Nonvolatile and Nonflammable Sulfolane-Based Electrolyte Achieving Effective and Safe Operation of the Li-O 2 Battery in Open O 2 Environment.

The Li-O 2 battery should operate effectively/safely in an open O 2 environment for practical applications, but not trapped in sealed/closed atmosphere. However, the typical use of volatile and flammable electrolyte restricts Li-O 2 battery to be able to be running in open O 2 environment. We report herein, for the first time, a highly electrochemical reversible Li-O 2 battery operated in an open O 2 environment, i.e., under the condition of keeping O 2 flowing continuously based on a nonvolatile and nonflammable sulfolane (TMS) solvent. The electrochemical irreversibility of Li 2 O 2 /O 2 conversion and incompatibility between Li metal anodes and electrolyte have been addressed via dissolving LiNO 3 in concentrated TMS electrolyte. The tuned electrolyte not only enables a stable solid electrolyte interphase (SEI) with conformal inorganic components (including LiF, LiN x O y , and Li 2 O) that promotes a uniform Li electro-plating/stripping process but also results in a low charge overpotential, a stable discharge terminal plateau, and reversible O 2 generation of the Li-O 2 battery conducted in an open O 2 environment.