▎ 摘　　要

NOVELTY - Preparing polyimide based on conjugated carbonyl group, comprises (1) dissolving the dianhydride monomer in N-methylpyrrolidone (NMP), stirring evenly, adding the diamine monomer, and performing a polycondensation reaction to obtain a polyimide acid solution; (2) cooling the polyimide acid solution to normal temperature, drying and removing the solvent to obtain a polyimide acid block, grinding the block, calcining by thermal imidization process under condition of inert gas, obtaining target product; and (3) mixing polyimide with conductive additive and binder, coating it on the copper foil substrate, drying, performing series of electrochemical tests under three-electrode system in solution containing iron ions. USE - The polyimide is used as electrode material in storing iron ions in field of large-scale energy storage. ADVANTAGE - The polyimide: store iron ions at a lower electrochemical potential with excellent performance; and has long cycle life, high stability, high safety, and environmental protection.