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.　©　2018