Tin-copper-carbon composite negative electrode material of sodium ion battery and preparation method and application of tin-copper-carbon composite negative electrode material

The invention discloses a tin-copper-carbon composite negative electrode material of a sodium ion battery and a preparation method and application of the tin-copper-carbon composite negative electrode material, and belongs to the technical field of sodium ion batteries, the negative electrode material has at least one of the following characteristics: (1) the negative electrode material is a sphere with a core-shell structure and a size of 200-800nm; (2) the negative electrode material comprises a copper-tin alloy coating layer with the thickness of 2-20 nm; (3) in the negative electrode material, the mass percent of copper is 0.5-50%; (4) in the negative electrode material, the mass percent of tin is 10-95%; (5) in the negative electrode material, the mass percent of carbon is 5-60%, and a carbon layer with the thickness of 5-50 nm is formed; compared with the prior art, the negative electrode material provided by the invention has low battery internal resistance and excellent cycling stability, and solves t