Application of Co3O4/Nitrogen-doped carbon composite electrode material derived form Zeolitic imidazolate frameworks-67 in supercapacitors

•Co3O4/Nitrogen-doped carbon (Co3O4/NC) composite was successfully prepared by a two-step calcination method with ZIF-67 as precursor.•The specific capacitance of Co3O4/NC at a current density of 1 A g−1 is 1144F g−1.•The Co3O4/NC//AC two-electrode capacitor generates the highest energy density of 40 Wh kg−1 at a power density of 1037 W kg−1.