Conjugated microporous polyimide cathodes for sodium/lithium-ion batteries with ultra-long cycling performance

Abstract

Conjugated microporous polyimides (CMPs) have been emerging as the promising electrode materials for sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs) owing to their low cost, tunable structures, environmental benefit, and high porosity. However, the low intrinsic conductivity, poor structural stability and sluggish diffusion kinetics have hindered their further applications. Herein, a novel conjugated microporous polyimide trapped by multi-walled carbon nanotubes (TAPBA-NTCDA@MWCNTs) as cathodes for SIBs/LIBs have been prepared by in situ polycondensation. The addition of MWCNTs profits greatly in conductivity and structural stability of electrode materials. Consequently, when explored as cathode materials for SIBs, TAPBA-NTCDA@MWCNTs exhibits the good reversible specific capacity, predominant rate capability and ultra-long cycling stability. Moreover, the reaction mechanism and outstanding reversibility are investigated by the detailed ex-situ XPS/FT-IR/SEM analysis. Finally, the cathode also delivers an excellent lithium storage performance. In view of the outstanding cycle stability and such simple synthetic route, this work perhaps provides an effective strategy to fabricate high-performance conjugated microporous polyimide-based cathodes for energy storage and conversion devices.