Processes for the Preparation of Silicon-Containing Composite Particles

Abstract

A process for preparing composite particles comprising the steps of providing a charge of porous particles in a reaction zone, continuously introducing a gaseous feed stream comprising a silicon precursor gas into the reaction zone while maintaining conditions of temperature and pressure that are effective to cause deposition of silicon into the pores of the porous particles, a deposition phase during which the flow rate of the silicon precursor gas into the reaction zone is more than 2.0 × 10-6 grams of silicon per square metre of surface area per minute based on the total BET surface area of the charge of porous particles, and either or both of an initiation phase prior to deposition or a termination phase after deposition during which the flow rate of the silicon precursor gas into the reaction zone is less than 2.0 × 10-6 grams of silicon per square metre of surface area per minute. The particles may be used as anode active materials in rechargeable lithium-ion batteries.