Patent ID: 8715855
Filing Date: 2014-05-06
Classification: H01G,H01M,Y02E,Y10T

Abstract:
1. An electrode material for a negative electrode of an energy storage device capable of electrochemically storing and releasing lithium ions, the electrode material comprising silicon primary particles composed of crystal particles each having a diameter of 5 nm to 200 nm and an amorphous surface layer having a thickness of 1 nm to 10 nm, wherein the amorphous surface layer of each of the primary particles is formed of at least a metal oxide; Gibbs free energy when the metal oxide is produced by oxidation of a metal is smaller than Gibbs free energy when silicon is oxidized; and the metal oxide has higher thermodynamic stability than silicon oxide, wherein the crystal particles of the silicon primary particles are formed into a network structure with fibrous (filamentous) substances, and a surface of each of the fibrous (filamentous) materials is coated with at least an oxide, and wherein the fibrous (filamentous) substances each have a core-shell structure, the core portion comprises a silicon crystal, and the shell portion comprises an amorphous silicon oxide or an amorphous metal oxide.