Liu Haiping

Variable-temperature preparation and performance of NiCl 2 as a cathode material for thermal batteries

Nickel(II) chloride materials were synthesized via a novel two-step variable-temperature method for the use as a cathode material in Li-B/NiCl2 cells with the LiCl-LiBr-LiF electrolyte. The influence of temperature on its structure, surface morphology, and electrochemical performance was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical measurements of single cells. XRD results showed that after pre-dehydration for 2 h at 270°C followed by sintering for 5 h at 600°C, the crystal water in nickel chloride hexahydrate could be removed effectively. The SEM results showed that particles recombined to form larger coarse particles and presented a layered structure. Discharge tests showed that the 600°C-treated materials demonstrated remarkable specific capacities of 210.42 and 242.84 mA h g−1 at constant currents of 0.5 and 2.0 A, respectively. Therefore, the Li-B/NiCl2 thermal battery showed excellent discharge performance. The present work demonstrates that NiCl2 is a promising cathode material for thermal batteries and this two-step variable-temperature method is a simple and useful method for the fabrication of NiCl2 materials.摘要本文采用两步变温法制备了无水氯化镍材料. 并以所制备的氯化镍为正极, 锂硼合金为负极, LiCl-LiBr-LiF 为电解质, 组成单体锂热电 池. 通过XRD、SEM和单体电池电化学测试分析了温度对氯化镍材料的结构、表面形貌以及电化学性能的影响. XRD结果表明270°C预处理 2 h, 600°C高温烧结5 h后, 氯化镍中的结晶水能够被完全去除; SEM结果表明氯化镍热处理后晶粒重组长大并呈现层状结构. 经600°C热处理 后的氯化镍材料在0.5 A和2.0 A恒流放电时的比容量分别可达210.42和242.84 mA h g−1, 表明以热处理后的氯化镍为正极的锂热电池具有良好 的放电性能. 本文研究结果表明氯化镍是一种非常有潜力的热电池正极材料, 而两步变温法是制备无水氯化镍材料的一种简单实用的方法.