▎ 摘　　要

A novel Co3O4/flocculent graphene (FG) hybrid on commercial Ni foam (NF) has been prepared. The unique flocculent graphene structure is prepared by combining a rapid filtering approach through Ni foam and a template method, in which the thermally expanded graphite is used as precursor and polystyrene (PS) microspheres are used as templates. The PS spheres play an important role in preventing the re-stacking of graphene nanosheets and the formation of flocculent graphene on NF. The PS spheres were first introduced as a guest material and were subsequently removed by calcination. The resulting freestanding FG/NF provides a three-dimensional and high conductivity scaffold for the hydrothermal growth of Co3O4 nanoclusters. The obtained Co3O4/FG/NF hybrid could be directly used as a binder-free supercapacitor electrode. Moreover, the Co3O4 nanoclusters on FG/NF scaffold exhibit improved specific capacitance of 1615 F g(-1) compared to that of the bare NF. The 3D active material layer of Co3O4/FG/NF hybrid, high conductivity of 3D FG/NF scaffold and functional features of the Co3O4 nanocluster morphology synergistically result in an improved electrochemical performance.