Modified silicon-based active material and preparation and application thereof

The invention belongs to the field of silicon-based electrode materials, and particularly relates to a preparation method of a modified silicon-based active material, which comprises the following steps: pre-treating a silicon raw material in an oxidizing acid solution to obtain a pre-treated material; the pretreated material is subjected to carbon coating treatment, and a carbon-coated material is obtained; performing lithiation roasting on the carbon-coated material and a lithium source to obtain a lithiated material; and placing the lithiated material in a modification liquid, and carrying out modification treatment to prepare the modified silicon-based active material, the modification liquid contains (NH4) 2S2O3. The invention also discloses the material prepared by the preparation method and application thereof. According to the method disclosed by the invention, the first-effect and high-magnification long-range cycle stability of the modified silicon-based material can be improved. 本发明属于硅基电极材料领域，具体涉及改