Mercedes-Benz for its new long-range G-class electric SUV, expected to debut in 2025. (The German automaker led Sila’s Series E funding round in 2019.)
Sila’s Titan Silicon anode powder consists of micrometer-sized particles of nano-structured silicon and replaces graphite in traditional lithium-ion batteries. This switch-out for EVs could soon enable 500-mile nonstop trips and 10-minute recharges. What’s more, the anode swap doesn’t require new manufacturing techniques. The black powder already powers the five-day battery life of the latest Whoop activity-tracking wearable.
“It took us 12 years and 80,000 iterations to get to this point,” said Sila’s cofounder and CEO, Gene Berdichevsky. “It’s sophisticated science.” Berdichevsky started his career at Tesla, becoming the seventh employee in 2004. He was the lead for Tesla’s Roadster battery system, leaving when the company had about 300 employees. After further study, he cofounded Sila with Tesla colleague Alex Jacobs and Gleb Yushin, a materials science professor at Georgia Tech.
Compared to graphite, silicon stores up to 10 times more energy, so using silicon instead of graphite for anodes—the part that releases electrons during discharge—can significantly improve a battery’s energy density. However, the material swells during repeated charging, with the resulting cracks radically reducing battery life.
Sila’s technology allows for this expansion by using nanoscale carbon “scaffolding” to keep the silicon in check. “Titan Silicon is a nanocomposite 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 shipped to battery makers.
“We can replace anywhere from 50 to 100 percent of the graphite in lithium-ion batteries,” claims Berdichevsky. A full-fat replacement could deliver a 40 percent increase in mileage for a typical EV, and reduce the wait to 80 percent charge to the time it takes to leisurely fill a tank with gas.
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 an International Energy Agency report, 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.
Silicon is the world’s second most abundant element in the Earth’s crust (oxygen is the first), and the high-purity quartz used in silane gas production is mined in the US.
Since 2017, Sila’s anode powder destined for consumer electronics has been made in a pilot facility at the company headquarters in Alameda, California. Still, to produce at an automotive scale, the company is now fitting out a never-used 600,000-square-foot fiberglass factory in Moses Lake, Washington, initially employing 100 mostly local people with plans for an additional 600 as the company grows.
Moses Lake—noted for its potatoes, but just a speck on the map halfway between Seattle and Spokane—is now a hydroelectric hub attracting next-gen industries keen on the area’s cheap, clean power.
Berdichevsky states that if you’re supplying European customers, it now pays to be off the dirty grid. A regulation passed by the European Parliament in June made it a no-brainer for Sila to locate in the town. Brussels now requires every EV battery destined for the EU market to carry a label declaring its carbon footprint; “battery passports” must digitally track batteries and their materials through the supply chain.
There are also supply-chain requirements in the Inflation Reduction Act (IRA) of 2022. To qualify for EV subsidies, battery minerals must be sourced domestically or from allies. The climate-change-focused parts of IRA mandate the US sourcing of minerals to the tune of 40 percent 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.
Sila is not the only automotive-focused silicon nanocomposite maker attracted to the clean power of Moses Lake. One mile down the road from the former fiberglass factory, Group14 Technologies has broken ground on a new-build factory that will make similar powder for Porsche.
The German automaker led a $614 million funding round in Group14 last year. When the 7-year-old company’s plant opens in 2024, it will produce enough of its SCC55 anode powder 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.”
Not coincidentally, Moses Lake is also home to REC Silicon, a formerly shuttered supplier to the photovoltaics industry, and now one of only two US makers of silane gas. Group14 will be sourcing locally; Berdichevsky preferred not to say where Sila is sourcing its silane. Both companies received federal grants of $100 million to build their silicon anode factories.
Jay Turner, an environmental studies professor at Wellesley College, tells WIRED that large-scale domestic manufacturing of new EV battery technologies is understandably a big deal. “It marks an important break with history,” says the battery historian who tracks new North American EV production.
“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.”
However, they are just two of the silicon anode producers in the US. Californian companies OneD Battery Sciences and Amprius grow silicon nanowires that they claim are less prone to swelling than nano silicon powders.
Amprius, founded in 2008 by Stanford materials science professor Yi Cui, has focused on silicon anodes for the aviation sector, while OneD Battery Sciences will be putting its silicon nanotechnology into GM’s Ultium batteries.
Instead of engineering silicon nanoparticles or nanowires, Enevate, also of California, deposits nanoscale silicon films directly onto copper foil. Its silicon anode batteries are already used in electric motorbikes.
Chicago startup NanoGraf makes a silicon oxide material for anodes that it pre-swells for stability. Its anodes are used in military electronics.
Developers of other battery chemistries are looking to supplant traditional lithium-ion completely. Tesla is already producing cars with lithium-iron-phosphate batteries; Toyota has teased industry insiders with its solid-state batteries; Chinese firms are developing sodium-ion (Na-ion) technologies that require little to no lithium, nickel, or cobalt; and Samsung SDI is perfecting high-manganese batteries.
There could well be room for all the above in a growing global EV market. Indeed, the UK’s Advanced Propulsion Centre, a specialist in emerging battery technologies, says this shift in electric tech is “not about one type [of battery chemistry] winning over the other, as the performance characteristics mean that user cases vary.”
Source : Wired