Biomass-derived porous carbon-incorporated MnO2 composites thin films for asymmetric supercapacitor: synthesis and electrochemical performance

The synthesis and application of biomass-derived carbon in energy storage have drawn increasing research attention due to the ease of fabrication, cost effectiveness, and sustainability of the meso/microporous carbon produced from various biological precursors, including plants, fruits, microorganisms, and animals. Many attempts have been given to this topic of research due to the huge potential of composite electrodes with carbon and transition metal oxides as a potential classic state of electrode for future energy storage systems. The low-temperature solution grown process was used to create a sweet potato-derived carbon framework with nanorods of MnO2 anchored to it, which would be simple, low cost, and suitable for large-scale commercial development. The prepared electrode samples were characterized by XRD, Raman, SEM, AFM, XPS, and BET. From the GCD profile, at a current density of 2 mAg−1, the specific capacitance values of MnO2 and MnO2@C are 468 Fg−1 and 718 Fg−1, accordingly. After 5000 cycles, the capacitance retention of the pure MnO2 and MnO2@C composite electrodes delivers 78% and 89%, respectively. Meanwhile, an asymmetric supercapacitor has been successfully assembled using MnO2/SPCF as the positive electrode while AC as the negative electrode, with an energy density of 66.4 Whkg−1 at a corresponding power density of 1980 Wkg−1. These excellent electrochemical performances provide reliable results for the use of this type of SCs in practical applications.