Oxygen-enriched electrolytes based on perfluorochemicals for high-capacity lithium-oxygen batteries

Electrolytes highly enriched with oxygen for lithium-oxygen (Li-O₂) batteries were prepared by combining perfluorohexyl bromide as an oxygen-uptake perfluorochemical (PFC) medium with lithium perfluorooctane sulfonate (LiPFOS) as a perfluoro-surfactant and a supporting electrolyte, which allowed an exceptionally high miscibility of PFCs with tetraethylene glycol dimethyl ether (TEGDME). The electrochemical reduction current of oxygen was enhanced three times in the LiPFOS-TEGDME electrolyte with ca. 60 wt% PFC content in comparison with that of a conventional Li-O₂ battery electrolyte, which was ascribed to the high oxygen solubility of the electrolyte. A Li-O₂ cell fabricated with the PFC-based electrolyte exhibited an excellent discharging capacity of 6500 mA h g^-1 which was approximately 1.5 times higher than that obtained with the conventional electrolyte.