▎ 摘　　要

NOVELTY - Preparing diaphragm functional material comprises (i) dissolving 6-14 mmol potassium sulfate, 3-6 mmol sodium tungstate and 1-4 mmol sodium citrate as raw material in 70 ml distilled water as solvent containing 60-100 mg graphene oxide, stirring until solid raw material is completely dissolved, adjusting pH value to 1-2 with hydrochloric acid as pH adjuster to obtain mixed solution, (iii) pouring mixed solution into 100 ml reaction kettle, performing hydrothermal reaction at 160-200degreesC for 18-36 hours, naturally cooling to room temperature, filtering, cleaning, freezing and drying to obtain tungsten oxide and graphene oxide complex precursor, and (iv) taking 0.5-1 g product obtained in step (iii), placing it in ceramic boat, raising temperature in ammonia gas atmosphere of tube furnace at 600-700degreesC under heating rate of 2-5degreesC/minutes for 2-5 hours, and cooling to room temperature. USE - The method is useful for preparing diaphragm functional material, which is useful for improving electrochemical performance of lithium metal battery, modifying the membrane lithium metal battery, improving the electrolyte wettability, mechanical strength and thermal stability of the lithium metal battery separator to improve the cycle stability and rate performance of the lithium metal battery (all claimed). ADVANTAGE - The method: is simple, efficient, and fast; has environmental friendly raw materials, mild reaction conditions, good repeatability, and large-scale production; utilizes cheap sodium citrate as complex surfactant, sodium tungstate as tungsten source, hydrochloric acid as acidity regulator; and firstly synthesizes tungsten precursor by complexing surfactant auxiliary hydrothermal method, and aminates to obtain the nitrogen-doped graphene nanoflowers embedded with ditungsten trinitride. The material has good lithium affinity, high ionic conductivity, thermal stability and mechanical strength because the growth of the lithium dendrite can pierce the diodes to cause short circuit of the battery; and improves the safety of battery from the mechanical angle. The embedded layer of nitrogen-doped graphene provides structural stability of the whole material as well as the lithium metal battery.