Facile synthesis of Co3O4 nanoflowers grown on Ni foam with superior electrochemical performance

► Nanostructures directly grown on current-collectors displayed much higher capacitance than that of the conventional Co3O4 powders. In this paper, we report a simple solvothermal-thermal decomposition method to prepare flower-like Co3O4 grown on Ni foam. ► There have been some reports on the synthesis of one-dimensional (such as nanowires, nanotubes) and two-dimensional (such as nanoflakes) cobalt oxide on substrates. However, there are few reports on the formation of three-dimensional (3D) Co3O4 nanostructures on substrates, except the Co3O4 bowl-like nanostructures on Ni-Cu alloy film using an electrochemical method. To the best of our knowledge, there has been no report on the synthesis of Co3O4 two-dimensional nanoflower (NF) structures on substrates. In this paper, novel large-scale Co3O4 NFs on Ni foam are prepared for the first time. ► Electrochemical results show that the NFs have a high specific capacitance of 1936.7 F g−1 at a current density of 0.2 A g−1 and a capacity retention of 78.2% after 1000 cycles at a high current density of 3 A g−1 (1309.4 F g−1). Because of their ease of fabrication and optimizable performance, these NFs grown on Ni foam will hold promise in practical supercapacitors.