▎ 摘　　要

NOVELTY - Positive electrode material is a polyimide/graphene composite. USE - The positive electrode material is useful in a rechargeable magnesium battery (claimed). ADVANTAGE - The positive electrode material avoids low rate performance and cycle reversibility caused by the dissolution of organic substances with redox activity in the electrolyte and conductivity difference and provides the assembled magnesium battery exhibiting excellent electrochemical magnesium storage performance. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing the positive electrode material involving (i) adding graphene into an N-methylpyrrolidone solution and performing an ultrasonic treatment to obtain a graphene dispersion liquid, (ii) adding 1,4,5,8-naphthalenetetracarboxylic dianhydride to the graphene dispersion liquid, adding p-phenylenediamine and refluxing for 5-10 hours under nitrogen protection, (iii) cooling to room temperature, filtering the product, washing with N-methyl-2-pyrrolidone and vacuum drying at 100-150 degrees C for 12-25 hours and (iv) finally, sintering at 300 degrees C for 6-10 hours under nitrogen atmosphere to yield the final product.