Achieving Ultra-Long Cycle Life of Zn Anode Using ZnSn(OH)6 Coating Layer via Desolvation Effect and Uniform Zn2+ Flux.

Aqueous zinc-ion batteries (AZIBs) are considered as a promising energy storage system because of good safety, low cost, abundant resources, and environmental friendliness. However, the bottlenecks including dendrite growth, hydrogen evolution, and corrosion seriously limit their practical application. Herein, a novel ZnSn(OH)6 coating layer with rich hydroxyl groups is employed to achieve highly stable Zn anode. The hydroxyl groups can feasibly interact with H2O molecules, contributing to the desolvation of hydrated Zn2+ and the inhibition of side reactions on Zn anode surface. Furthermore, according to the DFT calculation, the adsorption energy of Zn2+ among various sites on the surface of ZnSn(OH)6 coating layer is relatively large, which helps the uniform distribution of Zn2+ flux and the prevention of dendrite growth. Consequently, the ZnSn(OH)6@Zn anode delivers ultra-long cycle life (6770 h), low polarization voltage (27 mV), and high Coulombic efficiency (99.2% over 800 cycles) at 1 mA cm-2, 1 mAh cm-2. Besides, the assembled NaV3O8·xH2O//ZnSn(OH)6@Zn full cell can operate stably for 1500 cycles at 2 A g-1 with a high specific capacity of 144.9 mAh g-1, demonstrating an excellent application potential. This simple and effective coating layer with high electrochemical performance provides an appealing strategy for the development of rechargeable AZIBs.

Tailoring Zn2+ Flux by an Ion Acceleration Layer Modified Separator for High-Rate Long-Lasting Zn Metal Anodes.

A large concentration gradient originating from sluggish ion transport on the surface of Zn metal anodes will result in uneven Zn2+ flux, giving rise to severe dendrite growth, especially at high current density. Herein, an ion acceleration layer is introduced by a facile separator engineering strategy to realize modulated Zn2+ flux and dendrite-free deposition. Zinc hexacyanoferrate as the modifying agent featuring strong zincophilicity and rapid diffusion tunnel can enable fast trap for Zn2+ near the electrode surface and immediate transport onto deposition sites, respectively. The ion acceleration effect is substantiated by improved ion conductivity, decreased activated energy, and promoted Zn2+ transference number, which can moderate concentration gradient to guide homogenous Zn2+ flux distribution. As a result, the separator engineering guarantees Zn||Zn symmetrical cells with long-term stability of 2700 h at 2 mA cm-2, and 1770 h at a large current density of 10 mA cm-2. Moreover, cycling stability and rate capability for full cells with different cathodes can be substantially promoted by the modified separator, validating its superior practical feasibility. This study supplies a new scalable approach to tailoring ion flux near the electrode surface to enable robust Zn metal anodes at a high current density.

High-Performance Aqueous Calcium Ion Batteries Enabled by Zn Metal Anodes with Stable Ion-Conducting Interphases.

Aqueous calcium ion batteries, promising for energy storage, are still challenged by very limited anode choices. Although a Zn metal anode is popular in aqueous batteries, interface instability due to incessant corrosion and severe Zn dendrites hinders its development. Here, an interphase layer with densely packed nanocrystals of Ca3(CO3)2(OH)2·1.5H2O and ZnF2, and amorphous organic species, is demonstrated for a Zn metal anode with 1 M calcium trifluoromethyl sulfonate aqueous electrolyte. The hybrid interface fully avoids direct Zn-H2O contact, maintains fast ion conductivity, and effectively prevents corrosion and dendrite growth. Therefore, the symmetric cell stably lasts for 1600 h at 0.5 mA cm-2 and 2.5 mAh cm-2, far superior to 150 h for the control cell. Furthermore, the device maintains 80% capacity retention after 700 cycles at 1 A g-1, outperforming 13% retention after 200 cycles for the control device. This work indicates that interface and interphase engineering is also crucial for aqueous batteries.

Nonflammable Fluorinated Electrolyte Realizing High Voltage Anode-Free Zn Dual-Ion Batteries.

Due to the low decomposition potential of H2O and its corrosive effect to Zn foil, the Zn metal battery with aqueous electrolytes operates within a narrow electrochemical window and exhibits low anode utilization ratio. Fluorinated carbonate ester, exhibiting low highest occupied molecular orbital (HOMO) energy level, is suitable for constructing high-voltage batteries, yet its application in Zn metal battery has been scarcely explored. Herein, we propose an electrolyte based on fluorinated solvents and ethoxy (pentafluoro) cyclotriphosphazene (PFPN) additive, which exhibits a high decomposition voltage of 2.75 V in Zn batteries. The fluorinated carbonate esters possess non-flammability and exhibit reduced solvation capacity which in turn promotes the incorporation of anions into Zn2+ solvation shell. Consequently, an anion-derived interface layer is formed on Zn anode, aiding the compact and planar growth of deposited Zn. Therefore, the Zn//Zn cell exhibits an impressive Zn utilization of 91% for 140 h, a level seldom reported previously. Benefitting from the oxidation resistant solvents and cathode-electrolyte interface layer formed by PFPN additive, the Zn//graphite dual-ions battery shows an extended cycling life of 1000 cycles. Furthermore, an anode-free cell was constructed and stably operated for 100 cycles, with a notably high average discharge midpoint voltage of 1.84 V.

High-Entropy-Inspired Multicomponent Electrical Double Layer Structure Design for Stable Zinc Metal Anodes.

Regulating the electrical double layer (EDL) structure can enhance the cycling stability of Zn metal anodes, however, the effectiveness of this strategy is significantly limited by individual additives. Inspired by the high-entropy (HE) concept, we developed a multicomponent (MC) EDL structure composed of La3+, Cl-, and BBI anions by adding dibenzenesulfonimide (BBI) and LaCl3 additives into ZnSO4 electrolytes (BBI/LaCl3/ZnSO4). Specifically, La3+ ions accumulate within EDL to shield the net charges on the Zn surface, allowing more BBI anions and Cl- ions to enter this region. Consequently, this unique MC EDL enables Zn anodes to simultaneously achieve uniform electric field, robust SEI layer, and balanced reaction kinetics. Moreover, the synergistic parameter - a novel descriptor for quantifying collaborative improvement - was first proposed to demonstrates the synergistic effect between BBI and LaCl3 additives. Benefitting from these advantages, Zn metal anodes achieved a high reversibility of 99.5 % at a depth of discharge (DoD) of 51.3 %, and Zn|MnO2 pouch cells exhibited a stable cycle life of 100 cycles at a low N/P ratio of 2.9.

Selection of Negative Charged Acidic Polar Additives to Regulate Electric Double Layer for Stable Zinc Ion Battery.

Zinc-ion batteries are promising for large-scale electrochemical energy storage systems, which still suffer from interfacial issues, e.g., hydrogen evolution side reaction (HER), self-corrosion, and uncontrollable dendritic Zn electrodeposition. Although the regulation of electric double layer (EDL) has been verified for interfacial issues, the principle to select the additive as the regulator is still misted. Here, several typical amino acids with different characteristics were examined to reveal the interfacial behaviors in regulated EDL on the Zn anode. Negative charged acidic polarity (NCAP) has been unveiled as the guideline for selecting additive to reconstruct EDL with an inner zincophilic H2O-poor layer and to replace H2O molecules of hydrated Zn2+ with NCAP glutamate. Taking the synergistic effects of EDL regulation, the uncontrollable interface is significantly stabilized from the suppressed HER and anti-self-corrosion with uniform electrodeposition. Consequently, by adding NCAP glutamate, a high average Coulombic efficiency of 99.83% of Zn metal is achieved in Zn|Cu asymmetrical cell for over 2000 cycles, and NH4V4O10|Zn full cell exhibits a high-capacity retention of 82.1% after 3000 cycles at 2 A g-1. Recapitulating, the NCAP principle posted here can quicken the design of trailblazing electrolyte additives for aqueous Zn-based electrochemical energy storage systems.

Sieving-type Electric Double Layer with Hydrogen Bond Interlocking to Stable Zinc Metal Anode.

The stability of aqueous zinc metal batteries is significantly affected by side reactions and dendrite growth on the anode interface, which primarily originate from water and anions. Herein, we introduce a multi H-bond site additive, 2, 2'-Sulfonyldiethanol (SDE), into an aqueous electrolyte to construct a sieving-type electric double layer (EDL) by hydrogen bond interlock in order to address these issues. On the one hand, SDE replaces H2O and SO42- anions that are adsorbed on the zinc anode surface, expelling H2O/SO42- from the EDL and thereby reducing the content of H2O/SO42- at the interface. On the other hand, when Zn2+ are de-solvated at the interface during the plating, the strong hydrogen bond interaction between SDE and H2O/SO42- can trap H2O/SO42- from the EDL, further decreasing their content at the interface. This effectively sieves them out of the zinc anode interface and inhibits the side reactions. Moreover, the unique characteristics of trapped SO42- anions can restrict their diffusion, thereby enhancing the transference number of Zn2+ and promoting dendrite-free deposition and growth of Zn. Consequently, utilizing an SDE/ZnSO4 electrolyte enables excellent cycling stability in Zn//Zn symmetrical cells and Zn//MnO2 full cells with lifespans exceeding 3500 h and 2500 cycles respectively.

Organic Cations Texture Zinc Metal Anodes for Deep Cycling Aqueous Zinc Batteries.

Manipulating the crystallographic orientation of zinc (Zn) metal to expose more (002) planes is promising to stabilize Zn anodes in aqueous electrolytes. However, there remain challenges involving the non-epitaxial electrodeposition of highly (002) textured Zn metal and the maintenance of (002) texture under deep cycling conditions. Herein, a novel organic imidazolium cations-assisted non-epitaxial electrodeposition strategy to texture electrodeposited Zn metals is developed. Taking the 1-butyl-3-methylimidazolium cation (Bmim+) as a paradigm additive, the as-prepared Zn film ((002)-Zn) manifests a compact structure and a highly (002) texture without containing (100) signal. Mechanistic studies reveal that Bmim+ featuring oriented adsorption on the Zn-(002) plane can reduce the growth rate of (002) plane to render the final exposure of (002) texture, and homogenize Zn nucleation and suppress H2 evolution to enable the compact electrodeposition. In addition, the formulated Bmim+-containing ZnSO4 electrolyte effectively sustains the (002) texture even under deep cycling conditions. Consequently, the combination of (002) texture and Bmim+-containing electrolyte endows the (002)-Zn electrode with superior cycling stability over 350 h under 20 mAh cm-2 with 72.6% depth-of-discharge, and assures the stable operation of full Zn batteries with both coin-type and pouch-type configurations, significantly outperforming the (002)-Zn and commercial Zn-based batteries in Bmim+-free electrolytes.

Lithiation Induced Hetero-Superlattice Zn/ZnLi as Stable Anode for Aqueous Zinc-Ion Batteries.

Three dimensional (3D) framework structure is one of the most effective ways to achieve uniform zinc deposition and thus inhibit the Zn dendrites growth in working Zn metallic anode. A major challenge facing for the most commonly used 3D zincophilic hosts is that the zincophilic layer tends to peel off during repeatedly cycling, making it less stable. Herein, for the first time, a hetero-superlattice Zn/ZnLi (HS-Zn/ZnLi) anode containing periodic arrangements of metallic Zn phase and zincophilic ZnLi phase at the nanoscale, is well designed and fabricated via electrochemical lithiation method. Based on binding energy and stripping energy calculation, and the operando optical observation of plating/stripping behaviors, the zincophilic ZnLi sites with a strong Zn adsorption ability in the interior of the 3D ZnLi framework structure can effectively guide uniform Zn nucleation and dendrite-free zinc deposition, which significantly improves the cycling stability of the HS-Zn/ZnLi alloy (over 2800 h without a short-circuit at 2 mA cm-2). More importantly, this strategy can be extended to HS-Zn/ZnNa and HS-Zn/ZnK anodes that are similar to the HS-Zn/ZnLi microstructure, also displaying significantly enhanced cycling performances in AZIBs. This study can provide a novel strategy to develop the dendrite-free metal anodes with stable cycling performance.

Hybrid Molecular Sieve-Based Interfacial Layer with Physical Confinement and Desolvation Effect for Dendrite-free Zinc Metal Anodes.

The side reactions and dendrite growth at the interface of Zn anodes greatly limit their practical applications in Zn metal batteries. Herein, we propose a hybrid molecular sieve-based interfacial layer (denoted as Z7M3) with a hierarchical porous structure for Zn metal anodes, which contains 70 vol % microporous ZSM-5 molecular sieves and 30 vol % mesoporous MCM-41 molecular sieves. Through comprehensive molecular dynamics simulations, we demonstrate that the mesopores (∼2.5 nm) of MCM-41 can limit the disordered diffusion of free water molecules and increase the wettability of the interfacial layer toward aqueous electrolytes. In addition, the micropores (∼0.56 nm) of ZSM-5 can optimize the Zn2+ solvation structures by reducing the bonded water molecules, which simultaneously decrease the constraint force of solvated water molecules to Zn2+ ions, thus promoting the penetrability and diffusion kinetics of Zn2+ ions in Z7M3. The synergetic effects from the hybrid molecular sieves maintain a constant Zn2+ concentration on the surface of the Zn electrode during Zn deposition, contributing to dendrite-free Zn anodes. Consequently, Z7M3-coated Zn electrodes achieved excellent cycling stability in both half and full cells.

Decoration of Ag Species into Reduced Graphene Oxide Foam as a Superelastic and Robust Host toward Stable Zn Metal Anodes under Dwell-Fatigue Condition.

Deep-sea equipment usually operates under dwell-fatigue condition, which means the equipped energy storage devices must survive under the changing pressure. Special mechanical designs should be considered to maintain the electrochemical performance of electrodes under this extreme condition. In this work, an effective assembly strategy is proposed to accommodate the dwell-fatigue loading using Ag decorated reduced graphene oxide (rGO) foam (denoted as AGF) as a superelastic and robust Zn host. The wet-press assembly process enables the formation of highly porous and robust framework. The strong synergetic effect between rGO and Ag further guarantees AGF's superelasticity and ultrahigh mechanical strength. Meanwhile, the homogeneously distributed Ag species on the rGO sheets act as zincophilic sites to effectively facilitate Zn plating. Furthermore, AGF offers enough space to address the expansion during the charge and discharge cycles. As expected, the symmetrical cell using this AGF@Zn host demonstrates a long lifespan over 400 h at a depth-of-discharge of 50%. It is worth mentioning that the superelastic AGF host realizes stable Zn plating/stripping under varying pressures.

Blocking Interfacial Proton Transport via Self-Assembled Monolayer for Hydrogen Evolution-Free Zinc Batteries.

Aqueous Zn-ion batteries (ZIBs) are promising next-generation energy storage devices, yet suffer from the issues of hydrogen evolution reaction (HER) and intricate side reactions on the Zn anode surface. The hydrogen (H)-bond networks play a critical role in interfacial proton transport that may closely relate to HER but are rarely investigated. Herein, we report a self-assembled monolayer (SAM) strategy which is constructed by anchoring ionic liquid cations on Ti3C2Tx substrate for HER-free Zn anode. Molecule dynamics simulations reveal that the rationally designed SAM with a high coordination number of water molecules (25-27, 4-6 for Zn2+) largely reduces the interfacial densities of H2O molecules, therefore breaking the connectivity of H-bond networks and blocking proton transport on the interface, by which the HER is suppressed. Then, a series of in situ characterizations demonstrate that negligible amounts of H2 gas are collected from the Zn@SAM-MXene anode. Consequently, the symmetric cell enables a long-cycling life of 3000 h at 1 mA cm-2 and 1000 h at 5 mA cm-2. More significantly, the stable Zn@SAM-MXene films are successfully used for coin full cells showing high-capacity retention of over 94 % after 1000 cycles and large-area (10×5 cm2) pouch cells with desired performance.

Unveiling the Mysteries: Acetonitrile's Dance with Weakly-Solvating Electrolytes in Shaping Gas Evolution and Electrochemical Performance of Zinc-ion Batteries.

Aqueous Zn-metal battery (AZMB) is a promising candidate for future large-scale energy storage with commendable capacity, exceptional safety characteristics, and low cost. Acetonitrile (AN) has been widely used as an effective electrolyte constituent to improve AZMBs' performance. However, its functioning mechanisms remain unclear. In this study, we unveiled the critical roles of AN in AZMBs via comparative in situ electrochemical, gaseous, and morphological analyses. Despite its limited ability to solvate Zn ions, AN-modulated Zn-ion solvation sheath with increased anions and decreased water achieves a weakly-solvating electrolyte. As a result, the Zn||Zn cell with AN addition exhibited 63 times longer cycle life than cell without AN and achieved a 4 Ah cm-2 accumulated capacity with no H2 generation. In V2O5||Zn cells, for the first time, AN suppressing CO2 generation, elevating CO2-initiation voltage from 2→2.44 V (H2: 2.43→2.55 V) was discovered. AN-impeded transit and Zn-side deposition of dissolved vanadium ions, known as "crosstalk," ameliorated inhomogeneous Zn deposition and dendritic Zn growth. At last, we demonstrated an AN-enabled high-areal-capacity AZMB (3.3 mAh cm-2) using high-mass-loading V2O5 cathode (26 mg cm-2). This study shed light on the strategy of constructing fast-desolvation electrolytes and offered insights for future electrolyte accommodation for high-voltage AZMB cathodes.

Dilute Aqueous-Aprotic Electrolyte Towards Robust Zn-Ion Hybrid Supercapacitor with High Operation Voltage and Long Lifespan.

With the merits of the high energy density of batteries and power density of supercapacitors, the aqueous Zn-ion hybrid supercapacitors emerge as a promising candidate for applications where both rapid energy delivery and moderate energy storage are required. However, the narrow electrochemical window of aqueous electrolytes induces severe side reactions on the Zn metal anode and shortens its lifespan. It also limits the operation voltage and energy density of the Zn-ion hybrid supercapacitors. Using 'water in salt' electrolytes can effectively broaden their electrochemical windows, but this is at the expense of high cost, low ionic conductivity, and narrow temperature compatibility, compromising the electrochemical performance of the Zn-ion hybrid supercapacitors. Thus, designing a new electrolyte to balance these factors towards high-performance Zn-ion hybrid supercapacitors is urgent and necessary. We developed a dilute water/acetonitrile electrolyte (0.5 m Zn(CF3SO3)2 + 1 m LiTFSI-H2O/AN) for Zn-ion hybrid supercapacitors, which simultaneously exhibited expanded electrochemical window, decent ionic conductivity, and broad temperature compatibility. In this electrolyte, the hydration shells and hydrogen bonds are significantly modulated by the acetonitrile and TFSI- anions. As a result, a Zn-ion hybrid supercapacitor with such an electrolyte demonstrates a high operating voltage up to 2.2 V and long lifespan beyond 120,000 cycles.

Secondary Amines Functionalized Organocatalytic Iodine Redox for High-Performance Aqueous Dual-Ion Batteries.

Aqueous dual-ion batteries (ADIBs) based on the cooperative redox of cations and iodine anions at the anode and cathode respectively, are attracting increasing interest because of high capacity and safety. However, the full-cell performance is limited by the sluggish iodine redox kinetics between iodide and polyiodide involving multiple electron transfer steps, and the undesirable shuttling effect of polyiodides. Here, this work reports a versatile conjugated microporous polymer functionalized with secondary amine groups as an organocatalytic cathode for ADIB, which can be positively charged and electrostatically adsorb iodide, and organocatalyze iodine redox reactions through the amine groups. Both theoretical calculations and controlled experiments confirm that the secondary amine groups confine (poly)iodide species via hydrogen bonding, which is essential for accelerating iodine redox kinetics and reducing the polyiodide shuttling effect. The ADIB achieves an ultrahigh capacity of 730 mAh g-1 with an ultrasmall overpotential of 47 mV at 1 A g-1, which also exhibits excellent rate performance and long cycling stability with a capacity retention of 74% after 5000 cycles at a high current density of 5 A g-1. This work demonstrates the promise of developing organocatalysts for accelerating electrochemical processes, which remains a virtually unexplored area in electrocatalyst design for clean energy applications.

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.

Surface Patterning of Metal Zinc Electrode with an In-Region Zincophilic Interface for High-Rate and Long-Cycle-Life Zinc Metal Anode.

The undesirable dendrite growth induced by non-planar zinc (Zn) deposition and low Coulombic efficiency resulting from severe side reactions have been long-standing challenges for metallic Zn anodes and substantially impede the practical application of rechargeable aqueous Zn metal batteries (ZMBs). Herein, we present a strategy for achieving a high-rate and long-cycle-life Zn metal anode by patterning Zn foil surfaces and endowing a Zn-Indium (Zn-In) interface in the microchannels. The accumulation of electrons in the microchannel and the zincophilicity of the Zn-In interface promote preferential heteroepitaxial Zn deposition in the microchannel region and enhance the tolerance of the electrode at high current densities. Meanwhile, electron aggregation accelerates the dissolution of non-(002) plane Zn atoms on the array surface, thereby directing the subsequent homoepitaxial Zn deposition on the array surface. Consequently, the planar dendrite-free Zn deposition and long-term cycling stability are achieved (5,050 h at 10.0 mA cm-2 and 27,000 cycles at 20.0 mA cm-2). Furthermore, a Zn/I2 full cell assembled by pairing with such an anode can maintain good stability for 3,500 cycles at 5.0 C, demonstrating the application potential of the as-prepared ZnIn anode for high-performance aqueous ZMBs.

Horizontally Arranged Zn Platelet Deposition Regulated by Bi2O3/Bi toward High-Rate and Dendrite-Free 3D Zn Composite Anode.

Aqueous Zn-metal battery is considered as a promising energy-storage system. However, uncontrolled zinc dendrite growth is the main cause of short-circuit failure in aqueous Zn-based batteries. One of the most efficient and convenient strategies to alleviate this issue is to introduce appropriate zincophilic nucleation sites to guide zinc metal deposition and regulate crystal growth. Herein, this work proposes Bi2O3/Bi nanosheets anchored on the cell wall surface of the 3D porous conductive host as the Zn deposition sites to modulate Zn deposition behavior and hence inhibit the zinc dendrite growth. Density functional theory and experimental results demonstrate that Bi2O3 has a super zinc binding energy and strong adsorption energy with zinc (002) plane, as a super-zincophilic nucleation site, which results in the deposition of zinc preferentially along the horizontal direction of (002) crystal plane, fundamentally avoids the formation of Zn dendrites. Benefiting from the synergistic effect Bi2O3/Bi zincophilic sites and 3D porous structure in the B-BOGC host, the electrochemical performance of the constructed Zn-based battery is significantly improved. As a result, the Zn anode cycles for 1500 cycles at 50 mA cm-2 and 1.0 mAh cm-2. Meanwhile, the Zn@B-BOGC//MnO2 full cell can operate stably for 2000 cycles at 2.0 A g-1.

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 2000 h. The resulting Zn-MnO2 battery displays a low capacity decay rate of 0.009% over 2000 cycles at 2000 mA g-1. Overall, this work provides valuable insights to facilitate the realization of dendrite-free Zn-metal anodes through the molecular engineering of HEs.

Constructing a Topologically Adaptable Solid Electrolyte Interphase for a Highly Reversible Zinc Anode.

The performance of aqueous zinc metal batteries is significantly compromised by the stability of the solid electrolyte interphase (SEI), which is intimately linked to the structure of the electrical double layer (EDL) between the zinc anode and electrolyte. Furthermore, understanding the mechanical behavior of SEI is crucial, as it governs its response to stress induced by volume changes, fracture, or deformation. In this study, we introduce l-glutamine (Gln) as an additive to regulate the adsorbed environment of the EDL and in situ produce a hybrid SEI consisting of ZnS and Gln-related species. The results of the nanoindentation test indicate that the hybrid SEI exhibits a low modulus and low hardness, alongside exceptional shape recovery capability, which effectively limits side reactions and enables topological adaptation to volume fluctuations in zinc anodes during zinc ion plating/stripping, thereby enabling Zn//Zn symmetric cells to exhibit an ultralong cycle life of 4000 h in coin cells and a high cumulative capacity of 18,000 mA h in pouch cells. More importantly, the superiority of the formulated strategy is further demonstrated in Zn//NH4V4O10 full cells at different N/P ratios of 5.2, 4.9, 3.5, and 2.4. This provides a promising approach for future interfacial modulation in aqueous battery chemistry.