Zn Deposits Research Articles

Formation of Hierarchical Zn/N‐doped Carbon Hollow Nanofibers towards Dendrite‐Free Zn Metal Anodes

AbstractRechargeable aqueous Zn metal batteries are considered as promising next‐generation energy storage device because of their intrinsic safety and low cost. Nonetheless, the poor lifespan stemming from uncontrollable dendrite growth and inevitable parasitic reactions of metallic Zn impede their large‐scale application. Herein, the formation of the hierarchical lotus root‐like Zn/N‐doped carbon hollow nanofibers‐based paper is reported decorated with interconnected Zn/N‐doped carbon nanocages (denoted as LRZCF@ZCC) as a freestanding host with multifunctionality for Zn metal anode. Of note, the interconnected porous structure mitigates the internal stress to ensure robust structure. Besides, the concave surface of inner LRZCF@ZCC channel facilitates the nucleation of Zn2+ to geometrically guide the Zn deposition. Meanwhile, the well‐distributed metallic Zn and N‐doped carbon species can serve as the zincophilic sites to reduce the nucleation overpotential and avoid the evolution of hydrogen bubbles. As expected, the LRZCF@ZCC exhibits low polarization for the controllable Zn deposition with small voltage hysteresis. Both the symmetric cell and the full cell using this unique host demonstrate long‐term cycling duration and enhanced rate capability.

Enhancing Zn2+ diffusion for dendrite-free zinc anodes via a robust zincophilic clay mineral coating

Clay minerals as artificial solid electrolyte interphase (SEI) layers have played a crucial role in protecting zinc metal anodes for aqueous Zn-ion batteries (AZIBs) due to their unique layered structure, negatively charged lamellas, ion exchange ability, and electronic insulation. However, the clay mineral layers exhibit limited ability to suppress dendrites and side reactions on the Zn anode in the water-based working environment. This limitation is attributed to the severe volumetric expansion, poor mechanical performance, and inferior zinc ion conductivity. To address these issues, montmorillonite (MMT) is intercalated with urea in this study. The resulting dense and robust UMMT coating layer enhances the diffusion of Zn2+ and increases the Zn2+ concentration at the Zn deposition surface through strong absorption of Zn2+ at −C=O and −NH2 active sites. As a result, it facilitates the uniform deposition of Zn2+ and inhibits dendrite growth. Additionally, the UMMT coating layer acts as a desolvation layer, mitigating parasitic reactions originated from active water. Consequently, the UMMT coating layer enables stable Zn plating/stripping compared to MMT layer. In symmetric cells, MMT@Zn electrode exhibits a significantly longer lifespan of over 1300 h at 6 mA cm−2 with a capacity of 3 mAh cm−2. Furthermore, it demonstrates enhanced cyclic performance of 254 mAh g−1 at 10 A g−1 after 4000 cycles in Zn//V2O5 full cells. This present work presents a strategy to intercalate small-molecule organics into clay minerals, enhancing their protective capacity and expanding their application as SEI layers in AZIBs.

Understanding the Electrical Mechanisms in Aqueous Zinc Metal Batteries: From Electrostatic Interactions to Electric Field Regulation.

Aqueous Zn metal batteries are considered as competitive candidates for next-generation energy storage systems due to their excellent safety, low cost, and environmental friendliness. However, the inevitable dendrite growth, severe hydrogen evolution, surface passivation, and sluggish reaction kinetics of Zn metal anodes hinder the practical application of Zn metal batteries. Detailed summaries and prospects have been reported focusing on the research progress and challenges of Zn metal anodes, including electrolyte engineering, electrode structure design, and surface modification. However, the essential electrical mechanisms that significantly influence Zn2+ ions migration and deposition behaviors have not been reviewed yet. Herein, in this review, the regulation mechanisms of electrical-related electrostatic repulsive/attractive interactions on Zn2+ ions migration, desolvation, and deposition behaviors are systematically discussed. Meanwhile, electric field regulation strategies to promote the Zn2+ ions diffusion and uniform Zn deposition are comprehensively reviewed, including enhancing and homogenizing electric field intensity inside the batteries and adding external magnetic/pressure/thermal field to couple with the electric field. Finally, future perspectives on the research directions of the electrical-related strategies for building better Zn metal batteries in practical applications are offered.

Extending Cycling Life Beyond 300000 Cycles in Aqueous Zinc Ion Capacitors Through Additive Interface Engineering.

Developing low-cost and long-cycling-life aqueous zinc (Zn) ion capacitors (AZICs) for large-scale electrochemical energy storage still faces the challenges of dendritic Zn deposition and interfacial side reactions. Here, an interface engineering strategy utilizing a dibenzenesulfonimide (BBI) additive is employed to enhance the stability of the Zn metal anode/electrolyte interface. The first-principles calculation results demonstrate that BBI anions can be chemically adsorbed on Zn metal. Meanwhile, the experimental results confirm that the BBI-Zn interfacial layer converts the original water-richelectric double layer (EDL) into a water-poor EDL, effectively inhibiting the water related parasitic reaction at the electrode/electrolyte interface. In addition, the BBI-Zn interfacial layer introduces an additional Zn ions (Zn2+) migration energy barrier, increasing the Zn2+ de-solvation activation energy, consequently raising the Zn2+ nucleation overpotential, and thus achieving the compact and uniform Zn deposition behavior. Furthermore, the solid electrolyte interphase (SEI) layer derived from the BBI-Zn interfacial layer during cycling can further maintain the interfacial stability of the Zn anode. Owing to the above favorable features, the assembled AZIC exhibits an ultra-long cycling life of over 300000 cycles based on the additive engineering strategy, which shows application prospects in high-performance AZICs.

Establishing an Ion-Sieving Separator by Depositing Oxygen-Deficient SiOx Layer for Stabilized Zinc Metal Anode.

Stable plating/stripping of Zn metal anode remains a great challenge owing to uncontrollable dendrite growth and side reactions. Ion-sieving separators is a unique and promising solution, that possess Zn2+ permeability and promote Zn2+ transport, can effectivelyalleviate the abovementioned problems. Ion-sieving on glass fiber separator by deposition of oxygen-deficient SiOx layer via active screen plasma technology is achieved. While having chemical composition similar to the glass fiber, the SiOx nanoparticles contain oxygen-rich vacancies that promoted dissociation of the adsorbed water and generation of the hydroxyl groups. The negatively-charged hydroxylated SiOx layer can repel SO4 2- and attract Zn2+, which can alleviate the side reactions. The strong interplay between hydroxyl groups and Zn2+ can boost Zn affinity and yield fast Zn2+ transport. Consequently, the SiOx-deposited GF separator enabled dendrite-free Zn deposition morphology, which displays loweroverpotential of 18mV and longer cycling life over 2000h for Zn symmetric cell. Such a separator can also be easily scaled up to prepare the high-performance large-area (4×6 cm2) pouch Zn-based devices, showing remarkable flexibility and practicality.

Sandwich-Structured Anode Enables High Stability and Enhanced Zinc Utilization for Aqueous Zn-Ion Batteries

Constructing a current collector is a promising approach to modifying the zinc anode. However, most collectors exhibit top zinc deposition patterns, leading to unsatisfactory zinc utilization and instability. To address this issue, we have developed a new sandwich deposition approach in which a boron nitride layer (BN layer) is applied onto Cu foils as the current collector, which allows us to achieve the sandwich-structured anode (BN-Zn-Cu). Through experimental characterization and theoretical calculations, the deposition mechanisms of Zn2+ have been explored and verified. The insulating BN layer, the upper layer of the anode, acts as the protective barrier of deposited zinc and accelerates the transmission of zinc ions. The zincophilic Cu substrate, the bottom layer of the anode, promotes Zn deposition without dendrites. Under the synergistic effect of the BN layer and substrate, the sandwich-structured anode enables superior reversibility with 99.49 % coulombic efficiency over 700 cycles and realizes 66.7% zinc utilization at 4 mAh cm−2. Moreover, the assembled BN-Zn-Cu||CNT/MnO2 cells display high stability with an average fading of 0.06% per cycle for 600 cycles. Our work verifies the feasibility of sandwich-structured anodes in enhancing the performance of aqueous zinc-ion batteries, providing an innovative idea for the structural design of metal anodes.

Chaotropic Salt‐Aided “Water‐In‐Organic” Electrolyte for Highly Reversible Zinc‐Ion Batteries Across a Wide Temperature Range

AbstractAqueous zinc‐ion batteries are promising alternatives to lithium‐ion batteries due to their cost‐effectiveness and improved safety. However, several challenges, including corrosion, dendrites, and water decomposition at the Zn anode, hinder their performance. Herein, an approach is proposed, that deviates from the conventional design by adding water into a propylene carbonate‐based organic electrolyte to prepare a non‐flammable “water‐in‐organic” electrolyte. The chaotropic salt Zn(ClO4)2 exploits the Hofmeister effect to promote the miscibility of immiscible liquid phases. Interactions between propylene carbonate and water restrict water activity and mitigate unfavorable reactions. This electrolyte facilitates preferential Zn (002) deposition and the formation of solid electrolyte interphase. Consequently, the “water‐in‐organic” electrolyte achieves a 99.5% Coulombic efficiency at 1 mA cm−2 over 1000 cycles in Zn/Cu cells, and constant cycling over 1000 h in Zn/Zn symmetric cells. A Na0.33V2O5/Zn battery exhibits impressive cycling stability with a capacity of 175 mAh g−1 for 800 cycles at 2 A g−1. Additionally, this electrolyte enables sustainable cycling across a wide temperature range from −20 to 50 °C. The design of a “water‐in‐organic” electrolyte employing a chaotropic salt presents a potential strategy for high‐performance electrolytes in zinc‐ion batteries with a large stability window and a wide temperature range.

Controlling dendrite growth and side reactions in anode-free Zn-ion aqueous batteries with PMMA:Zn coated electrode

In this study, we propose the implementation of a protective layer consisting of a dense polymethylmethacrylate matrix containing Zn ions (PMMA:Zn) on the Cu electrode in Zn-ion aqueous batteries (ZABs). By introducing Zn2+ ions into the PMMA matrix, the PMMA:Zn coating layer exhibited significantly improved ion conductivity, enabling uniform Zn deposition between the PMMA layer and the current collector. This innovative coating effectively mitigated dendrite growth, hydrogen evolution reactions, and ZnO film formation, leading to enhanced electrochemical performance. The half-cell with PMMA:Zn-coated Cu foil exhibited remarkable stability, achieving near 100 % Coulombic efficiency and enhanced rate capability even under high current densities of 10 mA cm−2. Moreover, in an anode-free configuration, the PMMA:Zn coating layer enabled extended cycling life and consistent operation. Furthermore, employing ZnMnO2 cathodes in the full cell configuration demonstrated elevated specific capacity of 257 mAh g−1 at a current density of 1 A g−1 and outstanding capacity retention over 80 % at the 300th cycle. These findings underscore the immense potential of the PMMA:Zn coating layer as a promising strategy for enhancing the performance and reliability of ZABs, thereby opening up possibilities for their practical integration in diverse energy storage systems.

Effects of hydroxy methionine zinc on growth performance, immune response, antioxidant capacity, and intestinal microbiota of red claw crayfish (Procambarus clarkii)

This study aimed to evaluate the effects of varying zinc (Zn) levels on the growth performance, non-specific immune response, antioxidant capacity, and intestinal microbiota of red claw crayfish (Procambarus clarkii (P. clarkii)). Adopting hydroxy methionine zinc (Zn-MHA) as the Zn source, 180 healthy crayfish with an initial body mass of 6.50 ± 0.05 g were randomly divided into the following five groups: X1 (control group) and groups X2, X3, X4, and X5, which were fed the basal feed supplemented with Zn-MHA with 0, 15, 30, 60, and 90 mg kg−1, respectively. The results indicated that following the addition of various concentrations of Zn-MHA to the diet, the following was observed: Specific growth rate (SGR), weight gain rate (WGR), total protein (TP), total cholesterol (TC), the activities of alkaline phosphatase (AKP), phenoloxidase (PO), total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD) and catalase (CAT), the expression of CTL, GPX, and CuZn-SOD genes demonstrated a trend of rising and then declining—with a maximum value in group X4—which was significantly higher than that in group X1 (P < 0.05). Zn deposition in the intestine and hepatopancreas, the activity of GSH-PX, and the expression of GSH-PX were increased, exhibiting the highest value in group X5. The malonaldehyde (MDA) content was significantly reduced, with the lowest value in group X4, and the MDA content of the Zn-MHA addition groups were significantly lower than the control group (P < 0.05). In the analysis of the intestinal microbiota of P. clarkii, the number of operational taxonomic units in group X4 was the highest, and the richness and diversity indexes of groups X3 and X4 were significantly higher than those in group X1 (P < 0.05). Meanwhile, the dietary addition of Zn-MHA decreased and increased the relative abundance of Proteobacteria and Tenericutes, respectively. These findings indicate that supplementation of dietary Zn-MHA at an optimum dose of 60 mg kg−1 may effectively improve growth performance, immune response, antioxidant capacity, and intestinal microbiota richness and species diversity in crayfish.

Insights into ore genesis of the Beishan Pb–Zn deposit in Guangxi, South China: Evidence from Rb–Sr dating and in-situ S–Pb isotopes

The Beishan Pb–Zn deposit, situated in the transitional zone between the Yangtze Block and Cathaysia Block, is a significant source of non-ferrous metal ore in Guangxi, China. The orebodies are hosted within distinct fine- and coarse-grained dolomites, exhibiting layered and lenticular shapes controlled by stratigraphy and structural factors, demonstrating good continuity. No evidence of magmatic activity has been observed in the Beishan deposit. To ascertain the sources of ore-forming materials, age of formation, and genesis of the Beishan deposit, this study employed a systematic approach involving trace element analysis, Rb–Sr dating, and in-situ S–Pb isotope analysis of representative sulfide minerals, namely, sphalerite, pyrite, and galena. The sphalerite within the Beishan deposit displayed enrichment of Cd, Ga, and Ge, while exhibiting depletion of Fe, Mn, and In, indicating a medium–low formation temperature. An in situ S isotope study suggests that sulfur primarily originates from seawater sulfate, with bacterial sulfate reduction (BSR) and thermochemical sulfate reduction (TSR) processes playing a crucial role in mineral deposition. In-situ Pb isotope analysis indicated that Pb was derived from a combination of crustal and mantle sources. Multiple geochemical findings indicate that the Beishan deposit is a typical Mississippi Valley Type (MVT) Pb–Zn deposit. Furthermore, the obtained Rb–Sr isochron age of 330 ± 12 Ma (1σ) indicates that the Beishan deposit was formed during the Hercynian orogeny, aligning with the formation timing of the Siding Pb–Zn deposit in northwestern Guangxi.

Tailoring the solvation shells of dual metal ions for high-performance aqueous zinc ion batteries

For a long time, the issue of dendrites in neutral/mild electrolyte-based aqueous zinc-ion batteries (AZIBs) has been a matter of concern. The dendrites resulting from this problem lead to short-circuit faults and significantly reduce the cycle life, which is quite troublesome. Here, we induce uniform Zn deposition by utilizing the enhanced electrostatic shielding effect of a hybrid additive of Na2SO4 and EDTA. The limited tip-blocking effect of Na+ is due to the higher exchange reaction rate constant (kex) of water molecules in the solvation shell. The coordination of EDTA can provide a more stable solvation shell for Na+, ensuring a stronger blocking effect on Zn deposition at the tip. This enhanced electrostatic shielding effect effectively suppresses the growth of Zn dendrites. In addition, EDTA also enters the solvation shell of Zn2+ and displaces some coordinated water molecules, allowing for more reversible Zn plating/stripping without significant side reactions occurring at the Zn anode.

Guiding Zn Uniform Deposition with Polymer Additives for Long-lasting and Highly Utilized Zn Metal Anodes.

The parasitic side reaction on Zn anode is the key issue which hinders the development of aqueous Zn-based energy storage systems on power-grid applications. Here, a polymer additive (PMCNA) engineered by copolymerizing 2-methacryloyloxyethyl phosphorylcholine (MPC) and N-acryloyl glycinamide (NAGA) was employed to regulate the Zn deposition environment for satisfying side reaction inhibition performance during long-term cycling with high Zn utilization. The PMCNA can preferentially adsorb on Zn metal surface to form a uniform protective layer for effective water molecule repelling and side reaction resistance. In addition, the PMCNA can guide Zn nucleation and deposition along 002 plane for further side reaction and dendrite suppression. Consequently, the PMCNA additive can enable the Zn//Zn battery with an ultrahigh depth of discharge (DOD) of 90.0% for over 420 h, the Zn//active carbon (AC) capacitor with long cycling lifespan, and the Zn//PANI battery with Zn utilization of 51.3% at low N/P ratio of 2.6.

Guiding Zn Uniform Deposition with Polymer Additives for Long‐lasting and Highly Utilized Zn Metal Anodes

AbstractThe parasitic side reaction on Zn anode is the key issue which hinders the development of aqueous Zn‐based energy storage systems on power‐grid applications. Here, a polymer additive (PMCNA) engineered by copolymerizing 2‐methacryloyloxyethyl phosphorylcholine (MPC) and N‐acryloyl glycinamide (NAGA) was employed to regulate the Zn deposition environment for satisfying side reaction inhibition performance during long‐term cycling with high Zn utilization. The PMCNA can preferentially adsorb on Zn metal surface to form a uniform protective layer for effective water molecule repelling and side reaction resistance. In addition, the PMCNA can guide Zn nucleation and deposition along 002 plane for further side reaction and dendrite suppression. Consequently, the PMCNA additive can enable the Zn//Zn battery with an ultrahigh depth of discharge (DOD) of 90.0 % for over 420 h, the Zn//active carbon (AC) capacitor with long cycling lifespan, and the Zn//PANI battery with Zn utilization of 51.3 % at low N/P ratio of 2.6.

Diethylene glycol dimethyl ether effectively regulates the electrochemical behavior of zinc anode

A non-proton polar solvent Diethylene glycol dimethyl ether(DGDE) was used as a cosolvent in aqueous electrolyte, the strong binding of O lone pair electrons in the CO bond to Zn2+ enabled DGDE to participate in the first solvent sheath to reconstruct the Zn2+ solvation structure. Meanwhile, the adsorption of DGDE on the surface of zinc electrode and the steric hindrance effect of DGDE molecule induced the horizontal deposition of hexagonal Zn(002) crystal plane, suppressed the zinc dendrite growth, while formed a dense protective layer on the surface of the zinc electrode to avoid it from the corrosion by the electrolyte. The initial CE of Zn‖Cu semi-battery was increased from 77 % with pure ZnSO4 electrolyte to 87 % with 0.1 M DGDE added at 0.5 mA cm−2 and 1 mAh cm−2, and the average CE at 1 mA cm−2 and 1 mAh cm−2 was maintained at 98.7 % during the long cycle. As cycled at 3C (1C = 308mAh g −1) in 0.1 M DGDE electrolyte, Zn‖ε-MnO2 full battery demonstrated much slower discharge decay, after 580 cycles, the capacity retained 138mAh g −1, 3.5 times of the system of 1 M ZnSO4. Adding trace DGDE to aqueous electrolyte can effectively improve CE and inhibit the zinc dendrite growth, not only maintains the low-cost, quick assembly advantages of aqueous zinc-ion battery, but also lays a foundation for its further application.

Engineering Fluorine‐rich Double Protective Layer on Zn Anode for Highly Reversible Aqueous Zinc‐ion Batteries

AbstractThe high thermodynamic instability and side reactions of Zn‐metal anode (ZMA), especially at high current densities, greatly impede the commercialization of aqueous zinc‐ion batteries (AZIBs). Herein, a fluorine‐rich double protective layer strategy is proposed to obtain the high reversibility of AZIBs through the introduction of a versatile tetradecafluorononane‐1,9‐diol (TDFND) additive in aqueous electrolyte. TDFND molecule with large adsorption energy (−1.51 eV) preferentially absorbs on the Zn anode surface to form a Zn(OR)2− (R=−CH2−(CF2)7−CH2−) cross‐linking complex network, which balances space electric field and controls the Zn2+ ion flux, thus enabling the uniform and compact deposition of Zn (002) crystal planes. Meanwhile, TDFND with low Lowest unoccupied molecular orbital (LUMO, 0.10 eV) energy level is priorly decomposed to regulate the interfacial chemistry of ZMA by building a ZnF2‐rich solid electrode/electrolyte interface (SEI) layer. It is found that a 14 nm‐thick SEI layer delivers excellent structural integrity to suppress parasitic reactions by blocking the direct contact of active water and ZMA. Consequently, the Zn electrode exhibits a superior cycling life over 430 h at 10 mA cm−2 and a high average Coulombic efficiency of 99.8 % at 5 mA cm−2. Furthermore, a 68 mAh pouch cell delivers 80.3 % capacity retention for 1000 cycles.

Engineering Fluorine-rich Double Protective Layer on Zn Anode for Highly Reversible Aqueous Zinc-ion Batteries.

The high thermodynamic instability and side reactions of Zn-metal anode (ZMA), especially at high current densities, greatly impede the commercialization of aqueous zinc-ion batteries (AZIBs). Herein, a fluorine-rich double protective layer strategy is proposed to obtain the high reversibility of AZIBs through the introduction of a versatile tetradecafluorononane-1,9-diol (TDFND) additive in aqueous electrolyte. TDFND molecule with large adsorption energy (-1.51 eV) preferentially absorbs on the Zn anode surface to form a Zn(OR)2- (R= -CH2-(CF2)7-CH2-) cross-linking complex network, which balances space electric field and controls the Zn2+ ion flux, thus enabling the uniform and compact deposition of Zn (002) crystal planes. Meanwhile, TDFND with low Lowest unoccupied molecular orbital (LUMO, 0.10 eV) energy level is priorly decomposed to regulate the interfacial chemistry of ZMA by building a ZnF2-rich solid electrode/electrolyte interface (SEI) layer. It is found that a 14 nm-thick SEI layer delivers excellent structural integrity to suppress parasitic reactions by blocking the direct contact of active water and ZMA. Consequently, the Zn electrode exhibits a superior cycling life over 430 h at 10 mA cm-2 and a high average Coulombic efficiency of 99.8% at 5 mA cm-2. Furthermore, a 68 mAh pouch cell delivers 80.3% capacity retention for 1000 cycles.

Ionic-cellulose-adhesive modulated aqueous electrolyte enables water-poor and stable anion-derived electrolyte interphase for durable and dendrite-free zinc metal batteries

The development of aqueous zinc-ion batteries (ZIBs) as attractive candidates is largely limited by the unstable anode/electrolyte interface (AEI), which causes dendrite formation and by-products. Here, an inexpensive ionic cellulose adhesive, carboxymethylcellulose sodium (CMC), is utilized as an interface stabilizer to controllably manipulate the AEI for reversible Zn plating/stripping behaviors. The CMC derived anions have a propensity to initially gather on the Zn surface, forming a unique H2O-poor and CMC--rich electrical double layer (EDL) for relieving the water-induced side reactions and promoting fast Zn2+ transport kinetics. Meanwhile, an adaptive solid electrolyte interphase (SEI) can be triggered during cycling to further tune interfacial Zn2+ deposition behaviors. Such a combination enables exposure of (002) facets with dendrite-free and compact Zn deposition on Zn metal. Accordingly, the Zn//Zn symmetric cells with CMC-based electrolyte achieve outstanding lifespan with a 26-fold enhancement for 3125 h at 1 mA cm−2 and 1 mA h cm−2. Also, the Zn anode is promoted to run over 4000 cycles with high Zn reversibility of 99.7%. When paired with NaV3O8·1.5 H2O (NVO) cathode, the full cell with CMC achieves a prominent stability for 2500 cycles at 3 A g−1, much better than that in pure ZnSO4 electrolyte.

Gradient Structural and Compositional Design of Conductive MXene Aerogels for Stable Zn Metal Anodes

AbstractAqueous rechargeable zinc‐ion batteries (ZIBs) are a safe and low‐cost energy storage technology. However, practical ZIB exploitation faces critical challenges in achieving stable Zn metal anodes, which suffer from hydrogen evolution reaction (HER) corrosion and Zn dendrite growth. To address these challenges, a Zn2+‐induced assembly process to fabricate Ti3C2Tx MXene‐reduced graphene oxide aerogels with ZnO crust layers on Zn plates (abbreviated as ZnO/MG aerogel–Zn) that serve as stable Zn metal anodes is reported. By applying a constant voltage to a Zn plate, Zn2+ is gradually released to ionically crosslink MG nanosheets. After spontaneous hydrolysis and freeze‐drying, a crust layer composed of ZnO nanoparticles is in situ formed. Additionally, the gradient Zn−O/Zn−F profiles across the ZnO/MG aerogel can facilitate Zn2+ transport and collectively suppress HER, enabling fast electrochemical kinetics and dendrite‐free Zn deposition. Symmetric cells with ZnO/MG aerogel–Zn electrodes present stable cycling for 1200 h at 10 mA cm−2, and full cells achieve long lifespans at high rates (&gt;500 cycles at 1.0 A g−1). Combining the advantages of an insulating protective layer and a conductive structured host, the ZnO/MG aerogel–Zn electrode with gradient structures and compositions creates synergistic advances in stable Zn metal anodes.

A Double‐Charged Organic Molecule Additive to Customize Electric Double Layer for Super‐Stable and Deep‐Rechargeable Zn Metal Pouch Batteries

AbstractThe electrochemical performance of aqueous zinc metal batteries (AZMBs) is highly dependent on the electric double layer (EDL) properties at Zn electrode/electrolyte interface. Herein, a novel reconfigured EDL is constructed via a double‐charged theanine (TN) additive for super‐stable and deep‐rechargeable AZMBs. Experiments and theoretical computations unravel that the positively charged TN not only serves as preferential anchor to form a water‐poor Helmholtz plane onto the Zn anode, but also its anionic end could coordinate with Zn2+ to tailor the solvation structure in the diffusion layer and further reconstruct the inner H‐bonds networks, thus effectively guiding uniform Zn deposition and suppressing the water‐induced side reactions. Consequently, the Zn//Zn cells acquire outstanding cycling stabilities of nearly 800 h at a high depth of discharge of 80%. Moreover, the Zn//VOX full cells deliver substantial capacity retention (94.12% after 1400 cycles at 2 A g−1) under practical conditions. Importantly, the designed 2.7 Ah Zn//VOX pouch cell harvests a recorded energy density of 42.3 Wh Kgcell−1 and 79.5 Wh Lcell–1, with a remarkable capacity retention of 85.93% after 220 cycles at 50 mA g−1. This innovative design concept to reshape the EDL chemistry would inject fresh vitality into developing advanced AZMBs and beyond.

Towards dendrite-free Zn metal batteries via formation of fluorinated interfacial layer with functional additive

Rechargeable aqueous zinc metal batteries are considered as an alternative in grid-scale energy storage since they offer several intrinsic merits that make them a promising choice including absolute safety, abundant reservoir, cost-effectiveness and sustainability, whereas the Zn anode sustained poor reversibility induced by active water-related parasitic reaction and uncontrollable Zn dendrite growth. In this work, we employed fluorophosphate ester (FEP) as functional additive for ZnSO4 aqueous electrolyte, which not only participated in the formation of protective fluorinated layer on surface of Zn electrode to facilitate the Zn2+ diffusion, but also preferentially adsorb on the Zn surface to manipulate the Zn deposition orientation. Consequently, dendrite-free Zn anode was achieved with extended cycling span of over 1800 h at 10 mA cm−2, 10 mAh cm−2 in Zn symmetric cell and appealing Coulombic efficiency up to 98.9% after 500 times of zinc plating/stripping in Zn||Cu asymmetric cell. Additionally, the FEP contained electrolyte supports full cells work when paired with MnO2 and commercial LiFePO4 cathode. This feasible strategy with electrolyte functional additive provides insightful direction in the design of interfacial layers to harvest stable Zn anodes in aqueous metal-based battery technology.