Rapid hydrothermal synthesis of snowflake-like ZnCo2O4/ZnO mesoporous microstructures with excellent electrochemical performances

Abstract Snowflake-like ZnCo2O4/ZnO microstructures with size of ca. 4 μm were successfully synthesized through a simple and rapid hydrothermal route at 120 °C for 1 h with a post annealing process in air. The mesoporous ZnCo2O4/ZnO composites exhibited a BET specific surface area of 32.3 m2 g−1 and an average pore size of 16.4 nm, respectively. It was found that the amount of urea played a key role for controlling the shapes of final composites. The electrochemical performances of these ZnCo2O4/ZnO snowflakes based electrode were evaluated in 2 M of KOH electrolyte using a typical three-electrode system. Such ZnCo2O4/ZnO-modified electrode delivered a specific capacity of 372 C g−1 at 1 A g−1 and a good rate capability of 69.6% with the current density increasing from 1 to 15 A g−1. After 5000 charge-discharge cycles at 5 A g−1, the specific capacity still remained 68.7%, showing a good long-term cycling stability. The present synthesis is simple and rapid, and can be extended for the preparation of other metal oxides with remarkable electrochemical properties as well as their further applications in the field of energy storage.