Optimizing the structure of Ni–Ni(OH)2/NiO core-shell nanowire electrodes for application in pseudocapacitors: The influence of metallic core, Ni(OH)2/NiO ratio and nanowire length
An experimental analysis was performed to optimize the structure of Ni–Ni(OH)2/NiO core-shell nanowire electrodes for improving their application in pseudocapacitors. Thickness and composition of the active phase shell were compared after thermal treatments at 40, 70 and 300 °C. A Ni(0) core was found by XPS in the electrode treated at 40 °C, it was still present after a temperature increase to 70 °C but with a lower Ni(OH)2/NiO ratio of the active phase shell, and disappeared after annealing at 300 °C, with a corresponding increase of the charge transfer resistance.