Unveiling the Synergistic Effect of MnCo LDH Adorned MnCo₂S₄ Nanocomposite as Efficient Bifunctional Electrode for Asymmetric Supercapacitor and Overall Water Splitting

Metal-based LDHs incorporated with TMDs, exhibiting excellent synergistic effects, have attracted significant interest from researchers for energy production and storage applications due to their outstanding properties. In the present research, manganese cobalt sulfide incorporated into a manganese cobalt layered double hydroxide (MnCo₂S₄@MnCo LDH) composite has been developed for supercapacitors and overall water splitting. At a current density of 1 mA cm^-2, the MnCo₂S₄@MnCo LDH-NF exhibits the highest specific capacitance (475.8 F g^-1) compared to other electrodes. The MnCo₂S₄@MnCo LDH//AC ASCD demonstrates an energy density of 5.27 Wh kg^-1 and a power density of 851.06 W kg^-1, along with high cyclic stability, retaining 93.75% of its capacitance and 98.36% Coulombic efficiency. Furthermore, MnCo₂S₄@MnCo LDH-NF shows lower overpotentials (ƞ₁₀) and Tafel slopes for HER (-163.9 mV and 96.2 mV dec^-1) and OER (-150.68 mV and 50.95 mV dec^-1) compared to control electrodes. The fabricated water-splitting cell (MnCo₂S₄@MnCo LDH_{(+, -)}) efficiently generates both oxygen (O₂) and hydrogen (H₂) bubbles at a low voltage of 1.38 V. These results demonstrate that the MnCo₂S₄@MnCo LDH composite is an excellent candidate for both energy storage (supercapacitor) and green energy production (water splitting), showing potential for future renewable energy systems.