Understanding oxygen reactions in aprotic Li-O2 batteries

Although significant progress has been made in many aspects of the emerging aprotic Li-O2 battery system, an indepth understanding of the oxygen reactions is still underway. The oxygen reactions occurring in the positive electrode distinguish Li-O2 batteries from the conventional Li-ion cells and play a crucial role in the Li-O2 cell＇s performance （capacity, rate capability, and cycle life）. Recent advances in fundamental studies of oxygen reactions in aprotic Li-O2 batteries are reviewed, including the reaction route, kinetics, morphological evolution of Li2O2, and charge transport within Li2O2. Prospects are also provided for future fundamental investigations of Li-O2 chemistry.