Hard carbon (HC) is a promising anode material for sodium‐ion batteries, yet still suffers from low initial Coulombic efficiency (ICE) and unstable solid electrolyte interphase (SEI). Herein, sodium diphenyl ketone (Na‐DK) is applied to realize dual‐function presodiation for HC anodes. It compensates the irreversible Na uptake at the oxygen‐containing functional groups and reacts with carbon defects of five/seven‐membered rings for quasi‐metallic sodium in HC. The as‐formed sodium induces robust NaF‐rich SEI on HC in 1.0 M NaPF6 in diglyme, favoring the interfacial reaction kinetics and stable Na+ insertion and extraction. This renders the presodiated HC (pHC) with high ICE of ≈100 % and capacity retention of 82.4 % after 6800 cycles. It is demonstrated to couple with Na3V2(PO4)3 cathodes in full cells to show high capacity retention of ≈100 % after 700 cycles. This work provides in‐depth understanding of chemical presodiation and a new strategy for highly stable sodium‐ion batteries.

Oxygen vacancies on CoFe2O4 NSs and lattice oxygens that participate in the reaction deliver a high current density and low overpotential for the OER.

Non-aqueous Li−O 2 batteries have aroused considerable attention because of their ultrahigh theoretical energy density, but they are severely hindered by slow cathode reaction kinetics and large overvoltages, which are closely associated with the discharge product of Li 2 O 2 . Herein, hexagonal conductive metal−organic framework nanowire arrays of nickel-hexaiminotriphenylene (Ni-HTP) with quadrilateral Ni-N 4 units are synthesized to incorporate Ru atoms into its skeleton for NiRu-HTP. The atomically dispersed Ru-N 4 sites manifest strong adsorption for the LiO 2 intermediate owing to its tunable d-band center, leading to its high local concentration around NiRu-HTP. This favors the formation of film-like Li 2 O 2 on NiRu-HTP with promoted electron transfer and ion diffusion across the cathodeelectrolyte interface, facilitating its reversible decomposition during charge. These allow the Li−O 2 battery with NiRu-HTP to deliver a remarkably reduced charge/ discharge polarization of 0.76 V and excellent cyclability. This work will enrich the design philosophy of electrocatalysts for regulation of kinetic behaviors of oxygen redox.

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Sodium-ion batteries (SIBs) are recognized as a promising alternative for lithium-ion batteries (LIBs) in large-scale energy storage applications, because of the low cost and abundant sodium resources. Electrode materials govern the electrochemical performance of SIBs and are crucial to their development. Sodium manganese oxide (Na x MnO 2 ) is widely studied as cathode materials of SIBs, because of its structural diversity and rich manganese resources. It exhibits many polymorphs and different structural characteristics with the change of sodium contents, including layered, three-dimensional tunnel, and spinel structures. Herein, a comprehensive review on the structure features, charge compensation, phase transition, and the relationship between the structural characteristics and electrochemical performance of sodium manganese oxide as cathode materials of SIBs is presented, and a perspective is provided for the development of SIBs.