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Aqueous batteries employing Zinc metal anodes (ZMAs) are considered to be promising next‐generation energy storage systems. However, the severe interfacial side reactions and dendrite growth restrict the practical application of ZMAs in aqueous electrolytes. Herein, a water‐insoluble dual‐ionic electrolyte additive of yttrium 2,4,5‐trifluorophenylacetate (YTFPAA) is developed to stabilize the aqueous ZMAs. Notably, the ethanol‐solvated TFPAA− can capture H+ and thus buffer the decreased electrolyte pH caused by the hydrolysis of Y3+. Furthermore, the ethanol‐solvated TFPAA− can dynamically adsorb onto the surface of ZMAs through a reversible oxidation‐reduction reaction, effectively suppressing the interfacial side reactions by forming a water‐poor interface, and enhancing the reversibility of Zn2+ deposition/stripping by redistributing the Zn2+ flux. These favorable effects of TFPAA− combined with the dynamic electrostatic shielding effect of Y3+ ultimately enable uniform and dense Zn2+ deposition. As a result, the Zn/Zn cells assembled with 0.25YTFPAA electrolyte exhibit an impressive cycle life of 2100 h at 0.5 mA cm−2–0.25 mAh cm−2. More importantly, the assembled V2O5/Zn full cell shows an ultra‐long cycle life of up to 18000 cycles at 5.0 A g−1. This work highlights the rational design of multifunctional ionic additives for stabilizing aqueous ZMAs. [ABSTRACT FROM AUTHOR]

A typical polyanionic based material Na3V2(PO4)2O2F (Na3VPO2F) attracts much interest as a cathode for large‐scale sodium‐ion batteries in consideration of its stable structure and remarkable energy density. Nevertheless, the large coulombic attraction and repulsion suffered by the mobile Na+ from structural anions and surrounding Na+, respectively, result in a torpid reaction kinetics and inferior rate capability. Herein, Br−‐doped and Na+ vacancy preinstalled Na3−yVPO2−xBrxF is prepared to dilute the charges on and inside the Na+ transportation tunnel. In virtue of density functional theory analysis, Na3−yVPO2−xBrxF reveals a reduction in the bandgap and an increase in electronic conductivity. Meanwhile, the almost electrostatically shielded tunnel in Na3−yVPO2−xBrxF alleviates the coulombic hindrance imposed on Na+ during its (de)intercalation, which demonstrates a Na+ diffusivity about five times higher than that of Na3VPO2F. Consequently, the Na3−yVPO2−xBrxF cathode shows a superior rate capacity of 77.7 mAh g−1 under 50 C and great cycling property corresponding to a high capacity retention of 94.4% over 800 cycles at 10 C. The assembled Na3−yVPO2−xBrxF//hard‐carbon sodium‐ion full‐cell presents excellent specific energy/power (226 Wh kg−1@15424.2 W kg−1) as well as outstanding long‐term cyclic stability over 1000 cycles at 5 C. [ABSTRACT FROM AUTHOR]

The serious safety issues caused by uncontrollable lithium (Li) dendrite growth, especially at high current densities, seriously hamper the rapid charging of Li metal‐based batteries. Here, the construction of Al–Li alloy/LiCl‐based Li anode (ALA/Li anode) is reported by displacement and alloying reaction between an AlCl3‐ionic liquid and a Li foil. This layer not only has high ion‐conductivity and good electron resistivity but also much improved mechanical strength (776 MPa) as well as good flexibility compared to a common solid electrolyte interphase layer (585 MPa). The high mechanical strength of the Al–Li alloy interlayer effectively eliminates volume expansion and dendrite growth in Li metal batteries, so that the ALA/Li anode achieves superior cycling for 1600 h (2.0 mA cm−2) and 1000 cycles at an ultrahigh current density (20 mA cm−2) without dendrite formation in symmetric batteries. In lithium–sulfur batteries, the dense alloy layer prevents direct contact between polysulfides and Li metal, inhibiting the shuttle effect and electrolyte decomposition. Long cycling performance is achieved even at a high current density (4 C) and a low electrolyte/sulfur (6.0 µL mg−1). This easy fabrication process provides a strategy to realize reliable safety during the rapid charging of Li‐metal batteries. [ABSTRACT FROM AUTHOR]