Preparation and Electrochemical Capacitance Performance of MnFePBA/rGO/CC Composite Electrode

MnFe-Prussian blue analog (MnFePBA) nanocubes were in-situ grown on graphene oxide (GO) surface by co-precipitation. The composite powders with different MnFePBA to GO mass ratios (1:0.1, 1:0.3, 1:0.5) were prepared, and then ultrasonically sprayed onto preheated carbon cloth (CC) substrate. The MnFePBA/rGO/CC composite electrode was prepared by converting GO to reduced graphene oxide (rGO) by chemical reduction. The microstructure and electrochemical capacitance performance of the composite electrode were investigated. The results show that when the mass ratio of MnFePBA to GO was 1: 0.1, agglomeration of MnFePBA particles occurred. When the mass ratio was 1:0.5, obvious stacking of GO nanoflakes was found. With the MnFePBA to GO mass ratio of 1:0.3, uniform hybridization of GO and MnFePBA was achieved, and the as-prepared MnFePBA/GO/CC composite electrode exhibited the best electrochemical performance with the largest specific capacitance, the smallest internal resistance and the largest ion diffusion rate. When the mass ratio of MnFePBA to GO was 1:0.3, the specific capacitance at 1 A·g^-1 of MnFePBA/rGO/CC composite electrode prepared by chemical reduction increased from 888 F·g^-1 before chemical reduction to 1 032 F·g^-1. As the current density increased from 1 A·g^-1 to 10 A·g^-1, the specific capacitance retention was enhanced from 44.93% before chemical reduction to 54.55%. After cycling 3 000 cycles at 7 A·g^-1, the MnFePBA/rGO/CC composite electrode still maintained 94.78% of specific capacitance retention.