(北京有色金属研究总院 分析测试中心， 北京 100088)
摘 要: 通过“管道式合成”工艺制备了球形氢氧化镍， 然后以化学沉积法在氢氧化镍表面包覆氢氧化钴， 制备了表面覆钴含量不同(0.75％~6.00％， 质量分数， 下同)的覆钴型氢氧化镍。 利用X射线衍射、 扫描电镜和恒流充放电技术测试了其相结构、 表面微观形貌和质量比容量、 循环寿命等， 研究了覆钴型氢氧化镍表面不同含量的钴对组织结构及电化学性能的影响。 X射线衍射和扫描电镜分析表明： 表面包覆不同含量钴的氢氧化镍结构仍为β相， 但其表面形貌各有不同。 电化学测试结果表明： 表面覆钴含量1.5％~2.0％左右的氢氧化镍具有优良的电化学循环稳定性及大电流(2C)充放电性能优异， 300次循环后比容量仍能保持约80％， 可作为氢镍动力电池的正极材料。
关键字: 球形氢氧化镍； 表面包覆； Co(OH)2； 相结构； 电化学性能
（Analysis and Testing Center, General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract: Nickel hydroxides were prepared through “conduit synthesizing technology”, and then were coated with different amounts of cobalt hydroxide ranging from 0.75% to 6.00%(mass fraction, the same below) by chemical precipitation method. The properties of these materials were tested by X-ray diffractrometry, scanning electron microscopy and constant-current charge/discharge test. Studies were focused on the effects of different amounts of cobalt coating on structure and electrochemical characteristics of Ni(OH)2. The results show that nickel hydroxide coated by several amounts of cobalt is still β phase, but some differences exist in their surface morphologies. And the results of electrochemical test exhibit that the electrochemical cycle stability and the large current charging/discharging performance (2C) of nickel hydroxide coated by cobalt between 1.5% and 2.0% are all excellent. After 300 times cycling the specific capacity of Ni(OH)2 still keeps almost 80% compared with the original one, so it is possible that this material be applied to positive electrode of Ni-MH power batteries.
Key words: spherical nickel hydroxide; coating; Co(OH)2; phase structure; electrochemical properties
