A kind of preparation method of pitch-coated silicon-doped natural flake graphite negative electrode material

Abstract

The invention provides a method for preparing a pitch-coated silicon-doped natural flake graphite negative electrode material, belonging to the technical field of negative electrode material preparation, comprising the following steps: mixing nitric acid solution with natural flake graphite, magnetic stirring reaction, filtering, washing, and drying Weigh nano-silica powder, add it to anhydrous ethanol to dissolve, then add sodium hexametaphosphate, stir it, then ultrasonically oscillate, adjust the pH value, add silane coupling agent, magnetically stir, heat and reflux, fully react, then centrifuge, bake dry, grind; mix the treated natural flake graphite with the treated nano silicon powder, grind, add toluene, nitrogen protection, stir for reaction, filter, wash, dry; mix NG / Si composite material with asphalt toluene solution, Take the material, dry it in the shade, then dry it at a constant temperature, grind it, and pyrolyze it to obtain the product. The method of the invention improves the electrochemical cycle performance and discharge specific capacity of the natural flake graphite.

Description

technical field [0001] The invention belongs to the technical field of graphite modification, and in particular relates to a preparation method of a pitch-coated silicon-doped natural flake graphite negative electrode material. Background technique [0002] Lithium-ion battery is a representative of contemporary high-performance batteries, a green new energy product, widely used in information, telecommunications and power industries. At present, commercial lithium-ion batteries widely use carbon anode materials. Among them, graphite-based anode materials have become the main type of carbon anode materials due to their extensive sources, stable performance, energy saving and environmental protection. [0003] Graphite materials mainly include natural graphite, artificial graphite and various graphitized carbons (such as graphitized coke, graphitized carbon fiber, graphitized mesocarbon microspheres). Natural graphite refers to the natural graphite material obtained from na...

AI Technical Summary

Problems solved by technology

The main problems of flake graphite as the negative electrode material of lithium ion battery are: the compatibility between natural graphite and electrolyte is poor, during the first charging and discharging process, the organic solvent and lithium ions are co-embedded in the graphite sheet to reduce and generate gas, and consume a part of lithium, resulting in Low efficiency for the first time; the graphite spacing is smaller than the interlayer spacing of the lithium interlayer compound Li-GIC, resulting in repeated expansion and contraction of graphite particles during charge and discharge, resulting in peeling and pulverization of the graphite layer, which affects the cycle stability of the battery

However, the specific capacity of the negative electrode material obtained by this method is low