Combining Nature-Inspired, Graphene-Wrapped Flexible Electrodes with Nanocomposite Polymer Electrolyte for Asymmetric Capacitive Energy Storage

Two kinds of free-standing electrodes, reduced graphene oxide (rGO)-wrapped Fe-doped MnO2 composite (G-MFO) and rGO-wrapped hierarchical porous carbon microspheres composite (G-HPC) are fabricated using a frozen lake-inspired, bubble-assistance method. This configuration fully enables utilization of the synergistic effects from both components, endowing the materials to be excellent electrodes for flexible and lightweight electrochemical capacitors. Moreover, a nonaqueous HPC-doped gel polymer electrolyte (GPE-HPC) is employed to broad voltage window and improve heat resistance. A fabricated asymmetric supercapacitor based on G-MFO cathode and G-HPC anode with GPE-HPC electrolyte achieves superior flexibility and reliability, enhanced energy/power density, and outstanding cycling stability. The ability to power light-emitting diodes also indicates the feasibility for practical use. Therefore, it is believed that this novel design may hold great promise for future flexible electronic devices.