▎ 摘　　要

NOVELTY - Preparing a nitrogen-doped graphene material involves dissolving glucose, ammonium chloride and urea in water to obtain a mixed solution, and heating and evaporating the mixed solution to obtain a mixture. The mixture is calcined in an inert gas atmosphere at 1000-1200 degrees C to obtain a nitrogen-doped graphene material. USE - Method for preparing a nitrogen-doped graphene material for preparing a composite positive electrode material of diaphragm (all claimed). ADVANTAGE - The method enables to prepare a nitrogen-doped graphene material with stable structure and uniform pores. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing a composite positive electrode material, which involves: (A) mixing and grinding the nitrogen-doped graphene material and sublimed sulfur to obtain a mixture powder; and (B) calcining the mixture powder at 150-155 degrees C in an inert gas atmosphere to obtain a composite positive electrode material.