The Salt Matters: Enhanced Reversibility of Li-O Batteries with a Li[(CF SO )(n-C F SO )N]-Based Electrolyte.

The safety hazards and cycle instability of lithium metal anodes (LMA) constitute significant barriers to progress in lithium metal batteries. This situation is worse in Li-O batteries because the LMA is prone to be chemically attacked by O shuttled from the cathode. Notwithstanding, efforts on LMA are much sparse than those on the cathode in the realm of Li-O batteries. Here, a novel lithium salt of Li[(CF SO )(n-C F SO )N] (LiTNFSI) is reported, which can effectively suppress the parasitic side reactions and dendrite growth of LMA during cycling and thereby significantly enhance the overall reversibility of Li-O batteries. A variety of advanced research tools are employed to scrutinize the working principles of the LiTNFSI salt. It is revealed that a stable, uniform, and O -resistive solid electrolyte interphase is formed on LMA, and hence the "cross-talk" between the LMA and O shuttled from the cathode is remarkably inhibited in LiTNFSI-based Li-O batteries.