Process for producing graphene/silicon nanowire hybrid material for a lithium-ion battery

A process for producing a silicon (Si) nanowire/graphene hybrid material as a lithium-ion battery anode active material, said process comprising:

• (A) preparing a mixture of catalyst metal-coated Si particles, graphene sheets, and a blowing agent, wherein said Si particles have a particle diameter from 50 nm to 50 μm and said catalyst metal is in a form of nanoparticles having a diameter from 0.5 nm to 100 nm or a thin coating having a thickness from 0.5 nm to 100 nm deposited on surfaces of said Si particles and on surfaces of graphene sheets, and wherein said Si particles contain pure Si having at least 99.9% by weight of Si element or a Si alloy or mixture having from 70% to 99.9% by weight of Si therein;
• (B) exposing said mixture to a high temperature environment, including a temperature from 100° C. to 2,500° C., for a period of time sufficient to induce volatile gas molecules from said graphene sheets or to activate said blowing agent for producing a porous graphene structure or a graphene foam and to enable a catalyst metal-catalyzed growth of multiple Si nanowires emanating from said Si particles as a feed material to form an amount of graphene foam-protected or porous graphene structure-enclosed Si nanowires;
• wherein said Si nanowires have a diameter from 2 nm to 100 nm, a length from 50 nm to 20 μm, and a length-to-diameter aspect ratio of at least 5 and said Si nanowires are in an amount from 0.5% to 99% by weight based on the total weight of said graphene and said Si nanowires combined;
• and (C) operating a mechanical breaking means to mechanically break said graphene foam-protected or porous graphene structure-enclosed Si nanowires to produce said Si nanowire/graphene hybrid material in a powder mass form.