Probing the reaction interface in Li–O2 batteries using electrochemical impedance spectroscopy: dual roles of Li2O2

Abstract

Li₂O₂ is revealed to play a positive role by facilitating the kinetics of the oxygen reduction reaction in aprotic Li–O₂ batteries, in addition to the well-known negative role by passivating the electrode surface. Moreover, it is inferred that the oxygen reduction reaction takes place at the Li₂O₂/electrolyte interface, rather than the electrode/Li₂O₂ interface, in our cell.