Overlooked Factors Required for Electrolyte Solvents in Li-O 2 Batteries: Capabilities of Quenching 1 O 2 and Forming Highly-Decomposable Li 2 O 2 .

Although sufficient tolerance against attack by superoxide radicals (O 2 - ) has been mainly recognized as an important property for Li-O 2 battery (LOB) electrolytes, recent evidence has revealed that other critical factors also govern the cyclability, prompting a reconsideration of the basic design guidelines of LOB electrolytes. Here, we found that LOBs equipped with a N,N-dimethylacetamide (DMA)-based electrolyte exhibited better cyclability compared with other standard LOB electrolytes. This superior cyclability is attributable to the capabilities of quenching 1 O 2 and forming highly decomposable Li 2 O 2 . The 1 O 2 quenching capability is equivalent to that of a tetraglyme-based electrolyte containing a several millimolar concentration of a typical chemical quencher. Based on these overlooked factors, the DMA-based electrolyte led to superior cyclability despite its lower O 2 - tolerance. Thus, the present work provides a novel design guideline for the development of LOB electrolytes.