Zinc Metal Anode Research Articles

Extending temperature windows of practical zinc batteries by water-locking hydrated eutectic solvents

Aqueous zinc metal batteries have gained widespread attention in recent years due to their high safety and environmental friendliness. However, zinc metal anode still suffers from corrosion and hydrogen evolution reaction from the active water, and performances will be worse in high/low-temperature. Herein, a water-locking hydrated eutectic solvent (HES) electrolyte is developed for zinc metal batteries to solve the problem of poor temperature tolerance and low reversibility of Zn anode. BF4− anions and succinonitrile molecules are able to "lock" water molecules by hydrogen bond to inhibit water decomposition and zinc corrosion caused by water molecules. Therefore, the resulting aqueous zinc metal battery achieves continuous zinc plating/stripping for more than 2500 h, with an average Coulombic efficiency of up to 99.4 %, furthermore, it can stable cycle above 750 h at 60 °C and 3000 h at −25 °C. In addition, using the HES electrolyte, the 21700-type cylindrical battery assembled with gram class load vanadium-based cathode and limited supply of Zn anode shows excellent capacity and safety, and their assembled battery pack can show potential practical application prospects.

A self-regulated interface enabled by trivalent gadolinium ions toward highly reversible zinc metal anodes

Aqueous zinc-ion batteries (AZIBs) have become an ideal candidate for large-scale energy storage systems owing to their inherent safety and highly competitive capacity. However, severe dendrite growth and side reactions on the surface of zinc metal anodes lead to quick performance deterioration, seriously impeding the commercialization of AZIBs. In this work, a self-regulated zinc metal/electrolyte interface is constructed to solve these problems by incorporating the trivalent Gd3+ additive with a lower effective reduction potential into the aqueous ZnSO4 electrolyte. It is revealed that the inert Gd3+ ions preferentially adsorb on the active sites of the zinc anode, and the induced electrostatic shielding layer is beneficial to uniform Zn deposition. Meanwhile, the adsorbed Gd3+ ions act as a buffer interface to lower the direct contact of the zinc anode with water molecules, thereby suppressing the interfacial parasitic reaction. These features endow the Zn//Zn battery using 0.2 M Gd3+ ions with 2940 h of cycling life at 5 mA cm−2 and a cumulative plating capacity (CPC) of 6.2 Ah cm−2 at 40 mA cm−2. When assembling with a MnO2 cathode, the full cell using the modified electrolyte exhibits a high capacity of 268.9 mAh/g at 0.2 A/g, as well as improved rate capability and cycle stability. The results suggest the great potential of a rare earth ion additive in reinforcing Zn metal anodes for developing practical AZIBs.

Increasing the Cycle Life of Zinc Metal Anodes and Nickel-Zinc Cells Using Flow-Through Alkaline Electrolytes

Alkaline electrolyte flow through porous Zn anodes and Ni(OH)2 cathodes can overcome diffusion limits, reduce dendrite growth, and improve cycle life. Zinc deposition morphology improves with low flow rates electrolyte in KOH/ZnO electrolytes at current densities near the diffusion-limit regime. Zinc dendrites present without flow are suppressed by micrometer-per-second flow at concentrations ranging from 0.2 to 0.6 M ZnO dissolved in 6 M and 10 M KOH solutions. Zn-Cu asymmetric cell tests reveal that flowing electrolyte increases the lifespan by more than 6 times in the diffusion-limit regime by suppressing gas evolution and dendrite formation. Ni-Zn cell tests show that a flow-assisted battery cycles 1500 times with over 95% Coulombic efficiency (CE) at 35 mA cm−2 current density and 7 mAh/cm2 charge capacity, increasing the battery lifespan by 17 times compared with a stagnant Ni-Zn cell. Flow-through electrolyte also stabilizes the Zn electrode in the over-limiting regime, achieving approximately 4 times increased lifespan and 297 cycles with over 90% CE at 52 mA cm−2.

Achieving an ion-homogenizing and corrosion-resisting interface through nitro-coordination chemistry for stable zinc metal anodes

Suppression of uncontrollable dendrite growth and water-induced side reactions of Zn metal anodes is crucial for achieving long-lasting cycling stability and facilitating the practical implementations of aqueous Zn-metal batteries. To address these challenges, we report in this study a functional nitro-cellulose interfacial layer (NCIL) on the surface of Zn anodes enlightened by a nitro-coordination chemistry strategy. The NCIL exhibits strong zincophilicity and superior coordination capability with Zn2+ due to the highly electronegative and highly nucleophilic nature of the nitro functional group. This characteristic facilitates a rapid Zn-ion desolvation process and homogeneous Zn plating, effectively preventing H2 evolution and dendrite formation. Additionally, the negatively charged surface of NCIL acts as a shield, repelling SO42− anions and inhibiting corrosive reactions on the Zn surface. Remarkably, reversible and stable Zn plating/stripping is achieved for over 5100 h at a current density of 1 mA cm−2, which is nearly 30 times longer than that of bare Zn anodes. Furthermore, the Zn//V2O5 full cells with the functional interface layer deliver a high-capacity retention of 80.3% for over 10,000 cycles at 5 A g−1. This research offers valuable insights for the rational development of advanced protective interface layers in order to achieve ultra-long-life Zn metal batteries.

Organic electrochemical transistors for monitoring dissolved oxygen in aqueous electrolytes of zinc ion batteries

Dissolved oxygen (DO) in the electrolyte of aqueous zinc ion batteries (AZIBs) can cause irreversible side reactions in zinc metal anode. Therefore, the accurate detection of the DO concentration in the aqueous electrolyte is crucial for the performance promotion and mechanistic studies of AZIBs. Herein, organic electrochemical transistor (OECT) based DO sensors are developed by utilizing a carbon fiber (CF) derived CF/platinum/Nafion/polydimethylsiloxane composite as the gate electrode and amine-doped poly(3,4-ethylenedioxythiophene): polystyrene sulfonate as the channel semiconductor. Operating at a gate-source voltage of −0.1 V and a drain-source voltage of −0.025 V, the OECT-DO sensor demonstrates a high sensitivity (141 mV decade−1), a low detection limit (0.0011 mg L−1), a wide linear range (0.027–8.7 mg L−1), and good stability, which are attributed to the transconductance capability of OECT. The exceptional performance of the OECT-DO sensor enables the accurate monitoring of DO content in aqueous zinc sulfate electrolyte, which provides an opportunity to gain an insight of the impact of DO concentration on the zinc metal electrode. This study not only provides a cost-effective and efficient solution for detecting DO concentration in aqueous electrolytes, but also explores the potential applications of OECT sensors in the energy storage devices.

Electrolyte Additive for Interfacial Engineering of Lithium and Zinc Metal Anodes

AbstractElectrolytes play a crucial role in facilitating the ionic movement between cathode and anode, which is essential for the flow of electric current during the charging and discharging process of the rechargeable batteries. In particular, electrolyte additives are considered as effective and economical approaches into the advancements of the battery technologies in both the conventional non‐aqueous and burgeoning aqueous electrolyte systems. Herein, a systematic and comprehensive review of the electrolyte additives is reported for the interfacial engineering of Li and Zn metal anodes in the non‐aqueous and aqueous electrolytes, respectively. The types of electrolyte additives and their corresponding functionalities for the protection of these two metal anodes are discussed along with the electrochemical features of solid electrolyte interphase (SEI) derived from electrolyte additives. The recent progress on electrolyte additives for these two battery systems are also addressed from the perspectives of electrode, electrolyte, and the associated SEI. Finally, the outlook and perspective on the current issues and future directions in the field of electrolyte additive engineering are presented for next‐generation battery technologies beyond the conventional Li‐ion batteries.

Heterostructure Engineering of NiCo-LDHs for Enhanced Energy Storage Performance in Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries (AZIBs) are considered a promising device for next-generation energy storage due to their high safety and low cost. However, developing high-performance cathodes that can be matched with zinc metal anodes remains a challenge in unlocking the full potential of AZIBs. In this study, a typical transition metal layered double hydroxides (NiCo-LDHs) can be in situ reconstructed to NiCo-LDHs/Ni(Co)OOH heterostructure using an electrochemical cycling activation (ECA) method, serving as a novel cathode material for AZIBs. The optimized ECA-NiCo-LDHs cathode demonstrates a high capacity of 181.5 mAh g-1 at 1 A g-1 and retains 75% of initial capacity after 700 cycles at 5 A g-1. The abundant heterointerfaces of the NiCo-LDHs/Ni(Co)OOH material can activate additional active sites for zinc-ion storage and accelerate ion diffusion. Theoretical calculations also suggest the heterostructure can boost charge transfer and regulate ion-adsorption capability, thereby improving the electrochemical performance. Additionally, the flexible AZIBs device exhibits good service performance. This study on interface engineering introduces a new possibility for utilizing LDHs in AZIBs and offers a novel strategy for designing electrode materials.

Dual effect of organic/inorganic artificial protective layer to construct high-performance zinc metal anode

Owing to their high specific capacity, low cost, environmental friendliness and safety, aqueous zinc ion batteries (AZIBs) have been one of the most popular battery systems. Nevertheless, dendrite growth, corrosion, hydrogen evolution and passivation on the anode side can seriously affect the lifetime of AZIBs. In view of this, this work constructs a protective layer compounded from inorganic (titanium silicate molecular sieve, TS) and organic (polyacrylonitrile, PAN) materials to realize the high-performance and dendrite-free zinc anode (Zn@PAN-TS). The cyano group in PAN has a coordination effect with zinc ions, which facilitates the transport of zinc ions. The porous TS can regulate the zinc ion flux through ion-confinement effect. Thus, the PAN-TS composite protective layer provides fast and orderly ion transport channels that modulate the uniform deposition of zinc through dual effect. Moreover, the experimental results show that the Zn@PAN-TS 50:1 anode has the best electrochemical performance. The corresponding MnO2 full cell maintained a high discharge capacity of 217.2 mAh·g−1 with a high retention rate of 81.1 % after 500 cycles at 0.3 A·g−1. This strategy offers fresh insight into constructing multifunctional hybrid interface for dendrite-free AZIBs.

Regulating interfacial behavior of zinc metal anode via metal-organic framework functionalized separator

Aqueous zinc ion batteries (AZIBs) are one of the promising energy storage devices. However, uncontrolled dendrite and side reactions have seriously hindered its further application. In this study, the metal–organic framework (MOF) functionalized glass fiber separator (GF-PFC-31) was used to regulate interfacial behavior of zinc metal anode, enabling the development of high-performance AZIBs. In PFC-31, there are π-π interactions between two adjacent benzene rings with a spacing of 3.199 Å. This spacing can block the passage of [Zn(H2O)6]2+ (8.6 Å in diameter) through the GF-PFC-31 separator to a certain extent, which promotes the deposition process of Zn ions. In addition, the sulfonic acid group (–SO3H) contained in GF-PFC-31 can form a hydrogen bonding network with H2O, which can provide a desolvation effect and reduce the side reaction. Consequently, GF-PFC-31 separator achieves uniform deposition of Zn ions. The Zn||GF-PFC-31||Zn symmetric cell exhibits stable cycle life (3000 h at 1.2 mA cm−2, 2000 h at 0.3 mA cm−2, and 2000 h at 5.0 mA cm−2), and Zn||GF-PFC-31||MnO2 full cell with GF-PFC-31 separator can cycle for 1000 cycles at 1.2 A g−1 with capacity retention rate of 82.5%. This work provides a promising method to achieve high-performance AZIBs.

Realizing High Reversible Zinc Metal Anode by Modulating Surface Chemistry and Crystal Structure

AbstractThe uncontrollable dendrite growth on the Zn metal anode severely deteriorates the capacity and cycling stability of aqueous zinc–ion batteries (AZIBs), thereby retarding their practical application. In this work, through the combination of surface chemistry and crystal structure regulation, a duplex route of plasma sputtering and mechanical stretching is proposed to remove surface passivation layer and increase surface crystal defect (dislocations and textures) of Zn metal anode itself. Plasma sputtering can almost completely remove the surface passivation layer, ensuring a uniform Zn2+ flux at the interface, which is conducive to uniform nucleation. Mechanical stretching can increase the surface dislocation density and (002) texture, the former can reduce Zn2+ nucleation barrier, while the latter can guide Zn to grow parallel to the surface, inhibiting the growth of dendrites. Consequently, the as‐fabricated symmetrical cells exhibit stable and long lifespan (3560 h at 0.5 mA cm−2 for 0.5 mA h cm−2). The assembled full cells with α‐MnO2 cathode deliver a nearly 100% average coulombic efficiency even after 1000 cycles at 5 A g−1. Coupling a surface chemistry regulation with crystal structure control will be enlightening for solve the issues of metallic anodes in advanced metallic‐based batteries.

Modulating the solvation structure and electrode interface through phosphate additive for highly reversible zinc metal anode

Aqueous zinc-ion batteries (ZIBs) are considered one of the ideal battery systems for large-scale energy storage. However, ZIBs usually show a limited cycle life due to side reactions and dendrite growth at Zn anode. In this study, an ultra-trace amount of β-glycerophosphate sodium (β-GADS) was employed as an additive in aqueous electrolyte to enable highly reversible Zn plating/stripping. For the first time, we show that the phosphate groups in β-GADS could participate in the cation solvation structure, which is more favorable for the de-solvation and diffusion of Zn2+. Moreover, phosphate can absorb on the surface of Zn, and Na+ tend to accumulate at the surface protrusions to form an electrostatic shield that prevent formation of dendrites. Benefitting from the triply synergistic effects of the β-GADS additive, the Zn anode shows the inhibition of dendrites, hydrogen evolution reaction, corrosion reactions, and the formation of by-products. Operated based on 2 M ZnSO4 electrolyte with β-GADS additive, Zn||Zn symmetric cells demonstrated stable cycling for over 1,900 h at 0.5 mA cm−2 and over 1,200 h at a high current density of 5 mA cm−2. The Zn||(NH4)2V7O16·3.2H2O full cell with the above electrolyte also delivered a high capacity and excellent stability for over 1,000 cycles.

Achieving stable zinc metal anode by eliminating the surface heterogeneity

Aqueous zinc-ion batteries (AZIBs) are regarded as one of the promising alternatives for lithium-ion batteries in large-scale energy storage systems. However, the further development of AZIBs is limited by the challenges related to the heterogeneity of zinc anode, which arises from the harmful micro-regions and the accumulation of corrosion products. We employ a simple and effective molecular self-assembly method to modify the anode with a homogeneous (Octadecanethiol) ODT molecular layer through the combination of zinc and sulfhydryl (-SH) groups. The molecular-scale modification method can precisely repair the harmful micro-regions and ensure the homogeneity of the surface. In addition, the hydrophobic alkyl chains of the ODT molecules inhibit the corrosion reaction, thus avoiding the enhancement of heterogeneity due to the accumulation of corrosion products. Theoretical calculations and simulations show that this homogeneous molecular layer effectively eliminates the surface heterogeneity and thus has a profound impact on the deposition process. Benefiting from above, all the ODT-Zn symmetrical batteries can cycle at 5 mA cm−2 for more than 1000 h. The full battery using MnO2 cathode can cycle for more than 1000 times with a capacity retention rate is 90 %.

Ultrathin Reed Membranes: Nature's Intimate Ion‐Regulation Skins Safeguarding Zinc Metal Anodes in Aqueous Batteries

AbstractThe practical realization of aqueous zinc‐ion batteries relies crucially on effective interphases governing Zn electrodeposition chemistry. In this study, an innovative solution by introducing an ultrathin (≈2 µm) biomass membrane as an intimate artificial interface, functioning as nature's ion‐regulation skin to protect zinc metal anodes is proposed. Capitalizing on the inherent properties of natural reed membrane, including multiscale ion transport tunnels, abundant ─OH groups, and remarkable mechanical integrity, the reed membrane demonstrates efficacy in regulating uniform and rapid Zn2+ transport, promoting desolvation, and governing Zn (002) plane electrodeposition. Importantly, a unique in situ electrochemical Zn─O bond formation mechanism between the reed membrane and Zn electrode upon cycling is elucidated, resulting in a robustly adhered interface covering on the zinc anode surface, ultimately ensuring remarkable dendrite‐free and highly reversible Zn anodes. Consequently, the approach achieves a prolonged cycle life for over 1450 h at 3 mA cm−2/1.5 mAh cm−2 in symmetric Zn//Zn cells. Moreover, exceptional cyclic performance (88.95%, 4000 cycles) is obtained in active carbon‐based cells with an active mass loading of 5.8 mg cm−2. The approach offers a cost‐effective and environmentally friendly strategy for achieving stable and reversible zinc anodes for aqueous batteries.

Nanodiamond Implanted Zinc Metal Anode for Long‐Life Aqueous Zinc Ion Batteries

AbstractThe practical application of aqueous zinc ion batteries is greatly hindered by the severe dendrite growth and side reactions on the Zn metal anode. To address these challenges, nanodiamond (ND) particles are implanted on the Zn foil surface by a straightforward mechanical rolling process, which serves as heterogeneous seeds, enhancing the cycling stability of Zn metal anode. ND particles with carboxyl groups facilitate the even distribution of electric fields and Zn2+ ions in their vicinity, which promotes the homogeneous deposition of Zn. Moreover, the excellent corrosion resistance of ND particles alleviates the side reactions of the electrode, thus effectively protecting the Zn metal anode in aqueous electrolyte. Benefited from these advantages, the ND@Zn anode shows over 4100 h reversible cycles in symmetric cells, and 99.7% Coulombic efficiency in asymmetric cells. The ND@Zn||MnO2 full cell achieves a stable life of 1000 cycles with 87.0% capacity retention at 1 A g−1 current density. This cost‐effective fabrication process holds the potential for scalability, making it amenable to large‐scale production of zinc metal anodes.

Artificial Hydrophilic Organic and Dendrite-Suppressed Inorganic Hybrid Solid Electrolyte Interface Layer for Highly Stable Zinc Anodes.

Aqueous zinc-ion batteries (AZIBs) have gained significant attentions for their inherent safety and cost-effectiveness. However, challenges, such as dendrite growth and anodic corrosion at the Zn anode, hinder their commercial viability. In this paper, an organic-inorganic coating layer (Nafion-TiO2) was introduced to protect the Zn anode and electrolyte interface. Briefly, Nafion effectively shields against the corrosion from water molecules through the hydrophobic wall of -CF3 and guided zinc deposition from the -SO3 functional group, while TiO2 particles with a higher Young's modulus (151 GPa vs 120 GPa from Zn metal) suppress the zinc dendrite formation. As a result, with the protection of Nafion-TiO2, the symmetrical Zn∥Zn battery shows an improved cycle life of 1,750 h at 0.5 mA cm-2, and the full cell based on Zn∥MnO2 shows a long cycle life over 1,500 cycles at 1 A g-1. Our research offers a novel approach for protecting zinc metal anodes, potentially applicable to other metal anodes such as those in lithium and sodium batteries.

Interfacial Engineering of Zn Metal via a Localized Conjugated Layer for Highly Reversible Aqueous Zinc Ion Battery.

Aqueous zinc-ion batteries are regarded as promising and efficient energy storage systems owing to remarkable safety and satisfactory capacity. Nevertheless, the instability of zinc metal anodes, characterized by issues such as dendrite growth and parasitic side reactions, poses a significant barrier to widespread applications. Herein, we address this challenge by designing a localized conjugated structure comprising a cyclic polyacrylonitrile polymer (CPANZ), induced by a Zn2+-based Lewis acid (zinc trifluoromethylsulfonate) at a temperature of 120 °C. The CPANZ layer on the Zn anode, enriched with appropriate pyridine nitrogen-rich groups (conjugated cyclic -C=N-), exhibits a notable affinity for Zn2+ with ample deposition sites. This zincophilic skeleton not only serves as a protective layer to guide the deposition of Zn2+ but also functions as proton channel blocker, regulating the proton flux to mitigate the hydrogen evolution. Additionally, the strong adhesion strength of the CPANZ layer guarantees its sustained protection to the Zn metal during long-term cycling. As a result, the modified zinc electrode demonstrates long cycle life and high durability in both half-cell and pouch cells. These findings present a feasible approach to designing high performance aqueous anodes by introducing a localized conjugated layer.

Interfacial Engineering of Zn Metal via a Localized Conjugated Layer for Highly Reversible Aqueous Zinc Ion Battery

AbstractAqueous zinc‐ion batteries are regarded as promising and efficient energy storage systems owing to remarkable safety and satisfactory capacity. Nevertheless, the instability of zinc metal anodes, characterized by issues such as dendrite growth and parasitic side reactions, poses a significant barrier to widespread applications. Herein, we address this challenge by designing a localized conjugated structure comprising a cyclic polyacrylonitrile polymer (CPANZ), induced by a Zn2+‐based Lewis acid (zinc trifluoromethylsulfonate) at a temperature of 120 °C. The CPANZ layer on the Zn anode, enriched with appropriate pyridine nitrogen‐rich groups (conjugated cyclic −C=N−), exhibits a notable affinity for Zn2+ with ample deposition sites. This zincophilic skeleton not only serves as a protective layer to guide the deposition of Zn2+ but also functions as proton channel blocker, regulating the proton flux to mitigate the hydrogen evolution. Additionally, the strong adhesion strength of the CPANZ layer guarantees its sustained protection to the Zn metal during long‐term cycling. As a result, the modified zinc electrode demonstrates long cycle life and high durability in both half‐cell and pouch cells. These findings present a feasible approach to designing high performance aqueous anodes by introducing a localized conjugated layer.

Anion electrostatic insertion boosts efficient zinc ferrocyanide cathode for aqueous dual-ion battery

Prussian blue analogs (PBAs) have been considered as a kind of promising cathode materials, but its poor cycle performance severely hinders their industrialization. Herein, by combining a zinc ferrocyanide (ZnHCF) cathode with aqueous ZnSO4/LiTFSI electrolyte and zinc metal anode, we achieved a stable anion insertion-type aqueous dual-ion battery (DIB) which displays a discharge specific capacity of 75.9 mAh g–1, an energy density of 124 Wh kg–1, and a discharge plateau of 1.8 V at 5 A g–1. Its specific capacity can still reach 57.4 mAh g–1 after 1200 cycles with a Coulombic efficiency of 97 %. A reversible anion insertion mechanism of ZnHCF cathode based on the changes of the valency of iron and the insertion of TFSI– ion on crystal surface caused by electrostatic interaction is proposed and confirmed with a series of characterizations and density functional theory calculations (DFT). This work proposes the study of anion energy storage mechanism of PBAs and brings more opportunities for their large-scale applications in the future.

Polycarbonyl polymer with zincophilic sites as protective coating for highly reversible zinc metal anodes

The Zn anode of aqueous zinc ion batteries (AZIBs) have suffered from a series of rampant side reactions such as dendrite growth and corrosion, which seriously affect the reversibility and stability of Zn anodes. Herein, a polycarbonyl polymer poly(1,4,5,8-naphthalene tetracarboxylic anhydride anthraquinone) imine (PNAQI) as the protective coating is synthesized through a simple solvothermal method with the raw materials of the equimolar 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA) and 2, 6-aminoanthraquinone (2,6-DAAQ). A series of characterizations such as contact angle measurement and ex-situ XRD analysis confirm that it can effectively prevent some side reactions. Moreover, CO on PNAQI can regulate the uniform distribution of zinc, thereby preventing the occurrence of zinc dendrites. Finally, the PNAQI@Zn//PNAQI@Zn symmetrical cell demonstrates a long cycle life exceeding 1000 h at current density of 1.0 mA cm−2 and a capacity of 1.0 mAh cm−2. The result significantly outperforms the cycling performance of the cell with bare zinc anode. Especially, the full battery of PNAQI@Zn//NH4V4O10 demonstrates an excellent capacity retention and prolonged cycle life (96.9 mAh/g after 1000 cycles at 1.0 A/g) compared to Zn//NH4V4O10. This work provides an effective, simple and low-cost solution for developing high-performance AZIBs.

Molecular Engineering Enables Hydrogel Electrolyte with Ionic Hopping Migration and Self-Healability toward Dendrite-Free Zinc-Metal Anodes.

Hydrogel electrolytes (HEs), characterized by intrinsic safety, mechanical stability, and biocompatibility, can promote the development of flexible aqueous zinc-ion batteries (FAZIBs). However, current FAZIB technology is severely restricted by the uncontrollable dendrite growth arising from undesirable reactions between the HEs with sluggish ionic conductivity and Zn metal. To overcome this challenge, this work proposes a molecular engineering strategy, which involves the introduction of oxygen-rich poly(urea-urethane) (OR-PUU) into polyacrylamide (PAM)-based HEs. The OR-PUU/PAM HEs facilitate rapid ion transfer through their ionic hopping migration mechanism, resulting in uniform and orderly Zn2+ deposition. The abundant polar groups on the OR-PUU molecules in OR-PUU/PAM HEs break the inherent H-bond network, tune the solvation structure of hydrated Zn2+, and inhibit the occurrence of side reactions. Moreover, the interaction of hierarchical H-bonds in the OR-PUU/PAM HEs endows them with self-healability, enabling in situ repair of cracks induced by plating/stripping. Consequently, Zn symmetric cells incorporating the novel OR-PUU/PAM HEs exhibit a long cycling life of 2000h. The resulting Zn-MnO2 battery displays a low capacity decay rate of 0.009% over 2000 cycles at 2000mA g-1. Overall, this work provides valuable insights to facilitate the realization of dendrite-free Zn-metal anodes through the molecular engineering of HEs.