Hydrothermal regulation of MnO on a wood-based RGO composite for achieving wide voltage windows and high energy density supercapacitors.

The increasing need for improved energy storage devices renders it particularly important that inexpensive electrodes with high capacitance, excellent cycling stability, and environment-friendly characteristics are developed. In this study, a wood-derived carbon@reduced graphene (WRG) conductive precursor with an average conductivity of 15.38 S/m was firstly synthesized. The binder-free WRG-MnO electrode was successfully constructed by growing MnO onto a WRG under hydrothermal conditions. The asymmetric supercapacitor assembled with the WRG-MnO cathode exhibited excellent electrochemical capacitive behavior with a voltage window of 0-2 V, maximum energy density of 52.3 Wh kg, and maximum power density of 1642.7 W kg, which is mainly due to the distinctive icicle-shaped structure of the MnO. Thus, a facile strategy for developing high-performance hierarchical porous carbon electrodes that can be used in supercapacitors was developed herein, which may provide new opportunities to improve the high added value of poplar wood.