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

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.