Patent ID: 8715857
Filing Date: 2014-05-06
Classification: B22F,C22C,H01M,Y02E

Abstract:
1. A negative electrode active material, comprising: an Si—Sn—Fe—Cu based alloy, wherein an Si phase has an area ratio in a range of from 35% to 80% in an entire negative electrode active material, wherein the Si phase is dispersed in a matrix phase, wherein the matrix phase comprises an Si—Fe compound phase crystallized around the Si phase and further comprises an Sn—Cu compound phase crystallized to surround the Si phase and the Si—Fe compound phase, wherein the Si—Fe compound phase is crystallized in a ratio of from 35% to 90% in terms of an area ratio in an entire matrix phase, and wherein the matrix phase further comprises an Sn phase unavoidably crystallized in the matrix phase in a ratio in a range from greater than 0% to 15% in terms of the area ratio in the entire matrix phase.