Temperature-dependent self-assembly of NiO/Co3O4 composites for supercapacitor electrodes with good cycling performance: from nanoparticles to nanorod arrays

Abstract

A facile approach for the fabrication of temperature-dependent NiO/Co₃O₄ composites, such as nanoparticles, mixed morphology and nanorod arrays, has been presented. The as-synthesized NiO/Co₃O₄ composites, especially for the uniform nanorod array structure, show a good rate capability even at high current densities and an excellent long-term cycling stability (more than 90% retained after 3000 cycles). This improvement can be attributed to the uniform morphology and synergistic effect of NiO and Co₃O₄ as individual constituents, which promote fast Faradaic charging–discharging reactions and act as an “ion reservoir” that can shorten the diffusion distance. These NiO/Co₃O₄ composites can be a promising candidate material for high-capacity and low-cost electrodes for supercapacitors.