Activated carbon-supported LaNiO₃ perovskite nanocomposite supercapacitor electrode material exhibiting superior power density and life cycle

Perovskite nanocomposite electrodes, which are made of activated carbon (AC) and lanthanum nickel oxide (LaNiO₃), have unique electrical and chemical properties. LaNiO₃ was synthesized using the sol–gel method, whereas the LaNiO₃@AC nanocomposite was generated by the ultrasonication process several times, keeping LaNiO₃ and AC in a solvent of 1-methyl-2-pyrrolidone (NMP). Examine the electrochemical performance after making a supercapacitor cell by coating electrode materials on Ni foam with a 4 mg/cm² mass loading. The pure LaNiO₃ electrode exhibits moderate specific capacitance (C_s) of 136.82 F/g at 0.5 A/g current density with cyclic stability of 62.09% capacitance retention after 10000 cycles, including energy density and power density of 19.00 W h/kg and 1.55 kW/kg, respectively. However, the LaNiO₃@AC nanocomposite electrode produced a high C_s of 260.45 F/g at 0.5 A/g current density and exhibited remarkable cyclic stability, maintaining around 80.78% of the specific capacitance retention after 10,000 cycles. It also demonstrated an exceptional energy density of 36.17 W h/kg and a high-power density of 1.58 kW/kg. Further investigation on the storage contribution has been conducted with b-fitting, Dunn’s, and Randles Sevcik’s models. The DFT investigation provides more insight into the stability and electrochemical characteristics of the LaNiO₃ material.