新型Ni(OH)2.05电极材料的电化学性能研究

采用化学氧化法制备了碱性二次电池用正极材料Ni(OH)2.05, 考察了其作为镍氢电池正极活性材料的电化学性能. 结果表明: 以氧化处理过的样品为正极材料组装成镍氢模拟电池在0.2 C倍率下放电容量为281 mAh•g－1; 1 C充放电条件下, 270次循环后容量保持98% 以上. 交流阻抗分析和循环伏安测试表明, 经过氧化修饰的镍电极具有更小的电荷传递电阻、更快的质子扩散速度; ΔEa,c小于未处理样品70 mV, 电化学可逆性优于未处理样品; 对不同放电截止电压下的充放电测试发现: 放电截止电压进一步降低后, 相对于未处理过的样品, 氧化处理后样品无明显的二次放电平台, 第一放电平台末的容量与未处理样品二次放电平台末容量相当, 从而有效地抑制了二次放电平台现象.

Electrochemical Performance of New-type Electrode Material Ni(OH)2.05

The positively active matter Ni(OH)2.05 for Ni-based rechargeable alkaline batteries was prepared through a simple route of chemical oxidation, and its electrochemical performance was investigated. Results illuminate that the simulant Ni/MH battery with the above treated sample as positively active matter shows considerable electrochemical performance with a discharge capacity of 281 mAh•g－1 under 0.2 C and a capacity maintenance of 98% after 270 cycles under 1 C. Cyclic voltammograms indicate a faster diffusion rate as well as a better electrochemical reversibility for the modified electrode than that of the aboriginal one. Besides, a lower charge-transfer resistance for the modified electrode was detected by impedance spectrum. The charge/discharge tests under different cut voltage indicate that the modified electrode shows an unconspicuous second discharge plateau compared with the untreated one, which results in a comparable capacity between the modified electrode at the first discharge plateau and the primary electrode at a deeper cut voltage.