Si-Based-Alloy Anode Material

A Si-based alloy anode material for lithium ion secondary batteries, comprising an alloy phase composed of a Si principal phase comprising Si and a compound phase comprising two or more elements,

• wherein the two or more elements comprise a first additional element A being at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb and Mg and a low-melting second additional element B being at least one selected from the group consisting of S, Se, Te, Sn, In, Ga, Pb, Bi, Zn, and Al,
• wherein the compound phase comprises:
• a first compound phase comprising Si and the first additional element A;
• a second compound phase comprising the first additional element A and the second additional element B;
• and
• one or both of a third compound phase comprising two or more of the second additional elements B and a single phase of the second additional element B, or, alternatively, comprises:
• a compound phase comprising Si and the first additional element A;
• and
• one or both of a compound phase comprising two or more of the second additional elements B and a single phase of the second additional element B, and
• wherein the Si principal phase has an average minor axis width of 4 μm or less.