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.