Facile and low-cost fabrication of nanostructured NiCo2O4 spinel with high specific capacitance and excellent cycle stability

Nanostructured NiCo2O4 spinel was fabricated with a facile, low-cost coprecipitation process. The ethylene glycol was applied to serve as a stabilizer to govern over the nucleation, growth, and agglomeration processes. The influence of the calcination time was also studied on the coprecipitation reaction. Both the reaction conditions have statistically significant effects on the size distribution, crystallinity, electronic conductivity and the electrochemical performances of the products. The optimized, 5–10 nm NiCo2O4 spinel, calcinated at 375 °C for 8 h, had excellent crystallinity and electric conductivity. It showed a superior-specific capacitance of 671 F g−1 at a current density of 1 A g−1. The delay in the specific capacitance was insignificant, after a 7000-cycle test, revealing the high stability of the product. The simplicity and practicability of the modified coprecipitation process may facilitate the successful commercial applications in electrochemical capacitors for nanostructured NiCo2O4 spinel.