Interconnected δ-MnO2 nanosheets anchored on porous carbon derived from reed residue waste as high-performance electrode for supercapacitor

Coupling with carbon materials and creating synergies of individual counterparts is one of the most significant ways to improve the electrochemical properties of MnO2 for supercapacitor electrode materials. Some useful chemicals such as L-(+)-arabinose and D-(+)-xylose can be extracted from a perennial and herbaceous plant giant reed, and the remaining of extracted reed (reed residue waste) was selected as the precursor to prepare biomass porous carbon through carbonization and activation. A pompon mum-like C/MnO2 nanocomposite was obtained through a simple reduction reaction between activated carbon and potassium permanganate. The reaction time can tailor the morphology, the degree of crystallization, and the mass of MnO2 anchoring onto the activated carbon. The C/MnO2 (1 h) electrode material presented satisfactory electrochemical performances with high specific capacitance of 128.75 F g(-1) at a current density of 0.5 A g(-1) and good rate capability (43.65 F g(-1) at a current density of 10 A g(-1)). The C/MnO2 (1 h) electrode material also displayed superior cycling stability with 98.7% capacitance retention after charging-discharging for 10,000 cycles at a current density of 5 A g(-1). Results of this study demonstrated that the synthesized C/MnO2 (1 h) nanocomposite with unique nanostructure had great potential in future practical application of supercapacitors.