What is a silicon anode battery?

How it works

In a standard lithium-ion cell the anode, the electrode that holds lithium when the battery is charged, is made of graphite. Lithium ions slip between graphite's carbon layers without warping the material, the University of Washington's Clean Energy Institute explains. Silicon instead alloys with lithium, which the institute says gives it a larger capacity. By weight, silicon can hold 10 times as many lithium ions as graphite, IEEE Spectrum reported in May 2023.

Why silicon is hard to use

The alloying reaction makes silicon swell. A 2021 review in Nature Communications put the volume change at more than 280% when silicon is fully loaded with lithium. It said this cracks and pulverizes anodes. Battery makers had so far added only small amounts of silicon, under about 6% to 8% by weight, the review said. Far higher shares remained an obstacle, it said, partly because swelling breaks down the protective layer between anode and electrolyte.

Newer materials aim to contain it. Group14 and Sila, two U.S. startups, make powders in which silicon sits inside a porous scaffold that Sila says leaves it room to expand, IEEE Spectrum reported. Both companies said their powders could replace graphite at existing battery plants.

A 2021 perspective in Nature Energy argued that silicon's chemistry worsens calendar aging, degradation that depends on time, not only charge cycles. The authors wrote that automotive batteries must last well over a decade. They said long-term test data for silicon cells were scarce.

Where things stand in 2026

Silicon anode materials are already in some consumer electronics: Whoop wearables use Sila's material and some smartphones use Group14's, TechCrunch reported in March 2026. It said the far larger electric vehicle (EV) market would require startups to make much more material than they had so far. Group14 said that month it had begun production at a South Korean factory. It said the factory can make up to 2,000 metric tons of material a year, enough for about 100,000 long-range EVs.

Sila began production in Moses Lake, Washington, in September 2025 and said in July 2026 it had raised $300 million to expand the plant, TechCrunch reported. The outlet said Sila's material can store up to 40% more energy than graphite anodes. Citing Benchmark Mineral Intelligence, it added that Chinese companies control about three-quarters of the graphite anode supply chain, prompting automakers outside China to seek alternatives.