Boosting the electrochemical activities of MnO2 for next-generation supercapacitor application: Adaptation of multiple approaches

Abstract

A novel Ag-MnO2/MXene on nickel foam (Ag-MnO2/MXene@NF) electrode has been developed by incorporating hydrothermal and post-sonication processes. Ag-doping, MXene reinforcement, nanotechnology approaches, and highly porous current collector (Nickel foam) play a decisive role in boosting the overall activity of the Ag-MnO2/MXene@NF. The Ag-doping tunes the band structure of MnO2 and intrinsically improves its specific conductivity. At the same time, the sandwiching of Ag-MnO2 NWs between the MXene sheet's voids and their dispersion over the MXene sheet's surface led to the formation of a hetero-structured composite with superb conductivity, a high surface area, lower crystallinity, and structural openings. The nanostructured nature of MnO2 (NWs) and their addition to MXene, a conductive and porous matrix, resulted in better capacitance retention and faster ion diffusion. The nano-sized and spongy structure of the Ag-MnO2/MXene@NF not only exposes the bulk of the electrode for charge storage but also buffers the electrode from pulverization as a result of tedious cyclic tests and facilitates the electrolyte ions' mobility. These induced features enabled the Ag-MnO2/MXene@NF to show a higher capacitance of 1188 F g(-1) @ 1Ag(-1), impressive rate capability (85.8 % @9 A g(-1)), and superb cyclic activity of 96.4 % after 6000 tests. The combination of various techniques boosts the overall electrochemical performance of our developed Ag-MnO2/MXene electrode, making it an acceptable option for use in advanced energy storage devices.