Effects of Al- and Mn-contents in the negative MH alloy on the self-discharge and long-term storage properties of Ni/MH battery

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• 作者：L. Kong^a ; ^b ; B. Chen^a ; K. Young^c ; ^{kwoyoung@yahoo.com} ; J. Koch^c ; A. Chan^c ; W. Li^b
• 关键词：Hydrogen absorbing materials ; Transition metal alloys ; Metal hydride electrode ; Electrochemical reactions ; Nickel metal hydride battery
• 刊名：Journal of Power Sources
• 出版年：2012
• 期刊代码：58_03787753
• 类别：ce
• 出版时间：1 September, 2012
• 卷：213
• 期：Complete
• 页码：128-139
• 文件大小：3566 K

摘要

The charge retention and long-term storage properties of AB₅-based Ni/MH batteries were studied by聽partial/complete replacements of Al- and Mn-contents by Ni in the AB₅ alloys, separately. A聽high-temperature accelerated testing scheme (60 掳C and 60-days) was proven to be capable of predicting the status of batteries after long-term storages at room temperature (6-months and 293-days). Charge retention and impedance measured from the accelerated scheme can be correlated to the open-circuit voltage and impedance after long-term storage, respectively. While both Al and Mn were important to聽maintain good charge retention, Al, with its good oxidation resistance to slow down the oxidation/corrosion of the MH alloy, contributed to a lower internal impedance, Mn, on the other hand, slowed down the pulverization rate and reduced the irreversible capacity loss, however, contributed to a higher reversible capacity loss. The addition of Y₂O₃ in the positive electrode was found to raise the open-circuit voltage and reduce both reversible capacity loss and impedance increase during long period storage by slowing down the oxidation/corrosion of the MH alloy in the negative electrode.