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

JOURNAL OF ALLOYS AND COMPOUNDS

卷:856

Article

Schiavi, Pier Giorgio¹  Altimari, Pietro¹  Marzolo, Flavio¹  Rubino, Antonio¹  Zanoni, Robertino¹  Pagnanelli, Francesca¹ 

[1] Sapienza Univ Rome, Dept Chem, Piazzale Aldo Moro 5, I-00185 Rome, Italy

关键词: Core-shell nanowires;    Nickel pseudocapacitors;    Electrodeposition;    Nanowires;    Supercapacitor;   

DOI  :  10.1016/j.jallcom.2020.157718

来源: Elsevier

【 摘 要 】

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 degrees C. A Ni(0) core was found by XPS in the electrode treated at 40 degrees C, it was still present after a temperature increase to 70 degrees C but with a lower Ni(OH)(2)/NiO ratio of the active phase shell, and disappeared after annealing at 300 degrees C, with a corresponding increase of the charge transfer resistance. The capacitance values increased from 40 to 70 degrees C and drop to a minimum for the electrode treated at 300 degrees C. A tailoring of the capacitance of the nanowire electrodes by controlling their length was evaluated. A constant capacitance per nanowires length unit was attained between 5 and 21 mu m, indicating that the corresponding mass transfer resistance was negligible over the explored range. These results evidence the relevance to tightly control the thickness and ratio between the Ni(OH)(2) and NiO in the nanowires shell and provide a guideline to optimize the capacitance of the electrode by controlling the nanowire length. (C) 2020 Elsevier B.V. All rights reserved.

【 授权许可】

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