Highly Reversible O 2 Conversions by Coupling LiO 2 Intermediate through a Dual‐Site Catalyst in Li‐O 2 Batteries

The reduction of O(2)to solid Li(2)O(2)on discharge and the reverse oxidation of Li(2)O(2)to O(2)on recharge are the essential processes to determine the performance of Li-O(2)batteries. The discovery of effective catalysts with a favorable Li(2)O(2)formation/decomposition mechanism is vital for the development of high-performance Li-O(2)batteries. Here, a soluble catalyst of iodosylbenzene (PhIO) that can offer a highly reversible O(2)conversion is reported for the first time. Benefiting from its ability to capture and couple the LiO(2)intermediate, which is endowed by its polarized I3+(sic)O(2-)bond where the I atom and O atom can serve as a Lewis acidic site and basic site (dual site) to interact with O(2)(-)and Li+, respectively, the formation and decomposition of Li(2)O(2)by a one-electron pathway can be effectively promoted, thus greatly improving the electrode surface passivation issue and the reaction kinetics. In addition, the side reactions caused by the traditional high-reactive LiO(2)intermediate can also be effectively suppressed by forming a series of low-reactive intermediates (LiO2-3PhIO, (LiO2)(2)-4PhIO, and Li2O2-4PhIO) instead. Consequently, the PhIO-catalyzed Li-O(2)batteries exhibit a low overpotential, a large capacity, and a good cyclability.