Zinc Dendrites Research Articles

Achieving Stable Orientational Zinc Deposition for Reversible Zinc Anode through Supramolecular Anchoring Mechanism.

Aqueous zinc-ion batteries have been impeded by the hydrogen evolution reaction (HER), uncontrolled zinc dendrites, and side reactions on the Zn anode. In this work, a Zn-polyphenol supramolecular network is rationally designed for stabilizing Zn anodes (ZPN@Zn) even at high current density. Theoretical calculations and experiments show that the zinc-polyphenol supramolecular layer effectively inhibits the hydrogen evolution reaction by capturing water molecules through strong hydrogen bonding networks while also facilitating the rapid replenishment of Zn2+ ions at the interface through supramolecular anchoring. Additionally, it results in preferential deposition of Zn on the (002) plane, thereby contributing to nondendritic and highly reversible Zn plating/stripping behaviors even under high rates. Concomitantly, the ZPN@Zn achieves superior stability of nearly 1200 h at a high current density of 20 mA cm-2 and maintains a high CE efficiency of 99.86% after 3000 cycles at 1 mAh cm-2 and 5 mA cm-2. Remarkably, the full cell assembled with ZPN@Zn and NaV3O8 (NVO) endures 25 000 cycles at 20 A g-1, achieving an impressive performance for the realization of dendrite-free Zn anodes by supramolecular modulation.

Electrostatic Shielding Engineering for Stable Zn Metal Anodes

AbstractAqueous Zn‐ion batteries (AZIBs) are promising energy storage systems due to their low cost, excellent safety, and environmental friendliness. However, challenges like uncontrollable dendrite growth and side reactions during battery operation limit their commercialization. Addressing these issues requires regulating ion deposition behavior at the anode/electrolyte interface. The electrostatic shielding effect, which leverages the interplay between electric potential and ionic motion, provides a unique mechanism to inhibit zinc dendrites and side reactions effectively. Despite significant progress in understanding electrostatic shielding in AZIBs, a comprehensive summary of its effects is still lacking. This paper first reviews the primary challenges in AZIBs and then describes how the electrostatic shielding effect can optimize their performance. Existing strategies for achieving electrostatic shielding through anode structure optimization and electrolyte optimization‐are classified and analyzed. Finally, the review summarizes current electrostatic shielding strategies for stabilizing zinc anodes, identifies existing challenges, and discusses the future potential, and for this approach in AZIBs.

Regulating the Zn electrode/electrolyte interface with lactose additive for high performance Zn anode

The practical utilization of rechargeable aqueous zinc metal batteries (AZMBs) has been constrained by the formation of zinc dendrites and other associated issues. This article introduces lactose, a compound rich in hydroxyl groups, as an electrolyte additive into the aqueous solution of the electrolyte with the objective of suppressing the harmful growth of zinc dendrites. The lactose additive, with its strong zincophilicity, robust intermolecular hydrogen bonding, and a large number of exposed high electronegativity hydroxyl groups, enables lactose to effectively modulate the electrode/electrolyte interface in a dynamic manner, thereby achieving the stability and reversibility of the zinc anode. The findings presented in this work demonstrate the uniform deposition and stripping of zinc in a 2 M ZnSO4 electrolyte with the addition of lactose, thereby enhancing the cycling performance of Zn||Zn batteries. The alteration of the zinc ion environment on the surface of the zinc electrode, in conjunction with the dynamic modulation of the Gouy-Chapman-Stern (GCS) layer by lactose, increases the nucleation overpotential, thereby facilitating to a uniform deposition morphology in lieu of the formation of large-scale dendrites. Furthermore, the formation of hydrogen bonds serves to prevent the occurrence of side reactions. These factors act in concert to enhance the electrochemical performance of AZMBs. The addition of lactose to the electrolyte has resulted in a significant enhancement in the Coulombic efficiency of the card-type Zn||Cu asymmetric battery, reaching 99.7 %. The biodegradability of lactose and the sustainability of its source make this research conducive to the development of environmentally friendly battery electrolyte additives.

High-Entropy Multiple-Anion Aqueous Electrolytes for Long-Life Zn-Metal Anodes.

Aqueous zinc-ion batteries (AZIBs) hold great promise for large-scale energy storage applications, however, their practical use is significantly hindered by issues such as zinc dendrite growth and hydrogen evolution. To address these challenges, we propose a high-entropy (HE) electrolyte design strategy that incorporates multiple zinc salts, aimed at enhancing ion kinetics and improving the electrochemical stability of the electrolyte. The interactions between multiple anions and Zn2+ increase the complexity of the solvation structure, resulting in smaller ion clusters while maintaining weakly anion-rich solvation structures. This leads to improved ion mobility and the formation of robust interphase layers on the electrode-electrolyte interface. Moreover, the HE electrolyte effectively suppresses hydrogen evolution and corrosion side reactions while facilitating uniform and reversible Zn plating/stripping processes. Impressively, the optimized electrolyte enables dendrite-free Zn plating/stripping for over 3000 h in symmetric cells and achieves a high Coulombic efficiency of 99.5% at 10 mA cm-2 in asymmetric cells. Inspiringly, full cells paired with Ca-VO2 cathodes demonstrate excellent performance, retaining 81.5% of the initial capacity over 1800 cycles at 5 A g-1. These significant findings highlight the potential of this electrolyte design strategy to improve the performance and lifespan of Zn-metal anodes in AZIBs.

Preparation of Hierarchical Porous ZIF-67 and Its Application in Zinc Battery Separator

This study successfully prepared a hierarchically porous ZIF-67 (H-ZIF-67) by incorporating the polyvinylpyrrolidone (PVP) at room temperature. Compared to standard control ZIF-67 (C-ZIF-67) with a yield of 81% and a BET specific surface area of 1228 m2·g−1, the H-ZIF-67 not only exhibited improved crystallinity and pore structure but also achieved a yield of up to 93% and a BET specific surface area of 1457 m2·g−1. Due to its hierarchically porous structure, H-ZIF-67 demonstrated excellent adsorption capacity and efficiency for methylene orange (MO). Additionally, the composite separator created by combining H-ZIF-67 with nanocellulose (CNF) exhibited remarkable uniformity and dispersion in zinc batteries. In comparison to a conventional CNF separator, the porous structure and high specific surface area of H-ZIF-67 significantly enhanced its electrolyte wettability and Zn2+ transport rates. Its abundant Lewis acid sites effectively promoted the uniform deposition of Zn2+, thereby suppressing the formation of zinc dendrites and improving the cycling and safety performance of zinc-ion batteries. Experimental results indicate that the ion conductivity of the membrane was 4.31 mS·cm−1, the electrolyte absorption rate was 316%, and it could cycle stable for over 4000 h at a current density of 1 mA·cm−2 with a discharge capacity of 1 mAh·cm−2. This achievement will open up new avenues for the preparation and application of ZIF-67 composite separators in aqueous zinc-ion batteries.

Multidentate Chelating Ligands Enable High-Performance Zinc-Bromine Flow Batteries.

Zinc bromine flow battery (ZBFB) is a promising battery technology for stationary energy storage. However, challenges specific to zinc anodes must be resolved, including zinc dendritic growth, hydrogen evolution reaction, and the occurrence of "dead zinc". Traditional additives suppress side reactions and zinc dendrite formation by altering the solvation structure of Zn2+ and adsorbing onto the zinc surface through only a limited number of zincophilic sites, resulting in weak adsorption on zinc metal and potential inability to simultaneously optimize the solvation structure of zinc ions. Obviously, increasing the number of potential zincophilic sites in the additive can significantly enhance the interaction with zinc. Herein, we propose a strong chelate, ethylenediamine tetramethylene phosphonic acid (EDTMPA) as the additive, which boasts six potent zincophilic sites, not only promotes the formation of the water-deficient inner Helmholtz plane but also plays a crucial role in restructuring the solvation environment of Zn2+. As a result, the zinc symmetric flow battery with EDTMPA exhibited exceptional coulombic efficiency of 99.4% over 800 cycles, surpassing the previous studies by a significant margin. Furthermore, the assembled ZBFB has showcased a dendrite-free and enduring cycling over 400 cycles at 80 mA cm-2.

Multidentate Chelating Ligands Enable High‐Performance Zinc‐Bromine Flow Batteries

Zinc bromine flow battery (ZBFB) is a promising battery technology for stationary energy storage. However, challenges specific to zinc anodes must be resolved, including zinc dendritic growth, hydrogen evolution reaction, and the occurrence of "dead zinc". Traditional additives suppress side reactions and zinc dendrite formation by altering the solvation structure of Zn2+ and adsorbing onto the zinc surface through only a limited number of zincophilic sites, resulting in weak adsorption on zinc metal and potential inability to simultaneously optimize the solvation structure of zinc ions. Obviously, increasing the number of potential zincophilic sites in the additive can significantly enhance the interaction with zinc. Herein, we propose a strong chelate, ethylenediamine tetramethylene phosphonic acid (EDTMPA) as the additive, which boasts six potent zincophilic sites, not only promotes the formation of the water‐deficient inner Helmholtz plane but also plays a crucial role in restructuring the solvation environment of Zn2+. As a result, the zinc symmetric flow battery with EDTMPA exhibited exceptional coulombic efficiency of 99.4% over 800 cycles, surpassing the previous studies by a significant margin. Furthermore, the assembled ZBFB has showcased a dendrite‐free and enduring cycling over 400 cycles at 80 mA cm−2.

The analysis of the overall failure of practical Zn−Ni battery

Zn−Ni batteries are viewed as promising power sources for electric tools and electric vehicles (EVs) due to their benefits of high safety, high working voltage and attractive rate performance. However, the practical applications of the Zn−Ni batteries are hampered by poor cycling performance, posing significant challenges for their widespread utilization. To effectively address this pressing concern, a profound investigation of the intrinsic failure mechanisms underlying Zn−Ni batteries holds paramount importance. This paper carries out a thorough analysis of battery behavior to simulate industrial application scenarios using two different assembly methods of Zn−Ni batteries. One type is a battery composed of one Ni(OH)2 cathode and one Zn anode (abbreviated as OO). The other type is the battery assembled with one Ni(OH)2 cathode and two Zn anodes (abbreviated as OT). Ultimately, it is revealed that the principal factors of Zn anode failure in OO battery are the growth of zinc dendrites, passivation and uneven current distribution. In contrast, for OT battery, the cathode emerges as the failed electrode. Specifically, the rupture of spheres on the positive electrode surface and the detached powder from the substrate result in the decline in capacity and finally the failure of the battery. Two classical battery assembly methodologies were employed to investigate in-depth the failure mechanisms of Zn−Ni batteries, ultimately revealing that the reasons for battery failure mechanism differed, thus providing valuable and practical guidance for future research aimed at enhancing battery lifespan.

Stabilizing zinc anodes by a solvation sheath modification with toluenesulfonate additive

As an advanced electrochemical energy storage device, aqueous zinc-ion batteries offer high theoretical capacity and energy density, employing water-based electrolytes to reduce fire and explosion risks. However, zinc tends to form dendrites during charge-discharge processes, leading to reduced electrode surface area and shortened cycling lifespan. In this study, we propose the use of a commonly used and cost-effective additive, sodium p-toluenesulfonate (OTM), to stabilize zinc anodes. Experimental and theoretical simulations demonstrate that OTM can enter the solvation sheath of Zn2+, reduce the activity of nearby H2O molecules, facilitate uniform Zn2+ deposition, and suppress zinc dendrite formation. Therefore, Zn//Zn symmetric batteries utilizing ZnSO4 (ZSO) electrolytes containing OTM achieved outstanding long-term performance exceeding 1700 h at 1 mA cm−2, significantly surpassing those employing ZSO electrolytes. Additionally, Zn//VO2 full batteries with OTM additives exhibited enhanced cycling stability and an initial discharge capacity of 180 mAh g−1 at 3 A g−1, demonstrating its superior application potential.

High-Conductivity and Ultrastretchable Self-Healing Hydrogels for Flexible Zinc-Ion Batteries.

Aqueous zinc-ion batteries are promising candidates for flexible energy storage devices due to their safety, economic efficiency, and environmental friendliness. However, the uncontrollable dendrite growth and side reactions at the zinc anode hinder their commercial application. Herein, we designed and synthesized a dual network self-healing hydrogel electrolyte with zwitterionic groups (PAM-PAAS-QCS), which can be used for the large deformations of flexible devices due to its excellent stretchability (ε = 5100%). The incorporation of zwitterionic groups into the PAM-PAAS-QCS hydrogel electrolyte endows it with high ionic conductivity (33.61 mS/cm), a wide electrochemical stability window, and the ability to suppress zinc dendrite formation and side reactions. Besides, the Zn//Zn symmetric cell with PAM-PAAS-QCS can stably plate and strip zinc for 1500 h at 0.5 mA/cm2, and the Zn//Polyaniline full cell retains 82.4% of its capacity after 1500 cycles at 1 A/g. Additionally, flexible batteries based on both the original and self-healed PAM-PAAS-QCS hydrogel electrolytes demonstrate good cycling stability and stable charge-discharge performance under various bending conditions. This self-healing hydrogel electrolyte with excellent stretchability and high ionic conductivity is expected to pave the way for the development of high-performance flexible energy storage and wearable devices.

Suppression of Zinc Dendrite Growth by Enhanced Polyacrylamide Gel Electrolytes in Zinc-Ion Battery.

Aqueous zinc-ion batteries have become a promising energy storage battery due to high theoretical specific capacity, abundant zinc resources and low cost. However, zinc dendrite growth and hydrogen evolution reaction limit their application. This study aims to improve the cycling performance and stability of aqueous zinc-ion batteries by improving the gel electrolyte. Polyacrylamide (PAM) is selected as the base material of the gel electrolyte, which has good stability and safety, but the water retention capacity, Zn2+ migration number, and ionic conductivity of PAM are low, which affects the long-term stability of the battery. In response to these problems, we optimized PAM by chemical cross-linking method, and formed an enhanced PAM gel by adding disodium citrate dihydrate (SC). Experimental results show that the introduction of an appropriate amount of SC in the enhanced PAM gel electrolyte can significantly improve its electrochemical performance. The zinc-ion symmetric battery achieved a stable cycle of more than 2100 hours at a current density of 0.5 mA cm-2, which is mainly attributed to the inhibitory effect of the enhanced PAM gel on zinc dendrite growth and hydrogen evolution reaction. This study provides a new direction for the development and application of flexible zinc-ion batteries.

Symmetry Donor-Acceptor Molecule Regulating Hydrogen-Bonding Network for Improved Metal Zinc Anode.

The issues of zinc dendrites and side reactions caused by active water molecules have seriously affected the development of aqueous zinc batteries (AZBs). Herein, a symmetry hydrogen-bond donor-acceptor molecule additive named 1,3-bis(hydroxymethyl)urea (BHMU) can preferentially adsorb on the anode surface and lock up water molecules through hydrogen bonding, thus isolating water molecules and reducing side reactions caused by active water molecules. With these advantages, the mixed electrolyte containing BHMU additive impels a reversible Zn anode with a high Coulombic efficiency (99.7% over 1000 cycles at 1 mA cm-2), while it also enables a stable symmetric cell operated at 1 mA cm-2 (1 mAh cm-2, 6.89% DODZn) for 2250 h and 10 mA cm-2 (10 mAh cm-2, 68.9% DODZn) for 350 h. More importantly, the Zn||PTO full battery also delivered superior cycling stability and higher capacity after 3000 consecutive 3000 cycles of circulation at 5 A g-1. This study has great significance for the use of symmetry donor-acceptor molecules to modulate the solvation structure and the interface stability of the Zn anode in aqueous electrolytes.

"Anions-in-Colloid" Hydrated Deep Eutectic Electrolyte for High Reversible Zinc Metal Anodes.

Zn metal as a promising anode for aqueous batteries suffers from severe zinc dendrites, anion-related side reactions, hydrogen evolution reaction (HER) and narrow electrochemical stable window (ESW). Herein, an "anions-in-colloid" hydrated deep eutectic electrolyte consisting of Zn(ClO4)2 ⋅ 6H2O, β-cyclodextrin (β-CD), and H2O with mass ratio of 7 : 4.5 : 3 (ACDE-3) is designed to improve the stability of zinc anode. The ACDE-3 reconfigures the hydrogen-bond (HB) network and regulates the solvation shell. More importantly, the hydroxyl-rich β-cyclodextrins (β-CDs) in ACDE-3 self-assemble into micelles, in which the steric effect between adjacent β-CDs in micelles restricts the movement of anions. This unique "anions-in-colloid" structure enables the eutectic system with a high Zn2+ transference number (tZn 2+) of 0.84. Thus, ACDE-3 inhibits the formation of dendrite, prevents the anion-involved side reactions, suppresses the HER, and enlarges the ESW to 2.32 V. The Zn//Zn symmetric cell delivers a long lifespan of 900 hours at 0.5 mA cm-2, and the Zn//Cu half cells have a high average columbic efficiency (ACE) of 97.9 % at 0.5 mA cm-2 from cycle 15 to 200 with a uniform and compact zinc deposition. When matched with a poly(1,5-naphthalenediamine) (poly(1, 5-NAPD)) cathode, the full battery with a low negative/positive capacity (N/P) ratio of 2 can still cycle steadily for 200 cycles at a current density of 1.0 A g-1. Additionally, this electrolyte has been proven to be operative over a wide temperature range from -40 °C to 40 °C.

Indium Nanoparticle‐Decorated Graphite Felt Electrodes for Efficient and Long‐Cycle Zinc‐Bromine Flow Batteries

AbstractZinc‐bromine flow batteries (ZBFBs) offer the potential for large‐scale, low‐cost energy storage; however, zinc dendrite formation on the electrodes presents challenges such as short‐circuiting and diminished performance. Herein, an indium nanoparticle‐decorated graphite felt composite electrode for ZBFBs is proposed to mitigate zinc dendrite formation, improve performance, and prolong operational longevity. Using a facile in situ electrodeposition method, indium nanoparticles are uniformly and densely distributed on the carbon fiber surface, demonstrating exceptional efficacy in regulating zinc deposition. Thus, a higher prevalence of Zn (002) crystal planes and a smoother and more compact surface morphology are obtained, compared with those of thermally treated graphite felt. Furthermore, integration of the composite electrode into the negative side of a ZBFB yielded substantial improvements in cell performance, achieving an energy efficiency of 66.83% ± 0.45% at 120 mA cm−2, significantly surpassing the performance of batteries utilizing thermally treated graphite felt (52.64% ± 1.50%). Notably, the cycle life of the battery is extended by more than five‐fold with the composite electrode, underscoring the remarkable zinc deposition‐regulating capabilities of the indium nanoparticles.

Quasi-Homogeneous Bromine Phase in Zinc-Bromine Batteries with Advanced Energy Efficiency and Energy Density

Abstract Regarding energy density, kinetics, and reversibility, the zinc-bromine batteries (ZBBs) exhibit advantages comparable to the conventional metal hydride nickel batteries as aqueous systems. However, the development of ZBBs has been impeded by two critical challenges: the self-discharge of Br-Br species cross-over and the short circuit caused by zinc dendrites. Achieving high energy density necessitates a large areal capacity electrode and tight battery assembly, which introduces additional hurdles. Addressing these challenges, we have successfully implemented a novel quasi-homogeneous bromine phase. Our optimized approach has realized ZBBs with a remarkable energy efficiency (EE) of 92.7% based on an areal capacity of 12 mA h cm-2 in a period duration of 13 h, an energy density of whole battery (EDB) of 80 W h L-1 with average EE of 92.5% for an extended cycle life of approximately 500 cycles, and a maximum EDB of 186 W h L-1 without pre-added zinc metal. This innovative work holds practical significance for developing ZBBs and providing insights and solutions to critical challenges.

Zinc-tin binary alloy interphase for zinc metal batteries

Aqueous zinc ion batteries are rapidly developing as the most propitious energy storage system due to their high security, high specific capacity and low cost, etc. However, zinc anodes suffered from dendrite growth and hydrogen evolution reactions during cycling, so it is of utmost importance to upgrade zinc anode properties. In this study, the homogeneous layer of ZnSn alloy interphase was formed by introducing metallic tin to the anode surface using an ion sputtering technique. ZnSn alloy can reduce the hydrogen evolution over-potential of anode and the corrosion current, inhibiting the occurrence of hydrogen evolution and corrosion reaction. Moreover, the ZnSn alloy anode can provide uniform nucleation sites and uniformize the electric field on the anode surface, promote the uniform deposition of Zn2+, thus inhibiting the formation of zinc dendrites. Notably, compared to the Zn foil//Zn foil cell (400 h), the ZnSn alloy symmetric cell showed excellent cycling performance by cycling for 1000 h at 0.5 mA cm−2. Furthermore, even at current density of 1 A/g, the capacity retention of the ZnSn alloy//MnO2 full cell was up to 89.5 % compared to only 32.3 % for Zn foil//MnO2 cell. The preparation of this ZnSn alloy anode may provide new ideas for future alloying strategies.

Effects of SiO2 Particle Size in Soggy‐Sand Electrolyte on Electrochemical Performance of Zinc‐Ion Batteries

AbstractThe presence of free water molecules in the aqueous electrolyte leads to serious side reactions at the interface, easy dissolution of the cathode material, and uncontrolled growth of zinc dendrites in Zn‐ion batteries, which hinders their practical applications. Here, we propose a type of SiO2‐based soggy‐sand electrolyte (ZnSO4+MnSO4 electrolyte with SiO2, SiO2‐ZMSO4) and focus on the effect of the SiO2 nanoparticle size on the performance of soggy‐sand electrolyte. It is found that SiO2 with smaller nanoparticle size provides higher porosity, and the SiO2 network‐formed can effectively trap the free water in the electrolyte, which increases the ionic conductivity of electrolyte, widens working voltage window, and decreases the internal resistance of batteries. As a result, the Zn//MnO2 batteries with 20 nm SiO2‐based soggy‐sand electrolyte show stable cycling performance and rate capacities. The specific capacity of the battery can be maintained at 198.5 mAh g−1 after 1200 cycles at 1 A g−1 without capacity degradation. The specific capacity can be increased by 100 mAh g−1 even at a high rate of 5 A g−1. This study provides the rule of particle selection for the development of aqueous soggy‐sand electrolytes used in aqueous rechargeable batteries.

Toward the Rechargeable Aqueous Zinc Ion Batteries with Improved Overall Performance: Electrolyte with Surface Adsorptive Additive.

Aqueous zinc-ion batteries (AZIBs) with slightly acidic electrolytes process advantages such as high safety, competitive cost, and satisfactory electrochemical performance. However, the failure behaviors of both electrodes, regarding zinc dendrite growth, interfacial parasitic reactions, and the collapse of cathode materials hinder the practical application of ZIBs. To alleviate the issues of both anode and cathode at the same time, D-xylose (DX) is introduced to the electrolyte as a multifunctional additive. As a result, the side reaction of the anode is suppressed and the metallic deposition behavior is regulated due to the hydrogen bonding network reconstruction and preferential surface adsorption of DX; for the MnO2 cathode, the DX adsorption can help the interfacial charge transfer and increase the reactive sites. Benefiting from these merits, DX-optimized Zn//Zn battery displays reveal a prolonged lifespan of 6912h and an ultra-high cumulative capacity of 17.28Ahcm-2 at 5mAcm-2. With the function of water reactivity suppression, the Coulombic efficiency reaches 99.91% at 2mAcm-2; the Zn||MnO2 full batteries exhibit excellent cyclability over 2000 cycles at 5C with an increased capacity of 118.9mAhg-1, indicating the dual functions to both of the electrodes for AZIBs.

Advancing Zinc Anodes: Strategies for Enhanced Performance in Aqueous Zinc-Ion Batteries.

The promising features of aqueous zinc ion batteries (AZIBs), including their inherent safety, environmental friendliness, abundant raw materials, cost-effectiveness, and simple manufacturing process, position them as strong candidates for large-scale energy storage. However, their practical application faces significant challenges, such as uncontrolled dendritic growth, undesirable side reactions, and hydrogen evolution reactions (HER), which undermine the efficiency and longevity of the system. To address these issues, extensive research has been conducted to improve these batteries' energy density and lifespan. This comprehensive review explores the fundamental mechanisms of zinc dendrite formation, its properties, and the interfacial chemistry between the electrode and electrolyte. It also delves into strategies for protecting the zinc anode, with a focus on the modulation of zinc ion deposition dynamics at the electrolyte interface. The discussion concludes with an evaluation of the current challenges and future prospects of AZIB, aiming to enhance their viability for grid-scale energy storage solutions.

Unraveling chemical origins of dendrite formation in zinc-ion batteries via in situ/operando X-ray spectroscopy and imaging

To prevent zinc (Zn) dendrite formation and improve electrochemical stability, it is essential to understand Zn dendrite growth, particularly in terms of morphology and relation with the solid electrolyte interface (SEI) film. In this study, we employ in-situ scanning transmission X-ray microscopy (STXM) and spectro-ptychography to monitor the morphology evolution of Zn dendrites and to identify their chemical composition and distribution on the Zn surface during the stripping/plating progress. Our findings reveal that in 50 mM ZnSO4, the initiation of moss/whisker dendrites is chemically controlled, while their continued growth over extended cycles is kinetically governed. The presence of a dense and stable SEI film is critical for inhibiting the formation and growth of Zn dendrites. By adding 50 mM lithium chloride (LiCl) as an electrolyte additive, we successfully construct a dense and stable SEI film composed of Li2S2O7 and Li2CO3, which significantly improves cycling performance. Moreover, the symmetric cell achieves a prolonged cycle life of up to 3900 h with the incorporation of 5% 12-crown-4 additives. This work offers a strategy for in-situ observation and analysis of Zn dendrite formation mechanisms and provides an effective approach for designing high-performance Zn-ion batteries.