Preparation And Electrochemical Performance Of Graphene/PANI/CO₃O₄ Composite

Carbon material, metal oxide and conductive polymer were used for supercapactior as mainly three kinds electrode material. As the conductive material, graphene was composited with metal oxide or conductive polymer which could improve the integrated electrochemical performance of composite material by synergistic effect. Therefor, we designed a new method?two-step method? to synthesize the reduced graphene oxide?RGO?/PANI/Co₃O₄ ternary composite, and its electrochemical properties were also studied.Graphene oxide was used to prepare grapheme/polyaniline/Co₃O₄ composite in two steps. XRD, Raman, FTIR, XPS, SEM were used to characterize the structure and morphology. The results showed that the ternary complex was lamella-frame structure. Polyaniline band could keed grapheme as 2D structure and Co₃O₄ dispersed on the surface of graphene sheets. Electrochemical tests showed that the composite had double layer capacitor in Na2SO4 solution. Specific capacitance was 153 F/g when the charging and discharging current was 0.5 A/g. After 1000 cycles, specific capacitance was changed to 60% of before. Meanwhile, the composite had both double layer capacitor and pseudocapacitor in KOH solution. Specific capacitance was 220 F/g when the charging and discharging current was 0.5 A/g. After 1000 cycles, specific capacitance climbed to 250 F/g.Asynchronous and synchronous method were used to doped polyaniline with Co²⁺ to improve the conductivity of polyaniline. SEM, FTIR results showed Co²⁺ doping polyaniline had little morphology difference from before, but conductivity was increased. Co²⁺ doping polyaniline was also used to synthesis grapheme/polyaniline /Co₃O₄. XPS results showed composite material made by asynchronous method had a doping rate of 16%, which was similar to no-doping, and asynchronous method was 28%. Electrochemical tests showed the charge transfer resistance of composite material decreased to 0.386 ? and 0.102 ?. At 500 mV/s, the retention of capacitor of two kinds composite material is 1.38 times and 1.82 times of original.