摘要
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0.2C倍率下放电容量为281mAh?g-1;1C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70mV,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.
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.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2009年第12期1343-1348,共6页
Acta Chimica Sinica
基金
国家自然科学基金(No.50772133)资助项目
