Separator designs for aqueous zinc-ion batteries

In situ engineering of a glutathione-derived hydrophobic layer for durable and dendrite-free Zn anodes

Aqueous Zn-ion batteries (AZIBs) are gaining increasing attention for large-scale energy storage due to their cost-effectiveness, safety, and high volumetric energy density. However, their practical application is still hindered by challenges such as uncontrolled growth of Zn dendrites and unwanted side reactions. In this study, we introduce an interfacial engineering strategy by applying a glutathione (GSH) functional layer on the surface of the Zn anode (GSH@Zn). The GSH layer not only mitigates corrosion by increasing the hydrophobicity of Zn anodes but also guides uniform Zn deposition. Moreover, the native oxides on Zn anodes are etched by glutathione, resulting in an increased electrochemical active area and reduced interfacial impedance, which improves reaction kinetics. Therefore, the GSH@Zn anode demonstrates stable, long-term plating/stripping cycling, operating dendrite-free for 4500 h at 1 mA cm-2, significantly outperforming bare Zn anodes, which short-circuit after only 130 h. When paired with a vanadium-based cathode, the full cell shows excellent cycling stability and rate capability, retaining 86 % of its capacity after 2000 cycles and releasing 60 % of its capacity at 4 A g-1. This work offers an effective strategy to enhance the stability and reversibility of Zn anodes in aqueous electrolytes, laying the groundwork for the development of durable, high-performance Zn-based energy storage systems.

Breaking Performance Limits of Zn Anodes in Aqueous Batteries by Tailoring Anion and Cation Additives

Crystallographic engineering of Zn anodes to favor the exposure of (002) planes is an effective approach for improving stability in aqueous electrolytes. However, achieving non-epitaxial electrodeposition with a pronounced (002) texture and maintaining this orientation during extended cycling remains challenging. This study questions the prevailing notion that a single (002)-textured Zn anode inherently ensures superior stability, showing that such anodes cannot sustain their texture in ZnSO4 electrolytes. We then introduced a novel electrolyte additive, benzyltriethylammonium chloride (TEBAC), which preserves the (002) texture over prolonged cycling. Furthermore, we successfully converted commercial Zn foils into highly crystalline (002)-textured Zn without any pretreatment. Experiments and theoretical calculations revealed that the cationic TEBA+ selectively adsorbs onto the anode surface, promoting the exposure of the Zn(002) plane and suppressing dendrite formation. A critical discovery was the pitting corrosion caused by chloride ions from TEBAC, which we mitigated by anion substitution. This modification leads to a remarkable lifespan of 375 days for the Zn||Zn symmetric cells at 1 mA cm-2 and 1 mAh cm-2. Furthermore, a TEBA+-modified Zn||VO2 full cell demonstrates high specific capacity and robust cycle stability at 10.0 A g-1. These results provide valuable insights and strategies for developing long-life Zn ion batteries.

Nickel silicate nanotubes modifying the surface of Zn anode tuning the uniform zinc deposition for high-performance Zn metal battery

Among many new types of ion batteries, aqueous Zn-ion batteries (AZIBs) have gained more and more interest because of their unique characteristics such as abundant metal Zn reserves and high capacity. Herein, a nickel silicate nanotube (NSO) is synthesized for protecting Zn metal anode by the surface modification strategy (NSO-Zn). On the one hand, the pores generated by the stacking of NSO nanotubes uniformly guide the deposition of Zn2+ on Zn plate, which greatly reduces the risk of the battery's short-circuit due to the dendrite growth puncturing the diaphragm. On the other hand, the hydrophilic nature of NSO is more conducive to the penetration of electrolyte. Thanks to the inherent material and structural properties of NSO nanotubes, the symmetric cells prepared with NSO-Zn electrodes have a long cycle life of more than 2500 h at 1 mA·cm-2. Finite element simulations of the electrical field and Zn2+ intensity demonstrate that the NSO-Zn electrodes can well reduce the local current density resulting in homogenizing electric field distribution. The present study not only provides a facile and large-grid synthesis of NSO nanotubes, but also demonstrates that NSO nanotubes can protect high-reversible zinc metal anodes and guide the uniform zinc deposition for long-cycle AZIBs.

Aspartame Endowed ZnO-Based Self-Healing Solid Electrolyte Interface Film for Long-Cycling and Wide-Temperature Aqueous Zn-Ion Batteries

Metallic Zn anodes suffer from hydrogen evolution and dendritic deposition in aqueous electrolytes, resulting in low Coulombic efficiency and poor cyclic stability for aqueous Zn-ion batteries (AZIBs). Constructing stable solid electrolyte interphase (SEI) with strong affinity for Zn and exclusion of water corrosion of Zn metal anodes is a promising strategy to tackle these challenges. In this study, we develop a self-healing ZnO-based SEI film on the Zn electrode surface by employing an aspartame (APM) as a versatile electrolyte additive. The hydrophobic nature and strong Zn affinity of APM can facilitate the dynamic self-healing of ZnO-based SEI film during cyclic Zn plating/stripping process. Benefiting from the superior protection effect of self-healing ZnO-based SEI, the Zn║Cu cells possess an average coulombic efficiency more than 99.59% over 1,000 cycles even at a low current density of 1 mA cm-2 - 1 mAh cm-2. Furthermore, the Zn║NH4+-V2O5 full cells display a large specific capacity of 150 mAh g-1 and high cyclic stability with a capacity retention of 77.8% after 1,750 cycles. In addition, the Zn║Zn cell delivers high temperature adaptability at a wide-temperature range from - 5 to 40 °C even under a high DOD of 85.2%. The enhanced capability and durability originate from the self-healing SEI formation enabled by multifunctional APM additives mediating both corrosion suppression and interfacial stabilization. This work presents an inspired and straightforward approach to promote a dendrite-free and wide-temperature rechargeable AZIBs energy storage system.

Regulating triazine number in covalent organic frameworks modified separator to achieve high-energy-density performance in aqueous zinc-iodine batteries

The development of separator by tunning the zincophilic and iodide ion-repulsive properties of covalent organic frameworks (COFs) that regulate cycle lifespan and capacity of aqueous zinc-iodine (Zn-I2) batteries is one of challenges. In this work, we have shown a systematic strategic-driven investigation to elucidate the role of functional triazine properties in COF modified separator towards overall performance of aqueous Zn-I2 batteries. As such, three COFs with the same topology but different triazine number in their structures, have been synthesized, among which the triazine-richest framework, TAPA-TTB-COF-based separator demonstrated to be most effective to guide uniform Zn2+ flux and simultaneously inhibit polyiodide shuttling due to the zincophilic nature and good iodide ion-repulsive capability of triazine. Consequently, the Zn||Gr@TAPA-TTB-COF@GF||Zn symmetric battery achieves a long life of more than 2100 h (5.0 mA cm-2) and the initial area capacity of the Zn||Gr@TAPA-TTB-COF@GF||I2 battery reaches up to 5.5 mAh cm-2 (20 mA cm-2). After 2000 cycles, the discharge capacity can still maintain at3.0 mAh cm-2 with a capacity decay rate of only 0.023 % per cycle. This study provides guidance for the rational design of functional COFs separators and promotes their application in high energy storage systems.

Towards Ultra-Stable Wide-Temperature Zinc-Ion Batteries by Using Ion-Sieving Organic Framework Membrane

Aqueous zinc-ion batteries (AZIBs) offer notable advantages in safety and cost-efficiency, but Zn dendrite growth and unstable interfacial reactions hinder their commercial viability. A crucial factor in addressing these challenges lies in optimizing the separator to regulate ion transport and stabilize electrode interfaces. Herein, we propose a covalent organic framework (COF)-based separator with quasi-single-ion conduction, specifically a Zn2+-substituted sulfonate COF (COF-Zn) membrane, designed to tackle these issues. Featuring a high Zn transference number (0.87) and a thin 25 μm profile, the COF-Zn separator allows for reduced electrolyte usage (20 μL mg-1) while effectively minimizing cathode dissolution. Its quasi-single-ion conductivity and electronegative properties improve Zn anode's stability by lowering water activity. This separator enables ultra-stable AZIBs, as demonstrated in various full cells including Zn//4,5,9,10-pyrenetetrone (PTO), Zn//I2 and Zn//V2O5. Remarkably, the Zn//PTO cell achieves an energy density of 260 Wh kg-1, 100 % capacity retention under reduced electrolyte conditions, and stable all-weather cycling from -40 to +100 °C with a customized electrolyte.

Electrochemical engineering in aqueous metal-ion batteries

Aqueous metal ion batteries (AMIBs), with merits of safety, ambient assembly, and eco-friendliness, demonstrate great potential in various energy storage scenarios. Despite the laboratory-scale progress in battery components and mechanisms featured by large specific capacities and long lifespans, AMIBs' practical use meets challenges with electrodes and electrolytes. It is crucial to prepare a review discussing the problems and solutions for the battery performance degradation during the electrode/battery scaleup from the perspectives of ion mass transfer and electrode reaction, which is proposed as the electrochemical engineering in AMIBs. We first introduce the anodic reactions and their effective reinforcement by molecule chemistry and electrodeposition. Then, we discuss the ion diffusion in electrolytes by learning from the Nernst-Planck theory, followed by the interphase ion diffusion at the electrolyte-cathode interface. After that, we highlight the lattice-void and particle-gap ion diffusion in cathodes and the cathodic reactions reinforced by catalysis and micro-reactor construction. Finally, we present the challenge and perspective of this blooming field toward the lab-to-market transition of AMIBs.

Synergistic interface regulation for achieving fast kinetics and highly reversible zinc metal anodes

Uncontrolled zinc dendrite growth and adverse side reactions at the Zn anode interface severely limit its practical application. Based on theoretical calculations, this study in situ constructs a functional interface (ICFI Zn) on the Zn anode surface, consisting of a surface-textured structure and a zinc-philic protective layer. Benefiting from the synergistic effect of ion regulation and atomic anchoring of this functional interface, the ICFI Zn anode achieves homogenised regulation of ion fluxes, facilitates ion transport kinetics, effectively suppresses side reactions and guides the deposition of dendrite-free Zn. Consequently, this functional interface endows the zinc anode with significantly enhanced cycling stability, lower nucleation barriers, and reduced voltage polarization. Surprisingly, the ICFI Zn anode exhibits over 3000 h of stable cycling performance at a high current density of 2 mA cm-2. Even at high current densities of 5, 10, and 20 mA cm-2, it still maintains high reversibility. Furthermore, in practical applications with the ICFI Zn||MnO2 battery, it also demonstrates ultra-long cycling stability. The one-step in situ construction of this functional interface provides a novel strategy for developing zinc metal anodes with rapid kinetics and high reversibility.

Dehydroxylated Polyvinyl Alcohol Separator Enables Fast Kinetics in Zinc-Metal Batteries

Separators are critical components of zinc-metal batteries (ZMBs). Despite their high ionic conductivity and excellent electrolyte retention, the widely used glass fiber (GF) membranes suffer from poor mechanical stability and cannot suppress dendrite growth, leading to rapid battery failure. Contrarily, polymer-based separators offer superior mechanical strength and facilitate more homogeneous zinc (Zn) deposition. However, they typically suffer from sluggish ion transport kinetics and poor wettability by aqueous electrolytes, resulting in unsatisfactory electrochemical performance. Here a dehydroxylation strategy is proposed to overcome the above-mentioned limitations for polyvinyl alcohol (PVA) separators. A dehydroxylated PVA-based membrane (DHPVA) is synthesized at a relatively low temperature in a highly concentrated alkaline solution. Part of the hydroxyl groups are removed and, as a result, the hydrogen bonding between PVA chains, which is deemed responsible for the sluggish ion transport kinetics, is minimized. At 20 °C, the ionic conductivity of DHPVA reaches 12.5 mS cm-1, which is almost 4 times higher than that of PVA. Additionally, DHPVA effectively promotes uniform Zn deposition, leading to a significantly extended cycle life and reduced polarization, both in a/symmetric (Cu/Zn and Zn/Zn) and full cells (Zn/NaV3O8). This study provides a new, effective, yet simple approach to improve the performance of ZMBs.

Investigating the role of non-ionic surfactants as electrolyte additives for improved zinc anode performance in aqueous batteries

Zinc metal anodes encounter significant challenges, including dendrite growth, hydrogen evolution, and corrosion, all of which impede the rate capability and longevity of aqueous zinc-ion batteries (AZIBs). To effectively tackle these issues, we introduced Tween-80 into the traditional ZnSO4 electrolyte as an additive. Tween-80 possesses electronegative oxygen atoms that enable it to adsorb onto the zinc (Zn) anode surface, facilitating the directional deposition of Zn metal along the (002) orientation. The hydroxyl and ether groups within Tween-80 can displace some of the coordinated water molecules in the Zn2+ inner solvation shell. This disruption of the hydrogen bond network regulates the solvation structure of Zn2+ ions and suppresses the possibility of hydrogen evolution. Moreover, the long hydrocarbon chain present in Tween-80 exhibits excellent hydrophobic properties, aiding in the resistance against corrosion of the Zn anode by water molecules and reducing hydrogen evolution. Consequently, a symmetric cell equipped with the Tween-80 additive can cycle stably for over 4000 h at 1 mA cm-2 and 1 mA h cm-2. When paired with the V2O5 cathode, the full cell demonstrates a high-capacity retention rate exceeding 80 % over 1000 cycles at a current density of 2 A g-1. This study underscores the advantages of utilizing non-ionic surfactants for achieving high-performance aqueous zinc-ion batteries.

Designing Multi-functional Separators With Regulated Ion Flux and Selectivity for Macrobian Zinc Ion Batteries

The success of achieving scale-up deployment of zinc ion batteries is to selectively regulate the rapid and dendrite-free growth of zinc anodes. Herein, this is proposed that a creative design strategy of constructing multi-functional separators (MFS) to stabilize the zinc anodes. By in situ decorating metal-organic-framework coating on commercial glass fiber, the upgraded separator is of remarkable benefit for strong anion (SO4 2-) anchoring, uniform ion flux across the interface, and boosted Zn2+ desolvation. Such a feature selectively promotes the Zn2+ transportation efficiency, which enables a high Zn2+ transference number of 0.81, enhanced ionic conductivity, and a superb exchange current density of 12.80 mA cm-2. Consequently, the zinc anode can be operated stably with an ultra-long service lifetime of over 4800 h in symmetric cells and improved cycling endurance in full batteries. This work paves an attractive pathway to design multi-functional separators with regulated ion flux and selectivity toward high-energy metal batteries beyond zinc chemistry.

Suppressing hydrogen evolution and promoting dendrite free zinc deposition by fluorinated triazine framework towards robust aqueous zinc ion batteries

Aqueous zinc-ion batteries (AZIBs) have become a research hotspot, but the inevitable zinc dendrites and parasitic reactions in the zinc anode seriously hinder their further development. In this study, three covalent triazine frameworks (DCPY-CTF, CTF-1 and FCTF) have been synthesized and used as artificial protective coatings, in which the fluorinated triazine framework (FCTF) increases the zinc-philic site, thus better promoting dendritic free zinc deposition and inhibiting hydrogen evolution reactions. Excitingly, both experimental results and theoretical calculations indicate that the FCTF interface adjusts the deposition of Zn2+ along the (002) plane, effectively alleviating the formation of zinc dendrites. As expected, Zn@FCTF symmetric cells exhibit cycling stability of over 4000 h (0.25 mA cm-2), meanwhile Zn@FCTF//NHVO full cells provide a high specific capacity of 280 mAh/g at 1.0 A/g, which are superior to those of bare Zn anode. This work provides new insights for suppressing hydrogen evolution and promoting dendrite-free zinc deposition to construct highly stable and reversible AZIBs.

Modulating Ion Behavior by Functional Nanodiamond Modified Separator for High-Rate Durable Aqueous Zinc-Ion Battery

Aqueous zinc-ion batteries (AZIBs) have garnered widespread attention due to their promising development and application prospects. However, progress of AZIBs has been hindered by zinc (Zn) dendrites and side reactions at the electrode-electrolyte interface (EEI). In particular, the large and uneven pores of commercial glass fiber (GF) separators lead to nonuniform Zn2+ transport, which causes side reactions. In this study, we employed nanodiamonds (NDs) to regulate the separator pore structure and utilized its surface oxygen-containing functional groups to control the Zn2+ transport properties. Due to their excellent chemical inertness, superhardness, ultrahigh thermal conductivity, and abundant surface functional groups, NDs modified GF separators for dendrite-free and high-performance AZIBs. Experimental outcomes demonstrate that Zn||Zn symmetric cells using NDs-GF separators exhibit regular charge-discharge profiles, minimal fluctuations, and an ultralong cycling lifespan of nearly 1800 h under a current density of 5 mA cm-2 with a capacity density of 1 mAh cm-2 and 240 h under a high current density of 10 mA cm-2 with a capacity density of 10 mAh cm-2. The Zn||MnO2 full cells using NDs-GF separators showcase a high retention after 1000 cycles at 1 A g-1. This research proposes a modification method for developing advanced separators in AZIBs technology.

Electrolyte Engineering with TFA- Anion-Rich Solvation Structure to Construct Highly Stable Zn2+/Na+ Dual-Salt Batteries

Electrolyte engineering is recognized as an effective technique for high-performance aqueous zinc-ion rechargeable batteries, addressing difficulties such as free water decomposition, zinc anode corrosion, and zinc dendrite growth. Different from traditional strategies in aqueous electrolyte systems, this work focuses on organic electrolytes involving zinc trifluoroacetate hydrate (Zn(TFA)2·xH2O), sodium trifluoroacetate (NaTFA) dual-salt and acetonitrile (AN) solvent, in which trifluoroacetate anions (TFA- anions) have strong affinity toward zinc ions to form anion-rich solvates, thus inducing an inorganic-rich solid electrolyte interphase (SEI) to protect Zn from dendrite growth and side reactions. The Zn anode manifests long-term cycling over 2400 h at a current density of 0.5 mA cm-2 with a high Coulombic efficiency (CE) of 99.75%, showing an areal capacity as high as 5 mAh cm-2. Owing to the high reversibility of the sodium ions intercalation/deintercalation process in Na2MnFe(CN)6, the Zn//Na2MnFe(CN)6 full cells with the dual-salt electrolyte perform much better in terms of capacity retention than a device with Zn(TFA)2/AN electrolyte. This approach may open a new avenue for efficient zinc-ion rechargeable batteries via developing organic electrolytes.

Modulating Interfacial Zn2+ Desolvation and Transport Kinetics through Coordination Interaction toward Stable Anodes in Aqueous Zn-Ion Batteries

Aqueous Zn-ion batteries (AZIBs) are promising candidates for grid-scale energy-storage applications, but uneven Zn2+ flux distribution and undesirable water-related interfacial side reactions seriously hinder their practical application. Herein, a strategy of regulating the coordination interaction between Zn2+ and artificial interphase layers (AILs) to modulate the interfacial Zn2+ desolvation/transport behaviors and relieve side reactions for building stable Zn anodes is proposed. By selectively choosing appropriate polymers with different functional groups, it is shown that compared with the strong interaction offered by aryl groups in polystyrene-based AILs, cyano groups in polyacrylonitrile (PAN)-based AILs provide a moderate coordination interaction with Zn2+, which not only accelerates interfacial Zn2+desolvation kinetics but also enables efficient Zn2+ transport within AILs. Moreover, the Zn2+ transport kinetics of PAN-based AILs can be further enhanced with the incorporation of an ionic conductor, zinc phosphate (ZP). Because of these advantages, the Zn anodes decorated with the hybrid AILs composed of PAN and ZP can steadily operate for >2000 h at 0.2 mA cm-2 and >350 h at a high current density of 10 mA cm-2. This work provides a valuable guideline for selective design of AILs at the molecular level for durable AZIBs.

Surface engineering of zinc plate by self-growth three-dimensional-interconnected zinc silicate nanosheets effectively guiding the deposition of zinc ion for aqueous Zn metal battery

Among battery technologies, aqueous zinc ion batteries (AZIBs) have hit between the eyes in the next generation of extensive energy storage devices due to their outstanding superiority. The main problem that currently restricts the development of AZIBs is how to obtain stable Zn anodes. In this study, taking the improvement of a series of problems caused by the physically attached artificial interfacial layer on Zn anode as a starting point, a nanosheet morphology of ZnSiO3 (denoted as ZnSi) is constructed by self-growth on Zn foil (Zn@ZnSi) by a simple hydrothermal reaction. The ZnSi nano-interfacial layer effectively slices the surface of the Zn foil into individual microscopic interfacial layers, constructing abundant pores. The nanosheets of Zn@ZnSi construct rich nanoscale Zn2+ transport channels, which provide higher electron and ion transport paths, thus achieving the effect of effectively homogenizing the electric field distribution and decreasing the local current density. Thanks to its inherent and structural properties, the Zn@ZnSi anode has a high specific capacity and good cycling stability compared with the Zn electrode. The lifetime of the Zn@ZnSi//Zn@ZnSi symmetric cell is much higher than that of the Zn//Zn symmetric cell at 1 mA cm-2. The capacity of the Zn@ZnSi//NH4V4O10 full cell can still reach 98 mAh g-1 after 1000 cycles at 1 A/g. The low-cost and scalable synthesis of ZnSi nano-interfacial layer on Zn is expected to provide new perspectives on interfacial engineering for Zn anodic protection.

Ion-Sieving Separator Functionalized by Natural Mineral Coating toward Ultrastable Zn Metal Anodes

Aqueous zinc-ion batteries (AZIBs) exhibit promising prospects in becoming large-scale energy storage systems due to environmental friendliness, high security, and low cost. However, the growth of Zn dendrites and side reactions remain heady obstacles for the practical application of AZIBs. To solve these challenges, a functionalized Janus separator is successfully constructed by coating halloysite nanotubes (HNTs) on glass fiber (GF). Impressively, the different electronegativity on the inner and outer surfaces of HNTs endows the HNT-GF separator with ion-sieving property, leading to a significantly high transference number of Zn2+ (tZn2+ = 0.71). Meanwhile, the HNT-GF separator works as an interfacial ion comb to regular Zn2+ flux and realizes multisite progressive nucleation, bringing decreased nucleation overpotential and uniform Zn2+ deposition. Consequently, the HNT-GF separator enables the Zn anode to display an ultralong plating/stripping life of 3000 h and high rate tolerance with a stable long cycle life even under a density of 50 mA cm-2. Moreover, the Z n ∥ H N T - G F ∥ M n O 2 full cell represents an ultrastable cycling stability with a high capacity retention of 93.4% even after 1000 cycles at a current density of 2 A g-1. This work provides a convenient method for the separator modification of AZIBs.

Phosphorus and nitrogen supramolecule for fabricating flame-retardant, transparent and robust polyvinyl alcohol film

Supramolecular flame retardants have attracted increasing attention recently due to their simple and eco-friendly preparation process. In this study, a novel flame retardant HEPFR was prepared using supramolecular self-assembly technology between piperazine and 1-hydroxy ethylidene-1,1-diphosphonic acid (HEDP). It was introduced into polyvinyl alcohol (PVA) matrix to form PVA/HEPFR composite film. Subsequently, the transparency, mechanical properties, thermal stability, and flame retardancy of PVA/HEPFR films were studied. Due to the hydrogen bonded cross-linked network structure between PVA and HEPFR, the mechanical properties of PVA/HEPFR films have been improved, while maintaining good transparency. With 10 wt% addition of HEPFR, PVA films can reach the VTM-0 level in UL-94 testing. And the limiting oxygen index can be increased from 18.5% of pure PVA to 26.5%. The peak heat release rate was reduced by 61.5%. The flame retardancy and thermal stability of PVA/HEPFR films have been greatly improved. This study provides a "one stone, three birds" strategy for preparing flame-retardant, transparent, and robust PVA film.

Berlin Green with tunable iron content as ultra-high rate host for efficient aqueous ammonium ion storage

Prussian blue analogues (PBAs) are regarded as promising cathode materials for ammonium-ion batteries (AIBs) because of their low cost and superb theoretical capacity. However, its inherently poor conductivity and structural collapse can significantly limit the enhancement of rate property and cycling stability. In this work, Berlin Green (BG) electrode materials with similar wool-like clusters were constructed by direct precipitation method to accelerate the kinetic, which realizes outstanding cycling stability. Berlin Green with the appropriate amount of iron (BG-2) has a fast ion transport channel, enhanced structure stability, highly reversible insertion/extraction of NH4+, and fine electrochemical reaction activity. Benefiting from the unique architecture and component, the BG-2 electrode shows an excellent rate performance with a discharge/charge specific capacity of 60.1/59.3 mAh g-1 at 5 A g-1. Even at 5 A g-1, BG-2 exhibits remarkable cycling stability with an initial discharge capacity of 59.5 mAh g-1 and a capacity retention rate of approximately 76% after 30,000 cycles. The BG-2 reveals exceedingly good electrochemical reversibility during the process of NH4+ (de)insertion. BG materials indicate huge potential as a cathode material for the next generation of high-performance aqueous batteries.

Stabilizing Zinc Anode through Ion Selection Sieving for Aqueous Zn-Ion Batteries

Uncontrollable dendrite growth and corrosion induced by reactive water molecules and sulfate ions (SO42-) seriously hindered the practical application of aqueous zinc ion batteries (AZIBs). Here we construct artificial solid electrolyte interfaces (SEIs) realized by sodium and calcium bentonite with a layered structure anchored to anodes (NB@Zn and CB@Zn). This artificial SEI layer functioning as a protective coating to isolate activated water molecules, provides high-speed transport channels for Zn2+, and serves as an ionic sieve to repel negatively charged anions while attracting positively charged cations. The theoretical results show that the bentonite electrodes exhibit a higher binding energy for Zn2+. This demonstrates that the bentonite protective layer enhances the Zn-ion deposition kinetics. Consequently, the NB@Zn//MnO2 and CB@Zn//MnO2 full-battery capacities are 96.7 and 70.4 mAh g-1 at 2.0 A g-1 after 1000 cycles, respectively. This study aims to stabilize Zn anodes and improve the electrochemical performance of AZIBs by ion-selection sieving.

Organic solid-electrolyte interface layers for Zn metal anodes

Zinc ion batteries (ZIBs) have emerged as promising candidates for renewable energy storage owing to their affordability, safety, and sustainability. However, issues with Zn metal anodes, such as dendrite growth, hydrogen evolution reaction (HER), and corrosion, significantly hinder the practical application of ZIBs. To address these issues, organic solid electrolyte interface (SEI) layers have gained traction in the ZIB community as they can, for instance, help achieve uniform Zn plating/stripping and suppress side reactions. This article summarizes recent advances in organic artificial SEI layers for ZIB anodes, including their fabrication methods, electrochemical performance, and degradation suppression mechanisms.

Woven fabric-based separators with low tortuosity for sodium-ion batteries

In order to achieve high-performance and stable sodium-ion batteries, numerous attempts have been made to construct continuous ion transport pathways, in which a separator is one of the key components that affects the battery performance. In this study, a novel low-tortuosity woven fabric separator is fabricated by combining a weaving technique with a cellulose-solution method, followed by an infusion of a TEMPO-oxidized bacterial cellulose slurry into woven fabric substrates. The macropores in the fabric combine with the micropores in the oxidized bacterial cellulose to form a separator with a suitable pore structure and low tortuosity, forming a continuous sodium ion transport channel within the sodium-ion battery and effectively enhancing ion transport dynamics. The results show that, compared with a commercial polypropylene separator, the TEMPO-oxidized bacterial cellulose-woven fabric separator has a special weaving structure and lower tortuosity (0.77), as well as significant advantages in tensile strength (3.07 MPa), ionic conductivity (1.15 mS c), ionic transfer number (0.75), thermal stability, and electrochemical stability. This novel and simple preparation method provides new possibilities for achieving high-performance separators of sodium-ion batteries through rational structural design by textile technology.