摘要
<正>氧的电化学还原作为锌-空气电池的正极反应,提升其反应效率是提高锌-空气电池性能的关键因素之一。由于在传统碱性水溶液中氧还原反应的低效率和不可逆性,二次锌-空气电池的研究进展被严重制约。离子液体作为新一代绿色电解液,具有电化学稳定性高、不挥发、不易燃等特性,有望解决锌-空气电池中的电极反应所面临的问题,为新型二次锌-空气电池的研究开发带来突破。在离子液体中氧还原反应的基础研究具有重要的理论和应用价值。本工作研究了多种离子液体中钯和银电极上氧还原的电化学行为,并考察了痕量水的引入对于氧还原反应的影响。结果表明,在纯的咪唑类离子液体中,氧分子在钯电极上的电化学还原是受扩散控制的、可逆的1电子反应过程。微量水的引入使得氧还原反应由可逆1电子过程转变为不可逆的2电子还原过程。而在银电极上的氧还原在水分子的影响下表现出相反的行为。随着水引入量的增加,氧还原反应可逆性逐步提高,并且电流密度增加。本文对在离子液体中不同金属电极上的氧还原反应机理进行了探讨。
Employment of ionic liquids as the electrolyte in electrochemical devices has attracted wide attentions. Replacement of the alkaline solution used for traditional Zn-air battery with ionic liquids could hopefully enhance the development of rechargeable Zn-air battery. Since oxygen reduction reaction(ORR) is essential to the performance of Zn-air battery, the investigation of the ORR in ionic liquids is important. Herein, the ORR has been investigated on Pd and Ag electrodes respectively in several ionic liquids systems. The effect of trace water on ORR has also been studied. The results indicate that the behavior of the ORR is largely different on the two electrode. The mechanism has been discussed.
引文
[1]Walsh,D.A.;Ejigu,A.;Smith,J.;Licence,P.,Phys.Chem.Chem.Phys.2013,15:7548-7554.
[2]Wang,Z.L.;Xu,D.;Xu,J.J.;Zhang,X.B.,Chem.Soc.Rev.2014,43:7746-7786.
