A method for preparing C-Si2N2O-Si composite anode material for lithium-ion batteries

Abstract

This invention discloses a method for preparing C-Si2N2O-Si composite anode material for lithium-ion batteries, belonging to the field of lithium-ion battery technology. The method comprises the following steps: (1) Si3N4 and SiO2 are mixed evenly and then subjected to high-temperature heat treatment under a nitrogen atmosphere to obtain Si2N2O@Si3N4 composite powder; (2) The Si2N2O@Si3N4 composite powder is mixed evenly with a carbon source and subjected to high-temperature heat treatment under an inert atmosphere to obtain C@Si2N2O@Si3N4 composite powder; (3) The C@Si2N2O@Si3N4 composite powder is subjected to high-temperature vacuum heat treatment to decompose Si3N4 and form dispersed porous nano-Si particles, thereby obtaining the C-Si2N2O-Si composite anode material. The C-Si2N2O-Si composite anode material obtained by this preparation method has a hollow structure with nanoporous Si particles dispersed inside, a Si2N2O layer coating the surface of the porous Si particles, and a C layer coating the surface of the composite material particles. This structure can alleviate the volume expansion generated during charging and discharging and prevent the Si particles from falling off, thus exhibiting excellent electrochemical performance.

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