Construction of Artificial SEI on Graphite Electrode through Electropolymerization of p-Sulfonated Polyallyl Phenyl Ether

Abstract The artificial inert layer is a dense passivation film formed on the electrode, which can effectively maintain the phase stability of the electrode. Here, p-sulfonated allyl phenyl ether monomer (SAPE) was prepared and a layer of polymer coating with ionic conductivity was electropolymerized on the surface of a graphite electrode as an artificial solid electrolyte interphase (SEI) film using cyclic voltammetry. The overall electrochemical performance of lithium ion batteries can be significantly improved by using p-sulfonated polyallyl phenyl ether/graphite composites (SPAPE/NG) as cathode materials for lithium ion batteries. The large amount of sulphonic acid groups in SPAPE is beneficial to improving the lithium ion transport rate at the graphite electrode interface, and the polymer layer can effectively inhibit the adverse side reactions at the electrode/electrolyte interface. The SPAPE/NG electrode with 20 cycles of electropolymerizing shows the best electrochemical performance. After 150 cycles at a 0.2C rate, the SPAPE/NG electrode still retains a discharge specific capacity of 221.6 mAh·g-1, which is higher than that of the pure graphite electrode (155.3 mAh·g-1).