Aqueous Zn Research Articles

Use of sludge stabilization products for remediation of heavy metal (loid)s-contaminated mine tailings: Physicochemical, biochemical and microbial mechanisms

The sludge stabilization products (hereinafter referred to “Composts”) added in different addition ratios (30 %, 50 % and 80 %) were applied to remediate the heavy metal(loid)s-contaminated mine tailings. Physicochemical, biochemical and microbial characteristics at day 0 and 180 were systematically investigated. The Composts added in different ratios could all remediate the mine tailings in terms of significantly decreased bulk density, increased organic matters, porosity, germination index, pH and DHA activity, as well as obviously declined aqueous extractable Cu, Pb, As, Cd, Hg, Cr, Zn and Ni (p < 0.05). Taken phytotoxicity alleviation and metal (loid)s mobility inhibition into consideration, the 50 % Composts was the most recommended in this study, with the highest reduction (82.9 %∼91.4 %) in aqueous heavy metal (loid)s concentration comparted to the un-amended. The transformation of Cu, Pb, As, Cd and Hg from exchangeable to more stable forms (especially organically-bound form), due to their enhanced complexation with humus through promoted organic matters aromatization, was considered to drive the alleviation of their leaching pollution in mine tailing soil. While the declined aqueous extractable Cr, Zn and Ni were more likely ascribed to the increased pH value. Further, different from fungal communities not sensitive during remediation, the highest porosity and DHA activity by the 50 % Composts amendment benefited the improved archaeal diversity and enriched bacterial family Bacillaceae (capable of heavy metals biomineralization), further significantly (p < 0.05) contributing to the decrease in Cd mobility. Overall, this study highlights the effective role of the Composts in alleviating heavy metal(loid)s pollution in mine tailings and further clarifies the multiple mechanisms including immobilization, pH adjusting and microbial effects.

Promoting the circular economy: Valorization of a residue from industrial char to activated carbon with potential environmental applications as adsorbents

Pyrolysis of residues enriched with carbon, such as in agroforestry or industrial activities, has been postulated as an emerging technology to promote the production of biofuels, contributing to the circular economy and minimizing waste. However, during the pyrolysis processes a solid fraction residue is generated. This work aims to study the viability of these chars to develop porous carbonaceous materials that can be used for environmental applications. Diverse chars discharged by an industrial pyrolysis factory have been activated with KOH. Concretely, the char residues came from the pyrolysis of olive stone, pine, and acacia splinters, spent residues fuel, and cellulose artificial casings. The changes in the textural, structural, and composition characteristics after the activation process were studied by N2 adsorption-desorption isotherms, scanning electron microscopy, FTIR, elemental analysis, and XPS. A great porosity was developed, SBET within 776–1186 m2 g−1 and pore volume of 0.37–0.59 cm3 g−1 with 70–90% of micropores contribution. The activated chars were used for the adsorption of CO2, leading to CO2 maximum uptakes of 90–130 mg g−1. There was a good correlation between the CO2 uptake with microporosity and oxygenated surface groups of the activated chars. Moreover, their ability to adsorption of contaminants in aqueous solution was also evaluated. Concretely, there was studied the adsorption of aqueous heavy metals, i.e., Cd, Cu, Ni, Pb, and Zn, and organic pollutants of emerging concern such as caffeine, diclofenac, and acetaminophen.

Zinc‐Coordinated Imidazole‐Based Ionic Liquid as Liquid Salt for All‐Temperature Aqueous Zinc‐Ion Batteries

AbstractOwing to the intrinsically high safety, low cost, natural abundance, and high energy density of Zn metal, aqueous Zn ion batteries (AZIBs) have become a promising candidate for large‐scale energy conversion and storage. However, the practical application of AZIBs is hampered by the severe Zn dendrites growth and the poor low‐temperature performance due to the elevated freezing point of aqueous electrolyte. Herein, the study proposes a new kind of room‐temperature liquid Zn salt, which is called Zn coordinated ionic liquid (i.e., (EMIM)5Zn(OTF)7), for all‐temperature AZIBs. The aqueous electrolyte containing 0.261 mol kg−1 (EMIM)5Zn(OTF)7 in Ethylene Glycol (EG) / H2O (6:4) exhibits ultralow freezing point below −100 °C. The liquid Zn salt and EG molecules not only modulate the solvation structure of Zn2+ ion, reducing the coordinated H2O in the first solvation sheath, but also suppresses the parasitic side reaction. As a proof of concept, Zn || Zn symmetric cells and Zn || PANI full cells with the designed electrolyte achieve improved cycling stability and can operate under wide temperature (from −40 to 60 °C). Even with high Zn utilization ratio of 40%, long cycle life over 70 times with capacity retention of 80% is achieved.

Energy-dense aqueous Zn//MnO2 rechargeable battery constructed on dual three-dimensional conductive skeletons

Enhancing the energy density of aqueous rechargeable zinc-based batteries is critical for boosting their application in a variety of practical scenarios. Herein we demonstrate a strategy to improve specific energies of Zn//MnO2 batteries in mild electrolyte via utilizing three-dimensional (3D) current collectors for both the anode and cathode. By electrodepositing limited amounts of Zn on surface-alloyed Ag mesh and coupling it with MnO2 cathode electrodeposited on carbon cloth with no binder, the resultant batteries exhibit specific energy up to 253 and 196 Wh/kg (based on total mass of active materials) at negative-to-positive electrode capacity (N/P) ratios of 1:1 and 2:1. By elevating the working temperature to 35 °C, the specific energy and life span of the battery with N/P = 2 can be further increased to 216 Wh/kg and >225 cycles, respectively. The key to achieving a high specific energy relies primarily on the great reversibility of the Zn anode, which is conferred by the 3D Ag mesh.

A New Design Strategy Enables High Mn‐Utilization Rate in Aqueous Zinc–Manganese Batteries: Constructing Cathodic Local Mn‐Rich Region

AbstractThe deposition–dissolution mechanism with a two‐electron transfer reaction endows aqueous Zn–Mn batteries with a desirable theoretical energy density. However, due to the limited solubility of traditional manganese‐based materials and the competitive Mn shuttle behavior, the practical performance is unsatisfactory. Herein, by synergistically incorporating a novel Mn‐rich Mn4N cathode with a plasma functionalized carbon nanotubes film (PCNT) interlayer, an aqueous Zn–Mn battery with a high Mn‐utilization rate and high energy/power density is successfully developed. Specifically, the Mn4N cathode boasts high manganese content and dissolution activity, thereby offering a copious supply of Mn2+ ions for the battery system. The PCNT interlayer, with abundant micropore structures and functional groups, not only restrains the Mn2+ shuttle by entrapping the dissolved Mn2+ but also offers copious reaction sites, ensuring concentrating Mn2+ on the cathodic side and maximizing their contribution to the electrochemical reaction. Consequently, Mn4N‐PCNT exhibits a low polarization voltage and superior Mn‐utilization rate (64.8%). Without the MnSO4 additive, Mn4N‐PCNT achieves an ultra‐high energy density of 821.9 W h kg−1 and remarkable long‐term cycling stability (90% capacity retention over 9000 cycles). The delightful results demonstrate the practical application potential of Mn4N‐PCNT and open up new avenues for the rational design of advanced Zn–Mn batteries.

Boosting the reversibility of Zn anodes via synergistic cation–anion interface adsorption with addition of multifunctional potassium polyacrylate

Rechargeable aqueous Zn batteries have the edge in resource reserve, cost, energy and conversion efficiency due to the inherent features of metal Zn anodes. However, the application of Zn-based batteries is being seriously hindered by Zn dendrites and water-induced side-reactions. Here, potassium polyacrylate (K-PAM) is proposed as the electrolyte additive to form a synergistic cation–anion interface on Zn surface. The carboxyl anions and K+ cations are preferentially adsorbed on the Zn surface due to the intrinsic surfactant characteristics, which could homogenize Zn plating and suppress parasitic reactions. The synergistic regulation of K-PAM additive endows the ZnZn symmetric cells with excellent cyclic durability of 1250 h at 1 mA cm−2, which is significantly better than the polyacrylic acid additive only with carboxyl anions. Moreover, trace K-PAM addition into traditional ZnSO4 electrolyte endows the ZnCu batteries with a considerable average Coulombic efficiency of 99.2 %. Additionally, higher capacity retention and excellent cycling stability of ZnVO2 cells further mark K-PAM as a potentially impressive aqueous electrolyte additive for high-performance Zn-based batteries. This work will provide a promising method for the synergistic regulation with cations and anions of electrolyte additives to improve the stability and reversibility of Zn anodes.

An Iodine‐Chemisorption Binder for High‐Loading and Shuttle‐Free Zn–Iodine Batteries

AbstractAqueous zinc–iodine (Zn–I2) batteries have attracted considerable research interest as an alternative energy storage system due to their high specific capacity, intrinsic safety, and low cost. However, the notorious shuttle effect of soluble polyiodides causes severe capacity loss and poor electrochemical reversibility, restricting their practical usage. Herein, this study reports a bifunctional binder (polyacrylonitrile copolymer, as known as LA133) with strong iodine‐chemisorption capability for aqueous Zn–I2 batteries to suppress polyiodide shuttling. From both calculation and experimental data, this study reveals that the amide and carboxyl groups in LA133 binder can strongly bond to polyiodides, significantly immobilizing them at cathode side. As a result, fewer byproducts, slower hydrogen evolution, and lesser Zn dendrite in the Zn–I2 battery are observed. Consequently, the battery shows high specific capacity (202.8 mAh g−1) with high iodine utilization efficiency (96.1%), and long cycling lifespan (2700 cycles). At the high mass loading of 7.82 mg cm−2, the battery can still retain 83.3% of its initial capacity after 1000 cycles. The specific capacity based on total cathode slurry mass reaches 71.2 mAh g−1, higher than most of the recent works. The strategy opens a new avenue to address the shuttling challenge of Zn–I2 batteries through bifunctional binder.

Dendrite-free zinc deposition enabled by MXene/nylon scaffold and polydopamine solid-electrolyte interphase for flexible zinc-ion batteries

The rapid growth of wearable and portable electronic devices calls for energy storage devices with good flexibility, high energy density, and safety. Rechargeable aqueous Zn ion batteries (ZIBs) with the merits of environmental benignity, high safety, and low cost have arisen as promising energy storage candidates for wearable electronic systems. However, the unstable Zn anode interface and notorious Zn dendrite formation hinder the application of flexible ZIBs. Herein, a highly stable and flexible Zn anode is developed by taking advantage of highly conductive Ti3C2 MXene coated nylon fabric (MXNY) as a three-dimensional (3D) Zn deposition skeleton and polydopamine (PDA) as a solid electrolyte interface (SEI). The combination of MXNY and PDA SEI provides synergistic benefits such as a stabilized interface for homogenous and dendrite-free Zn deposition and improved corrosion resistance. As a result, a flexible and stable Zn anode with improved Coulombic efficiency of 99.6 % at a current density of 10 mA cm–2 for 1 mA h cm–2, and long cycling stability of more than 3000 h at a current density of 0.5 mA cm–2 for 0.5 mA h cm–2 can be achieved. When paired with a flexible cathode, the quasi-solid-state ZIB can power various electronic devices under different mechanical deformations, indicating its promising potential as flexible energy storage devices for wearable and portable electronics.

Modulating metal-free Zn-bromine batteries with covalent organic framework anode

Recently, deploying a reversible Zn2+-host anode to fabricate metal-free aqueous Zn ion batteries (AZIBs) provides an effective solution to solve the hindrances of Zn metal anode. However, the unsatisfactory energy density (<100 Wh kg−1) of assembled metal-free AZIBs is limited by low operated voltage of device (0.8∼1 V) and insufficient capacity of anode (<150 mAh g−1). Herein, for the first time, we proposed a polyimide covalent organic framework (Tp-DANT-COF) with multiple redox centers (C=O) as metal-free anode. It is found that the highly order interlayer structure, robust covalent framework and extended π-conjugated domain play key roles to facilitate ion/electron transport, structural integrity and active centers accessibility. As results, the COF anode exhibits an excellent specific capacity of 235.7 mAh g−1 at 0.1 A g−1, superior rate performance of 179.1 mAh g−1 even at 10 A g−1 and cycling stability over 10,000 cycles. Besides, the dual cation charge storage mechanism and favorable co-accommodate configuration of Zn2+/H+ are revealed by various characterizations and theory calculation. Importantly, matched to bromine cathode (AC-KBr) with high redox potential, the fabricated Tp-DANT-COF//AC-KBr full device achieves high energy density of 110.9 Wh kg−1 with 1.2 V operating voltage, exceeding the most reported congenerical devices.

Insight into Sulfur-Containing Zwitter-Molecule Boosting Zn Anode: from Electrolytes to Electrodes.

Numerous organic electrolytes additives have been reported to improve Zn anode performance in aqueous Zn metal batteries (AZMBs). However, the modification mechanism needs to be further revealed in consideration of different environments for electrolytes and electrodes during the charge-discharge process. Herein, sulfur-containing zwitter-molecule (methionine, Met) is used as an additive for ZnSO4 electrolytes. In electrolytes, Met reduces the H2O coordination number and facilitates the desolvation process by virtue of functional groups (─COOH, ─NH2, C─S─C), accelerating Zn2+ transference kinetics and decreasing the amount of active water. On electrodes, Met prefers to adsorb on Zn (002) plane and further transforms into a zincophilic protective layer containing C─SOx─C through an in situ electrochemical oxidization, suppressing H2 evolution/corrosion reactions and guiding dendrite-free Zn deposition. By using Met-containing ZnSO4 electrolytes, the Zn//Zn cells show superior cycling performance under 30mAcm-2/30mAhcm-2. Moreover, the full cells Zn//NH4V4O10 full cells using the modified electrolytes exhibit good performance at temperatures from -8 to 60°C. Notably, a high energy density of 105.30Whkg-1 can be delivered using a low N/P ratio of 1.2, showing a promising prospect of Met electrolytes additives for practical use.

Enabling Stable Zn Anode with PVDF/CNTs Nanocomposites Protective Layer Toward High‐Performance Aqueous Zinc‐Ion Batteries

AbstractDue to its abundance of natural resources, high theoretical capacity, and suitable redox potential (−0.76 V vs SHE), Zn anode has received extensive attention both from academy and industry. However, the coexistence of Zn and H2O, which is unfortunately thermodynamically unstable, always involves severe metal corrosion, H2 evolution, dendrite growth, resulting in low reversibility of Zn anode. Herein, a phase transfer method is adapted to design a porous conductive protective layer on the Zn anode, denoted as (PVDF (Polyvinylidene fluoride)/CNTs(Carbon Nanotubes)‐PT(phase transfer) @ Zn). Based on in situ characterization, COMSOL simulation, and migration energy barrier calculation, it can be demonstrated that PVDF/CNTs‐PT @ Zn effectively inhibited the production of Zn dendrites and the side reactions triggered by H2O, achieving uniform deposition. Especially, the full picture of Zn deposition is observed using in situ computed tomography (CT). The symmetrical cell using the PVDF/CNTs‐PT @ Zn demonstrates dendrite‐free plating/stripping and possesses much better cycle stability than the bare Zn. A stable rechargeable full battery is demoed through coupling the PVDF/CNTs‐PT @ Zn anode with commercial V2O5. The strategy showcases a feasible pathway to inhibit Zn dendrite and side reactions in aqueous Zn ion battery, opening a promising avenue for the construction of metal anode protection layer.

Bimetal-Initiated Concerted Zn Regulation Enabling Highly Stable Aqueous Zn-Ion Batteries

Aqueous zinc ion batteries are highly sought after for the next generation of sustainable energy storage systems. However, their development is significantly impeded by the presence of undesired zinc dendrites, which greatly reduce their cycle life. It is well-received that surface passivation by introducing foreign metals represents a compelling measure to enhance the stability of Zn anodes. Nevertheless, the vast potential of effecting concerted interplay between multiple metal elements for enhanced overall performance in Zn ion batteries remains elusive, due to the overwhelming challenge in creating uniform textures from hetero-units and understanding the mechanism underlying the synergistic performance gain. In this work, an innovative bimetallic overlaying strategy is proposed that renders possible the synergy between AgZn3 and CuZn5 in effecting uniform Zn deposition in a laterally confined and compact manner. The seeded growth of Zn on the bimetal-modulated interface effectively reduces the nucleation potential barrier, yielding a low nucleation overpotential (25 mV). In full cell testing with a commercial MnO2 applied as the cathode, superb cycling stability, surpassing the results reported in previous works, is achieved. The cell delivers an outstanding remaining capacity of 215 mA h g−1 after 300 cycles with almost no capacity degradation observed. The simple and highly efficient bimetal design, which synergizes the strengths of distinct metals, has the potential to drive innovations in the development of multicomponent aqueous Zn batteries with exceptional performance.

Multifunctional Cellulose Nanocrystals Electrolyte Additive Enable Ultrahigh-Rate and Dendrite-Free Zn Anodes for Rechargeable Aqueous Zinc Batteries.

The design of aqueous zinc (Zn) chemistry energy storage with high rate-capability and long serving life is a great challenge due to its inhospitable coordination environment and dismal interfacial chemistry. To bridge this big gap, herein, we build a highly reversible aqueous Zn battery by taking advantages of the biomass-derived cellulose nanocrystals (CNCs) electrolyte additive with unique physical and chemical characteristics simultaneously. The CNCs additive not only serves as fast ion carriers for enhancing Zn2+ transport kinetics but regulates the coordination environment and interface chemistry to form dynamic and self-repairing protective interphase, resulting in building ultra-stable Zn anodes under extreme conditions. As a result, the engineered electrolyte system achieves a superior average coulombic efficiency of 97.27 % under 140 mA cm-2, and steady charge-discharge for 982 h under 50 mA cm-2, 50 mAh cm-2, which proposes a universal pathway to challenge aqueous Zn chemistry in green, sustainable, and large-scale applications.

Multifunctional Cellulose Nanocrystals Electrolyte Additive Enable Ultrahigh‐Rate and Dendrite‐Free Zn Anodes for Rechargeable Aqueous Zinc Batteries

AbstractThe design of aqueous zinc (Zn) chemistry energy storage with high rate‐capability and long serving life is a great challenge due to its inhospitable coordination environment and dismal interfacial chemistry. To bridge this big gap, herein, we build a highly reversible aqueous Zn battery by taking advantages of the biomass‐derived cellulose nanocrystals (CNCs) electrolyte additive with unique physical and chemical characteristics simultaneously. The CNCs additive not only serves as fast ion carriers for enhancing Zn2+ transport kinetics but regulates the coordination environment and interface chemistry to form dynamic and self‐repairing protective interphase, resulting in building ultra‐stable Zn anodes under extreme conditions. As a result, the engineered electrolyte system achieves a superior average coulombic efficiency of 97.27 % under 140 mA cm−2, and steady charge–discharge for 982 h under 50 mA cm−2, 50 mAh cm−2, which proposes a universal pathway to challenge aqueous Zn chemistry in green, sustainable, and large‐scale applications.

Dynamically Ion‐Coordinated Bipolar Organodichalcogenide Cathodes Enabling High‐Energy and Durable Aqueous Zn Batteries

AbstractBipolar organic cathode materials (OCMs) implementing cation/anion storage mechanisms are promising for high‐energy aqueous Zn batteries (AZBs). However, conventional organic functional group active sites in OCMs usually fail to sufficiently unlock the high‐voltage/capacity merits. Herein, we initially report dynamically ion‐coordinated bipolar OCMs as cathodes with chalcogen active sites to solve this issue. Unlike conventional organic functional groups, chalcogens bonded with conjugated group undergo multielectron‐involved positive‐valence oxidation and negative‐valence reduction, affording higher redox potentials and reversible capacities. With phenyl diselenide (PhSe‐SePh, PDSe) as a proof of concept, it exhibits a conversion pathway from (PhSe)− to (PhSe‐SePh)0 and then to (PhSe)+ as unveiled by characterization and theoretical simulation, where the diselenide bonds are periodically broken and healed, dynamically coordinating with ions (Zn2+ and OTF−). When confined into ordered mesoporous carbon (CMK‐3), the dissolution of PDSe intermediates is greatly inhibited to obtain an ultralong lifespan without voltage/capacity compromise. The PDSe/CMK‐3 || Zn batteries display high reversibility capacity (621.4 mAh gPDSe−1), distinct discharge plateau (up to 1.4 V), high energy density (578.3 Wh kgPDSe−1), and ultralong lifespan (12 000 cycles) at 10 A g−1, far outperforming conventional bipolar OCMs. This work sheds new light on conversion‐type active site engineering for high‐voltage/capacity bipolar OCMs towards high‐energy AZBs.

Dynamically Ion-Coordinated Bipolar Organodichalcogenide Cathodes Enabling High-Energy and Durable Aqueous Zn Batteries.

Bipolar organic cathode materials (OCMs) implementing cation/anion storage mechanisms are promising for high-energy aqueous Zn batteries (AZBs). However, conventional organic functional group active sites in OCMs usually fail to sufficiently unlock the high-voltage/capacity merits. Herein, we initially report dynamically ion-coordinated bipolar OCMs as cathodes with chalcogen active sites to solve this issue. Unlike conventional organic functional groups, chalcogens bonded with conjugated group undergo multielectron-involved positive-valence oxidation and negative-valence reduction, affording higher redox potentials and reversible capacities. With phenyl diselenide (PhSe-SePh, PDSe) as a proof of concept, it exhibits a conversion pathway from (PhSe)- to (PhSe-SePh)0 and then to (PhSe)+ as unveiled by characterization and theoretical simulation, where the diselenide bonds are periodically broken and healed, dynamically coordinating with ions (Zn2+ and OTF-). When confined into ordered mesoporous carbon (CMK-3), the dissolution of PDSe intermediates is greatly inhibited to obtain an ultralong lifespan without voltage/capacity compromise. The PDSe/CMK-3 || Zn batteries display high reversibility capacity (621.4 mAh gPDSe -1), distinct discharge plateau (up to 1.4 V), high energy density (578.3 Wh kgPDSe -1), and ultralong lifespan (12 000 cycles) at 10 A g-1, far outperforming conventional bipolar OCMs. This work sheds new light on conversion-type active site engineering for high-voltage/capacity bipolar OCMs towards high-energy AZBs.

Activating the redox chemistry of MnO2/Mn2+ in aqueous Zn batteries based on multi-ions doping regulation

Two electron reaction of MnO2/Mn2+ have attracted burgeoning attention, which endows rechargeable aqueous Zn-MnO2 batteries with high energy density besides intrinsic safety, and environmental friendliness. However, it also suffers uncontrolled anode corrosion, sluggish ion diffusion and irreversible structural transformation, leading to poor rate capability and severe fading. Herein, a multi-ions regulated MnO2 (CrNi-MnO2) is designed via a novel two-step electrochemical method under theoretical guidance, contributing to the enhanced electrochemical performance of Zn-MnO2 batteries in terms of dissolution-deposition chemistry. CrNi-MnO2 cathode can significantly improve the conductivity and lower electrostatic interaction, boosting the rate performance and cycling stability. Furthermore, reversible Cr3+/Cr2+ reaction can effectively reduce the accumulation of “dead” MnO2, which can promote the transformation of MnO2/Mn2+ thoroughly in acid-mild electrolyte. Various ex-situ analyses and theory calculations have revealed double-functional role of the doped ions for accelerating MnO2/Mn2+ transformation and Zn2+/H+ co-insertion kinetics. Hence, CrNi-MnO2 cathode exhibits ultra-high capacity, superior rate performance, and excellent cycling stability, providing new insight for developing superb Zn-MnO2 batteries.

Establishing Pinhole Deposition Mode of Zn via Scalable Monolayer Graphene Film.

The uneven texture evolution of Zn during electrodeposition would adversely impact upon the lifespan of aqueous Zn metal batteries. To address this issue, tremendous endeavors are made to induce Zn(002) orientational deposition employing graphene and its derivatives. Nevertheless, the effect of prototype graphene film over Zn deposition behavior has garnered less attention. Here, it is attempted to solve such a puzzle via utilizing transferred high-quality graphene film with controllable layer numbers in a scalable manner on a Zn foil. The multilayer graphene fails to facilitate a Zn epitaxial deposition, whereas the monolayer film with slight breakages steers a unique pinhole deposition mode. In-depth electrochemical measurements and theoretical simulations discover that the transferred graphene film not only acts as an armor to inhibit side reactions but also serves as a buffer layer to homogenize initial Zn nucleation and decrease Zn migration barrier, accordingly enabling a smooth deposition layer with closely stacked polycrystalline domains. As a result, both assembled symmetric and full cells manage to deliver satisfactory electrochemical performances. This study proposes a concept of "pinhole deposition" to dictate Zn electrodeposition and broadens the horizons of graphene-modified Zn anodes.

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.

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

HighlightsA stable Zn anode was obtained by patterning Zn foil surfaces and endowing a zincphilic interface in microchannels.The accumulation of electrons in the microchannel and the zincphilic interface promoted preferential heteroepitaxial Zn deposition in the microchannel region and subsequent homoepitaxial Zn deposition on the array surface.The Zn symmetrical cells could undergo repeated plating/stripping for more than 25,000 cycles at the current densities of 10 and 20 mA cm−2.