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The operation of traditional aqueous-electrolyte zinc-ion batteries is adversely affected by the uncontrollable growth of zinc dendrites and the occurrence of side reactions. These problems can be avoided by the development of functional hydrogel electrolytes as replacements for aqueous electrolytes. However, the mechanism by which most hydrogel electrolytes inhibit the growth of zinc dendrites on a zinc anode has not been investigated in detail, and there is a lack of a large-scale recovery method for mainstream hydrogel electrolytes. In this paper, we describe the development of a recyclable and biodegradable hydrogel electrolyte based on natural biomaterials, namely chitosan and polyaspartic acid. The distinctive adsorptivity and inducibility of chitosan and polyaspartic acid in the hydrogel electrolyte triggers a double coupling network and an associated synergistic inhibition mechanism, thereby effectively inhibiting the side reactions on the zinc anode. In addition, this hydrogel electrolyte played a crucial role in an aqueous acid-based Zinc/MnO2 battery, by maintaining its interior two-electron redox reaction and inhibiting the formation of zinc dendrites. Furthermore, the sustainable biomass-based hydrogel electrolyte is biodegradable, and could be recovered from the Zinc/MnO2 battery for subsequent recycling. Functional hydrogel electrolytes show promising potential for enhancing the sustainability of aqueous zinc-ion batteries. Here, the authors introduce a biomass-based hydrogel electrolyte that not only prevents side reactions on the zinc anode but also enables easy retrieval from the zinc batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • A bifunctional strategy is proposed to enhance Zn (0 0 2) plane over prolonged cycling. • Carboxylated chitosan (CCS) is demonstrated as a bifunctional electrolyte additive. • CCS can selectively etch Zn matrix with (0 0 2) texturing. • CCS can induce the assembly of Zn atoms along (0 0 2) direction. • Zn anodes with CCS exhibit extended cycling stability and high utilization rate. Although Zn (0 0 2) crystal plane make it highly competitive for the design of high-performance Zn anodes, manipulating the Zn (0 0 2) crystal plane and maintaining long-term stability are significant challenges. Herein, carboxylated chitosan (CCS) is introduced as a novel bifunctional polymer electrolyte additive to protect the intrinsic Zn (0 0 2) plane from resolution and induce the highly oriented assembly of Zn atoms along (0 0 2) direction, thereby self-adaptively enhancing the Zn (0 0 2) plane over prolonged cycling. Specifically, CCS with electron-rich groups can preferentially adsorb on Zn anode, selectively etch the Zn anode with (0 0 2) texturing and appropriately affect the assembly of Zn atoms along the (0 0 2) direction. As a result, a remarkable cycling lifespan of over 300 h is achieved at 30 mA cm−2 under a deep depth of discharge of 60 %. Moreover, a highly reversible Zn anode with a high Coulombic efficiency of 99.8 % can also be achieved at 10 mA cm−2 over 1000 cycles. Furthermore, the capacity stability of NH 4 V 4 O 10 ||Zn full cell and Zn||AC hybrid supercapacitor is significantly improved even under harsh conditions, such as high areal capacity, limited Zn resource and lean electrolyte. The CCS additive maintains a stable effect on the directional reconstruction of Zn anodes over prolonged cycling. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous Zn‐ion batteries (ZIBs) are always regarded as a promising energy storage device owing to their higher safety and durability. However, two problems have become the main trouble for the practical application of ZIBs such as the dendrite growth of Zn metal anode in electrolyte and the freezing of water solvent at low temperature. Herein, to overcome these challenges, a new strategy, multi‐component crosslinked hydrogel electrolyte, is proposed to inhibit Zn dendrites and realize low temperature environmental adaptability for ZIBs. Benefitting from the superior inhibition effect of the polyacrylamide and dimethyl sulfoxide (DMSO) on Zn dendrites, the coulombic efficiency of the symmetric cell of ≈99.5% is achieved during the Zn plating/stripping over 1 300 h, and the assembled full‐cell demonstrates the large specific capacity of 265.2 mAh g‐1 and high cyclic stability with the capacity retention of 95.27% after 3 000 cycles. In addition, the full‐cell delivers stable operation at a wide temperature range, from 60 to −40 °C, due to the introduction of additive DMSO. This work provides an inspired strategy and novel opportunities to realize a dendrite‐free and wide‐temperature rechargeable aqueous Zn‐ion energy storage system. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous zinc ion batteries have attracted increasing attention as a new energy storage system because of the high ionic conductivity and safe aqueous electrolyte. The spontaneous vanadium dissolution in aqueous electrolytes is one major problem because the water with serious polarity would corrode the crystal structure of vanadium‐based cathodes. Here, an in situ artificial cathode electrolyte interphase (CEI) strategy is proposed to kinetically suppress the vanadium dissolution in aqueous zinc ion batteries. The strontium ion is introduced into vanadium oxide layers as a sacrifice guest, which would directly precipitate upon getting out from the vanadium‐based cathode to in situ from a CEI coating layer on the surface. This strategy is proven with the help of various technologies, and the remarkable ability of the CEI layer to suppress cathode dissolution is evaluated by multiple electrochemical and chemical methods. As a result, the cathode after CEI conversion exhibits the best recharge capacity retention after open circuit voltage rest for 3 days in comparison with other cathodes. This work reports a general strategy to construct the electrode‐electrolyte interface for suppressing vanadium‐based cathodes dissolution in aqueous electrolytes and beyond. [ABSTRACT FROM AUTHOR]