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Chemical presodiation (CP) is an effective strategy to enhance energy density of sodium ion batteries. However, the sodiation reagents reported so far are basically polycyclic aromatic hydrocarbons (PAHs) wth low reductive potential (~0.1 V vs. Na+/Na), which could easily cause over‐sodiation and structural deterioration of the presodiated cathodes. In this work, Aromatic ketones (AKs) are rationally designed as mild presodiating reagents by introducing a carbonyl group (C=O) into PAHs to balance the conjugated and inductive effect. As the representatives, two compounds 9‐Fluorenoneb (9‐FN) and Benzophenone (BP) manifest favorable equilibrium potential of 1.55 V and 1.07 V (vs. Na+/Na), respectively. Note that 9‐FN demonstrates versatile presodiating capability toward multiple Na uptake hosts (tunneled Na0.44MnO2, layered Na0.67Ni0.33Mn0.67O2, polyanionic Na4Fe2.91(PO4)2P2O7, Na3V2(PO4)3 and Na3V2(PO4)2F3), enabling greatly improved initial charging capacity of the cathode to balance the irrevisible capacity of the anode. Our results indicate that the Aromatic ketones are competitive presodiating cathodic reagents for high‐performance sodium‐ion batteries, and will inspire more studies and application attempts in the future. [ABSTRACT FROM AUTHOR]

The application of lithium metal anodes for practical batteries is still impeded by safety issues and low Coulombic efficiency caused mainly by the uncontrollable growth of lithium dendrites. Herein, two types of free‐standing nitrogen‐doped amorphous Zn–carbon multichannel fibers are synthesized as multifunctional hosts for lithium accommodation. The 3D macroporous structures endow effectively reduced local current density, and the lithiophilic nitrogen‐doped carbon and functional Zn nanoparticles serve as preferred deposition sites with low nucleation barriers to guide uniform lithium deposition. As a result, the developed anodes exhibit remarkable electrochemical properties in terms of high Coulombic efficiency for more than 500 cycles at various current densities from 1 to 5 mA cm−2, and symmetric cells show long‐term cycling duration over 2000 h. Moreover, full cells based on the developed anode and a LiFePO4 cathode also demonstrate superior rate capability and stable cycle life. [ABSTRACT FROM AUTHOR]

Layered transition metal oxides have drawn much attention as a promising candidate cathode material for sodium‐ion batteries. However, their performance degradation originating from strains and lattice phase transitions remains a critical challenge. Herein, a high‐concentration Zn‐substituted NaxMnO2 cathode with strongly suppressed P2–O2 transition is investigated, which exhibits a volume change as low as 1.0% in the charge/discharge process. Such ultralow strain characteristics ensure a stable host for sodium ion storage, which significantly improves the cycling stability and rate capability of the cathode material. Also, the strong coupling between the highly reversible capacity and the doping content of Zn in NaxMnO2 is investigated. It is suggested that a reversible anionic redox reaction can be effectively triggered by Zn ions and is also highly dependent on the Zn content. Such an ion doping strategy could shed light on the design and construction of stable and high‐capacity sodium ion host. [ABSTRACT FROM AUTHOR]

Layered metal oxides have attracted increasing attention as cathode materials for sodium-ion batteries (SIBs). However, the application of such cathode materials is still hindered by their poor rate capability and cycling stability. Here, a facile self-templated strategy is developed to synthesize uniform P2-Na0.7CoO2 microspheres. Due to the unique microsphere structure, the contact area of the active material with electrolyte is minimized. As expected, the P2-Na0.7CoO2 microspheres exhibit enhanced electrochemical performance for sodium storage in terms of high reversible capacity (125 mAh g−1 at 5 mA g−1), superior rate capability and long cycle life (86 % capacity retention over 300 cycles). Importantly, the synthesis method can be easily extended to synthesize other layered metal oxide (P2-Na0.7MnO2 and O3-NaFeO2) microspheres. [ABSTRACT FROM AUTHOR]

3D graphene decorated NaTi2(PO4)3 (NTP@rGO) is successfully synthesized through a facile spray‐drying method. This NTP@rGO material can deliver high reversible capacity (130 mAh g−1 at 0.1 C), superior high‐rate rate capability (38 mAh g−1 at 200 C) and long cycling stability (77% capacity retention after 1000 cycles), suggesting its applicability as a high rate and cycle‐stable anode for the development of high‐power and long cycle life sodium ion batteries for energy storage applications. [ABSTRACT FROM AUTHOR]