Development of NiMH-based Fuel Cell/Battery (FCB) system: Characterization of Ni(OH)2/MnO2 positive electrode for FCB
Development of NiMH-based Fuel Cell/Battery (FCB) system: Characterization of Ni(OH)2/MnO2 positive electrode for FCB
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DOI：
10.1016/j.jpowsour.2009.06.039
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发表时间：
2009-12
影响因子：
9.2
通讯作者：
Bokkyu Choi;Sunmook Lee;C. Fushimi;A. Tsutsumi
中科院分区：
文献类型：
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作者：
Bokkyu Choi;Sunmook Lee;C. Fushimi;A. Tsutsumi
研究了由氢氧化镍（Ni（OH）2）和少量二氧化锰（MnO 2）组成的燃料电池正极的性能。结果表明，该正极不仅可以作为二次电池的活性物质，而且在充氧条件下还可以作为燃料电池的催化剂，这一点通过以下表征得到了证实：采用循环伏安法（CV）和恒电流放电曲线在氧气和无氧气氛下进行了电化学表征。Ni（OH）2/MnO 2正极的循环伏安曲线显示了Ni（OH）2的氧化还原反应和氧的还原反应。在半电池试验中，观察到充氧条件下正极的放电曲线有两个工作电位：一个来自氢氧化镍（NiOOH）的反应，另一个来自二氧化锰（MnO 2）的燃料电池反应。还观察到，当电池完全充电并且供应氧气时，在全电池测试中放电曲线具有两个工作电压：一个在1.2V处来自NiOOH的电池反应，另一个在0.8V处来自MnO 2的燃料电池反应。特别地，由于该系统通过使用由水电解产生的氧而具有作为燃料电池的附加功能，与相同电极数量的电池相比，过充电电池的放电容量提高了约2倍。XRD分析表明，充放电前后样品的晶体结构没有发生变化。总之，这些实验结果表明，与传统的二次电池相比，新型双功能FCB系统可以提供改进的单位重量的总能量密度。
The performance of the positive electrode composed of a mixture of nickel hydroxide (Ni(OH)2) and a small amount of manganese dioxide (MnO2) was investigated for the positive electrode of Fuel Cell/Battery (FCB) system. It was found that the positive electrode can function not only as an active material of secondary batteries when it is charged but also as a catalyst of fuel cells when oxygen is supplied, which was confirmed by the following characterization: electrochemical characterization was performed with cyclic voltammetry (CV) and galvanostatic discharge curve in oxygen and oxygen-free atmosphere. CV of Ni(OH)2/MnO2positive electrode exhibited the redox reaction of Ni(OH)2as well as oxygen reduction reaction. It was observed that the discharge curves of positive electrode had two working potentials in half cell test when the electrode was charged and oxygen was supplied: one from the reactions of nickel oxyhydroxide (NiOOH); the other from the fuel cell reactions of manganese dioxide (MnO2). It was also observed that the discharge curves had two working voltages in full cell test when the cell was fully charged and oxygen was supplied: one at 1.2V from the battery reactions of NiOOH; the other at 0.8V from the fuel cell reactions of MnO2. In particular, the discharge capacity of overcharged cell was improved approximately 2 times compared with a battery of the same electrode quantity due to the additional function of this system as a fuel cell by using oxygen generated by water electrolysis. XRD analysis showed that there was no crystal structure change before and after (over)charge–discharge cycles. In summary, these experimental results showed that the novel bi-functional FCB system could provide an improved overall energy density per weight compared with conventional secondary batteries.