In this work, CuCo2O4/CuO composite microspheres were easily prepared by an initial solvothermal method with a post annealing treatment of precursor in air. The microstructures and electrochemical performances of the electrode materials annealed at 400, 500, and 600 degrees C were investigated in details. It was revealed that the composite microspheres obtained at the annealing temperature of 400 degrees C (CuCo2O4/CuO-40 0) exhibited the best electrochemical properties including a high specific capacity of 279.36 C g(-1) at 1 A g(-1) and a good rate performance with 77.21% capacity retention at 10 A g(-1). In contrast, the CuCo2O4/CuO composite annealed at 500 and 600 degrees C delivered specific capacity of 254.94 C g(-1) and 224.93 C g(-1), respectively. A hybrid supercapacitor (HSC) was assembled with CuCo2O4/CuO composite as cathode and activated carbon (AC) as anode, and the CuCo2O4/CuO-400//AC HSC possessed superior performance such as an energy density of 19.18 W h kg(-1) at 770.41 W kg(-1) as well as 84.36% capacity preservation over 5000 cycles at 5 A g(-1). The present synthetic method is convenient and cost-effective, and can be extended to the preparation of other cobalt-based binary transition metal oxides with excellent electrochemical properties for energy storage and conversion. (C) 2021 Elsevier B.V. All rights reserved.
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