The Zn dendrite issue, which is closely related to the creation of the space-charge region upon local anion depletion during cycling, has plagued the practical applications of aqueous Zn metal batteries (ZMBs). Herein, we propose a Kevlar-derived hydrogel (KevlarH) electrolyte with immobilized anions to diminish the space-charge layer effect. SO 4 2− anions are strongly tethered to amide groups of polymer chains, which mitigates the concentration polarization of interfacial Zn 2+ ions by preventing the anion depletion. Furthermore, the relatively weak interaction between Zn 2+ cations and carbonyl groups can redistribute Zn 2+ -ion flux without sacrificing the ion diffusion rate. The synergistic "zincophilic" and "anionphilic" building blocks enable dendrite-free Zn deposition behavior and suppressed side reactions, thereby extending the lifespan of a Zn metal anode up to 3500 h with an ultrahigh Coulombic efficiency of 99.87%. Importantly, the KevlarH electrolyte can be directly used to assemble high-voltage bipolar ZMBs and break the 2 V barrier in aqueous ZMBs.

Aqueous zinc−iodine (Zn−I 2 ) batteries have attracted extensive attention due to their merits of inherent safety, wide natural abundance, and low cost. However, their application is seriously hindered by the irreversible capacity loss resulting from both anode and cathode. Herein, an anion concentrated electrolyte (ACE) membrane is designed to manipulate the Zn 2+ ion flux on the zinc anode side and restrain the shuttle effect of polyiodide ions on the I 2 cathode side simultaneously to realize long-lifetime separator-free Zn− I 2 batteries. The ACE membrane with abundant sulfonic acid groups possesses a multifunctional amalgamation of good mechanical strength, guided Zn 2+ ion transport, and effective charge repulsion of polyiodide ions. Moreover, rich ether oxygen, carbonyl, and S−O bonds in anionic polymer chains will form hydrogen bonds with water to reduce the proportion of free water in the ACE membrane, inhibiting the water-induced interfacial side reactions of the Zn metal anode. Besides, DFT calculations and in-situ UV−vis and in situ Raman results reveal that the shuttle effect of polyiodide ions is also significantly suppressed. Therefore, the ACE membrane enables a long lifespan of Zn anodes (3700 h) and excellent cycling stability of Zn−I 2 batteries (10000 cycles), thus establishing a substantial base for their practical applications. KEYWORDS: aqueous zinc−iodine batteries, anion concentrated electrolyte membrane, guided Zn 2+ ion flux, free water, polyiodide ions shuttle effect

Aqueous zinc‐ion batteries (AZIBs) have attracted widespread attention due to their intrinsic merits of low cost and high safety. However, the poor thermodynamic stability of Zn metal in aqueous electrolytes inevitably cause Zn dendrites growth and interface parasitic side reactions, resulting in unsatisfactory cycling stability and low Zn utilization. Replacing Zn anode with intercalation‐type anodes have emerged as a promising alternative strategy to overcome the above issues but the lack of appropriate anode materials is becoming the bottleneck. Herein, the interlayer structure of MoSe2 anode is preintercalated with long‐chain polyvinyl pyrrolidone (PVP), constructing a periodically stacked p‐MoSe2 superlattice to activate the reversible Zn2+ storage performance (203 mAh g−1 at 0.2 A g−1). To further improve the stability of the superlattice structure during cycling, the electrolyte is also rationally designed by adding 1,4‐Butyrolactone (γ‐GBL) additive into 3 M Zn(CF3SO3)2, in which γ‐GBL replaces the H2O in Zn2+ solvation sheath. The preferential solvation of γ‐GBL with Zn2+ effectively reduces the water activity and helps to achieve an ultra‐long lifespan of 12,000 cycles for p‐MoSe2. More importantly, the reconstructed solvation structure enables the operation of p‐MoSe2||ZnxNVPF (Na3V2(PO4)2O2F) AZIBs at an ultra‐low temperature of −40°C, which is expected to promote the practical applications of AZIBs.