An Ion-Pumping Quasi-Solid Electrolyte Enabled by Electrokinetic Effects for Stable Aqueous Zinc Metal Batteries.

The practical application of aqueous zinc (Zn) metal batteries (ZMBs) is hindered by the complicated hydrogen evolution, passivation reactions, and dendrite growth of Zn metal anodes. Here, an ion-pumping quasi-solid electrolyte (IPQSE) with high Zn2+ transport kinetics enabled by the electrokinetic phenomena to realize high-performance quasi-solid state Zn metal batteries (QSSZMBs) is reported. The IPQSE is prepared through the in situ ring-opening polymerization of tetramethylolmethane-tri-ß-aziridinylpropionate in the aqueous electrolyte. The porous polymer framework with high zeta potential provides the IPQSE with an electrokinetic ion-pumping feature enabled by the electrokinetic effects (electro-osmosis and electrokinetic surface conduction), which significantly accelerates the Zn2+ transport, reduces the concentration polarization and overcomes the diffusion-limited current. Moreover, the Zn2+ affinity of the polymer and hydrogen bonding interactions in the IPQSE changes the Zn2+ coordination environment and reduces the amount of free H2O, which lowers the H2O activity and inhibits H2O-induced side reactions. Consequently, the highly reversible and stable Zn metal anodes are achieved. The assembled QSSZMBs based on the IPQSE display excellent cycling stability with high capacity retention and Coulombic efficiency. The high-performance quasi-solid state Zn metal pouch cells are demonstrated, showing great promise for the practical application of the IPQSE.

Improving Aqueous Zinc Ion Batteries with Alkali Metal Ions.

Aqueous zinc (Zn) ion batteries have received broad attention recently. However, their practical application is limited by severe Zn dendrite growth and the hydrogen evolution reaction. In this study, three alkali metal ions (Li+, Na+, and K+) are added in ZnSO4 electrolytes, which are subjected to electrochemical measurements and molecular dynamics simulations. The studies show that since K+ has the highest mobility and self-diffusion coefficient among the four ions (Li+, Na+, K+, and Zn2+), it enables K+ to preferentially approach a zinc dendrite at an earlier time, driven by a negative electric field during a cathodic process. The electric double layer, with K+ around the negatively charged Zn dendrite, inhibits dendrite growth and mitigates the hydrogen evolution reaction on the Zn anode. Under this kinetic effect, the Zn-Zn symmetric cell with K+ exhibits a long cycling stability of 1000 h at 1 mA·cm-2 of 1 mAh·cm-2 and 190 h at 30 mA·cm-2 of 2 mAh·cm-2. Such a kinetic effect is also observed with additives Na+ and Li+, though less profound than that of K+.

Modulating solvated structure of Zn2+ and inducing surface crystallography by a simple organic molecule with abundant polar functional groups to synergistically stabilize zinc metal anodes for long-life aqueous zinc-ion batteries.

Aqueous zinc-ion batteries (AZIBs) have attracted significant attention owing to their inherent security, low cost, abundant zinc (Zn) resources and high energy density. Nevertheless, the growth of zinc dendrites and side reactions on the surface of Zn anodes during repeatedly plating/stripping shorten the cycle life of AZIBs. Herein, a simple organic molecule with abundant polar functional groups, 2,2,2-trifluoroether formate (TF), has been proposed as a high-efficient additive in the ZnSO4 electrolyte to suppress the growth of Zn dendrites and side reaction during cycling. It is found that TF molecules can infiltrate the solvated sheath layer of the hydrated Zn2+ to reduce the number of highly chemically active H2O molecules owing to their strong binding energy with Zn2+. Simultaneously, TF molecules can preferentially adsorb onto the Zn surface, guiding the uniform deposition of Zn2+ along the crystalline surface of Zn(002). This dual action significantly inhibits the formation of Zn dendrites and side reactions, thus greatly extending the cycling life of the batteries. Accordingly, the Zn//Cu asymmetric cell with 2 % TF exhibits stable cycling for more than 3,800 cycles, achieving an excellent average Columbic efficiency (CE) of 99.81 % at 2 mA cm-2/1 mAh cm-2. Meanwhile, the Zn||Zn symmetric cell with 2 % TF demonstrates a superlong cycle life exceeding 3,800 h and 2,400 h at 2 mA cm-2/1 mAh cm-2 and 5 mA cm-2/2.5 mAh cm-2, respectively. Simultaneously, the Zn//VO2 full cell with 2 % TF possesses high initial capacity (276.8 mAh/g) and capacity retention (72.5 %) at 5 A/g after 500 cycles. This investigation provides new insights into stabilizing Zn metal anodes for AZIBs through the co-regulation of Zn2+ solvated structure and surface crystallography.

Electrolyte Solvation Chemistry for Stabilizing the Zn Anode via Functionalized Organic Agents.

As a potential candidate for grid-scale energy storage technology, aqueous Zn-ion batteries (ZIBs) have attracted considerable attention due to their intrinsic safety, environmental friendliness, and ease of fabrication. Nevertheless, the road to industry for this technique is hindered by serious issues, including undesired side reactions, random growth of the Zn dendrites, electrode passivation, and anode corrosion, which are associated with the high reactivity of water molecules during the electrochemical reactions. These challenges are strongly dependent on electrolyte solvation chemistry (ESC), which subsequently determines the electrochemical behavior of the metal ions and water molecules on the electrode surface. In this work, a comprehensive understanding of optimized ESC with specified functional groups on the mixing agents to stabilize the Zn anode is provided. First, the challenges facing the ZIBs and their chemical principles are outlined. Specific attention is paid to the working principles of the mixing agents with different functional groups. Then the recent progress is summarized and compared. Finally, perspectives on future research for the aqueous Zn batteries are presented from the point of view.

A trinity strategy enabled by iodine-loaded nitrogen-boron-doped carbon protective layer for dendrite-free zinc-ion batteries.

Although aqueous zinc ion batteries (AZIBs) have the merits of environmental friendliness, high safety and theoretical capacity, the slow kinetics associated with zinc deposition and unavoidable interfacial corrosion have seriously affected the commercialization of aqueous zinc ion batteries. In this work, an ingenious "trinity" design is proposed by applying a porous hydrophilic carbon-loaded iodine coating to the zinc metal surface (INBC@Zn), which simultaneously acts as an artificial protective layer, electrolyte additive and anode curvature regulator, so as to reduce the nucleation overpotential of Zn and promote the preferential deposition of (002) planes to some extent. With this synergistic effect, INBC@Zn exhibits high reversibility and strong side reaction inhibition. As a result, INBC@Zn shows high symmetric cycling stability up to 4500 h at 1 mA cm-2. An ultra-long cycle stability of 1500 cycles with high Coulombic efficiency (99.8 %) is achieved in the asymmetric cell. In addition, the INBC@Zn//NVO full cells exhibit impressive capacity retention (96 % after 1000 cycles at 3 A/g). Importantly, the designed pouch cell demonstrates stable performance and shows certain prospects for application. This work provides a facile and instructive approach toward the development of high-performance AZIBs.

Preventing Dissolution of Cathode Active Materials by Ion-anchoring Zeolite-based Separators for Durable Aqueous Zinc Batteries.

Aqueous zinc batteries have emerged as promising energy storage devices due to their safety and low cost. However, they face challenges such as anodic dendrite formation and cathodic compound dissolution. Here, we present the development of a polymer-matrixed zeolite separator (SZ) by synthesizing zeolite materials on a flexible polymeric membrane. This separator acts as an effective ionic barrier, preventing the leaching and shuttling of vanadium from the cathode, while significantly inhibiting the formation of by-products and zinc dendrites. The SZ cells demonstrate stable operation for more than 400 cycles at 0.5 A g-1 , with an initial capacity of 375.4 mAh g-1 , and over 10,000 cycles at 15 A g-1 . Notably, when pre-anchored with vanadium ions, the SZ-V cells exhibited excellent capacity retention of up to 94.6 % over 1000 cycles. The SZ separator featuring an ion barrier represents a crucial advancement towards the commercialization of zinc storage devices.

Two Birds with One Stone: V4 C3 MXene Synergistically Promoted VS2 Cathode and Zinc Anode for High-Performance Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries (AZIBs) are considered to be a rising star in the large-scale energy storage area because of their low cost and environmental friendliness properties. However, the limited electrochemical performance of the cathode and severe zinc dendrite of the anode severely hinder the practical application of AZIBs. Herein, a novel 3D interconnected VS2 ⊥V4 C3 Tx heterostructure material is prepared via one-step solvothermal method. Morphological and structural characterizations show that VS2 nanosheets are uniformly and dispersedly distributed on the surface of the V4 C3 MXene substrate, which can effectively suppress volume change of the VS2 . Owing to the open heterostructure along with the high conductivity of V4 C3 MXene, the VS2 ⊥V4 C3 Tx cathode shows a high specific capacity of 273.9 mAh g-1 at 1 A g-1 and an excellent rate capability of 143.2 mAh g-1 at 20 A g-1 . The V4 C3 MXene can also effectively suppress zinc dendrite growth when used as protective layer for the Zn anode, making the V4 C3 Tx @Zn symmetric cell with a stable voltage profile for ≈1700 h. Benefitting from the synergistic modification effect of V4 C3 MXene on both the cathode and anode, the VS2 ⊥V4 C3 Tx ||V4 C3 Tx @Zn battery exhibits a long cycling lifespan of 5000 cycles with a capacity of 157.1 mAh g-1 at 5A g-1 .

Efficient Suppression of Dendrites and Side Reactions by Strong Electrostatic Shielding Effect via the Additive of Rb2 SO4 for Anodes in Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries (AZIBs) have attracted considerable attention due to their low cost and environmental friendliness. However, the rampant dendrite growth and severe side reactions during plating/stripping on the surface of zinc (Zn) anode hinder the practicability of AZIBs. Herein, an effective and non-toxic cationic electrolyte additive of Rb2 SO4 is proposed to address the issues. The large cation of Rb+ is preferentially adsorbed on the surface of Zn metal to induce a strong shielding effect for realizing the lateral deposition of Zn2+ ions along the Zn surface and isolating water from Zn metal to effectively inhibit side reactions. Consequently, the Zn||Zn symmetric cell with the addition of 1.5 mm Rb2 SO4 can cycle more than 6000 h at 0.5 mA cm-2 /0.25 mAh cm-2 , which is 20 times longer than that without Rb2 SO4 . Besides, the Zn||Cu asymmetric cell with Rb2 SO4 achieves a very high average Coulombic efficiency of 99.16% up to 500 cycles. Moreover, the electrolyte with Rb2 SO4 well matches with the VO2 cathode, achieving high initial capacity of 412.7 mAh g-1 at 5 A g-1 and excellent cycling stability with a capacity retention of 71.6% at 5 A g-1 after 500 cycles for the Zn//VO2 full cell.

Single-Ion-Conducting Hydrogel Electrolytes Based on Slide-Ring Pseudo-Polyrotaxane for Ultralong-Cycling Flexible Zinc-Ion Batteries.

Flexible zinc-ion batteries (ZIBs) with high capacity and long cycle stability are essential for wearable electronic devices. Hydrogel electrolytes have been developed to provide ion-transfer channels while maintaining the integrity of ZIBs under mechanical strain. However, hydrogel matrices are typically swollen with aqueous salt solutions to increase ionic conductivity, which can hinder intimate contact with electrodes and reduce mechanical properties. To address this, a single-Zn-ion-conducting hydrogel electrolyte (SIHE) is developed by integrating polyacrylamide network and pseudo-polyrotaxane structure. The SIHE exhibits a high Zn2+ transference number of 0.923 and a high ionic conductivity of 22.4 mS cm-1 at room temperature. Symmetric batteries with SIHE demonstrate stable Zn plating/stripping performance for over 160 h, with a homogenous and smooth Zn deposition layer. Full cells with La-V2 O5 cathodes exhibit a high capacity of 439 mA h g-1 at 0.1 A g-1 and excellent capacity retention of 90.2% after 3500 cycles at 5 A g-1 . Moreover, the flexible ZIBs display stable electrochemical performance under harsh conditions, such as bending, cutting, puncturing, and soaking. This work provides a simple design strategy for single-ion-conducting hydrogel electrolytes, which could pave the way for long-life aqueous batteries.

Progress and Prospect of Zn Anode Modification in Aqueous Zinc-Ion Batteries: Experimental and Theoretical Aspects.

Aqueous zinc-ion batteries (AZIBs), the favorite of next-generation energy storage devices, are popular among researchers owing to their environmental friendliness, low cost, and safety. However, AZIBs still face problems of low cathode capacity, fast attenuation, slow ion migration rate, and irregular dendrite growth on anodes. In recent years, many researchers have focused on Zn anode modification to restrain dendrite growth. This review introduces the energy storage mechanism and current challenges of AZIBs, and then some modifying strategies for zinc anodes are elucidated from the perspectives of experiments and theoretical calculations. From the experimental point of view, the modification strategy is mainly to construct a dense artificial interface layer or porous framework on the anode surface, with some research teams directly using zinc alloys as anodes. On the other hand, theoretical research is mainly based on adsorption energy, differential charge density, and molecular dynamics. Finally, this paper summarizes the research progress on AZIBs and puts forward some prospects.

Sieve-Like interface built by ZnO porous sheets towards stable zinc anodes.

Zn-based electrochemical energy storage (EES) systems are plagued by the uncontrollable generation of dendritic zinc and side reactions on zinc anodes. Herein, we report a ZnO porous sheets-assembled sieve-like interface to stabilize zinc anodes. Specifically, ZnO porous sheets are synthesized through the thermal decomposition of basic zinc sulfate nanoflakes and then served as an artificial zinc anode-electrolyte interface. Benefiting from the sieve-like interface formed by the ZnO porous sheets, Zn2+ flux is effectively homogenized during the zinc plating process and thus zinc dendrite growth is restricted. Meanwhile, the corrosion behavior of zinc anodes is alleviated thanks to the hydrophobic feature of the ZnO porous sheets. As a result, the electrochemical properties of zinc anodes are notably optimized under the protection of such a sieve-like interface. Cycling life evaluated at 1 mA cm-2 of the zinc anodes is prolonged from less than 100 h for bare zinc anodes to 2800 h for the protected zinc anodes (Zn@ZnO), and even at 5 mA cm-2, the latter ones can operate normally for 400 h. As expected, the cycling life of VO2//Zn@ZnO zinc-ion batteries is greatly increased, achieving 90% capacity retention after 1000 cycles at 5 A g-1 and activated carbon fiber//Zn@ZnO zinc-ion hybrid supercapacitors possess 96% capacity retention after 10,000 cycles at 1 A g-1. This work provides a promising approach for improving the electrochemical stability of the Zn-based EES system.

Constructing Hydrophobic Interface with Close-Packed Coordination Supramolecular Network for Long-Cycling and Dendrite-Free Zn-Metal Batteries.

Commercialization of aqueous zinc-metal batteries remains unrealistic due to the substantial dendrite growth and side reaction issues on the zinc anodes. It is highly demanded to develop easy-to-handle approaches for constructing stable, dense, as well as homogeneous solid anode/electrolyte interfaces. Herein, the authors construct the zinc anode interface with a close-packed Zn-TSA (TSA = thiosalicylate) coordination supramolecular network through the facile and up-scalable wet-chemical method. The hydrophobic Zn-TSA network can block solvated water and establish a solid-state diffusion barrier to well-distribute the interfacial Zn2+ , thus inhibiting hydrogen evolution and zinc dendrite growth on the anode. Meanwhile, the Zn-TSA network induces the formation of a uniform and stable solid electrolyte interphase composed of multiple inorganic-organic compounds. This denser structure can accommodate and self-heal the crack/degradation of the anode interphase associated with the repeated volume changes, and suppress the generation of detrimental by-product, Znx (OTF- )y (OH)2x-y ·nH2 O. Such a rationally fabricated anode/electrolyte interface further endows the assembled symmetric cells with superior plating/stripping stability for over 2000 h without dendrite formation (at 1 mA cm-2 and 1 mAh cm-2 ). Furthermore, this zinc anode has practical application in the Zn-MoS2 and Zn-V2 O5 full cells. This study provides a new train of thought for constructing the dense interface of zinc-metal anode.

Freeze-Tolerant Hydrogel Electrolyte with High Strength for Stable Operation of Flexible Zinc-Ion Hybrid Supercapacitors.

Constructing ionic conductive hydrogels with diversified properties is crucial for portable zinc-ion hybrid supercapacitors (ZHSCs). Herein, a freeze-tolerant hydrogel electrolyte (AF PVA-CMC/Zn(CF3 SO3 )2 ) is developed by forming a semi-interpenetrating anti-freezing polyvinyl alcohol-carboxymethyl cellulose (AF PVA-CMC) network filled with the ethylene glycol (EG)-containing Zn(CF3 SO3 )2 aqueous solution. The semi-interpenetrating AF PVA-CMC/Zn(CF3 SO3 )2 possesses enhanced mechanical properties, realizes the uniform zinc deposition, and impedes the dendrite growth. Notably, the interaction between PVA and EG suppresses the ice crystal formation and prevents freezing at -20 °C. Due to these advantages, the designed hydrogel owns high ionic conductivity of 1.73/0.75 S m-1 at 20/-20 °C with excellent tensile/compression strength at 20 °C. Impressively, the flexible AF quasi-solid-state ZHSC employing the hydrogel electrolyte achieves a superior energy density at 20/-20 °C (87.9/60.7 Wh kg-1 ). It maintains nearly 84.8% of the initial capacity after 10 000 cycles and a low self-discharge rate (1.77 mV h-1 ) at 20 °C, together with great tolerance to corrosion. Moreover, this device demonstrates a stable electrochemical performance at -20 °C under deformation. The obtained results provide valuable insights for constructing durable hydrogel electrolytes in cold environments.

Dendrite Issues for Zinc Anodes in a Flexible Cell Configuration for Zinc-Based Wearable Energy-Storage Devices.

A key application of aqueous rechargeable Zn-based batteries (RZBs) is flexible and wearable energy storage devices (FESDs). Current studies and optimizations of Zn anodes have not considered the special flexible working modes needed. In this study, we present the Zn accumulation on the folded line and curve areas of flexible anodes. The correlation between the bending radius and the lifespan of symmetric cells is proposed. The interface contact of hydrogel electrolytes when working in a bending mode is another key factor affecting cell lifespan. After detailed analysis, the ideal cell configuration is shown to be hydrogel electrolytes with suitable chemistry, satisfactory mechanical properties, and high adhesivity. Thus a water in salt (WIS) hydrogel is proposed that demonstrates a highly stable cell performance. This work provides a new perspective in Zn anode research for the development of FESDs.

Temperature-Dependent Nucleation and Electrochemical Performance of Zn Metal Anodes.

A fundamental understanding of the nucleation and growth behaviors of Zn metal anodes over a wide range of temperatures is of great value for suppressing Zn dendrite growth. However, work focused on the early nucleation and growth behavior of Zn metal at various temperatures is still absent. Here, we study the effect of cycling temperature on Zn nuclei size and areal density and find that low temperature induces a smaller and dense nucleus, which prevents the formation of dendrites. Based on this finding, a cooling-treatment-based self-healing strategy is developed to in situ eliminate dendrites, which effectively prolongs the lifespan of the Zn anode by 520%. This novel self-healing strategy could be employed as a reliable strategy for restoring batteries in situ to reach a longer lifespan.

Conductive copper glue constructs a reversible and stable zinc metal anode interface for advanced aqueous zinc ion battery.

Aqueous zinc (Zn) ion battery (AZIB) has become one of the research hotspot in the field of energy storage due to its low cost, green environmental protection, high theoretical capacity, and high safety. However, the unrestrained growth of the dendrites leads to the occurrence of side reactions, such as corrosion of the electrodes and generation of hydrogen, which reduces the coulombic efficiency and performance of the battery. Herein, a simple method reports pasting a conductive copper glue (CCG) coating on the surface of Zn anode to improve the serious dendrite growth. The coating has strong intermolecular interaction and high conductivity, which not only avoids the occurrence of side reactions but also facilitates the uniform deposition of Zn2+ ions, preventing dendrite formation. The symmetrical battery assembled with Zn anode modified by CCG coating delivers longer cycle life (167 h) and lower voltage hysteresis (≈26 mV), which is much better than that of bare Zn symmetrical battery (30 h, ≈67 mV). Furthermore, the full battery assembly with modified Zn anode and stainless steel (SS) supported V2O5 nanospheres (VO-SS) cathode exhibit high capacity and long cycle life (113.5 mAh g-1 after 4000 cycles at 4.8 A g-1).

Controlled Deposition of Zinc-Metal Anodes via Selectively Polarized Ferroelectric Polymers.

Aqueous zinc-ion batteries are regarded as ideal candidates for stationary energy-storage systems due to their low cost and high safety. However, zinc can readily grow into dendrites, leading to limited cycling performance and quick failure of the batteries. Herein, a novel strategy is proposed to mitigate this dendrite problem, in which a selectively polarized ferroelectric polymer material (poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE))) is employed as a surface protective layer on zinc anodes. Such a polarized ferroelectric polymer layer can enable a locally concentrated zinc-ion distribution along the coated surface and thus enable the horizontal growth of zinc plates. As a result, symmetrical zinc batteries using such anodes exhibit long cycling lifespan at 0.2 mA cm-2 , 0.2 mAh cm-2 for 2000 h, and a high rate performance up to 15 mA cm-2 . Also, the full cell (including a Zn-MnO2 battery and a zinc-ion capacitor) based on this anode is demonstrated. This work provides a novel strategy to protect the zinc anode and even other metal anodes exploiting polymer ferroelectricity.

Manipulating the Zinc Deposition Behavior in Hexagonal Patterns at the Preferential Zn (100) Crystal Plane to Construct Surficial Dendrite-Free Zinc Metal Anode.

Zinc metal has a severe dendrite issue caused by the uneven Zn plating/stripping during continual cycles, which hinders the practical application of ZIBs. The surficial atomic structure of zinc anode plays a decisive role in solving dendrites and improving the electrochemical performance. According to the density functional theory results, Zn (100) plane possesses a much stronger adsorption energy of zinc atom compared with the (002), thus zinc atom preferentially nucleates on the (100) surface. It subsequently continues to grow vertically on (100). Herein, the zinc anode is designed with hexagonal-hole patterns (h-Zn) through a phosphoric acid etching reaction. An abundance of Zn (100) crystal planes are exposed perpendicularly to the anode surface, while the (002) surfaces are at the bottom of these hexagonal holes. Zinc prefers to deposit in hexagonal holes at the (100) surfaces, favoring the restraining of the surficial dendrite growth and accelerating the Zn deposition kinetics. Thus, the symmetric cell using h-Zn exhibits a long cycling lifespan for over 1200 h and extremely low polarization voltage of ≈80 mV at 5 mA cm-2 and 1 mAh cm-2 . This work provides an insight into the surficial structure design and crystal plane regulation to fabricate brilliant zinc metal anodes.

Single-Ion Conducting Double-Network Hydrogel Electrolytes for Long Cycling Zinc-Ion Batteries.

As one of the promising alternatives of lithium-ion batteries, zinc-ion batteries (ZIBs) have received growing interest from researchers due to their good safety, eco-friendliness, and low cost. Nevertheless, aqueous ZIBs are still a step away from practical applications due to the nonuniform deposition of Zn and parasitic side reactions, which cause capacity fading and even short circuit. To tackle these problems, here we introduce a single-Zn-ion conducting hydrogel electrolyte (SIHE), P(ICZn-AAm), synthesized with iota carrageenan (IC) and acrylamide (AAm). The SIHE manifests single Zn2+ conductivity via the abundant sulfates fixed on the IC polymer backbone, delivering a high Zn2+ transference number of 0.93. It also exhibits outstanding ionic conductivity of 2.15 × 10-3 S cm-1 at room temperature. The enhanced compatibility at the electrode-electrolyte interface was verified by the stable Zn striping/plating performance along with a homogenous and smooth Zn deposition layer. It is also found that the passivation of the Zn anode can be effectively prohibited due to the lack of free anions in the electrolyte. The practical performance of the SIHE is further investigated with Zn-V2O5 batteries, which showed a stable capacity of 271.6 mA h g-1 over 150 cycles at 2 C and 127.5 mA h g-1 over 500 cycles at 5 C.

Realizing an All-Round Hydrogel Electrolyte toward Environmentally Adaptive Dendrite-Free Aqueous Zn-MnO2 Batteries.

Flexible energy storage devices are at the forefront of next-generation power supplies, one of the most important components of which is the gel electrolyte. However, shortcomings exist, more or less, for all the currently developed hydrogel electrolytes. Herein, a facile and cost-effective method is developed to construct an all-round hydrogel electrolyte by using cotton as the raw material, tetraethyl orthosilicate as the crosslinker, and glycerol as the antifreezing agent. The obtained hydrogel electrolyte has high ionic conductivity, excellent mechanical properties (e.g., high tensile strength and elasticity), ultralow freezing point, good self-healing ability, high adhesion, and good heat-resistance ability. Remarkably, this hydrogel electrolyte can provide a record-breaking high ionic conductivity of 19.4 mS cm-1 at -40 °C compared with previously reported aqueous electrolytes for zinc-ion batteries. In addition, this hydrogel electrolyte can significantly inhibit zinc dendritic growth and parasitic side reactions from -40 to 60 °C. With this hydrogel electrolyte, a flexible quasi-solid-state Zn-MnO2 battery is assembled, which shows remarkable energy densities from -40 to 60 °C. The battery also exhibits outstanding cycling durability and has high endurance under various harsh conditions. This work opens new opportunities for the development of hydrogel electrolytes.