Manganese ions conjugated on layered bismuth oxyhalides for high-performance pseudocapacitors and efficient oxygen evolution catalysts

Abstract

The modern demand for an alternative material maintaining excellent catalytic activities with better stability and low toxicity for application in the field of energy remains a hotspot for the scientific community. In the current work, we report a simple conjugation of BiOX with manganese because of their excellent electrical and optical properties. Mn-BiOX displays an average specific capacity of 220.8 mA h g⁻¹ (2291.35 F g⁻¹) in 2 M KOH electrolyte solution at current densities of 0.4–2.4 mA cm⁻²; additionally, it facilitates an efficient oxygen evolution reaction at an overpotential of 160 mV attributed to the synergistic effects, high surface accessibility, and excellent electronic conductivity. A capacitance retention of 86% is observed over 10 000 charging–discharging cycles at a current density of 2.4 mA cm⁻², demonstrating the exceptional stability of the synthesized material. The enhanced electrocatalytic activities are due to superior surface roughness paving the way for the intercalation of ions on the electrode surface, which is proven via atomic force microscopy and electrochemical impedance spectroscopy. These activities hold the merits of delivering high capacitance and catalytic performance suitable for advanced high energy storage applications.