3D porous MnO2@carbon nanosheet synthesized from rambutan peel for high-performing supercapacitor electrodes materials

[Display omitted] •3D porous MnO2@carbon nanosheet synthesized from rambutan peel was prepared.•The voltage window of the asymmetric supercapacitors was from 0 to 1.6 V.•The specific capacitance of nitrogen-doped rambutan peel carbon was 137F g−1.•The energy density reaches 9.2 Wh kg−1 at 0.5 A g−1.•The electrode material has excellent energy and power density characteristics. MnO2 nanosheets were prepared by hydrothermal deposition method, and supported on biomass-derived crosslinked carbon nanosheets to form a composite material (MnO2@R). First, rambutan peels were synthesized into porous carbon by pyrolysis and activation, and then MnO2 was fixed on the carbon nanosheets by hydrothermal deposition method. The MnO2@R composite material and nitrogen-doped porous carbon were assembled into an asymmetric supercapacitor. Among them, MnO2@R composite material and nitrogen-doped rambutan peel-derived porous carbon were used as positive electrode and negative electrode. Moreover, the asymmetric supercapacitor has excellent cycle stability. After 5000 cycles under 0.5 A g−1, its capacitance loss is only 12%. The asymmetric supercapacitors found in these studies have excellent energy and power density characteristics, which opens up application prospects for biomass carbon-derived composite materials.