Effects of the addition of ZnO and Y2O3 on the electrochemical characteristics of a Ni(OH)2 electrode in nickel-metal hydride secondary batteries
Effects of the addition of ZnO and Y2O3 on the electrochemical characteristics of a Ni(OH)2 electrode in nickel-metal hydride secondary batteries
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DOI：
10.1016/j.ijhydene.2010.04.067
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发表时间：
2010-12
影响因子：
7.2
通讯作者：
Kwan-Woo Jung;Dong-Cheol Yang;Choong-Nyeon Park;Chan‐Jin Park;Jeon Choi
中科院分区：
文献类型：
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作者：
Kwan-Woo Jung;Dong-Cheol Yang;Choong-Nyeon Park;Chan‐Jin Park;Jeon Choi
研究了添加ZnO和Y2 O3对Ni-MH二次电池Ni（OH）2电极电化学性能的影响。在0.2C倍率和25°C下，添加ZnO和Y2 O3对电极的放电容量影响较小。然而，Y2 O3的添加通过在1C和25°C的增加的C-倍率下增加电极的电荷转移电阻而劣化了电极的放电容量和循环寿命。在1C-倍率和60°C下的较低条件下，电极材料与集流体分离，因此，对于仅包含4wt%ZnO或4wt%Y2O3的电极，放电容量随着循环突然降低。相比之下，含有2wt%ZnO和2wt%Y2O3的电极表现出稳定的放电容量与循环和优异的循环寿命，由于析氧的高过电压。结果表明，ZnO和Y2 O3的最佳配比可抑制活性物质与集流体界面处的析氧，提高电极的循环寿命。
This study examined the effects of the addition of ZnO and Y2O3on the electrochemical characteristics of a Ni(OH)2electrode in nickel–metal hydride (Ni–MH) secondary batteries. The discharge capacity of the electrode was less affected by the addition of ZnO and Y2O3at a 0.2 C-rate and 25°C. However, the addition of Y2O3deteriorated the discharge capacity and the cycle life of the electrode by increasing the charge transfer resistance of the electrode at an increased C-rate of 1 C and 25°C. Under severer conditions at 1 C-rate and 60°C, the electrode materials were separated from the current collector and, accordingly, the discharge capacity was abruptly degraded with cycling for the electrodes comprising only 4wt% ZnO or 4wt% Y2O3. In contrast, the electrodes containing both 2wt% ZnO and 2wt% Y2O3exhibited stable discharge capacity with cycling and excellent cycle life due to the high overvoltage for oxygen evolution. The present results indicate that the addition of ZnO and Y2O3with an optimum composition suppresses oxygen evolution in the interfaces between active materials and the current collector and improves the cycle life of the electrode.