Sila raises $70 million for silicon anodes

Abstract

Sila Nanotechnologies, a start-up based in Alameda, Calif., has raised $70 million in its fourth round of venture funding from Sutter Hill Ventures; Next47, a venture firm backed by Siemens; and Amperex Technology, a Chinese battery maker. Sila is working to commercialize lithium-ion battery anodes made primarily of silicon. Researchers have long known that replacing traditional graphite anodes with ones made with silicon can greatly increase the energy density of lithium-ion batteries. But the trick is formulating the material to prevent its bad habit of swelling. Lithium-ion battery anodes store lithium that settles there when batteries are charged. Graphite is a cheap, durable anode material; however, it has limited storage capacity. “Batteries are a key component in the future of mobility and electrification, but the current technology can’t keep up,” says Next47 partner T.J. Rylander. Silicon can store much more lithium, but the resulting swelling ends up degrading the battery.