MnO2 and biomass-derived 3D porous carbon composites electrodes for high performance supercapacitor applications

MnO2/biomass-derived porous carbon (BPC) composites have been prepared by a hydrothermal method, in which the BPC 3D porous carbon structure was based on a banana peel. The banana peel, after freeze drying, can maintain its hierarchical natural porous structure, which provides enough growth space for MnO2 and reduces the agglomeration of MnO2 particles. The MnO2/BPC composites were characterized by XRD, FT-IR, XPS, TGA, SEM, TEM, BET. The electrochemical performance of the composites was tested in three-electrode supercapacitors using 1 M Na2SO4 aqueous solution as an electrolyte. Due to the large amounts of hierarchical pores and large pore volume, the as-prepared composites exhibited good electrochemical performance. Electrochemical measurements indicated that the MnO2/BPC composites applied in supercapacitors had a specific capacitance of 139.6 F g−1 at 300 mA g−1, and exhibited a good cycling stability with a capacitance retention ratio of 92.3% after 1000 cycles (at 1 A g−1). The MnO2/BPC composites with 3D porous structure are promising materials in the application of supercapacitors.