ELECTRODE COMPOSITION COMPRISING A SILICON POWDER AND METHOD OF CONTROLLING THE CRYSTALLINITY OF A SILICON POWDER

摘要

An electrode composition comprises a silicon powder comprising non-crystalline and crystalline silicon, where the crystalline silicon is present in the silicon powder at a concentration of no more than about 20 wt. %. An electrode for an electrochemical cell comprises an electrochemically active material comprising non-crystalline silicon and crystalline silicon, where the non-crystalline silicon and the crystalline silicon are present prior to cycling of the electrode. A method of controlling the crystallinity of a silicon powder includes heating a reactor to a temperature of no more than 650° C. and flowing a feed gas comprising silane and a carrier gas into the reactor while maintaining an internal reactor pressure of about 2 atm or less. The silane decomposes to form a silicon powder having a controlled crystallinity and comprising non-crystalline silicon.