MnO₂/carbon nanocomposite based on silkworm excrement for high-performance supercapacitors

MnO₂/biomass carbon nanocomposite was synthesized by a facile hydrothermal reaction. Silkworm excrement acted as a carbon precursor, which was activated by ZnCl₂ and FeCl₃ combining chemical agents under Ar atmosphere. The thin and flower-like MnO₂ nanowires were in situ anchored on the surface of biomass carbon, in which biomass carbon not only offered the high conductivity and good structural stability but also relieved the large volume expansion during the charge/discharge process. The obtained MnO₂/biomass carbon nanocomposite electrode exhibited a high specific capacitance (238 F g^-1 at 0.5 A g^-1) and a superior cycling stability with only 7% degradation after 2000 cycles. The good electrochemical performance is accredited to the high specific surface area, multi-level hierarchical structure, and good conductivity. This study proposes a promising method to make use of biological waste and broadens MnO₂ based electrode materials application for next-generation energy storage and conversion devices.