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A three-dimensional (3D) porous structure that designed based on MnCo 2 O 4 decorated graphene was synthesized by a two-step method. The precursor was prepared of MnCo 2 O 4 by solid phase synthesis method, then in the hydrothermal reaction course, the graphene nanosheets as well as this precursor were self-assembled into a 3D interconnected network. The resultant composite materials present a higher specific capacitance (503 F g−1 at 1 A g−1 current density) and an excellent cycling stability. After 5000 charge/discharge cycles at a current density of 10 A g−1, 97.4% of the specific capacitance was retained. Thus, this material has a promising application potential for supercapacitor, at the same time, this synthetic method can also provide an idea for synthesizing composites based on 3D graphene in the future. • Three-dimensional composites of MnCo 2 O 4 and graphene were synthesized. • Three-dimensional graphene provides a porous skeleton. • The MnCo 2 O 4 /3DG electrode exhibits excellent electrochemical properties. • The excellent supercapacitor performance is attributed to the synergistic effect. [ABSTRACT FROM AUTHOR]

The porous urchin-like and flower-like NiCo 2 O 4 microspheres have been synthesized by a mild hydrothermal method combined with a simple annealing treatment. With the addition of sodium dodecyl sulfate (SDS), the morphology of NiCo 2 O 4 microspheres changes from the urchin-like to the flower-like. The flower-like NiCo 2 O 4 microspheres（NCO-5）with a larger specific surface area of 158 m 2 /g constructed by interconnected nanosheets exhibit a higher specific capacitance of 1538 F/g at 10 A/g and an excellent cycling stability. When the current density is 10 A/g, high capacity retention ratio up to 92.3% can be achieved for the flower-like NiCo 2 O 4 microspheres electrode after 2500 cycles. The enhanced electrochemical performance can be mainly attributed to the hierarchical porous framework with a large specific surface area. Therefore, the remarkable capacitive performance of the flower-like NiCo 2 O 4 microspheres will undoubtedly make them more attractive for high performance supercapacitors. [ABSTRACT FROM AUTHOR]