▎ 摘　　要

NOVELTY - Preparing doped graphene involves mixing graphite with oxidant and dopant to obatin intercalated graphite, preferably mass ratio of graphite, oxidant and dopant is 1:1-20:0.1-10. The intercalated graphite is calcined to obtain expanded graphite. The doped graphene is obtained by stripping the expanded graphite obtained in with a solvent. USE - Method for preparing doped graphene used for preparing lithium ion battery (claimed). ADVANTAGE - The method enables to prepare doped graphene in cost-effective manner, which greatly improves specific capacity of the cathode material, and improves the cycle stability of the material. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a lithium ion battery negative electrode, which comprises lithium ion storage capacity increased on charge-discharge voltage platform of 0-0.5 Volt.