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Metallic aluminum is an attractive anode owing to its high specific capacity, earth abundance, and low cost. However, the poor reversibility of Al deposition/dissolution and Al dendrites have impeded its deployment. Herein, a strategy for constructing a lattice‐matching layer (LML) to regulate the behavior of Al deposition/dissolution is demonstrated. Various experiments and theoretical calculations validate that gold LML as an example can significantly enhance the nucleation density and reduce average particle size, which achieve highly reversible, dendrite‐free, durable, and anode‐free Al anodes. The metallic Al shows stable Al deposition/dissolution on Au@Ti substrate for more than 4500 h with an average Coulombic efficiency of 99.92%, which is a record‐high reported value. Furthermore, the anode‐free full cell based on Au@Ti anode and expanded graphite cathode exhibits outstanding long‐term stability for 900 cycles with the capacity retention rate of 80%. This study provides an effective strategy to enhance the reversibility and utilization of the Al anode, which provides inspiration for advanced Al batteries. [ABSTRACT FROM AUTHOR]

Aqueous zinc (Zn) battery with remarkable advantages of high safety, low cost, and high reversibility is highly applauded in next‐generation low‐speed electric vehicles and large‐scale energy storage applications. However, Zn anode suffers from a series of unfavorable reactions, hindering its progress toward industrialization. Herein, a functionalized hydrogel film is designed using polydopamine and polyacrylamide crosslinking (PDAM) as the Zn protective layer to stabilize the Zn anode. Benefiting from the strong interaction of Zn2+ with PDAM, the primary solvation shell of Zn2+ is regulated by PDAM into the form of PDAM–Zn2+‐5H2O. This remodeling prevents Zn dendrite growth and inhibits water‐induced side reactions. As a result, the Zn–MnO2 battery using PDAM‐coated Zn anode exhibits excellent cycling stability, demonstrating over 1150 cycles at an areal capacity of 5 mAh cm−2 with an average Coulombic efficiency (CE) of 96.5%. For a scaled‐up PDAM@Zn–MnO2 pouch cell with a capacity of 80 mAh, stable cycling of over 200 cycles with an average CE of 91.9% is achieved. The superior Zn–MnO2 battery enabled by the functionalized hydrogel protective film enlightens an arena toward next‐generation energy storage applications. [ABSTRACT FROM AUTHOR]

Mg batteries utilizing divalent Mg2+ as charge carriers have been attracting significant attention for energy storage owing to their uniqueness in terms of low cost, high safety, and high energy density. However, the short cycling life arising from the accumulation of a passivation layer on the Mg anode prohibits their further development. Here, a new strategy to suppress the accumulation of the passivation layer is presented, thus stabilizing the Mg anode by constructing a robust interfacial layer using organic solvent‐in‐water electrolytes. The organic solvents decompose on the Mg anode to form a MgO, polyether Mg enriched organic‐inorganic hybrid interfacial layer, preventing free water attack to the Mg anode. In addition, the organic solvent forms an H‐bond with H2O to suppress the water activity and therefore protecting the Mg anode. As an illustration to benefits of the solvent‐in‐water electrolytes, a Mg‐MnO2 battery that is coupled by a MnO2 cathode in Mn2+/MnO2 chemistry with the Mg anode is developed. The Mg‐MnO2 battery exhibits a well‐maintained discharge plateau at ≈2.5 V and a discharging capacity of ≈500 mAh g−1 over 1000 cycles. This result highlights the feasibility to stabilize the Mg anode by interface engineering through the solvent‐in‐water electrolyte design. [ABSTRACT FROM AUTHOR]

Electrolytic MnO2–Zn batteries with economic advantages and high energy density are viable candidates for large‐scale energy storage. However, the spontaneous reactions between acidic electrolytes and Zn metal anode cause severe proton‐induced hydrogen evolution which is difficult to avoid. Herein, a proton‐barrier separator (PBS) based on poly(vinyl alcohol) (PVA) is fabricated via the Hofmeister effect for preventing hydrogen evolution. Experiments and theoretical calculations demonstrate that the concentrated sulfate enables PVA chains to form a discontinuous hydrogen bond network as well as isolated hydrophilic cavities. This unique feature can effectively obstruct proton migration to impede proton‐induced hydrogen evolution, but allow for fast Zn2+ transfer with excellent stability. Electrolytic MnO2–Zn batteries with PBS deliver high energy retention (91.2% after 200 cycles) and largely enhanced rate performance (20 C) in a high areal capacity of 6.67 mAh cm−2 with a very low cost ($1 m−2) as compared to commercial anion exchange membranes (8 C). This work sheds light on new avenues for the development of stable electrolytic MnO2–Zn batteries by deploying PBS for preventing hydrogen evolution through a cost‐effective fabrication method, which is a universal approach that can be applied to design other stable aqueous metal‐ion batteries. [ABSTRACT FROM AUTHOR]

Solid Electrolyte Interface Regulated by Solvent-in-Water Electrolyte Enables High-Voltage and Stable Aqueous Mg-MnO2 Batteries (Adv. Mg anodes, Mg-MnO 2 batteries, MnO 2 cathodes, solid electrolyte interfaces, solvent-in-water electrolytes The regulated Mg anode enables highly stable aqueous Mg-MnO SB 2 sb batteries with a high discharge voltage of 2.5 V and a greatly improved specific capacity of 500 mAh g SP -1 sp for over 1000 cycles. [Extracted from the article]