Preparation of manganese oxide/graphene oxide hydrogel for capacitive energy storage

Electrodepositing manganese oxide into graphene hydrogel provides a facile and effective way to make full use of structural features of the hydrogel and capacity advantage of manganese oxide. The electrodeposition conditions play a key role in the deposition of manganese oxide, but little is known about their effect on electrochemical properties of the hybrid electrodes. Here, we systematically clarify the influences of deposition parameters (including current density, deposition time, Mn2+ concentration and bath temperature) on the capacitive performance (including apparent capacitance, specific capacitance, rate capability, cycling stability and charge storage mechanism) of manganese oxide/graphene oxide hydrogel hybrid electrodes. Under the proper preparation conditions, the highest specific capacitance of 453.7 F g(-1) is obtained, and 92.4% capacitance retention (419.2 F g(-1)) is maintained after 5000 charge/discharge cycles, indicating excellent charge storage capability and cycling stability. (C) 2019 Elsevier Ltd. All rights reserved.