A newly self-supported electrode composed of Mn3O4 on Ni foam/graphene (NF/graphene/Mn3O4) was synthesized in situ by electrodeposition, and was used as a supercapacitor electrode for the first time. An ultrahigh specific capacitance of 630 Fg(-1) can be achieved at a current density of 0.5 Ag-1. The maximum energy density of 94.4 Wh kg(-1) can be achieved, and the capacitance retention can be maintained about 97% after 20,000 cycles at 10 Ag-1. The electrochemical properties, including specific capacitance, energy density and cycling performance, were better than those in previous reports on Mn3O4-graphene electrodes. Such an outstanding property may be attributed to its unique characteristics, such as self-supported structure, favorable electric conductivity and cellular-like porous morphology. (C) 2018 Elsevier Inc. All rights reserved.