Structure, morphology and energy storage properties of imide conjugated microporous polymers with different cores and the corresponding composites with CNT

Abstract

Conjugated microporous polymers (CMPs) have attracted more and more attention owing to inherent pore and high specific area. However, the low conductivity for CMPs limits its application in energy storage. Herein, three kinds of imide conjugated microporous polymers (pNTCDA-TAPB, pNTCDA-TAPM and pNTCDA-TPAT) with different cores were achieved via the condensation reaction. Also, the corresponding composites (pNTCDA-TAPB@CNT, pNTCDA-TAPM@CNT and pNTCDA-TPAT@CNT) were prepared by the in-situ composition with CNT. Among the three polymers, pNTCDA-TPAT exhibits the highest specific capacity of 217.4 F g−1 at 0.5 A g−1 in the neutral electrolyte than that of others, which is a high value among the reported CMPs-based energy storage materials. FT-IR spectra at the applied voltages proved that the excellent energy storage capacity for pNTCDA-TPAT could be attributed to the involvement of the triazine central core except of imide units participating in the reduction of energy storage. However, the energy storage capacity of pNTCDA-TAPB after compositing with CNT has been greatly improved compared with the pure polymer while the energy storage capacity improvement for others two polymers with CNT (pNTCDA-TAPM@CNT and pNTCDA-TPAT@CNT) is not significant. SEM and HR-TEM results indicate that the distinct difference for the three polymers after composition with CNT could be attributed to the formation of unique core-shell structure for pNTCDA-TAPB@CNT system, which may be beneficial to the ion migration and electron transport.