Enhancing the electrochemical performance of Ni-doped CuCo₂O₄ electrode material through 2D layered sheets

In the present study, the structural and electrochemical properties on Ni–CuCo₂O₄ (0 ≤ x ≤ 10 %) was studied for the use of active electrode materials in asymmetric supercapacitors prepared by a simple hydrothermal process. The synthesized material’s morphology shows that the nanosheets are assembled with an average diameter of about 50 nm, and the X-ray diffraction results show the spinel cubic structure with the space group of Fd-3mz (No. 227). CuCo₂O₄ electrodes exhibit a high specific capacitance for the electrodes because of the abundant redox reactions of Co²⁺/Co³⁺ and Co³⁺/Co⁴⁺, and Ni at the Co site has displayed exceptional charge-discharge and cyclic stability properties. The electrochemical studies show that the Ni doped CuCo₂O₄ electrode has the highest pseudocapacitive nature, with ultra-specific capacitances of 803 F g⁻¹, 889 F g⁻¹, 924 F g⁻¹, and 1,086 F g⁻¹ at 1 A g⁻¹ respectively for pure, 2, 6, and 10 % Ni doped CuCo₂O₄ electrodes. Further, the excellent rate capability with 82 % capacitance retention and 92.3 % Coulombic efficiency were realized after 1,000 cycles. Moreover, the M-H study at room temperature showed paramagnetic behaviour. Additionally, the electrochemical and magnetic characteristics of the CuCo₂O₄ system is expected to improve as the doping quantity of Ni increased. This study may pave the way for enhanced properties of Ni doped CuCo₂O₄ for futuristic hybrid devices applications.