...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, C. Nanomaterials and interfaces >Elucidating the Mechanism of Oxygen Reduction for Lithium-Air Battery Applications
【24h】

Elucidating the Mechanism of Oxygen Reduction for Lithium-Air Battery Applications

机译：阐明锂空气电池应用中的氧气还原机理

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Unlocking the true energy capabilities of the lithium metal negative electrode in a lithium battery has until now been limited by the low capacity intercalation and conversion reactions at the positive electrodes. Abraham et al. (Abraham, K. M.; Jiang, Z. J. Electrochem. Soc. 1996, 143, 1-5) overcame this limitation by removing these electrodes and allowing lithium to react directly with oxygen in the atmosphere, forming the Li-air battery. The Li/02 battery redox couple has a theoretical specific energy of 5200 W h/kg and represents the ultimate, environmentally friendly electrochemical power source. In this work, we report for the first time the intimate role of electrolyte, in particular the role of ion conducting salts, in determining the reversibility and kinetics of oxygen reduction in nonaqueous electrolytes designed for such applications. Such fundamental understanding of this high energy density battery is crucial to harnessing its full energy potential. The kinetics and mechanisms of O2 reduction in solutions of hexafluorophosphate of the general formula A~+PF6~-, where A = tetrabutylammonium (TBA), K, Na, and Li, in acetonitrile are reported on glassy carbon electrodes using cyclic voltammetry (CV) and rotating disk electrode (RDE) techniques. The results show that the cations in the electrolyte strongly influence the reduction mechanism of O2. Larger cations represented by TBA salts displayed reversible O2/O2~- redox couple, in contrast to those containing the smaller Li (and other alkali metal) cations, where an irreversible one-electron reduction of O2 to LiO2, and other alkali metal superoxides, is shown to occur as the first process. It was also found the LiO2 formed initially decomposes to Li2O2. Electrochemical data support the view that alkali metal oxides formed via electrochemical and chemical reactions passivate the electrode surface, making the processes irreversible. The O2 reduction mechanisms in the presence of the different cations have been supplemented by kinetic parameters determined from detailed analyses of the CV and RDE data. The Lewis acid characteristics of the cation appear to be crucial in determining the reversibility of the system. The results of this study are expected to contribute to the rapid development of the Li-air battery.
机译：迄今为止，锂电池中锂金属负极的真实能量释放一直受到正极的低容量嵌入和转化反应的限制。亚伯拉罕等。 （Abraham，K.M。; Jiang，Z.J.Electrochem.Soc.1996，143，1-5）通过去除这些电极并允许锂与大气中的氧气直接反应来克服了这一限制，从而形成了锂空气电池。 Li / 02电池氧化还原电对的理论比能量为5200 W h / kg，代表了最终的，环境友好的电化学电源。在这项工作中，我们首次报告了电解质在确定用于此类应用的非水电解质中可逆性和确定氧还原动力学方面的直接作用，尤其是离子导电盐的作用。对这种高能量密度电池的这种基本了解对于发挥其全部能量潜力至关重要。使用循环伏安法（CV）在玻璃碳电极上报道了通式A〜+ PF6-〜的六氟磷酸盐（其中A =乙腈中的四丁基铵（TBA），K，Na和Li）在乙腈中的O2还原动力学和机理。 ）和旋转圆盘电极（RDE）技术。结果表明，电解质中的阳离子强烈影响O2的还原机理。以TBA盐为代表的较大阳离子显示出可逆的O2 / O2〜-氧化还原对，而含有较小Li（和其他碱金属）阳离子的阳离子则具有不可逆的单电子将O2还原为LiO2以及其他碱金属超氧化物，显示为第一个过程。还发现最初形成的LiO 2分解成Li 2 O 2。电化学数据支持这样的观点，即通过电化学和化学反应形成的碱金属氧化物会使电极表面钝化，从而使过程不可逆。通过对CV和RDE数据进行详细分析确定的动力学参数，可以补充存在不同阳离子时的O2还原机理。阳离子的路易斯酸特性似乎对于确定系统的可逆性至关重要。这项研究的结果有望为锂空气电池的快速发展做出贡献。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号