Aqueous zinc‐ion batteries have been considered as potential energy storage devices owing to their high safety and low cost. Traditional zinc‐ion batteries often implement a typical Zn2+ insertion/extraction mechanism. Compared with traditional Zn2+ insertion/extraction mechanism, supercapacitor‐liked dual‐ion mechanism often endow the batteries with higher operating voltage, better rate capability, and longer cycle life. Herein, aqueous Zn/polyaniline batteries are developed, which can combine the Zn2+ insertion/extraction and dual‐ion mechanisms. The Zn/polyaniline batteries deliver excellent electrochemical performance, especially a long cycle life up to 3000 cycles with high‐capacity retention of 92%. This hybrid mechanism provides a promising battery chemistry. Furthermore, Zn/polyaniline batteries can be assembled into quasi‐solid‐state soft‐packaged and cable‐type configurations and display stable electrochemical performance even under different bending states, showing potential applications for flexible electronics.

The self‐healing of zinc‐ion batteries (ZIBs) will not only significantly improve the durability and extend the lifetime of devices, but also decrease electronic waste and economic cost. A poly(vinyl alcohol)/zinc trifluoromethanesulfonate (PVA/Zn(CF3SO3)2) hydrogel electrolyte was fabricated by a facile freeze/thaw strategy. PVA/Zn(CF3SO3)2 hydrogels possess excellent ionic conductivity and stable electrochemical performance. Such hydrogel electrolytes can autonomously self‐heal by hydrogen bonding without any external stimulus. All‐in‐one integrated ZIBs can be assembled by incorporating the cathode, separator, and anode into hydrogel matrix since the fabrication of PVA/Zn(CF3SO3)2 hydrogel is a process of converting the liquid to quasi‐solid state. The ZIBs show an outstanding self‐healing and can recover electrochemical performance completely even after several cutting/healing cycles.

The co-insertion of dual ions can often offer

The self‐healing of zinc‐ion batteries (ZIBs) will not only significantly improve the durability and extend the lifetime of devices, but also decrease electronic waste and economic cost. A poly(vinyl alcohol)/zinc trifluoromethanesulfonate (PVA/Zn(CF3SO3)2) hydrogel electrolyte was fabricated by a facile freeze/thaw strategy. PVA/Zn(CF3SO3)2 hydrogels possess excellent ionic conductivity and stable electrochemical performance. Such hydrogel electrolytes can autonomously self‐heal by hydrogen bonding without any external stimulus. All‐in‐one integrated ZIBs can be assembled by incorporating the cathode, separator, and anode into hydrogel matrix since the fabrication of PVA/Zn(CF3SO3)2 hydrogel is a process of converting the liquid to quasi‐solid state. The ZIBs show an outstanding self‐healing and can recover electrochemical performance completely even after several cutting/healing cycles.

Aqueous zinc‐ion batteries (ZIBs) with low cost and high safety are promising energy‐storage devices. However, ZIBs with metal Zn anodes usually suffer from low coulombic efficiency and poor cycling performance due to the occurrence of side reactions on the Zn anodes. Here, a binary hydrate‐melt ZnCl2/Zn(OAc)2 electrolyte is designed to suppress the hydrogen evolution reaction and by‐product formation on Zn anodes by adjusting the Zn2+ solvation structure. In the solvation structure of the hydrate‐melt ZnCl2/Zn(OAc)2 electrolyte, the carboxylate group in OAc− will coordinate with the Zn2+, which will weaken the interaction between Zn2+ and H2O molecules to achieve higher ionization energy of H2O molecules. Simultaneously, these carboxylate groups of OAc− can serve as H‐bond acceptors to construct H‐bonds with H2O molecules in their neighboring solvation structures, forming a cross‐linking H‐bond network. Such a cross‐linking H‐bond network further suppresses the water activity in ZnCl2/Zn(OAc)2 electrolyte. As a result, in such an electrolyte, the side reactions are effectively restricted on Zn anodes and thus Zn anodes can achieve a high coulombic efficiency of 99.59% even after cycling. To illustrate the feasibility of the ZnCl2/Zn(OAc)2 electrolyte in aqueous ZIBs, Zn||p‐chloranil cells are assembled based on the ZnCl2/Zn(OAc)2 electrolyte. The resultant Zn||p‐chloranil cells exhibit enhanced cycling performance compared with the cases with a conventional ZnSO4 electrolyte.

Aqueous rechargeable metal batteries are intrinsically safe due to the utilization of low-cost and non-flammable water-based electrolyte solutions. However, the discharge voltages of these electrochemical energy storage systems are often limited, thus, resulting in unsatisfactory energy density. Therefore, it is of paramount importance to investigate alternative aqueous metal battery systems to improve the discharge voltage. Herein, we report reversible manganese-ion intercalation chemistry in an aqueous electrolyte solution, where inorganic and organic compounds act as positive electrode active materials for Mn2+ storage when coupled with a Mn/carbon composite negative electrode. In one case, the layered Mn0.18V2O5·nH2O inorganic cathode demonstrates fast and reversible Mn2+ insertion/extraction due to the large lattice spacing, thus, enabling adequate power performances and stable cycling behavior. In the other case, the tetrachloro-1,4-benzoquinone organic cathode molecules undergo enolization during charge/discharge processes, thus, contributing to achieving a stable cell discharge plateau at about 1.37 V. Interestingly, the low redox potential of the Mn/Mn2+ redox couple vs. standard hydrogen electrode (i.e., −1.19 V) enables the production of aqueous manganese metal cells with operational voltages higher than their zinc metal counterparts.

Air-rechargeable zinc batteries are a promising candidate for self-powered battery systems since air is ubiquitous and cost-free. However, they are still in their infancy and their electrochemical performance is unsatisfactory due to the bottlenecks of materials and device design. Therefore, it is of great significance to develop creative air-rechargeable Zn battery systems. Herein, an air-rechargeable Zn battery with H+-based chemistry was developed in a mild ZnSO4 electrolyte for the first time, where benzo­[i]­benzo­[6,7]­quinoxalino­[2,3-a]­benzo­[6,7]­quinoxalino­[2,3-c]­phenazine-5,8,13,16,21,24-hexaone (BQPH) was employed as cathode material. In this Zn/BQPH battery, a Zn2+ coordination with adjacent CO and CN groups leads to an inhomogeneous charge distribution in the BQPH molecule, which induces the H+ uptake on the remaining four pairs of the CO and CN groups in subsequent discharge processes. Interestingly, the large potential difference between the discharged cathode of the Zn/BQPH battery and oxygen triggers the redox reaction between them spontaneously, in which the discharged cathode can be oxidized by oxygen in air. In this process, the cathode potential will gradually rise along with H+ removal, and the discharged Zn/BQPH battery can be air-recharged without an external power supply. As a result, the air-rechargeable Zn/BQPH batteries exhibit enhanced electrochemical performance by fast H+ uptake/removal. This work will broaden the horizons of air-rechargeable zinc batteries and provide a guidance to develop high-performance and sustainable aqueous self-powered systems.

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