fig7

Figure 7. (A) HRTEM image and (B) schematic reaction mechanism of NiCo₂O₄/MnO₂. (A and B) are reprinted from Ref.^[82], under CC BY 4.0 license; (C) ORR free energy diagrams for FeN₄ and Fe₅/FeN₄ sites at 0 and 1.23 V vs. RHE. (C) is reprinted with permission from Ref.^[83], Copyright © 2025 Wiley; (D) HRTEM image of CeO₂/ZnCoS; (E) Charge/discharge polarization and corresponding power density curves of ZABs employing CeO₂/ZnCoS and Pt/C + RuO₂ as air cathodes. (D and E) are reprinted with permission from Ref.^[84], Copyright © 2024 Elsevier; (F) Energy density curve of Co/Co₂P at 20 mA cm^-2; (G) Reaction mechanism of Zn-Co/air hybrid batteries. (F and G) are reprinted with permission from Ref.^[85], Copyright © 2025 Wiley; (H) TEM image of p-NiSe₂/Ni/Ni₃N@NCNT@CC. (H) is reprinted with permission from Ref.^[86], Copyright © 2025 Wiley; (I) Gibbs free energy diagrams of ORR for Fe₂N@NC and Fe₂N/CrNx@NC at U = 0 V. (I) is reprinted with permission from Ref.^[87], Copyright © 2026 Wiley. PNCF: P/N-codoped carbon nanofiber; NC: N-doped carbon; HRTEM: high-resolution transmission electron microscope; TEM: transmission electron microscope; RHE: ORR: oxygen reduction reaction.