▎ 摘　　要

NOVELTY - Preparation of boron carbonitride nanosheet comprises weighing and mixing carbon source, boron source and nitrogen source to obtain mixed powder, drying and grinding to obtain amorphous phase precursor, subjecting to degassing treatment and heat treatment at 800-1200 degrees C to obtain treated boron carbonitride nanosheet, ball milling, and purifying. USE - The method is for preparation of boron carbonitride nanosheet used as supercapacitor electrode material for thermal insulation absorbing material or catalytic adsorption material (all claimed). ADVANTAGE - The method adopts high temperature heat treatment by ball milling, eliminates the process of dispersing in aqueous solution or other solvents and crystallizing which saves energy consumption of solvent evaporation and reduces production cost, and eliminates the process of dissolving the raw materials in water or other solvents and separating out, uses planetary ball mill for uniform mixing and refinement which increase the contact area of raw materials and increase reaction rate and degree of reaction. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a boron carbonitride nanosheet.