A promising approach: supercapattery and electrocatalytic hydrogen evolution utilizing magnesium manganese sulfide on MOF-encapsulated graphene

The quest for a revolutionary electrode material, one with exceptional electrochemical activity and remarkable stability, remains fervent as it promises to elevate the energy density of supercapacitors. A hydrothermal synthesis was used to successfully fabricate an improved electrode constituted of magnesium manganese sulfide nanosheets supported on MOF-Encapsulated Graphene Microspheres (MMP@MOF-EGM). The MMP@MOF-EGM electrode, which benefits from the distinctive characteristics and 3D electrode designs, had a high specific capacity of 2365 C/g at 2.0 A/g and outstanding cycling stability at 20 A/g. In addition, an asymmetric supercapacitor was developed by using an MMP@MOF-EGM and MOF-EGM. The energy density attained an amazing 68.3 Wh/kg at 1230 W/kg power. Additionally, the cycling stability of the MMP@MOF-EGM-2//MOF-EGM system demonstrated its mettle by sustaining an impressive 91% capacity through astonishing 25,000 cycles. The electrocatalyst MMP@MOF-EGM exhibited a significantly smaller Tafel slope of 53 mV/dec, indicating favorable reaction kinetics for the process. Additionally, the overpotential required for the catalyst to achieve a current density of 10 mA/cm2 was measured to be 143 mV, highlighting its efficient performance in facilitating the hydrogen evolution reaction. This innovative nanostructure design might pave the way for the development of high-performance supercapacitors.