Preparation and electrochemical performances of doughnut-like Ni(OH)2–Co(OH)2 composites as pseudocapacitor materials

Abstract

Doughnut-like nanostructured Ni(OH)₂–Co(OH)₂ composites were prepared by combining hydrothermal and chemical deposition routes. The electrochemical performances of the composites were investigated as pseudocapacitor materials through galvanostatic charge–discharge and cyclic voltammetry tests. The Ni(OH)₂–Co(OH)₂ composites delivered a specific capacitance of 2193 F g⁻¹ at 2 A g⁻¹ and 1398 F g⁻¹ at 20 A g⁻¹, much higher than those of pristine Ni(OH)₂. The enhancement of the overall electrochemical performances is ascribed to the synergetic contribution from nanostructured Ni(OH)₂ and electrically conductive CoOOH forming in the charge process.