Electrochemical evaluation of rGO and MnCo₂S₄ nanoparticle for pseudocapacitor electrodes

The pursuit of sustainable and efficient energy storage solutions has driven extensive research into advanced electrode materials for pseudocapacitors. In this work, manganese cobalt sulfide (MnCo₂S₄) and reduced graphene oxide (rGO) were synthesized hydrothermally. The presence of functional groups in crumpled sheet-like rGO having high surface area enhanced the charge storage ability. The existence of multiple oxidation states in MnCo₂S₄ accounts for the faradic process on the electrode surface. MnCo₂S₄ and rGO exhibit a specific capacitance of 414 F/g and 588 F/g at the scan rate of 5 mV/s with the faradic dominating behavior in 6 M potassium hydroxide electrolyte. Non-linear charge–discharge curves with plateaus denoted the voltage range for the occurrence of redox reaction. Low charge transfer resistance and solution resistance were observed along with Warburg diffusion resistance in impedance measurements. An asymmetric configuration of electrode containing anode, cathode, separator, and electrolyte was constructed to check the practical relevancy.