水热对纳米Ni(OH)_2电化学性能的影响

Effects of Hydrothermal Modification on the Electrochemical Properties of Nano-scale Nickel Hydroxide

采用微乳法制备纳米Ni(OH)2,用X射线衍射、扫描电子显微镜、透射电子显微镜、恒流充放电、循环伏安、交流阻抗等测试技术研究了纳米Ni(OH)2的微观结构、表面形貌和电化学性能。结果表明,140℃水热和微乳/水热2种方式处理得到的纳米Ni(OH)2具有不同形貌特征。水热和微乳/水热处理虽然不影响纳米Ni(OH)2的活化性能,但对纳米Ni(OH)2的放电比容量影响很大,采用140℃水热和微乳/水热处理比单纯的微乳法制备得到的纳米Ni(OH)2的放电比容量分别提高了24.6和74.8 mA.h/g。处理后的纳米Ni(OH)2的循环伏安峰电流增大、电荷转移电阻由2.633Ω分别降至2.464和1.679Ω。

Nano-scale nickel hydroxide was synthesized by micro-emulsion and its structure, surface morphology and electrochemical performance were tested and analyzed by means of X-ray diffraction （ XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, galvanostatic charge/discharge, cyclic vohammetry and electrochemical impedance spectroscopy. The results show that nano-scale nickel hydroxide turned to different morphologies after hydrothermal and micro-emulsion/hydrothermal modification. Though the results of the activation performance of unsettled and treated nano-scale nickel hydroxide were uniform, the discharging specific capacity of nano-scale nickel hydroxide was different. The discharging specific capacity of nano-seale nickel hydroxide, which underwent hydrothermal treatment at 140 ℃, was increased by 24.6 mA·h/g, while the nano-scale nickel hydroxide, which underwent micro-emulsion/hydrothermal treatment, was increased by 74. 8 mA · h/g. The peak current of cyclic vohammetry also increased and the charge-transfer resistances decreased from 2. 633 Ω to 2. 464 Ω and 1. 679 Ω respectively.