Two Coordination Polymers@Graphene Hybrid Electrodes for High-Performance Supercapacitors with Enhanced Rate Capability and Specific Capacitance

摘要

Hybrids of polyoxometalate(POM)/transition-metal complexes/graphene-based electrode materials not only integrate the advantages of the individual components completely but also ameliorate the shortcomings to some extent,providing an efficient approach to fabricate high-performance supercapacitors.In this work,we synthesized two novel isostructural compounds(Co(itmb)4[H2VW_(12)O_(40)] ·4H2O(1)and Zn-(itmb)4[H2VW_(12)O_(40)] ·3H2O(2))based on the Keggin ions via a hydrothermal method(itmb=1-(imidazo-1-ly)-4-(1,2,4-triazol-1-ylmethyl)benzene).The specific capacitance of 1@50%graphene(405.3 Fg~(-1))and 2@50%graphene(339.2 Fg~(-1))were 1.33 and 1.19 times of 1 and 2,respectively.In addition,the 1@50%graphene(93.5%)and 2@50%graphene(96%)possess higher rate performance than 1(90%)and 2(91 %),suggesting a significant enhancement of the electrical performance.