▎ 摘　　要

NOVELTY - Preparing diaphragm functional material comprises (i) using ferric nitrate raw materials, and calcining to obtain ferric oxide precursor, (ii) dispersing graphene oxide powder into 40 ml deionized water, and stirring to obtain graphene dispersion liquid, (iii) taking product obtained in the step (i) and adding to mixture containing sodium chloride, polydiallyldimethylammonium chloride and tris(hydroxymethyl)aminomethane in 50 ml of aqueous solution, stirring, filtering, cleaning and drying to obtain a pre-electrostatically treated ferric oxide precursor, (iv) taking product obtained in the step (iii) into dispersion liquid obtained in step (ii), stirring, washing and drying to obtain the precursor powder, and (v) taking 0.1-0.5 g product obtained in step (iv) and placing in porcelain boat, carrying out high-temperature ammoniation treatment in a tubular furnace in an ammonia gas atmosphere to obtain the finished product. USE - The material is useful for improving lithium metal battery performance, in modifying lithium metal battery diaphragm, improving lithiophilicity and mechanical strength of diaphragm, and improving cycle stability and thermal stability of lithium metal battery (all claimed), and in portable communication device and electric device field, research and development of high energy, high power density of recyclable charge and discharge battery. ADVANTAGE - The method provides a simple, fast, efficient, easy for large scale preparation and applied to lithium metal battery diaphragm modified core-shell structure nitrogen-doped graphene coated iron nitride functional material. The method is environment-friendly, mild in condition, capable of mass production, and has high mechanical strength and thermal stability. DETAILED DESCRIPTION - Preparing diaphragm functional material comprises (i) using 6-8 g ferric nitrate raw materials, and calcining to obtain ferric oxide precursor, (ii) dispersing 0.1-0.4 g graphene oxide powder into 40 ml deionized water through a cell crusher, and continuously stirring to obtain graphene dispersion liquid, (iii) taking 1-2 g product obtained in the step (i) and adding to a mixture containing 0.1-0.3 g sodium chloride, 1.5-2.5 g polydiallyldimethylammonium chloride and 0.2-0.6 g tris(hydroxymethyl)aminomethane in 50 ml of aqueous solution, continuously stirring for a specific period of time, filtering, cleaning and drying to obtain a pre-electrostatically treated ferric oxide precursor, (iv) taking 1-2 g product obtained in the step (iii) into dispersion liquid obtained in step (ii), continuously stirring, washing and drying to obtain the precursor powder, and (v) taking 0.1-0.5 g product obtained in step (iv) and placing in porcelain boat, carrying out high-temperature ammoniation treatment in a tubular furnace in an ammonia gas atmosphere to obtain the finished product.