Method of producing a battery anode active material comprising a porous host structure and silicon residing in the host pores

A method of producing a solid powder mass of multiple porous particulates having pores containing silicon (Si) therein for use as an anode active material of a lithium-ion or sodium-ion battery, said method comprising:

• (a) providing a porous conductive host structure having a volume fraction of pores from 5% to 99.9%, wherein the porous host structure is selected from a carbonaceous, graphitic, graphene, or metallic material in a bulk form or in a form of multiple porous particles;
• (b) introducing a reactant gas or vapor of a halogen that chemically reacts with a Si source disposed in a reaction chamber at a first temperature to form a silicon halide with or without using a catalyst, wherein the halogen is selected from F, Cl, I, Br, or a combination thereof and the silicon halide is selected from SiF4, SiCl4, SiI, SiBr4, SiXaZb, or a combination thereof wherein X and Z are each a halogen element and a=1-3, b=1-3, and a+b=4 and wherein the Si source is selected from Si or a Si-rich compound containing no less than 60% by weight of Si in the compound;
• and
• (c) vaporizing said silicon halide to form a vapor phase and, immediately or at a later time, directing said silicon halide vapor phase into pores of said porous host structure and facilitating said silicon halide to decompose, at a second temperature, into a halogen gas product and solid Si particles or coating deposited in said pores to form a Si-infiltrated or Si-impregnated porous host structure.