<p>In the present study, cerium oxide (CeO₂) was combined with nickel oxide (NiO) using a microwave-assisted method followed by post-annealing&#xa0;used for supercapacitor applications. The microwave-assisted method enabled rapid and uniform heating, which accelerated reaction kinetics and ensured precise nanostructure formation. Crystallographic and morphological analyses confirmed the formation of nanorod-like structures in the CeO₂–NiO nanocomposite without impurities. Electrochemical performance was evaluated using a three-electrode arrangement, revealing a maximum specific capacitance of 975 F g⁻¹ at a current density of 2 A g⁻¹, along with a low equivalent series resistance. An all-solid-state asymmetric supercapacitor was fabricated using the prepared material as the positive electrode, with activated carbon serving as the negative electrode. This device exhibited an energy density of 12 W&#xa0;h kg⁻¹ and a power density of 2000 W kg⁻¹, along with excellent cyclic stability, retaining 80% of its initial capacitance after 10,000 charge–discharge cycles. These findings highlight the enhanced electrochemical performance of the CeO₂–NiO nanocomposite and its potential for energy storage applications.</p> Graphical abstract <p></p>