US Patent 11309536 Silicon particles for battery electrodes

Silicon particles for use in an electrode in an electrochemical cell are provided. The silicon particles may have outer regions extending about 20 nm deep from the surfaces, the outer regions comprising an amount of aluminum such that a bulk measurement of the aluminum comprises at least about 0.01% by weight of the silicon particles. The bulk measurement of the aluminum may provide the amount of aluminum present at least in the outer regions.