Enhanced Electrochemical Performance of the Nanocomposite MnCo₂O₄ Nanoclusters for Supercapacitors Application

MnCo₂O₄ nanoclusters were prepared using a simple and cost-effective hydrothermal method followed by calcination at 400°C for 3 h. Their structural analysis showed the high crystalline nature of the spinel MnCo₂O₄ with an average crystalline size of 50 nm. The Fourier-transform infrared (FTIR) spectroscopic bands at 558 and 652 cm⁻¹ confirmed the chemical structural coordination of Mn-O and Co-O bonds in the case of the MnCo₂O₄ sample. The Raman vibrational bands observed at 196 cm⁻¹, 477 cm⁻¹, 607 cm⁻¹, and 680 cm⁻¹ confirmed the formation of crystalline MnCo₂O_4. The morphological analyses displayed the nanoclusters morphology for the MnCo₂O₄ and the energy dispersive spectroscopy (EDS) analysis confirmed the presence of Mn, Co, and O elements in the synthesized material. The x-ray photoelectron spectroscopy (XPS) results revealed the existence of the mixed Co²⁺/Co³⁺ and Mn³⁺/Mn⁴⁺ valence states in the prepared MnCo₂O₄ nanoclusters. The MnCo₂O₄ nanocluster-based electrode in 3 M KOH electrolyte revealed a better electrochemical performance, with a specific capacitance of 350 F g⁻¹ at a scan rate of 10 mV s⁻¹ from the cyclic voltammetry study, and exhibited a higher capacitance value of 333 F g⁻¹ at a current density of 1 A g⁻¹ from the galvanostatic charge–discharge (GCD) analysis. Long duration cycle stability studies revealed that the MnCo₂O₄ electrode exhibited high stability after 1000 GCD cycles and retained 80.5% of its initial capacitance at a current density of 5 A g⁻¹. These results suggest that the prepared MnCo₂O₄ nanoclusters might be well suited to be an efficient supercapacitor electrode material.