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Sodium‐ion batteries (SIBs) are recognized as promising energy storage devices. However, they suffer from rapid capacity decay at ultra‐low temperatures due to high Na+ desolvation energy barrier and unstable solid electrolyte interphase (SEI). Herein, a weakly solvating electrolyte (WSE) with decreased ion‐dipole interactions is designed for stable sodium storage in hard carbon (HC) anode at ultra‐low temperatures. 2‐methyltetrahydrofuran with low solvating power is incorporated into tetrahydrofuran to regulate the interactions between Na+ and solvents. The reduced Na+‐dipole interactions facilitate more anionic coordination in the first solvation sheath, which consistently maintains anion‐enhanced solvation structures from room to low temperatures to promote inorganic‐rich SEI formation. These enable WSE with a low freezing point of −83.3 °C and faster Na+ desolvation kinetics. The HC anode thus affords reversible capacities of 243.2 and 205.4 mAh g−1 at 50 mA g−1 at −40 and −60 °C, respectively, and the full cell of HC||Na3V2(PO4)3 yields an extended lifespan over 250 cycles with high capacity retention of ~100 % at −40 °C. This work sheds new lights on the ion‐dipole regulation for ultra‐low temperature SIBs. [ABSTRACT FROM AUTHOR]

Li‐O2 batteries have garnered much attention due to their high theoretical energy density. However, the irreversible lithium plating/stripping on the anode limits their performance, which has been paid little attention. Herein, a solvation‐regulated strategy for stable lithium anodes in tetraethylene glycol dimethyl ether (G4) based electrolyte is attempted in Li‐O2 batteries. Trifluoroacetate anions (TFA−) with strong Li+ affinity are incorporated into the lithium bis(fluorosulfonyl)imide (LiTFSI)/G4 electrolyte to attenuate the Li+‐G4 interaction and form anion‐dominant solvates. The bisalt electrolyte with 0.5 M LiTFA and 0.5 M LiTFSI mitigates G4 decomposition and induces an inorganic‐rich solid electrolyte interphase (SEI). This contributes to decreased desolvation energy barrier from 58.20 to 46.31 kJ mol−1, compared with 1.0 M LiTFSI/G4, for facile interfacial Li+ diffusion and high efficiency. It yields extended lifespan of 120 cycles in Li‐O2 battery with a limited Li anode (7 mAh cm−2). This work gains comprehensive insights into rational electrolyte design for Li‐O2 batteries. [ABSTRACT FROM AUTHOR]

The sodium extraction/insertion in layered transition‐metal oxide (TMO) cathode materials are typically accompanied by slab sliding and lattice changes, leading to microstructure destruction and capacity decay. Herein, negative lattice expansion is observed in an O3 type Ni‐based layered cathode of Na0.9Ni0.32Zn0.08Fe0.1Mn0.3Ti0.2O2 upon Na+ extraction. It is attributed to the weak Zn2+−O2− orbital hybridization and increased electron density of the surrounding oxygen for reinforced interlayer O−O repulsive force. This enables gliding of TMO slabs for the intergrowth phase transition of P3→OP2 to alleviate lattice strain with moderate lattice shrinkage, which exhibits general interslab spacings and volume changes as low as 2.4 % and 1.9 %, respectively. The strong Ti−O bonds accommodate the internal distortion of TMO6 octahedra due to the flexibility of TiO6 octahedra during cycling. These endow a high specific capacity of 144.9 mAh g−1 and excellent cycling performance of pouch‐type sodium‐ion batteries with 93 % capacity retention after 3600 cycles. [ABSTRACT FROM AUTHOR]

Aprotic Li‐O2 battery has attracted considerable interest for high theoretical energy density, however the disproportionation of the intermediate of superoxide (O2−) during discharge and charge leads to slow reaction kinetics and large voltage hysteresis. Herein, the chemically stable ruthenium tris(bipyridine) (RB) cations are employed as a soluble catalyst to alternate the pathway of O2− disproportionation and its kinetics in both the discharge and charge processes. RB captures O2− dimer and promotes their intramolecular charge transfer, and it decreases the energy barrier of the disproportionation reaction from 7.70 to 0.70 kcal mol−1. This facilitates the discharge and charge processes and simultaneously mitigates O2− and singlet oxygen related side reactions. These endow the Li‐O2 battery with reduced discharge/charge voltage gap of 0.72 V and prolonged lifespan for over 230 cycles when coupled with RuO2 catalyst. This work highlights the vital role of superoxide disproportionation for Li‐O2 battery. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]