▎ 摘　　要

NOVELTY - Blended polyamic acid solution, comprises rigid polyamic acid, flexible polyamic acid and a polar solvent. The rigid polyamic acid is formed by condensation polymerization of rigid dibasic acid anhydride and rigid diamine, and the flexible polyamic acid is formed by condensation polymerization of flexible dibasic acid anhydride and flexible diamine. The mass ratio of the rigid polyamic acid and the flexible polyamic acid is 1: 9-9: 1, preferably 3: 7-7: 3. The average molecular weight of the rigid polyamic acid and the flexible polyamic acid is 10000-500000, preferably 50000-200000. The solid content of the blended polyamic acid solution is 0.5-40 wt.%, preferably 10-25 wt.%. The intrinsic viscosity of the blended polyamic acid solution is 0.5-6.0 dL/g, preferably 1.5-3.5 dL/g. USE - Blended polyamic acid solution used in lithium-ion battery pole piece (claimed). ADVANTAGE - The blended polyimide adhesive has synergistic effect between rigid and flexible polyimide, which can suppress the volume change of the electrode material while having excellent thermal stability. The lithium-ion battery assembled with the lithium ion battery pole piece exhibits remarkable advantages such as outstanding high temperature safety, excellent electrochemical performance, higher discharge specific capacity and capacity retention rate. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: A blended polyimide adhesive, is obtained by imidizing the blended polyamic acid solution. A lithium-ion battery pole piece, which comprises an active material layer and a current collector. The active material layer comprises a positive electrode or negative electrode active material, a conductive agent and the blended polyimide binder. The positive active material is ternary materials of lithium cobaltate, lithium manganate, lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt aluminate and lithium nickel cobalt manganate. The negative active material is carbon material, silicon oxide, tin oxide, silicon-carbon composite material, silicon-oxygen-carbon composite material and tin-carbon composite material. The conductive agent is conductive carbon black, conductive graphite, graphene and carbon nano tubes. The active material layer comprises 80-99 wt.% of positive electrode or negative electrode active material, 0.5-10 wt.% conductive agent and 0.5-10 wt.% block polyimide. A method for preparing lithium-ion battery pole piece, which involves respectively using rigid dibasic acid anhydride and rigid diamine, and flexible dibasic acid anhydride and flexible diamine to prepare rigid polyamic acid solution and flexible polyamic acid solution by a condensation polymerization method in a polar solvent, and then mixing the rigid polyamic acid solution and the flexible polyamic acid solution to obtain the blending polyamic acid solution. The positive electrode or negative electrode active material, the blended polyamide acid solution, the conductive agent and the NMP solvent are fully mixed, and uniformly stirred to obtain electrode slurry. The electrode slurry is uniformly coated on a current collector, followed by drying, rolling, and finally carrying out heat treatment on the rolled pole piece to obtain the lithium ion battery pole piece containing the blending type polyimide adhesive.