Electrospun polyimide nanofiber-based separators containing carboxyl groups for lithium-ion batteries

A lithium-ion battery separator facilitates lithium-ion transportation and prevents direct contact between the cathode and anode. Polyimide separators exhibited superior thermal stability and electrolyte wettability. In this study, carboxylated polyimide separators were prepared by electrospinning carboxyl group-containing monomers. Polyimide separators were prepared with different content of carboxyl group-containing monomer. Moreover, the thermal property, mechanical property, and electrochemical performance of separators were studied. The carboxylated polyimide separators exhibited lower interfacial resistance and higher ionic conductivity compared with polyimide separators. Moreover, the LiFePO 4 /Li half-cell assembled using the carboxylated polyimide exhibited enhanced cycling stability and rate capability. Therefore, carboxylated polyimide separators with superior electrochemical performances are promising candidates for lithium-ion batteries.