Zn-ion Batteries Research Articles

Hydrated Eutectic Electrolyte Induced Bilayer Interphase for High-Performance Aqueous Zn-Ion Batteries with 100°C Wide-Temperature Range.

The practical implementation of aqueous zinc-ion batteries (AZIBs) encounters challenges such as dendrite growth, parasitic reactions, and severe decay in battery performance under harsh environments. Here, a novel hydrated eutectic electrolyte (HEE) composed of Zn(ClO4 )2 ·6H2 O, ethylene glycol (EG), and InCl3 solution is introduced to effectively extend the lifespan of AZIBs over a wide temperature range from -50 to 50°C. Molecular dynamics simulations and spectroscopy analysis demonstrate that the H2 O molecules are confined within the liquid eutectic network through dual-interaction, involving coordination with Zn2+ and hydrogen bonding with EG, thus weakening the activity of free water and extending the electrochemical window. Importantly, cryo-transmission electron microscopy and spectroscopy techniques reveal that HEE in situ forms a zincophobic/zincophilic bilayer interphase by the dissociation-reduction of eutectic molecules. Specifically, the zincophilic interphase reduces the energy barrier for Zn nucleation, promoting uniform Zn deposition, while the zincophobic interphase prevents active water from contacting the Zn surface, thus inhibiting the side reactions. Furthermore, the relationships between the structural evolution of the liquid eutectic network and interfacial chemistry at electrode/electrolyte interphase are further discussed in this work. The scalability of this design strategy can bring benefits to AZIBs operating over a wide temperature range.

Lotus Effect Inspired Hydrophobic Strategy for Stable Zn Metal Anodes.

Zn-ion batteries (ZIBs) have long suffered from the unstable Zn metal anode, which faces numerous challenges concerning dendrite growth, corrosion, and hydrogen evolution reaction. The absence of H2 O adsorption control techniques has become a bottleneck for the further development of ZIBs. Using the stearic acid (SA)-modified Cu@Zn (SA-Cu@Zn) anode as an example, this work illustrates how the lotus effect controls the H2 O adsorption energy on the Zn metal anode. In situ integrated Cu nanorods arrays and hydrophobic long-chain alkyl groups are constructed, which provide zincophilic ordered channels and hydrophobic property. Consequently, the SA-Cu@Zn anode exhibits long-term cycling stability over 2000h and high average Coulombic efficiency (CE) of 99.83% at 1mA cm-2 for 1 mAh cm-2 , which improves the electrochemical performance of the Zn||V2 O5 full cell. Density functional theory (DFT) calculations combined with water contact angle (CA) measurements demonstrate that the SA-Cu@Zn exhibits larger water CA and weaker H2 O adsorption than Zn. Moreover, the presence of Cu ensures the selective adsorption of Zn on the SA-Cu@Zn anode, well explaining how the excellent reversibility is achieved. This work demonstrates the effectiveness of the lotus effect on controllable H2 O adsorption and Zn deposition mechanism, offering a universal strategy for achieving stable ZIB anodes.

Rare earth metals ion intercalated hydrated vanadium oxides for high-performance aqueous zinc-ion batteries

Hydrated vanadium oxide (V2O5·nH2O) is promising cathode candidates for aqueous rechargeable Zn-ion batteries (ZIBs) owing to its high theoretical specific capacity, abundant resources and environmentally friendly. However, the higher charge density of Zn2+ lead to its structural instability, cyclic degradation and sluggish Zn2+ diffusion kinetics. Herein, rare earth metal ions intercalated into the interlayer of V2O5·nH2O materials (abbreviated as RE-VOH) are successfully synthesized to expand interlayer spacing and stabilize the layered structure via a simple sol-gel method, among, the yttrium ion intercalated V2O5·nH2O (Y–VOH) exhibits a honeycomb porous microstructure and a remarkably enlarged interlayer distance (13.6 Å), which can not only increase the contact area between the electrode material and the electrolyte but also offer rapid diffusion channel for Zn2+. Meanwhile, the problem of vanadium dissolution of cathode materials is inhibited by the electrolyte additive strategy through adding suitable vanadium oxide sol to aqueous electrolyte, furthermore, the zinc anode modification strategy in electroplating process inhibits the formation of zinc dendrites. Benefitting from the synergistic effect of modification design for the ZIBs systems of cathode, electrolyte and anode, the overall electrochemical performance of Y–VOH electrode is significantly improved, delivering a large specific capacity of 337 mAh g−1 at the current density of 500 mA g−1 and excellent rate capability of 170 mAh g−1 at 10 A g−1, along with an outstanding capacity retention of 90 % over 3000 cycles. Additionally, systematical ex situ characterizations prove the (de)intercalation reversibility of Zn2+ storage mechanism for the Y–VOH cathode. This research may provide a new way for exploiting high performance vanadium-based materials for aqueous ZIBs.

Co/Mn ratio-regulated hexacyanoferrates as a long-life and high-rate cathode for aqueous Zn-ion batteries

Among all kinds of cathodes for aqueous Zn-ion batteries, Mn-based hexacyanoferrates exhibit advantages of high-voltage and abundant resources. However, they suffer from inferior cycle-life and rate capability, which may be attributed to the structural instability and metal ion dissolution. In this work, a continuous element substitution (Mn replaced by Co) is employed to modify the electrochemical performance of Mn-based hexacyanoferrates. With the increasing ration of Co/Mn, the Mn, Co-based hexacyanoferrate (MnCoHCF) samples show unchanged crystalline phase with similar morphology and increasing Co dopant. Additionally, the initial specific capacity gradually decreases, but the electrochemical polarization is alleviated. Among the samples, MnCoHCF-4 (ratio of Co/Mn of 3:1) exhibits excellent cycling life (71.4% after 3000 cycles at 5 C) and rate performance (81.4 mA h g−1 at 10 C). In-situ techniques reveal the obvious metal ion dissolution with a low ratio of Co/Mn during the electrochemical process, resulting in poor structure stability and reaction kinetics of MnHCF electrode. However, When the ratio of Co/Mn is increased, the metal ion dissolution is effectively suppressed, and the MnCoHCF electrode shows improved structure stability and reaction kinetics. This work proposes an effective modification for hexacyanoferrates and other high-voltage Prussian blue analogues, which may promote the application of aqueous Zn-ion batteries.

Synergetic impact of oxygen and vanadium defects endows NH4V4O10 cathode with superior performances for aqueous zinc-ion battery

Owing to multi-electron redox reactions and versatile cation storage capabilities, laminated structured metallic vanadate of NH4V4O10 (NHVO) has been regarded as a kind of promising cathode materials for aqueous Zn-ion batteries with satisfactory electrochemical performance. Nevertheless, the NHVO cathode is still limited by the sluggish electrochemical kinetics and structural instability. Here, defect engineering was conducted to introduce the vanadium (V) and oxygen (O) dual defects into NHVO cathode for improving electrochemical performance. As revealed experimentally and theoretically, the migration of Zn-ion inside V/O-defected NHVO cathode can be effectively fostered by increasing active sites, lowering the migration barrier and reducing Gibbs free energy, which are rooted in the synergy impact of the presence of O defect and V defect. As the consequence, the outstanding electrochemical performance has been achieved, which delivers higher capacity of 489 mAh g−1 at 0.5 A g−1 with the capacity retention of 98 % after 100 cycles and exhibits singular cyclic stability at 15 A g−1, maintaining reversible capacity of 198 mAh g−1 after 8000 cycles. This synergistic strategy paves an avenue for accelerating the application of HNVO-based cathode for aqueous Zn-ion battery with satisfactory electrochemical performance and lifespan, advancing the approach of “carbon neutrality” society.

Controllable Solid Electrolyte Interphase by Ionic Environment Regulation for Stable Zn-Ion Battery.

Artificial solid electrolyte interphase in organic solutions is effective and facile for long-cycling aqueous zinc ion batteries. However, the specific effects on different ionic environments have not been thoroughly investigated. Herein, pyromellitic acid (PA) are employed as organic ligand to coordinate with Zn2+ under various ionic environments. The connection between the ionic environment and reaction spontaneity is analyzed to provide insights into the reasons behind the effectiveness of the SEI layer and to characterize its protective impact on the zinc anode. Notably, the PA solution (pH4) lacking OH- contributes to the formation of a dense and ultrathin SEI with Zn-PA coordination, preventing direct contact between the anode and electrolyte. Moreover, the presence of organic functional groups facilitates a uniform flux of Zn2+. These advantages enable stable cycling of the PA4-Zn symmetric cell at a current density of 3mA cm-2 for over 3500 h. The PA4-Zn//MVO full cell demonstrates excellent electrochemical reversibility. Investigating the influence of the ionic environment on SEI generation informs the development of novel SEI strategies.

Two-dimensional V2O3 nanosheets embedded in a carbon matrix with enhanced performance for aqueous Zn-ion battery

Two-dimensional (2D) V2O3 nanosheets embedded in carbon matrix (V2O3/C) were successfully synthesized through direct thermal decomposition of a mixture containing V2O5 and polyvinyl pyrrolidone (PVP) at 450 °C for 3 h in N2 atmosphere. Thanks to the synergistic effect between the expected 2D structural characteristics of V2O3 and the high conductivity of carbon, the V2O3/C achieved an impressive cyclic stability with 104 mAh·g−1 capacity retention after 4000 cycles at 10 A·g−1, a 489 mAh·g−1 high specific capacity at 1 A·g−1, as well as an outstanding rate capability. Additionally, we have successfully lit up light-emitting diode (LED) with Zn//V2O3/C battery, making it a prospective candidate for environmentally-friendly, high-performance, and low-cost energy storage device.

A Review on Covalent Organic Frameworks as Artificial Interface Layers for Li and Zn Metal Anodes in Rechargeable Batteries.

Li and Zn metals are considered promising negative electrode materials for the next generation of rechargeable metal batteries because of their non-toxicity and high theoretical capacity. However, the uneven deposition of metal ions (Li+ , Zn2+ ) and the uncontrolled growth of dendrites result in poor electrochemical stability, unsatisfactory cycle life, and rapid capacity decay of batteries assembled with Li and Zn electrodes. Owing to the unique internal directional channels and abundant redox active sites of covalent organic frameworks (COFs), they can be used to promote uniform deposition of metal ions during stripping/electroplating through interface modification strategies, thereby inhibiting dendrite growth. COFs provide a new perspective in addressing the challenges faced by the anodes of Li metal batteries and Zn ion batteries. This article discusses the stability and types of COFs, and summarizes some novel COF synthesis methods. Additionally, it reviews the latest progress and optimization methods of using COFs for metal anodes to improve battery performance. Finally, the main challenges faced in these areas are discussed. This review will inspire future research on metal anodes in rechargeable batteries.

Decoupled Design for Highly Efficient Perchlorate Anion Intercalation and High-Energy Rechargeable Aqueous Zn-Graphite Batteries.

Seeking new cathode chemistry with high onset potential and compatibility with electrolytes has become a challenge for aqueous Zn ion batteries. Anion intercalation in graphite (4.5V vs Li+ /Li) possesses the potentiality but usually shows a competitive relationship with oxygen evolution reaction (OER) in aqueous solutions. Herein, a decoupled design is proposed to optimize a full utilization of perchlorate ion intercalation in graphite cathode by pH adjustment. Benefiting from the decoupled design, high Coulombic efficiency is obtained by decelerating the kinetic of OER in acidic media. The decoupled Zn-graphite battery exhibits a wide potential window of 2.01V, as well as an attractive energy density of 231Whkg-1 . In addition, a Zn-graphite battery with insertion is assembled, which demonstrates the capability of the proposed decoupled strategy to integrate novel electrode chemistries for high-performance aqueous Zn-based energy storage systems.

Zn-In Alloying Powder Solvent Free Electrode Toward High-Load Ampere-Hour Aqueous Zn-Mn Secondary Batteries.

Aqueous Zn-ion batteries (ZIBs) are promising candidates for large-scale energy storage due to high safety, abundant reserves, low-cost, and high energy density. However, the reversibility of the metallic Zn anode in the mild electrolyte is still unsatisfactory, due to the Zn dendrite growth, hydrogen evolution, and corrosion passivation. Herein, a Zn-In alloying powder solvent free electrode is proposed to replace the Zn foil in ZIBs. The novel Zn anodes are constructed by a solvent-free manufacturing process with carbons, forming a 3D Zn deposition network and providing uniformly electric field distribution. The In on the Zn powder surface can increase the overpotential for hydrogen evolution and further improve the morphology of Zn deposition against dendrite growth. The Zn solvent-free electrodes enable the Zn-MnO2 batteries with high cathode loading mass of 10-20mg cm-2 to achieve >380 stable cycles. Furthermore, the assembled soft package batteries of 2.4 Ah (52Wh kg-2) is evaluated and the capacity retention is maintained at 80% after 200 cycles at a high areal capacity of 5 mAh cm-2 without gas evolution. This work offers a workable strategy to develop a durable Zn anode for the eventually commercial applications of aqueous Zn-Mn secondary batteries.

Ammonium intercalation engineering regulated structural stability of V6O13 cathodes for durable zinc ion batteries

Aqueous Zn-VO batteries have attracted more and more attention owing to their advantages of high capacity, low cost and stability. Nevertheless, the complex interaction between the inserted ions and the main lattice leading to structural instability, coupled with the interference of highly active free water, these factors lead to vanadium-based zinc batteries usually suffer from severe capacity attenuation. This work reports the optimization strategy of ammonium intercalation engineering to construct a robust V6O13 cathode with ammonium (V6O13-NH4+) for the stability of vanadium-based zinc batteries. Experiments and density functional theory (DFT) calculations illustrate that the ammonium intercalation could reduce the formation energy of VO-NH to improve cycling stability. The V6O13-NH4+ demonstrates high specific capacity (426.5 mAh g-1 capacity at 0.1 A/g) and high capacity retention rate (80.2%) after 10,000 cycles at 10 A/g. A soft-packed Zn/VO-NH battery maintains a desired capacity of 252.8 mAh g−1 after 2000 cycles at 5 A/g. This work proves that the ammonium intercalation is an effective way to achieve highly cycle stable of Aqueous Zn-ion batteries.

Dendrite-Free Zinc Anodes Enabled by Exploring Polar-Face-Rich 2D ZnO Interfacial Layers for Rechargeable Zn-Ion Batteries.

Zinc metal is a promising candidate for anodes in zinc-ion batteries (ZIBs), but its widespread implementation is hindered by dendrite growth in aqueous electrolytes. Dendrites lead to undesirable side reactions, such as hydrogen evolution, passivation, and corrosion, causing reduced capacity during prolonged cycling. In this study, an approach is explored to address this challenge by directly growing 1D zinc oxide (ZnO) nanorods (NRs) and 2D ZnO nanoflakes (NFs) on Zn anodes, forming artificial layers to enhance ZIB performance. The incorporation of ZnO on the anode offers both chemical and thermal stability and leverages its n-type semiconductor nature to facilitate the formation of ohmic contacts. This results in efficient electron transport during Zn ion plating and stripping processes. Consequently, the ZnO NFs-coated Zn anodes demonstrate significantly improved charge storage performance, achieving 348 mAh g-1, as compared to ZnO NRs (250 mAh g-1) and pristine Zn (160 mAh g-1) anodes when evaluated in full cells with V2O5 cathodes. One significant advantage of ZnO NFs lies in their highly polar surfaces, promoting strong interactions with water molecules and rendering them exceptionally hydrophilic. This characteristic enhances the ability of ZnO NFs to desolvate Zn2+ ions, leading to improved charge storage performance.

Acetamide-Caprolactam Deep Eutectic Solvent-Based Electrolyte for Stable Zn-Metal Batteries.

Aqueous Zn-ion batteries (AZIBs) are promising for grid-scale energy storage. However, conventional AZIBs face challenges including hydrogen evolution reaction (HER), leading to high local pH, and by-product formation on the anode. Hereby the hydrogen bonds in the aqueous electrolyte are reconstructed by using a deep eutectic co-solvent (DES) made of acetamide (H-bond donor) and caprolactam (H-bond acceptor), which effectively suppresses the reactivity of water and broadens the electrochemical voltage stability window. The coordination between Zn2+ and acetamide-caprolactam in DES-based electrolytes produces a unique solvation structure that promotes the preferential growth of Zn crystals along the (002) plane. This will inhibit the formation of Zn dendrites and ensure the uniform deposition of Zn-ions on the anode surface. In addition, it is found that this DES-based electrolyte can form a protective membrane on the anode surface, reducing the risks of Zn corrosion. Compared to conventional electrolytes, the DES-based electrolyte shows a long-term stable plating/stripping performance with a significantly improved Coulombic efficiency from 78.18% to 98.37%. It is further demonstrated that a Zn||VS2 full-cell with the DES-based electrolyte exhibits enhanced stability after 500 cycles with 85.4% capacity retention at 0.5Ag-1 .

Alleviating Mn<sup>3+</sup> Dissolution in ZnMn<sub>2</sub>O<sub>4</sub> Cathode for the Extended Cyclability via Particle Size Increase

ZnMn<sub>2</sub>O<sub>4</sub> (ZMO) cathode possesses a high theoretical capacity of 224 mAh g<sup>-1</sup> and high operating voltage (1.9 V vs. Zn<sup>2+</sup>/Zn) for aqueous Zn–ion batteries. However, the disproportionation reaction of Mn<sup>3+</sup> leads to Mn dissolution in the ZMO cathode, deteriorating lifespan. In this study, we attempted to reduce Mn dissolution by enlarging the particle size, thereby diminishing the electrode/electrolyte interfacial area. The ZMO particle grew with increasing the calcination temperatures of 400℃, 500℃, and 600℃. Higher calcination temperature created oxygen vacancies within the lattice, thereby increasing the contents of Mn<sup>3+</sup> for charge neutrality. The rate capability decreased with the increase in particle size, which is presumed to be due to the lengthening of the diffusion path of Zn ions. After a long–cycle experiment of Zn–ion batteries assembled with ZMO cathode and Zn anode, the Mn deposit amount on the anode was measured to reveal the Mn dissolution from the ZMO cathode based on the disproportionation reaction. The ZMO particle synthesized at 600℃ with the largest particle size demonstrated the highest cyclability of 48.1% at 1.0 A g<sup>-1</sup> based on the lowest Mn deposit on the anode. Hence, the ZMO electrode with a larger particle size exhibited improved cycle stability by alleviating of the disproportionation reaction from the reduced electrode/electrolyte interfacial area.

An electron/ion pathway reconstruction strategy enabling fast aqueous Zn2+ storage

Aqueous Zn-ion batteries (ZIBs) are considered ideal alternatives for scalable energy storage due to their reliable safety, affordable cost, and sustainability. However, the further development of ZIBs is limited by the design of the cathode, especially with the kinetic coupling of electron transfer and ion diffusion. Here, we develop an electron/ion pathway reconstruction strategy to enhance the kinetics of Zn storage by designing a composite of reduced graphene oxide-wrapped polyaniline/vanadium oxide superlattices. The superlattice structure of V–O layers stacked with polyaniline enables rapid Zn2+ diffusion due to the enlarged interlayer spacing and redistributed electron structure. Meanwhile, the lamellar superlattices wrapped with rGO optimize the electron transfer pathway and enhance mechanical stability. Therefore, the synergistic optimization between ion migration inside superlattices and charge transport in bulk materials achieves double acceleration for Zn2+ storage kinetics, showing superior rate capability (≥100 mAh/g at 20 A/g) and cycling durability. Moreover, the electrochemical mechanism investigation shows that the as-obtained composite cathode presents highly reversible Zn diffusion behavior and good structural stability through a series of in-situ spectroscopic characterizations. It is hoped that this electron/ion pathway reconstruction strategy can provide a new perspective for the development of high-performance cathodes for aqueous batteries.

Facile morphological construction of VO2 and its application in aqueous Zn-ion batteries

Three distinct morphologies of VO2, namely flake-shaped VO2 (VO2(PIAN)), disc-shaped VO2 (VO2(BING)) and rod-shaped VO2 (VO2(BANG)) were synthesized using a facile one-pot hydrothermal method. As a cathode for aqueous zinc-ion batteries (AZIBs), the VO2(PIAN) demonstrates relatively superior electrochemical performance for aqueous zinc storage, including the high discharge specific capacity and long cycle life. After 500 cycles at a current density of 1000 mA/g, it retains a discharge capacity of 208.83 mA h/g, with a Coulombic efficiency nearing 100%, which can be attributed to the larger specific surface area and shortened Zn[Formula: see text]diffusion distance, promoting faster electric transfer and Zn[Formula: see text]diffusion kinetics. This work broadens the understanding of the electrochemical behavior of VO2-based AZIBs.

In Situ Etching of Multifunctional Three-Dimensional Interfacial Layers for the Construction of Porous Zn Anodes with Enhanced Surface Textures.

Aqueous Zn-ion batteries offer the advantages of greater security and lower fabrication costs over their lithium-ion counterparts. However, their further advancement and practical application are hindered by the drastic decay in their performance due to the uncontrollable dendrite growth on Zn anodes. In this study, we fabricated a versatile three-dimensional (3D) interfacial layer (3D PVDF-Zn(TFO)2 (PVDF: poly(vinylidene fluoride); TFO: trifluoromethanesulfonate), which simultaneously formed porous Zn-metal anodes (PZn) with an enhanced (002) texture, via a in situ etching scheme. The 3D PVDF-Zn(TFO)2@PZn symmetrical cells leverage the advantages of surface coating and 3D porous architectures to yield extra-long cyclic lifetimes of over 5300 h (0.1 mA cm-2). The fabricated anodes were found to be compatible with MnO2 cathodes, and the resulting full batteries delivered an outstanding capacity of 336 mAh g-1 at 0.1 A g-1 and exhibited impressive long-term reversibility with a capacity retention of 78.7% for 2000 cycles. The proposed coating strategy is viable for developing porous structures with cutting-edge designs and for textured surface engineering.

In-Situ Construction of V2O5 Nanosheet/Nitrogen-Doped Carbon Nanosheet Heterostructures with Interfacial C─O Bridging Bonds as the Cathode Material for Zn Ion Batteries.

Layered oxides are widely used as the electrode materials for metal ion batteries. However, for large radius size ions, such as Zn2+ and Al3+, the tightly stacked layers and poor electrical conductivity of layered oxides result in restricted number of active sites and sluggish reaction kinetics. In this work, a facile in-situ construction strategy is provided to synthesize layered oxide nanosheets/nitrogen-doped carbon nanosheet (NC) heterostructure, which shows larger interlayer spacing and better electrical conductivity than the layered oxides. As a result, the Zn2+ ion diffusion inside the interlayer gallery is greatly enhanced and the storage sites inside the gallery can be better used. Meanwhile, the NC layers and oxide nanosheets are bridged by the C─O bonds to form a stable structure, which contributes to a better cycling stability than the pure layered oxides. The optimal V2O5@NC-400 cathode shows a capacity of 467mAhg-1 at 0.1Ag-1 for 300 cycles, and long-term cyclic stability of 4000 cycles at 5Ag-1 with a capacity retention of 92%. All these performance parameters are among the best for vanadium oxide-based cathode materials.

An Industrially Applicable Passivation Strategy for Significantly Improving Cyclability of Zinc Metal Anodes in Aqueous Batteries.

The cycling instability of metallic Zn anodes hinders the practicability of aqueous Zn-ion batteries, though aqueous Zn-ion batteries may be the most credible alternative technology for future electrochemical energy storage applications. Commercially available trivalent chromium conversion films (TCCF) are successfully employed as robust artificial interphases on Zn metal anodes (ZMAs). Fabricated through a simple immersion method, the TCCF-protected Zn (TCCF@Zn) electrode enables a superlow nucleation overpotential for Zn plating of 6.9mV under 1mA cm-2 , outstanding Coulombic efficiency of 99.7% at 3mA cm-2 for 1600 cycles in Zn||Cu asymmetric cells and superior cyclability in symmetric Zn||Zn batteries at 0.2, 2, and 5mA cm-2 for 2500h and 10mA cm-2 for 1200h. More importantly, the TCCF@Zn||V2 O5 full cell exhibits a specific capacity of 118.5 mAh g-1 with a retention of 53.4% at 3 A g-1 for 3000 cycles, which is considerably larger than that of the pristine Zn||V2 O5 full cell (59.7 mAh g-1 with a retention of 25.7%). This study demonstrates a highly efficient and low-cost surface modification strategy derived from an industrially applicable trivalent chromium passivation technique aimed at obtaining dendrite-free ZMAs with high reversibility for practical Zn batteries in the near future.

Sulfonated hydrogel electrolyte enables dendrite-free zinc-ion batteries

Metallic Zn anode is plagued by severe side reactions and dendrite growth, preventing the commercial development of Zn-ion batteries (ZIBs). Semi-solid state hydrogel electrolyte has received immense attention in aqueous Zn-ion batteries due to their intrinsic advantages (e.g., wider electrochemical windows, good interfacial compatibility, and multi-functional applications). However, their inferior ionic conductivity and mechanical deformation tolerance are the main barriers to realizing the true application in ZIBs. Herein, a hydrogel electrolyte with high ionic conductivity and high flexibility is fabricated through sulfonated chitosan and further cross-linking with polyacrylamide. Accordingly, the ion conductivity of the hydrogel electrolyte increases from 28.2 to 38.1 mS cm−1, whilst tensile strength is elevated from 19.1 to 54.2 kPa. With this hydrogel electrolyte, the Zn||Zn symmetric cells show exceptional cycle stability over 2600 h at the current density of 1 mA cm−2, and the Zn||Cu asymmetric cells demonstrate nearly 100 % coulomb efficiency over 1200 cycles. In addition, NH4V4O10||Zn full cells enable capacity retention of as high as 96.1 % even over 500 cycles, and the as-assembled flexible batteries can stand bending, twisting, and cutting operation without comprising the electrochemical performance.