US 9,142,830 B2 · Phase separated silicon-tin composite as negative electrode material for lithium-ion batteries

Abstract

A composite of silicon and tin is prepared as a negative electrode composition with increased lithium insertion capacity and durability for use with a metal current collector in cells of a lithium-ion battery. This electrode material is formed such that the silicon is present as a distinct amorphous phase in a matrix phase of crystalline tin. While the tin phase provides electron conductivity, both phases accommodate the insertion and extraction of lithium in the operation of the cell and both phases interact in minimizing mechanical damage to the material as the cell experiences repeated charge and discharge cycles. In general, roughly equal atomic proportions of the tin and silicon are used in forming the phase separated composite electrode material.

Claims18

Dependent claims

A lithium-ion secondary electrochemical cell or battery comprising a negative electrode composition;

lithium being inserted into a negative electrode composition during charging of the cell or battery and lithium being extracted from the negative electrode composition during discharge of the cell or battery;
the negative electrode material comprising a composite that consists of tin and silicon in which the tin and silicon are present in separate phases, the composite being further characterized by a phase of nanoscale islands of silicon, 30 to 70 nanometers in size, dispersed in a matrix phase of tin, the tin phase being crystalline or amorphous and the silicon phase being amorphous.

Dependencies are inferred from the claim text.

Phase separated silicon-tin composite as negative electrode material for lithium-ion batteries

Life of this patent

Phase separated silicon-tin composite as negative electrode material for lithium-ion batteries

Life of this patent

Abstract

Claims18