In this work, catalytic gasification combined with in-situ CO2 capture over Ni-CaO/Ca2Fe2O5 NPs catalyst is studied for hydrogen-rich synthesis gas production. The Ni-CaO/Ca2Fe2O5 NPs catalyst determined remarkable catalytic performance in changeover ability and synthesis gas. The carbon deposited Ni-CaO/Ca2Fe2O5 spent NPs catalyst was successfully reutilized as an electrode for supercapacitor using KOH electrolyte. This recycled catalyst demonstrates an extraordinarily higher capacity than the pristine catalyst. Attributable to these benefits, the carbon deposited spent catalyst conveyed a high specific capacitance of 1455 F g−1 established electrode mass and high-power density 19,224 W kg−1 with long cycle stability (96% retention after 10,000 cycles). The minimal cost of carbon deposited spent catalyst, along with this method for efficiently recycled carbon-deposited spent catalyst for energy storage applications, might be a promising and cost-effective spent catalyst reutilization technique.