Catalytic CoSn Perovskites for High-Performance Asymmetric Hybrid Supercapacitor and Efficient Oxygen Evolution Reaction: Experimental Investigation and DFT Validation

Developing a bifunctional electrode material for efficient energy storage and an effective electrocatalyst for the oxygen evolution reaction (OER) remains of significant scientific interest. Here, the electrochemical properties of perovskite hydroxide CoSn(OH)6 (CTH) and perovskite oxide CoSnO3–x (CTO) are systematically evaluated for their applications in asymmetric hybrid supercapacitors (AHSs) and as a catalyst for OER. Dunn analysis is employed to investigate the charge storage mechanism, and electrochemical impedance spectroscopy has been employed to study the charge transfer kinetics and diffusion kinetics associated with both the CTH and CTO electrodes. CTH and CTO exhibit specific capacitances of 1414 and 681 F/g, respectively, revealing that CTH notably manifests superior electrochemical performance. The DFT calculations are performed to elucidate the interaction of OH– ions with Co and Sn octahedral sites in CTH. Furthermore, the performance of CTH is assessed in a two-electrode system, with CTH acting as the positive electrode and reduced graphene oxide (RGO) as the negative electrode. The constructed CTH//RGO system exhibits an energy density of 83.5 W h/kg and a power density of 461 W/kg, which is a promising performance for energy storage applications. Furthermore, the OER activity was examined, demonstrating CTH’s superior electrocatalytic efficiency, making it an effective bifunctional electrode material for OER and AHS applications.