MnO2 nanosheets grown on N-doped agaric-derived three-dimensional porous carbon for asymmetric supercapacitors

Abstract

This work reports the design of layered MnO2 nanosheets grown on conductive frame of N-doped agaric derived porous carbon (N-APC) for asymmetric supercapacitors. The extremely high specific surface area of N-APC (2250 m2 g−1) provides a large contact area for MnO2. Meanwhile, the good retention of the unique three-dimensional pore structure of N-APC can effectively shorten the electron transport path. Therefore, the MnO2@N-APC composite exhibits excellent electrochemical performance with specific capacitance of 330 F g−1 at a current density of 1 A g−1. An asymmetric supercapacitor device is assembled using MnO2@N-APC composite as a positive electrode and N-APC as a negative electrode, respectively. The device displays excellent performance with a large voltage window of 2 V, and an energy density of 28 Wh kg−1 at a power density of 560 W kg−1. The results demonstrate an effective strategy for the construction of high performance supercapacitors through the combination of nanostructured metal oxides and biomass-derived porous carbon.