Limited Stability of Ether-Based Solvents in Lithium–Oxygen Batteries

Li–O2 batteries offer the tantalizing promise of a specific energy much greater than current Li ion technologies; however, many challenges remain before the development of commercial energy storage applications based on the lithium–oxygen couple can be realized. One of the most apparent limitations is electrolyte stability. Without an electrolyte that is resistant to attack by reduced oxygen species, optimizing other aspects of the redox performance is challenging. Thus, identifying electrolyte decomposition processes that occur early in the redox process will accelerate the discovery process. In this study, ATR–FTIR was used to examine various reported Li–O2 electrolytes taken directly from the cell separators of cycled electrochemical cells. Specifically, we examined, 1 M LiPF6 in propylene carbonate (PC), 1 M LiCF3SO3 in tetraethyleneglycoldimethylether (TEGDME), and 1 M LiCF3SO3 in a siloxane ether (1NM3) and looked for soluble decomposition products. Each electrolyte was tested using a regular Li–O2 ...