fig3
Figure 3. (A) Schematic diagram of reactions in a Li-O2 cathode (O2 + 2Li+ + 2e- ↔ Li2O2) during charge/discharge process in a typical electrolyte. Li2O2, an insulating and insoluble discharge product, develops on the surface of the conducting porous substrate and suppresses the electron transport. (B) The mediators M and M' mediate electron/hole transport. In an inner sphere process, the reduction mediator M can transfer electrons to O2 via an O2-binding transition state or in an outer sphere process via an O2-binding transition state. Reproduced with permission from Ref.[48] (Copyright 2017, Royal Society of Chemistry).
