Formation of MnFeO3 nanoparticles on WS2 nano-flakes for solid-state asymmetric supercapacitor to enhance storage properties

Transition metal dichalcogenides (TMDs) offer advantages, including robust conductivity, enhanced surface area, and quick oxidation-reduction activity for energy storage applications. Nevertheless, surface aggregation, oxidation, restacking, and termination collapse of the structure during cycling pose limitations to its commercial application. To overcome these issues, MnFeO3 nanoparticles were attached to the porous WS2 using a hydrothermal procedure. We have fabricated the series of WS2-MnFeO3 (WS-MFO-1, WS-MFO-2, and WS-MFO-3) electrodes with WS2:MnFeO3 ratios of 30:70, 35:65, and 40:60, respectively. Among them, the WS-MFO-2 nanocomposite electrode showed a specific capacitance of 1718.1 F g−1 at 1 A g−1 applied current density. An asymmetric solid-state supercapacitor (ASSS) configuration was also fabricated using a PVA-KOH gel electrolyte, with a positive electrode of WS-MFO-2 and a negative electrode activated carbon (AC). The WS-MFO-2//AC ASSS device exhibited a potential window of 1.7 V, an optimum specific capacitance of 187.6471 F g−1, and exceptional cycling stability. At 0.85 kW kg−1 power density, the ASSS device provided a specific energy of approximately 75.32 Wh kg−1. The practical application of the ASSS device was demonstrated by lighting different color LEDs for 300 s. The proposed asymmetric architecture provides a possible alternative cathode material to grow green energy storage technologies in various portable electronic systems.