Electrophoretic deposition of nickel cobaltite/polyaniline/rGO composite electrode for high performance all-solid-state asymmetric supercapacitors

Nickel cobaltite composite electrodes were fabricated by a fast, scalable, and cost-effective electrophoretic deposition for supercapacitor applications. NiCo2O4/PANI/rGO composite electrode went through heat treatment under nitrogen to carbonize PANI after electrophoretic deposition. NiCo2O4 platelets, distributed on carbonized polyaniline-rGO network, were active in charge storage with high capacitance, excellent rate capability (1235 F g(-1) at 60 A g(-1)), and acceptable cycling stability (3000 cycles at 10 A g(-1)) in a three-electrode assembly. The practical application of the composite electrode was investigated by an all-solid-state asymmetric supercapacitor cell using NiCo2O4/C-PANI/rGO as the cathode and activated carbon as the anode with specific capacitance of 262.5 F g(-1) at 1 A g(-1) and a good capacitance retention of 78% after 3500 cycles at an expanded working potential of 1.5 V. This work shows the importance of the composite assembly process that governs the microstructure of the composite.