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

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 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 improve 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 ).