Electrochemical behavior of V/Ce co-doped carbon shell-coated NiO nanocomposite for alkaline OER and supercapacitor applications

Developing highly efficient, versatile, durable, and non-precious electrode materials for sustainable electrochemical energy storage and conversion technologies is still a long-term challenge in the energy sector for researchers. Herein, we developed a sustainable and bifunctional electrode, based on V/Ce co-doped NiO coated with carbon grown on Ni foam substrate through a simple and cost-effective sol-gel method. OER activity and supercapacitance characteristics have been validated by coupling contact and morphological porous features (unique core-shell) and also demonstrated satisfying electronic structural attributes for grown material. The formation of defective lattice and oxygen vacancies in NiO by co-doping along with varying oxidation states of V, Ce, and Ni was confirmed by XPS. The modified material as a supercapacitor electrode, manifested superior specific capacitance of 1719 F g⁻¹ at 2 A g⁻¹ current density and outstanding cycling stability performance with 98.21 % retention after 5000th cycles. This highly efficient cycling is due to abundant redox states and surface redox functionalities of carbon, providing an easy pathway to transfer ions. The redox behavior of the composite catalyst also contributes toward high conductivity and the electrochemically active surface area thus showed a small Tafel slope of 35.4 mV dec⁻¹. The current density of 10 mA cm⁻² showed a low overpotential of 238 mV. In a practical system, it also revealed significant stability for OER over 100 h of continuous electrolysis, tested by chronoamperometry. The influence of co-doping and carbon support highlights the remarkable advantages of electrochemical performance and enriches its application prospect for efficient electrolysis and storage technology.