Fabrication of NiCo₂O₄@polyaniline heterostructure as positive electrode for asymmetrical supercapacitor

Abstract

NiCo₂O₄, as a low‐cost and high‐performance binary transition metal oxide material, has been widely used in the fabrication of supercapacitor electrodes. However, the low energy density of binary metal oxides limits their large‐scale practical applications in supercapacitors, so it is highly desirable to design the structure of the NiCo₂O₄‐based supercapacitor. Therefore, in this paper, NiCo₂O₄ is compounded with polyaniline (PANI) to improve its electrochemical performance by exploiting the synergistic effect. The NiCo₂O₄@PANI composite electrode exhibits a specific capacitance of 561.2 F/g at 10 mV/s. In this study, asymmetric supercapacitors are assembled with NiCo₂O₄@PANI as the positive electrode and MXene as the negative electrode. The NiCo₂O₄@PANI‐CC//MXene‐CC supercapacitor has a specific capacitance of 31.95 F/g at a scan rate of 10 mV/s and a good cycle retention capacity of 86.2% after 3000 cycles. The excellent electrochemical performances are attributed to the dynamic equilibrium and fast redox kinetics of the two electrodes.