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Unstable Zn interface with serious detrimental parasitic side‐reactions and uncontrollable Zn dendrites severely plagues the practical application of aqueous zinc‐ion batteries. The interface stability was closely related to the electrolyte configuration and Zn2+ depositional behavior. In this work, a unique Zn‐ion anchoring strategy is originally proposed to manipulate the coordination structure of solvated Zn‐ions and guide the Zn‐ion depositional behavior. Specifically, the amphoteric charged ion additives (denoted as DM), which act as zinc‐ion anchors, can tightly absorb on the Zn surface to guide the uniform zinc‐ion distribution by using its positively charged −NR4+ groups. While the negatively charged −SO3− groups of DM on the other hand, reduces the active water molecules within solvation sheaths of Zn‐ions. Benefiting from the special synergistic effect, Zn metal exhibits highly ordered and compact (002) Zn deposition and negligible side‐reactions. As a result, the advanced Zn||Zn symmetric cell delivers extraordinarily 7000 hours long lifespan (0.25 mA cm−2, 0.25 mAh cm−2). Additionally, based on this strategy, the NH4V4O10||Zn pouch‐cell with low negative/positive capacity ratio (N/P ratio=2.98) maintains 80.4 % capacity retention for 180 cycles. A more practical 4 cm*4 cm sized pouch‐cell could be steadily cycled in a high output capacity of 37.0 mAh over 50 cycles. [ABSTRACT FROM AUTHOR]

Anode‐free sodium metal batteries (AFSMBs) as one new battery configuration, have attracted more attention in recent years and considered as the promising next‐generation energy storage systems, owing to the advantages of high theoretical energy density, high safety, cost‐saving, and simplified fabrication process. The practical application of AFSMBs, however, is impeded by their poor cycle life arising from the low coulombic efficiency (CE), the growth of metal dendrite, and unstable solid electrolyte interphase (SEI). Recently, some works are reported to dissolve the above‐mentioned issues. In this review, it provides a comprehensive summary of AFSMBs including their origin, mechanism, advantages, challenges, strategies, and perspectives. First, the intrinsic issues of conventional sodium metal batteries are summarized as safety concerns and manufacturing difficulty, which is the background of promoting AFSMBs' birth. Subsequently, the mechanism, construction requirement, advantages, and challenges of AFSMBs are discussed. Furthermore, the strategies for improving AFSMBs performance in terms of the current collector, electrolyte, and protocols, are summarized based on an extensive literature survey. Finally, the summary and outlook on this emerging field are further discussed briefly. [ABSTRACT FROM AUTHOR]

Aqueous Zn‐ion batteries with mild acidic electrolytes are considered the promising energy storage solutions due to their outstanding merits of high energy density and cost‐effectiveness. However, the rampant dendrite growth and severe parasitic reactions caused by a series of factors such as irregular Zn2+ transport pathway and pH variation would result in poor cycling stability. Herein, a self‐regulated interface strategy implemented by ammonium persulfate ((NH4)2S2O8, denoted as APS) multifunctional additive is proposed to simultaneously address the above issues. The zincophilic NH4+ preferentially adsorbs on the Zn protuberance to exclude water molecules and shield the "tip effect," thus inhibiting side‐reactions and inducing uniform Zn deposition. Moreover, NH4+ and S2O82− can dynamically adjust H+ and OH− concentrations in a pH self‐buffer manner, thus effectively mitigating hydrogen evolution reaction and formation of by‐products. Consequently, with the existence of APS additive, Zn anode exhibits ultrahigh coulombic efficiency (CE) of 99.9% over 9000 cycles and ultra‐long lifespan of 4300 h at 5 mA cm−2. Furthermore, even under high NH4V4O10 mass loading (9.4 mg cm−2) and thin zinc foil (10 µm), the assembled NH4V4O10//Zn pouch cell with APS additive can still maintain stably over 210 cycles, demonstrating its excellent value for application. [ABSTRACT FROM AUTHOR]