▎ 摘　　要

NOVELTY - A composite binder comprises perfluorosulfonic acid, polyvinylidene fluoride and solvent. USE - Composite binder used in cathode slurry of silicon cathode sheet for lithium ion battery (all claimed). ADVANTAGE - The composite binder can effectively enhance the toughness of the electrode, reduce the phenomenon of electrode cracking to maintain the integrity of the silicon cathode structure, reduce the loss of the active species and improve the cycle performance of the battery. The perfluorosulfonic acid can form a strong hydrogen bond with the surface of the silicon cathode material, has excellent bonding effect to the silicon material and can effectively relieve the swelling effect of polyvinylidene fluoride in the electrolyte. The three-dimensional bonding network structure of the electrode is ensured, so that the lithium battery has high capacity retention rate. The perfluorosulfonic acid and polyvinylidene fluoride are combined as composite binder to improve the bonding strength of the binder to the silicon material and improve the whole electrical performance of the lithium battery. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) cathode slurry which comprises a silicon material, a conductive agent and a glue solution comprising the composite binder; (2) silicon cathode sheet, which comprises a current collector and a cathode main frame which is prepared using the cathode slurry; and (3) lithium ion battery, which comprises an anode sheet, an electrolyte and the cathode sheet.