Zn Dendrites Research Articles

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 1500cycles at 50mAcm-2 and 1.0 mAhcm-2. Meanwhile, the Zn@B-BOGC//MnO2 full cell can operate stably for 2000 cycles at 2.0Ag-1.

Interfacial adsorption and chelation approaches for Long-Life aqueous Zn batteries

Despite the advantages of high theoretical capacity and low cost, the commercialization of zinc-ion batteries (ZIBs) still faces the challenges of Zn dendrite growth and corrosion reactions. Here, chitosan (CS) is chosen as a dual-functional electrolyte additive with non-toxicity, low cost, and biodegradability features to simultaneously optimize the Zn2+ coordination structure and electrode interfacial environment. Density functional theory calculations and experimental results show that CS molecules can adsorb on the Zn electrode to form a water-poor electric double layer, inhibiting hydrogen evolution and side reactions. The specific adsorption induces preferential growth of the Zn(002) plane to form a flat and compact deposition layer. Furthermore, CS additives can decouple the original Zn(H2O)62+ structure through the chelation between CS and Zn2+, effectively reducing the water activity in ZIBs. Consequently, the Zn||Zn cells with CS electrolyte show excellent stability of 3000 h. Additionally, the Zn||MnO2 full cells show excellent stability with a capacity retention of 86.79 % after 500 cycles at 1 A g−1. This study presents a facile and feasible strategy to stabilize Zn anodes by regulating the electrode interface and solvation structure.

Potential–Dependent BDAC Adsorption on Zinc Enabling Selective Suppression of Zinc Corrosion for Energy Storage Applications

Utility-scale zinc (Zn) batteries are a promising solution to address the problem of intermittency of renewable energy sources; however, Zn-metal anodes in these batteries suffer from capacity loss due to spontaneous corrosion of the Zn especially when high-surface area anode configurations are employed. Additionally, Zn dendrites are known to form during battery charging limiting the cycle-life of these batteries. Electrolyte additives have been explored that prevent aforementioned issues, but these too come at a cost, i.e., surface-blocking additives polarize the electrode surface leading to loss in the voltaic and energy efficiencies of the battery. In this contribution, a novel electrolyte additive, benzyldimethylhexadecylammonium chloride (BDAC), is investigated for its ability to suppresses corrosion of Zn in an acidic (pH = 3) electrolyte. An attribute of BDAC distinct from previously studied additives is that it selectively suppresses electrochemical activity when the Zn electrode is at its corrosion potential; however, during high-rate Zn deposition (charging) or stripping (discharging), BDAC is essentially deactivated and thus it does not appreciably polarize the electrode surface, thus minimizing voltaic efficiency losses. This selective corrosion suppression behavior is explored using slow-scan voltammetry, which reveals hysteresis implying a potential- or current-dependent BDAC adsorption mechanism in which BDAC reaches higher surface coverages when the partial currents at the Zn surface are low (e.g., at or near the corrosion potential), but BDAC coverage is reduced considerably when the Zn deposition or stripping rates are increased. Numerical simulations of the BDAC diffusion-adsorption process corroborate this mechanism. Ramifications of our approach to the selective suppression of Zn dendrites are discussed.

Zn Anode Surviving Extremely Corrosive Polybromide Environment with Alginate-Graphene Oxide Hydrogel Coating.

Zinc-bromine (Zn-Br) redox provides a high energy density and low-cost option for next-generation energy storage systems, and polybromide diffusion remains a major issue leading to Zn anode corrosion, dendrite growth, battery self-discharge and limited electrochemical performance. A dual-functional Alginate-Graphene Oxide (AGO) hydrogel coating is proposed to prevent polybromide corrosion and suppress dendrite growth in Zn-Br batteries through negatively charged carboxyl groups and enhanced mechanical properties. The battery with anode of plain zinc coated with AGO (Zn]AGO) survives a severely corrosive environment with higher polybromide concentration than usual without a membrane, and achieves 80 cycles with 100% Coulombic and 80.65% energy efficiencies, four times compared to plain Zn anode. The promising performance is comparable to typical Zn-Br batteries using physical membranes, and the AGO coating concept can be well adapted to various Zn-Br systems to promote their applications.

Toward Simultaneous Dense Zinc Deposition and Broken Side-Reaction Loops in the Zn//V2 O5 System.

The Zn//V2 O5 system not only faces the incontrollable growth of zinc (Zn) dendrites, but also withstands the cross-talk effect of by-products produced from the cathode side to the Zn anode, inducing interelectrode talk and aggravating battery failure. To tackle these issues, we construct a rapid Zn2+ -conducting hydrogel electrolyte (R-ZSO) to achieve Zn deposition modulation and side reaction inhibition in Zn//V2 O5 full cells. The polymer matrix and BN exhibit a robust anchoring effect on SO4 2- , accelerating Zn2+ migration and enabling dense Zn deposition behavior. Therefore, the Zn//Zn symmetric cells based on the R-ZSO electrolyte can operate stably for more than 1500 h, which is six times higher than that of cells employing the blank electrolyte. More importantly, the R-ZSO hydrogel electrolyte effectively decouples the cross-talk effects, thus breaking the infinite loop of side reactions. As a result, the Zn//V2 O5 cells using this modified hydrogel electrolyte demonstrate stable operation over 1,000 cycles, with a capacity loss rate of only 0.028 % per cycle. Our study provides a promising gel chemistry, which offers a valuable guide for the construction of high-performance and multifunctional aqueous Zn-ion batteries.

Toward Simultaneous Dense Zinc Deposition and Broken Side‐Reaction Loops in the Zn//V2O5 System

AbstractThe Zn//V2O5 system not only faces the incontrollable growth of zinc (Zn) dendrites, but also withstands the cross‐talk effect of by‐products produced from the cathode side to the Zn anode, inducing interelectrode talk and aggravating battery failure. To tackle these issues, we construct a rapid Zn2+‐conducting hydrogel electrolyte (R‐ZSO) to achieve Zn deposition modulation and side reaction inhibition in Zn//V2O5 full cells. The polymer matrix and BN exhibit a robust anchoring effect on SO42−, accelerating Zn2+ migration and enabling dense Zn deposition behavior. Therefore, the Zn//Zn symmetric cells based on the R‐ZSO electrolyte can operate stably for more than 1500 h, which is six times higher than that of cells employing the blank electrolyte. More importantly, the R‐ZSO hydrogel electrolyte effectively decouples the cross‐talk effects, thus breaking the infinite loop of side reactions. As a result, the Zn//V2O5 cells using this modified hydrogel electrolyte demonstrate stable operation over 1,000 cycles, with a capacity loss rate of only 0.028 % per cycle. Our study provides a promising gel chemistry, which offers a valuable guide for the construction of high‐performance and multifunctional aqueous Zn‐ion batteries.

Galvanic stabilization of Zn metals for long-life aqueous batteries

Rechargeable aqueous Zn-ion batteries have received extensive attention due to their environmental friendliness, high safety, and low cost. However, the Zn dendrite growth during plating/stripping cycles, which deteriorates coulombic efficiency and shortens the cycle life, dramatically hinders the application of Zn anodes in batteries. Herein, we propose to grow an In layer on Zn foils through spontaneous Galvanic reaction to address the challenging Zn dendrites. In-situ optical observations show that this strategy effectively suppresses the dendrite growth, thereby leading to a robust and stable Zn metal anode with low voltage hysteresis (30 mV at 0.4 mA·cm−2) and long cycle life of over 1200 h in symmetric cells. Meanwhile, the full cell assembled with the modified Zn anode and MnO2 cathode exhibits excellent cycling performance over 2000 cycles and a high discharge capacity of 89.1 mAh·g−1. This work provides an efficient pathway for interfacial engineering towards stable Zn anodes.

Melamine induced co-regulation of solvation structure and interface engineering to achieve dendrite-free Zn-ion hybrid capacitors

Aqueous zinc (Zn)-based energy storage devices have attracted great attention due to their inherent low cost, intrinsic safety, and environmental friendliness. However, the growth of Zn dendrite and side reactions from water decomposition have limited the lifespan of Zn-ion energy storage. Herein, a green and multifunctional melamine (M) molecules is proposed as electrolyte additive and incorporated into the ZnSO4 electrolyte to modulate the deposition/stripping environment of Zn2+ and stabilize the Zn anode. The results of experiments coupled with density-functional theory (DFT) calculations and molecular dynamics (MD) simulations show that M molecules are able to optimize the electrolyte environment and regulate the electrode-electrolyte surface. More specifically, the hydrophilic group (-NH2) in the M molecule can effectively break the electrolyte sheath structure and reconstruct the hydrogen bonding network, because the M molecule has a stronger binding energy compared to H2O. Meanwhile, the -N= groups in M can anchor Zn2+ and cooperate with them to form a dynamic electrostatic protective layer, change the electric field distribution around the Zn deposition layer, provide more nucleation sites for Zn2+ and promote the deposition of Zn along the (002) crystal plane, thus inhibiting the random growth of Zn dendrite and the occurrence of side reactions. Consequently, the Zn//Zn symmetric cell assembled with the ZnSO4+M electrolyte presents boost the stable lifespan over 1,100 hours at a current density of 2 mA cm−2, 1 mAh cm−2, and also up to 1900 stable cycles with almost 100 % Coulomb efficiency for Zn//Cu asymmetric cell.

Screening Selection of Hydrogen Evolution-Inhibiting and Zincphilic Alloy Anode for Aqueous Zn Battery.

The hydrogen evolution reaction (HER) and Zn dendrites growth are two entangled detrimental effects hindering the application of aqueous Zn batteries. The alloying strategy is studied to be a convenient avenue to stabilize Zn anodes, but there still lacks global understanding when selecting reliable alloy elements. Herein, it is proposed to evaluate the Zn alloying elements in a holistic way by considering their effects on HER, zincphilicity, price, and environmental-friendliness. Screening selection sequence is established through the theoretical evaluation of 17 common alloying elements according to their effects on hydrogen evolution and Zn nucleation thermodynamics. Two alloy electrodes with opposite predicted effects are prepared for experimental demonstration, i.e., HER-inhibiting Bi and HER-exacerbating Ni. Impressively, the optimum ZnBi alloy anode exhibits one order of magnitude lower hydrogen evolution rate than that of the pure Zn, leading to an ultra-long plating/stripping cycling life for more than 11000 cycles at a high current density of 20mA cm-2 and 81% capacity retention for 170 cycles in a Zn-V2O5 pouch cell. The study not only proposes a holistic alloy selection principle for Zn anode but also identifies a practically effective alloy element.

All-Round Ionic Liquids for Shuttle-Free Zinc-Iodine Battery.

The practical implementation of aqueous zinc-iodine batteries (ZIBs) is hindered by the rampant Zn dendrites growth, parasite corrosion, and polyiodide shuttling. In this work, ionic liquid EMIM[OAc] is employed as an all-round solution to mitigate challenges on both the Zn anode and the iodine cathode side. First, the EMIM+ embedded lean-water inner Helmholtz plane (IHP) and inert solvation sheath modulated by OAc- effectively repels H2 O molecules away from the Zn anode surface. The preferential adsorption of EMIM+ on Zn metal facilitates uniform Zn nucleation via a steric hindrance effect. Second, EMIM+ can reduce the polyiodide shuttling by hindering the iodine dissolution and forming an EMIM+ -I3 - dominated phase. These effects holistically enhance the cycle life, which is manifested by both Zn || Zn symmetric cells and Zn-I2 full cells. ZIBs with EAc deliver a capacity decay rate of merely 0.01 ‰ per cycle after over 18,000 cycles at 4 A g-1 , and lower self-discharge and better calendar life than the ZIBs without ionic liquid EAc additive.

All‐Round Ionic Liquids for Shuttle‐Free Zinc‐Iodine Battery

AbstractThe practical implementation of aqueous zinc‐iodine batteries (ZIBs) is hindered by the rampant Zn dendrites growth, parasite corrosion, and polyiodide shuttling. In this work, ionic liquid EMIM[OAc] is employed as an all‐round solution to mitigate challenges on both the Zn anode and the iodine cathode side. First, the EMIM+ embedded lean‐water inner Helmholtz plane (IHP) and inert solvation sheath modulated by OAc− effectively repels H2O molecules away from the Zn anode surface. The preferential adsorption of EMIM+ on Zn metal facilitates uniform Zn nucleation via a steric hindrance effect. Second, EMIM+ can reduce the polyiodide shuttling by hindering the iodine dissolution and forming an EMIM+‐I3− dominated phase. These effects holistically enhance the cycle life, which is manifested by both Zn || Zn symmetric cells and Zn‐I2 full cells. ZIBs with EAc deliver a capacity decay rate of merely 0.01 ‰ per cycle after over 18,000 cycles at 4 A g−1, and lower self‐discharge and better calendar life than the ZIBs without ionic liquid EAc additive.

Atomic-scale inorganic carbon additive with rich surface polarity and low lattice mismatch for zinc to boost Zn metal anode reversibility

The renaissance of aqueous zinc-ion batteries (ZIBs) is impeded by the disordered Zn deposition and notorious water attack at the Zn-electrolyte interface. Electrolyte additive engineering plays a vital role in tuning the electrode–electrolyte interface chemistry to stabilize Zn anode but its long-term performance at high plating/stripping rates and capacities remains a challenge. Herein, we demonstrate highly reversible Zn anodes by employing the atomic-scale inorganic carbon nanomaterials (ICN) as a multifunctional electrolyte additive into the common ZnSO4 solution to regulate the Zn deposition behaviors. The ICN with rich surface polar groups modulates the primary Zn2+ solvation structure to avoid the side reactions, and preferentially absorbs on the Zn anode surface to build a passivated-protect interface to suppress Zn corrosion and dendrite growth. More importantly, its low lattice mismatch with zinc navigates the preferred Zn (002) deposition to induce smooth and dense Zn plating morphology, fundamentally eradicating the Zn dendrite issues and further Zn corrosion. Consequently, the electrolyte containing ICN additive endows the symmetric Zn cells with fabulous cumulative capacity (3500 mAh cm−2), decent Coulombic efficiency (99.69 %) at 10 mA cm−2, and excellent stability of 800 cycles with only 0.022 % capacity decay per cycle in the Zn||VOX battery under practical conditions of limited Zn supply, high-loading cathode and lean electrolyte. This work presents an effective strategy to advance the practical applications of rechargeable aqueous zinc batteries.

Enhancing Zn‐Metal Anode Stability: Key Effects of Electrolyte Additives on Ion‐Shield‐Like Electrical Double Layer and Stable Solid Electrolyte Interphase

AbstractOwing to zinc dendrites and parasitic reactions, aqueous Zn‐metal batteries often suffer from poor reversibility and cyclability. Electrolyte additives present a promising strategy to improve Zn anode stability. However, the ever‐evolving perspectives and mechanisms, paradoxically, complicate battery design, causing a scenario where any electrolyte additive seems to be effective. Herein, it is taken ionic liquid (IL) additives as an example and detailed explored the impact of three typical IL anions, namely OTF−, TFA−, and BF4−. It is identified that the primary determinant of electrolyte additives as their electrical double layer (EDL) structures and their subsequent solid‐electrolyte interface (SEI) composition. An advantageous EDL structure, akin to an ion‐shield, can reduce the absorption of H2O molecules, which further enrich the SEI with zincophilic and hydrophobic components, thereby mitigating parasitic reactions and Zn dendrite formation. As a result, the Zn||Zn cell with optimal [EMIM]OTF additives demonstrates an exceptional cycling life under challenging conditions, its cumulative plated capacity surpasses most previously reported results by utilizing different IL additives. This work extends beyond performance enhancements, representing a valuable exploration of key criteria for electrolyte additives is believed. These insights are expected to offer fundamental guidance for future research and electrolyte design.

Refining the inner Helmholtz plane adsorption for achieving a stable solid-electrolyte interphase in reversible aqueous Zn-ion pouch cells

The reversibility and stability of aqueous Zn ion batteries (AZIBs) is extremely dependent on inner Helmholtz plane (IHP) structure and properties at the zinc anode/aqueous electrolyte interface. The hydrogen evolution reaction, corrosion, passivation, and uncontrolled growth of Zn dendrites all stem from the abundant presence of active H2O and irregular deposition of Zn within the IHP. In this study, we propose a strategy by using N, N'-Methylenebisacrylamide (MBA) as a bis-zincophilic site additive to effectively regulate molecular distribution within the IHP. This approach can prevent active H2O molecules from decomposing and suppress side reactions, while also can homogenize ion flux to obtain the uniform Zn deposition and stripping. Moreover, the adsorption of MBA onto IHP promotes the formation of a compact and homogeneous solid-electrolyte interphase (SEI). As a result, the utilization of an MBA/ZnSO4 electrolyte resulted in exceptional Coulombic efficiency of 99.7 % for up to 1300 cycles. The Zn//Zn symmetric pouch cell demonstrated an impressively high accumulated capacity exceeding 15,000 mA h. Furthermore, the Zn//NH4V4O10 zinc-ion pouch cell exhibited a capacity retention rate of 85 % after undergoing 1000 cycles at a current density of 1 A g−1. These results highlight the significant potential of incorporating MBA additive into practical applications.

Recent Advances in Graphene-Based Materials for Zinc-Ion Batteries.

Zinc-ion batteries (ZIBs) are a promising alternative for large-scale energy storage due to their advantages of environmental protection, low cost, and intrinsic safety. However, the utilization of their full potential is still hindered by the sluggish electrode reaction kinetics, poor structural stability, severe Zn dendrite growth, and narrow electrochemical stability window of the whole battery. Graphene-based materials with excellent physicochemical properties hold great promise for addressing the above challenges foe ZIBs. In this review, the energy storage mechanisms and challenges faced by ZIBs are first discussed. Key issues and recent progress in design strategies for graphene-based materials in optimizing the electrochemical performance of ZIBs (anode, cathode, electrolyte, separator and current collector) are then discussed. Finally, some potential challenges and future research directions of graphene-based materials in high-performance ZIBs are proposed for practical applications.

A weakly solvating electrolyte towards practical rechargeable aqueous zinc-ion batteries

Structure deterioration and side reaction, which originated from the solvated H2O, are the main constraints for the practical deployment of both cathode and anode in aqueous Zn-ion batteries. Here we formulate a weakly solvating electrolyte to reduce the solvating power of H2O and strengthen the coordination competitiveness of SO42− to Zn2+ over H2O. Experiment results and theoretical simulations demonstrate that the water-poor solvation structure of Zn2+ is achieved, which can (i) substantially eliminate solvated-H2O-mediated undesirable side reactions on the Zn anode. (ii) boost the desolvation kinetics of Zn2+ and suppress Zn dendrite growth as well as structure aberration of the cathode. Remarkably, the synergy of these two factors enables long-life full cells including Zn/NaV3O8·1.5H2O, Zn/MnO2 and Zn/CoFe(CN)6 cells. More importantly, practical rechargeable AA-type Zn/NVO cells are assembled, which present a capacity of 101.7 mAh and stability of 96.1% capacity retention after 30 cycles at 0.66 C.

Long cycle‐life aqueous Zn battery enabled by facile carbon nanotube coating on Cu current collector

AbstractAs an alternative to Li‐ion batteries, aqueous Zn batteries have gained attention due to the abundance of Zn metal, low reduction potential (–0.76 V vs. standard hydrogen electrode), and high theoretical capacity (820 mAh g–1) of multivalent Zn2+ ion. However, the growth of Zn dendrites and the formation of irreversible surface reaction byproducts pose challenges for ensuring a long battery lifespan and commercialization. Herein, the Cu foil coated with a single‐walled carbon nanotube (SWCNT) layer using a facile doctor blade casting method is utilized. The SWCNT‐coated Cu foil demonstrates a significantly longer battery lifespan compared to the bare Cu in the half‐cell tests. Through operando optical microscopy imaging, we are able to provide intuitive evidence that Zn deposition occurs between the carbon nanotube (CNT) coating and Cu substrate, in agreement with the computational results. Also, with various imaging techniques, the flat morphology and homogeneous distribution of Zn beneath the SWCNT layer are demonstrated. In addition, the full‐cell using CNT‐coated Cu exhibits a long cycle life compared to the control group, thereby demonstrating improved electrochemical performance with limited Zn for the cycling process.

Interface regulation using a fluorinated vinylene-linked covalent organic framework for a highly stable Zn anode

Herein, a functional vinylene-linked COF with zincophilic fluorinated sites is well designed and applied as an interface layer to simultaneously manipulate the Zn plating/stripping behavior and interfacial side reactions.

A hydrophobic alloy-coated Zn anode for durable electrochromic devices.

To mitigate Zn corrosion, dendrite growth and hydrogen evolution reactions (HER) in Zn-anode based electrochromic devices, hydrophobic CuZn5 alloy was coated on Zn@CuZn with lower nucleation potential, high coulombic efficiency, inhibited HER, and prolonged reversibility, enabling improved switching kinetics and cycling stability in an electrochromic Zn@CuZn||Prussian Blue (PB) device.

Enabling stable aqueous Zn metal anodes using scandium acetate electrolyte additives

A scandium acetate electrolyte additive enables the improved stability of Zn metal anodes in an aqueous ZnSO4 electrolyte with suppressed side reactions and Zn dendrite formation due to the buffered pH value and homogenized Zn2+ distribution.