Microspheres of cubic spinel ZnCo2O4 were synthesized using a facile ethylene glycol-mediated hydrothermal method. The size and crystallinity of the ZnCo2O4 microspheres were tuned by simply varying the reaction times. The as-synthesized ZnCo2O4 microspheres had porous structures that were constructed by numerous small building blocks of primary nanoparticles, leading to the formation of sphere-like morphology. The ZnCo2O4 microspheres exhibited a large surface area of 37.27 m(2) g(-1) with mesopores, 24.66 nm in size, resulting in significantly enhanced electrochemical activity toward pseudocapacitors. Remarkably, the as-made ZnCo2O4 microspheres electrode delivered a high specific capacitance (853.6 F g(-1) at a current density of 2 A g(-1)), good rate performance (417.1 F g(-1) at 10 A g(-1)) and excellent cyclic stability (92.7% capacitance retention after 3000 cycles at a current density of 10 A g(-1)). Moreover, a symmetric supercapacitor based on ZnCo2O4 microsphere electrodes achieved an energy density of 11.8 Wh kg(-1) and a maximum power density of 2.5 kW kg(-1). The good electrochemical performances can be attributed to the unique porous microsphere texture, high surface area and good electrical conductivity due to the synergistic effect between the two metal elements. (C) 2016 The Electrochemical Society. All rights reserved.