Importance of Reaction Kinetics and Oxygen Crossover in aprotic Li–O 2 Batteries Based on a Dimethyl Sulfoxide Electrolyte

Although still in their embryonic state, aprotic rechargeable Li‐O 2 batteries have, theoretically, the capabilities of reaching higher specific energy densities than Li‐ion batteries. There are, however, significant drawbacks that must be addressed to allow stable electrochemical performance; these will ultimately be solved by a deeper understanding of the chemical and electrochemical processes occurring during battery operations. We report a study on the electrochemical and chemical stability of Li–O 2 batteries comprising Au‐coated carbon cathodes, a dimethyl sulfoxide (DMSO)‐based electrolyte and Li metal negative electrodes. The use of the aforementioned Au‐coated cathodes in combination with a 1  M lithium bis(trifluoromethane)sulfonimide (LiTFSI)–DMSO electrolyte guarantees very good cycling stability (>300 cycles) by minimizing eventual side reactions. The main drawbacks arise from the high reactivity of the Li metal electrode when in contact with the O 2 ‐saturated DMSO‐based electrolyte.