Composite anode material including surface-stabilized active material particles and methods of making same

An anode, comprising:

• capsules comprising graphene, reduced graphene oxide, graphene oxide, or a combination thereof;
• active material particles disposed inside of the capsules, each particle comprising:
• a core;
• and
• a buffer layer surrounding the core,
• wherein the buffer layer and the core comprise different materials;
• and
• a binder.

A method of forming an anode active material, the method comprising:

• heating crystalline silicon particles in an inert atmosphere at a first temperature ranging from about 700° C. to about 900° C.;
• heating the particles at the first temperature in an oxidizing atmosphere, for a first time period, to form oxidized particles that each comprise a silicon oxide layer surrounding a crystalline silicon core;
• and
• cooling the oxidized particles in an inert atmosphere.