THREE-DIMENSIONAL POROUS SILICON-BASED COMPOSITE NEGATIVE ELECTRODE MATERIAL OF LITHIUM ION CELL AND PREPARATION METHOD THEREOF

摘要

Disclosed are a porous silicon-based composite negative electrode material of a lithium ion cell and a preparation method thereof. The present invention adopts a three-dimensional grid structure, so that electrode active materials are evenly dispersed therein and on the surface, and the three-dimensional grid structure has a current collector material having a high-temperature resisting feature and fine conductivity, such as a copper foil mesh, a copper wire mesh, foamed copper, or foamed nickel. Moreover, a dipping method is used to combine slurry containing monatomic silicon or a mixture of monatomic silicon and metal M with the copper foil mesh, copper wire mesh, foamed copper, or foamed nickel, so as to form a three-dimensional porous silicon-based composite negative electrode material through heat treatment (alloying and annealing treatment). In the present invention, through the forming of the three-dimensional porous structure and the silicon metal alloy, and the fine bonding force between the negative electrode material and the three-dimensional porous current collector material, the cell prepared using the porous silicon-based composite negative electrode material has high discharge capacity and initial charge-discharge efficiency, and good cycle performance.