fig9

Figure 9. (A) Charge/discharge profiles of rechargeable Li-air batteries working with Fe@NC, Co@NC, and Co/Fe@NC catalysts in a 1 M LiTFSI/G4 electrolyte at a current density of 125 mA·g^-1[107]. (B) Schematic diagram of ORR and OER processes catalyzed by MnO₂/CNTs^[109]. (C) Comparison of OER and ORR bifunctional activities (ΔE) of different catalysts including pure CNTs, pure MnO₂, hortensia-like MnO₂/CNT, and noble metal catalysts^[109]. (D) Cycling performances of Li-air batteries working with UC-NiCo₂S₄, YS-NiCo₂S₄, and CNT in 1 M LiTFSI/G4 electrolyte at a current density of 100 mA·g^-1 and a controlled capacity of 500 mAh·g^-1[114]. Schematic diagrams of the possible catalyzed reaction routes of Li-air batteries working with iron phthalocyanine (FePc) in the electrolyte, discharge process (E), and charge process (F)^[116]. (G) Schematic diagram of the proposed redox mediation mechanisms for copper ions in Li-air batteries^[117]. Reproduced from Refs.^{[107,109,114,116,117]} with permission from the American Chemical Society, IOP Science, American Chemical Society, and the Royal Society of Chemistry, respectively. ORR: Oxygen reduction reaction; OER: oxygen evolution reaction.