Mechanistic Insight into the Superoxide Induced Ring Opening in Propylene Carbonate Based Electrolytes using in Situ Surface-Enhanced Infrared Spectroscopy
Mechanistic Insight into the Superoxide Induced Ring Opening in Propylene Carbonate Based Electrolytes using in Situ Surface-Enhanced Infrared Spectroscopy
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DOI：
10.1021/jacs.5b12494
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发表时间：
2016-03-23
影响因子：
15
通讯作者：
Hardwick, Laurence J.
中科院分区：
文献类型：
--
作者：
Vivek, J. Padmanabhan;Berry, Neil;Hardwick, Laurence J.
了解超氧化物引起的溶剂降解的机理细节，对于开发用于锂氧（Li-O-2）电池的稳定电解质是重要的。采用衰减全反射表面增强红外吸收光谱（ATR-SEIRAS）技术研究了碳酸丙烯酯（PC）在模拟电极表面上的分解过程。SEIRAS技术对界面区域的灵敏度允许在电化学反应期间调查界面区域中的细微变化。我们的SEIRAS研究表明，超氧化物诱导的开环反应的PC是由电解质阳离子。超氧化物与PC的拟议反应途径的计算建模显示，与四乙基铵（TEA（+））相比，Li+作为抗衡阳离子时，由于Li+与碳酸根官能团的配位，活化能势垒存在很大差异。虽然在Li-O-2电池放电过程中环状有机碳酸酯的降解是一个公认的案例，但了解这些细节对于合理选择Li-O-2电池电解质具有重要意义;我们的工作表明在这个方向上使用SEIRAS技术。
Understanding the mechanistic details of the superoxide induced solvent degradation, is important in the development of stable electrolytes for lithium oxygen (Li-O-2) batteries. Propylene carbonate (PC) decomposition on a model electrode surface is studied here using in situ attenuated total reflectance surface enhanced infrared absorption spectroscopy (ATR-SEIRAS). The sensitivity of the SEIRAS technique to the interfacial region allows investigation of subtle changes in the interface region during electrochemical reactions. Our SEIRAS studies show that the superoxide induced ring opening reaction of PC is determined by the electrolyte cation. Computational modeling of the proposed reaction pathway of superoxide with PC revealed a large difference in the activation energy barriers when Li+ was the countercation compared with tetraethylammonium (TEA(+)), due to the coordination of Li+ to the carbonate functionality. While the degradation of cyclic organic carbonates during the Li-O-2 battery discharge process is a well-established case, understanding these details are of significant importance toward a rational selection of the Li-O-2 battery electrolytes; our work signifies the use of SEIRAS technique in this direction.