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Uncontrollable growth of Zn dendrites, irreversible dissolution of cathode material and solidification of aqueous electrolyte at low temperatures severely restrict the development of aqueous Zn‐ion batteries. In this work, 2,2,2‐trifluoroethanol (TFEA) with a volume fraction of 50% as a highly compatible polar‐solvent is introduced to 1.3 M Zn(CF3SO3)2 aqueous electrolyte, achieving stable high‐performance Zn‐ion batteries. Massive theoretical calculations and characterization analysis demonstrate that TFEA weakens the tip effect of Zn anode and restrains the growth of Zn dendrites due to electrostatic adsorption and coordinate with H2O to disrupt the hydrogen bonding network in water. Furthermore, TFEA increases the wettability of the cathode and alleviates the dissolution of V2O5, thus improving the capacity of the full battery. Based on those positive effects of TFEA on Zn anode, V2O5 cathode, and aqueous electrolyte, the Zn//Zn symmetric cell delivers a long cycle‐life of 782 h at 5 mA cm−2 and 2 mA h cm−2. The full battery still declares an initial capacity of 116.78 mA h g−1, and persists 87.73% capacity in 2000 cycles at −25 °C. This work presents an effective strategy for fully compatible co‐solvent to promote the stability of Zn anode, V2O5 cathode and aqueous electrolyte for high‐performance Zn‐ion batteries. [ABSTRACT FROM AUTHOR]

Tetrahydrofurfuryl alcohol (THFA), a cost-effective electrolyte additive, is employed innovatively to optimize both the cathode and anode, thereby enhancing the performance of zinc-based batteries significantly. [Display omitted] Aqueous zinc-ion batteries (AZIBs) are highly regarded for their affordability, stability, safety, and eco-friendliness. Nevertheless, their practical application is hindered by severe side reactions and the formation of zinc (Zn) dendrites on the Zn metal anode surface. In this study, we employ tetrahydrofuran alcohol (THFA), an efficient and cost-effective alcohol ether electrolyte, to mitigate these issues and achieve ultralong-life AZIBs. Theoretical calculations and experimental findings demonstrate that THFA acts as both a hydrogen bonding donor and acceptor, effectively anchoring H 2 O molecules through dual-site hydrogen bonding. This mechanism restricts the activity of free water molecules. Moreover, the two oxygen (O) atoms in THFA serve as dual solvation sites, enhancing the desolvation kinetics of [Zn(H 2 O) 6 ]2+ and improving the deposition dynamics of Zn2+ ions. As a result, even trace amounts of THFA significantly suppress adverse reactions and the formation of Zn dendrites, enabling highly reversible Zn metal anodes for ultralong-life AZIBs. Specifically, a Zn-based symmetric cell containing 2 % THFA achieves an ultralong cycle life of 8,800 h at 0.5 mA cm−2/0.5 mAh cm−2, while a Zn//VO 2 full cell containing 2 % THFA maintains a remarkable 80.03 % capacity retention rate at 5 A g−1 over 2,000 cycles. This study presents a practical strategy to develop dendrite-free, cost-effective, and highly efficient aqueous energy storage systems by leveraging alcohol ether compounds with dual-site hydrogen bonding capabilities. [ABSTRACT FROM AUTHOR]

The low-cost small molecule nicotinamide serves as an electrolyte additive for aqueous zinc-ion batteries. Only 1 wt% of nicotinamide enables Zn||Zn symmetric cells to have an ultra-long lifespan of over 9700h at 1 mA cm−2, expanding nearly 808 times compared to that without nicotinamide. This work is remarkable among state-of-the-art novel aqueous zinc-ion batteries. [Display omitted] Aqueous zinc-ion batteries (AZIBs) have recently been paid great attention due to their robust safety features, high theoretical capacity, and eco-friendliness, yet their practical application is hindered by the serious dendrite formation and side reactions of Zn metal anode during cycling. Herein, a low-cost small molecule, nicotinamide (NIC), is proposed as an electrolyte additive to effectively regulate the Zn interface, achieving a highly reversible and stable zinc anode without dendrites. NIC molecules not only modify the Zn2+ solvation structure but also preferentially adsorb on the Zn surface than solvated H 2 O to protect the Zn anode and provide numerous nucleation sites for Zn2+ to homogenize Zn deposition. Consequently, the addition of 1 wt% NIC enables Zn||Zn symmetric cells an ultra-long lifespan of over 9700 h at 1 mA cm−2, which expands nearly 808 times compared to that without NIC. The advantages of NIC additives are further demonstrated in NaVO||Zn full cells, which exhibit exceptional capacity retention of 90.3 % after 1000 cycles with a high Coulombic efficiency of 99.9 % at 1 A/g, while the cell operates for only 42 cycles without NIC additive. This strategy presents a promising approach to solving the anode problem, fostering advancements in practical AZIBs. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable zinc‐sulfur (Zn‐S) batteries are a promising, cost‐effective, and high‐capacity energy storage technology. Still, they are challenged by the poor reversibility of S cathodes, sluggish redox kinetics, low S utilization, and unsatisfactory areal capacity. This work develops a facile strategy to achieve an appealing high‐areal‐capacity (above 5 mAh cm−2) Zn‐S battery by molecular‐level regulation between S and high‐electrical‐conductivity tellurium (Te). The incorporation of Te as a dopant allows for manipulation of the Zn‐S electrochemistry, resulting in accelerated redox conversion, and enhanced S utilization. Meanwhile, accompanied by the S‐ZnS conversion, Te is converted to zinc telluride during the discharge process, as revealed by ex‐situ characterizations. This additional redox reaction contributes to the S cathode's total excellent discharge capacity. With this unique cathode structure design, the carbon‐confined TeS cathode (denoted as Te1S7/C) delivers a high reversible capacity of 1335.0 mAh g−1 at 0.1 A g−1 with a mass loading of 4.22 mg cm−2, corresponding to a remarkable areal capacity of 5.64 mAh cm−2. Notably, a hybrid electrolyte design uplifts discharge plateau, reduces overpotential, suppresses Zn dendrites growth, and extends the calendar life of Zn‐Te1S7 batteries. This study provides a rational S cathode structure to realize high‐capacity Zn‐S batteries for practical applications. [ABSTRACT FROM AUTHOR]

Aqueous zinc‐ion batteries (AZIBs) suffer from rampant Zn dendrites growth, corrosion and sluggish transport kinetics, all of which have a serious impact on their performance and practical applications. Therefore, porous carbon nanofibers (BTO@PCNFs) loaded with BaTiO3 nanoparticles (BTO NPs) are constructed as a multifunctional interlayer for stabilizing the Zn anodes. Owing to the synergistic effect of BTO NPs and 3D porous carbon framework, this interlayer can achieve uniform electric field distribution, accelerate Zn2+ migration, and promote ion flux homogenization, thus leading to uniform Zn deposition. Meanwhile, the BTO@PCNFs interlayer demonstrates excellent anti‐corrosion effect, which can effectively prevent the side reactions. Benefiting from the synergistic effect of interlayers, the BTO@PCNFs multifunctional interlayers achieve a comprehensive optimization of the Zn anodes. The BTO@PCNFs‐Zn electrode exhibits lower nucleation overpotential (33.5 mV) at 0.5 mA cm−2. The Zn//Zn symmetrical cell with BTO@PCNFs interlayer exhibits ultra‐low overpotential (14 mV) and ultra‐long cycle life (5250 h at 0.5 mA cm−2). Even at high current density (30 mA cm−2), the BTO@PCNFs‐Zn electrode can be stably cycled for more than 830 h, achieving an ultra‐high cumulative capacity of 12 450 mAh cm−2. The multifunctional interlayers can provide a reference for the design of high‐performance Zn anodes.

Highlights Digital holography can realize the in situ observation of electrode/electrolyte interface and provide dynamic evolution information of the liquid phase of electrode, which is both efficient and effective in investing the interficial electrochemical mechanism and screening electrolyte additives. Thioacetamide electrolyte additive effectively enhances the electrochemical performance of Zn anode by regulating the interficial ion flux to induce dendrite-free Zn deposition and constructing adsorption molecule layers to inhibit side reactions.

Highlights: Digital holography can realize the in situ observation of electrode/electrolyte interface and provide dynamic evolution information of the liquid phase of electrode, which is both efficient and effective in investing the interficial electrochemical mechanism and screening electrolyte additives. Thioacetamide electrolyte additive effectively enhances the electrochemical performance of Zn anode by regulating the interficial ion flux to induce dendrite-free Zn deposition and constructing adsorption molecule layers to inhibit side reactions.Zinc ion batteries are considered as potential energy storage devices due to their advantages of low-cost, high-safety, and high theoretical capacity. However, dendrite growth and chemical corrosion occurring on Zn anode limit their commercialization. These problems can be tackled through the optimization of the electrolyte. However, the screening of electrolyte additives using normal electrochemical methods is time-consuming and labor-intensive. Herein, a fast and simple method based on the digital holography is developed. It can realize the in situ monitoring of electrode/electrolyte interface and provide direct information concerning ion concentration evolution of the diffusion layer. It is effective and time-saving in estimating the homogeneity of the deposition layer and predicting the tendency of dendrite growth, thus able to value the applicability of electrolyte additives. The feasibility of this method is further validated by the forecast and evaluation of thioacetamide additive. Based on systematic characterization, it is proved that the introduction of thioacetamide can not only regulate the interficial ion flux to induce dendrite-free Zn deposition, but also construct adsorption molecule layers to inhibit side reactions of Zn anode. Being easy to operate, capable of in situ observation, and able to endure harsh conditions, digital holography method will be a promising approach for the interfacial investigation of other battery systems. [ABSTRACT FROM AUTHOR]

Because of their high safety, low cost, and high volumetric specific capacity, zinc-ion batteries (ZIBs) are considered promising next-generation energy storage devices, especially given their high potential for large-scale energy storage. Despite these advantages, many problems remain for ZIBs—such as Zn dendrite growth, hydrogen evolution, and Zn anode corrosion—which significantly reduce the coulomb efficiency and reversibility of the battery and limit its cycle lifespan, resulting in much uncertainty in terms of its practical applications. Numerous electrolyte additives have been proposed in recent years to solve the aforementioned problems. This review focuses on electrolyte additives and discusses the different substances employed as additives to overcome the problems by altering the Zn ^2+ solvation structure, creating a protective layer at the anode–electrolyte interface, and modulating the Zn ^2+ distribution to be even and Zn deposition to be uniform. On the basis of the review, the possible research strategies, future directions of electrolyte additive development, and the existing problems to be solved are also described.

Abstract The need for large‐scale electrochemical energy storage devices in the future has spawned several new breeds of batteries in which aqueous zinc ion batteries (AZIBs) have attracted great attention due to their high safety, low cost, and excellent electrochemical performance. In the current research, the dendrite and corrosion caused by aqueous electrolytes are the main problems being studied. However, the research on the zinc metal anode is still in its infancy. We think it really needs to provide clear guidelines about how to reasonably configure the system of AZIBs to realize high‐energy density and long cycle life. Therefore, it is worth analyzing the works on the zinc anode, and several strategies are proposed to improve the stability and cycle life of the battery in recent years. Based on the crystal chemistry and interface chemistry, this review reveals the key factors and essential causes that inhibit dendrite growth and side reactions and puts forward the potential prospects for future work in this direction. It is foreseeable that guiding the construction of AZIBs with high‐energy density and long cycle life in various systems would be quite possible by following this overview as a roadmap.

Rechargeable Zn-based batteries (RZBs) have garnered a great interest and are thought to be among the most promising options for next-generation energy storage technologies due to their low price, high levels of safety, adequate energy density and environmental friendliness. However, dendrite formation during stripping/plating prevents rechargeable zinc-based batteries from being used in real-world applications. Dendrite formation is still a concern, despite the fact that inhibitory strategies have been put up recently to eliminate the harmful effects of zinc dendrites. Thus, in order to direct the strategies for inhibiting zinc dendrite growth, it is vital to understand the formation mechanism of zinc dendrites. Hence, for the practical application of zinc-based batteries, is essential to use techniques that effectively prevent the creation and growth of zinc dendrites. The development and growth principles of zinc dendrites are first made clear in this review. The recent advances of solutions to the zinc dendrite problem are then discussed, including strategies to prevent dendrite growth and subsequent creation as much as possible, reduce the negative impacts of dendrites, and create dendrite-free deposition processes. Finally, the challenges and perspective for the development of zinc-based batteries are discussed.

Zinc‐ion batteries (ZIBs) have been extensively investigated and discussed as promising energy storage devices in recent years owing to their low cost, high energy density, inherent safety, and low environmental impact. Nevertheless, several challenges remain that need to be prioritized before realizing the widespread application of ZIBs. In particular, the development of zinc anodes has been hindered by many challenges, such as inevitable zinc dendrites, corrosion passivation, and the hydrogen evolution reaction (HER), which have severely limited the practical application of high‐performance ZIBs. This review starts with a systematic discussion of the origins of zinc dendrites, corrosion passivation, and the HER, as well as their effects on battery performance. Subsequently, we discuss solutions to the above problems to protect the zinc anode, including the improvement of zinc anode materials, modification of the anode–electrolyte interface, and optimization of the electrolyte. In particular, this review emphasizes design strategies to protect zinc anodes from an integrated perspective with broad interest rather than a view with limited focus. In the final section, comments and perspectives are provided for the future design of high‐performance zinc anodes. [ABSTRACT FROM AUTHOR]

"Tip effect" triggered by uneven zinc deposition accelerates the growth of Zn dendrites. The unfavorable interfacial activity gradient aggravates zinc deposition at the tips, which is the root cause of zinc dendrites. This study reports an interfacial local activation strategy to reconfigure the interfacial activity gradient of zinc anode to promote more stable operation of zinc batteries. A locally activated zinc anode (Zn-ILA) is proposed as the proof-of-concept zinc anode by constructing high-active microchannels to induce preferential zinc deposition, while the remaining low-active region is accompanied by zinc epitaxial growth, thus achieving bottom-up zinc deposition at the anode interface. A fabrication method based on nanosecond pulsed laser is used to modify the zinc anode by creating high-active microchannels through thermal impingement. Additionally, low-active regions covered by dense ZnO nanoparticles are also formed due to the plasma effect. The laser-induced cross-scale oxide layers help improve the corrosion resistance at the full zinc anode interface. The proposed interfacial local activation strategy enables ordered selective deposition at the Zn-ILA interface owing to the activity gradient, as well as stabilizes the long-term operation of symmetric and full cells. The effectiveness of Zn-ILA is also validated in large-area pouch batteries, showing great potential for large-scale energy storage systems. [Display omitted] • An interfacial local activation strategy has been proposed to promote stable zinc anodes. • A gradient active interface has been developed to tailor the patterns of selective zinc deposition. • Corrosion resistance and charge transfer kinetics of the Zn-ILA electrode can be synergistically enhanced. • The optimized Zn-ILA electrode enables outstanding cycling stability in both coin and pouch cells. [ABSTRACT FROM AUTHOR]

Abstract Zinc‐ion batteries (ZIBs) have been extensively investigated and discussed as promising energy storage devices in recent years owing to their low cost, high energy density, inherent safety, and low environmental impact. Nevertheless, several challenges remain that need to be prioritized before realizing the widespread application of ZIBs. In particular, the development of zinc anodes has been hindered by many challenges, such as inevitable zinc dendrites, corrosion passivation, and the hydrogen evolution reaction (HER), which have severely limited the practical application of high‐performance ZIBs. This review starts with a systematic discussion of the origins of zinc dendrites, corrosion passivation, and the HER, as well as their effects on battery performance. Subsequently, we discuss solutions to the above problems to protect the zinc anode, including the improvement of zinc anode materials, modification of the anode–electrolyte interface, and optimization of the electrolyte. In particular, this review emphasizes design strategies to protect zinc anodes from an integrated perspective with broad interest rather than a view with limited focus. In the final section, comments and perspectives are provided for the future design of high‐performance zinc anodes.

• Aqueous rechargeable batteries with low-cost hybrid electrolytes can effectively improve the output voltage and alleviate the zinc dendrites. • The full cells assembled with potassium zinc hexacyanoferrate (KZnHCF) cathodes and zinc foil anodes reach an output voltage of 1.92 V and an energy density of 107.6 Wh kg−1. • The hybrid electrolyte contributes to the uniform deposition/stripping and suppress the zinc dendrites. The energy density of aqueous reachable batteries (ARBs) is limited by the output voltage in the aqueous electrolyte. Herein, low-cost aqueous hybrid electrolytes composed of ZnSO 4 and K 2 SO 4 dual salts effectively improve the output voltage and suppress the zinc dendrites. The aqueous full cells assembled with potassium zinc hexacyanoferrate (KZnHCF) cathodes and zinc foil anodes reach an output voltage of 1.92 V and an energy density of 107.6 Wh kg−1. It is demonstrated the reversible insertion/extraction of K+ at the cathodes and uniform zinc deposition/striping at the anode in hybrid electrolyte via a series in-situ and ex-situ investigation. The dual salt electrolyte can not only satisfy the reversible capacitive dominated process at the cathodes but also suppress the zinc dendrite. Density functional theory (DFT) calculation demonstrates the K+ preferential intercalation mechanism of KZnHCF in hybrid electrolyte and the inhibition effect of K+ insertion on Zn2+ insertion. This strategy presents a promising approach for development of high performance and low-cost aqueous electrolyte. [ABSTRACT FROM AUTHOR]

Abstract Aqueous zinc‐ion batteries (ZIBs) have been intensively investigated as potential energy storage devices on account of their low cost, environmental benignity, and intrinsically safe merits. With the exploitation of high‐performance cathode materials, electrolyte systems, and in‐depth mechanism investigation, the electrochemical performances of ZIBs have been greatly enhanced. However, there are still some challenges that need to be overcome before its commercialization. Among them, the obstinate dendrites, corrosion, and hydrogen evolution reaction (HER) on Zn anodes are critical issues that severely limit the practical applications of ZIBs. To address these issues, various strategies have been proposed, and tremendous progress has been achieved in the past few years. In this article, we analyze the origins and effects of the dendrites, corrosion, and HER on Zn anodes in neutral and mildly acid aqueous solutions at first. And then, a scientific understanding of the fundamental design principles and strategies to suppress these problems are emphasized. Apart from these, this article also puts forward some requirements for the practical applications of Zn anodes as well as several cost‐effective‐modifying strategies. Finally, perspectives on the future development of Zn anodes in aqueous solutions are also briefly anticipated. This article provides pertinent insights into the challenges on anodes for the development of high‐performance ZIBs, which will greatly contribute to their practical applications.

The inherent safety and high energy density of aqueous Zn-ion batteries (AZIBs), coupled with the abundant reserves of Zn, make them an ideal candidate for the following generation of energy storage devices. Nevertheless, the growth of dendrites and water decomposition seriously hinder the commercialization of AZIBs. This work proposes depositing a thin polydimethylsiloxane (PDMS) layer on the Zn surface through a simple vapor method (PDMS@Zn) to address the above challenges. Significantly, the presence of this PDMS layer degrades the resistance of nucleation, optimizes the crystal orientation of Zn2+ deposition, isolates and protects Zn anode, and restricts the flow of Zn2+, improving the kinetics of Zn2+ deposition and homogenizes Zn2+ stripping/plating. The assembled PDMS@Zn symmetrical batteries exhibit 25 mV low voltage hysteresis for 1500 h cycles at 1 mA cm−2, 0.5 mA h cm−2, and the full-cell with an ultra-long cycle life of 2500 cycles. • The PDMS layer is prepared on Zn metal using a one-step vapor deposition method. • The PDMS layer presents an excellent desolvation effect. • The hydrophobic PDMS layer isolates the Zn anode and inhibits water decomposition. • The gap structure of the layer limits Zn2+ flux and facilitates Zn2+ a uniform deposition. [ABSTRACT FROM AUTHOR]

Abstract Rechargeable Zn‐based batteries (RZBs) have attracted much attention and been regarded as one of the most promising candidates for next‐generation energy storage featured with high safety, low costs, environmental friendliness, and satisfactory energy density. The aqueous electrolyte system exhibits great potential to power the future wearable electronics. Apart from the achievements of high capacity cathode and stable electrolyte, the anode suffers from problems of dendrite growth, hydrogen evolution, and passivation with limited attention. The dendrite formation strongly restricts the battery lifespan. Therefore, strategies focused on dendrite suppression are carefully categorized and summarized in this review, including crystallographic orientation manipulation, electric field control, ion flux regulation, and mechanical shield. Each strategy and the detailed approaches are critically dissected. Finally, remaining challenges are emphasized in this review, expecting to supply further research with potential directions to fulfill the high performance of the Zn anodes.

Atomic-scale inorganic carbon nanomaterials (ICN) with rich surface polarity and low lattice mismatch for zinc is proposed as a green and effective electrolyte additive to regulate the Zn deposition behavior, rending dendrite-free and side reactions-free Zn metal anodes. [Display omitted] • A multifunctional electrolyte additive of ICN is developed for Zn-ion batteries. • The high surface polarity of ICN mitigates the water-induced side reactions. • The low lattice mismatch with Zn(0 0 2) nanosheets guides parallel Zn deposition. • The full battery harvests excellent cycling performance under practical conditions. 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 ZnSO 4 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 (0 0 2) 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||VO X 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. [ABSTRACT FROM AUTHOR]

[Display omitted] • ZnSO 4 electrolyte is functionalized with AgNO 3 to uniformize the Zn+ deposition. • Chemical and electrochemical synergistic weaved Ag layer feature zincophilic sites. • Ag+ additive can effectively induce zinc dendrites growth and inhibit HER for AZIBs. • AZIBs with AgNO 3 additive deliver longevous cycle life over 1350 h. Dendrites growth and hydrogen evolution reaction of Zn anode greatly hinder the practical application of aqueous zinc ion batteries. Interface engineering strategies have attracted immense interest in addressing these challenges. Herein, a chemical and electrochemical method is proposed to synergistically weave a stable interface by introducing AgNO 3 additive in conventional aqueous ZnSO 4 electrolyte. The formed compact Ag layer acts as zincophilic sites, which is beneficial for zinc ion nucleation and growth. Consequently, the cell cycled in 2 M ZnSO 4 with 3 mM AgNO 3 electrolyte exhibits much more stable electrochemical properties than its counterpart. To be specific, the Zn || Zn half cell using the electrolyte with 3 mM AgNO 3 shows reversible Zn plating/stripping behavior over 1350 h at 5.0 mA cm−2 with an ultra-low potential hysteresis. Moreover, Zn || V 2 O 5 full cell using the electrolyte with 3 mM AgNO 3 exhibits glorious rate capability and more stable cycling performance, attributing to the inhibited zinc dendrites growth by the weaved interfacial layer. This work sheds new light on improving the electrochemical performance of rechargeable batteries. [ABSTRACT FROM AUTHOR]

The in-situ protective layer of ultrafine Sn particles on zinc foil featuring enhanced uniform electric field and more exposed active sites markedly promotes Zn2+ transport kinetics and lowers the nucleation energy barrier to achieve even zinc deposition at high current density. [Display omitted] • A protective layer by ultrafine particles is facilely in-situ formed. • The anode features enhanced uniform electric field and more exposed active sites. • The reduced energy barrier realizes ultralow voltage hysteresis (16 mV) at 1 mA cm−2. • Prolonged lifespan (300 h) and high depth of discharge (87.8 %) are achieved at 10 mA cm−2. The ramped-up dendritic deposits, hydrogen evolution reaction, and corrosion of the zinc anode at high current density and high areal capacity constitute enormous obstacles to commercializing of aqueous zinc ion batteries (ZIBs). Here, a facile impregnation treatment is reported for the in-situ controllable synthesis of a protective layer composed of ultrafine metallic tin particles on the zinc foil for the first time. Compared with the protection layer with large particles, the surface with ultrafine particles demonstrates an enhanced homogeneous electric field and more active sites to achieve accelerated transport kinetics of zinc ions. Additionally, the nucleation energy barrier is effectively reduced due to the higher surface energy of the ultrafine particles to guarantee the stability of deep electrodeposition at high areal capacity. Therefore, the electrode delivers a durable and steady stripping/plating behaviour over 2000 h at 1 mA cm−2 (1 mAh cm−2) with an extremely reduced voltage hysteresis (≈16 mV). At a high areal capacity of 10 mAh cm−2, it stably cycles for over 300 h with a high depth of discharge (87.8 %). The feasibility of its practical implementation has been validated in coin cells and flexible pouch cells. This work sheds new light on improving the electrochemical deposition behaviour of ZIBs for deep plating/stripping under high current densities, serving as a reference for the design of nanoscale protective layers for ZIBs or other metal batteries. [ABSTRACT FROM AUTHOR]

Aqueous Zn-based batteries (AZBs) have attracted great attention due to their high safety, low cost, and environmental friendliness. However, the Zn anode suffers from problems such as the formation of Zn dendrites. And there are only few active cathode materials which can allow the insertion/extraction of Zn2+ ions. Thereinto, Prussian blue analogs (PBAs) are promising active cathode materials for AZBs, having high operation voltage but poor electrochemical stability. Herein, K 2 Zn 3 [Fe(CN) 6 ] 2 (KZnHCF) particles with cubic morphology are prepared for AZBs, and the electrochemical stability is improved by simply adjusting the composition of the electrolyte solvent in the battery system. Electrochemical tests indicate that the electrolyte with ethanol (EA) as solvent can promote the uniform deposition of zinc, thereby inhibiting the growth of Zn dendrites. Furthermore, ex-situ XRD results prove that the structural damage of KZnHCF during charging-discharge process is greatly alleviated when EA is used as the electrolyte solvent. Nonetheless, using pure EA as electrolyte solvent exposes the batteries to potential safety hazards, and compared with the Zn/KZnHCF batteries with H 2 O as solvent, the specific capacities of the batteries with EA as solvent are lower. Hence, the mixed electrolytes with different volume ratios (H 2 O/EA-1:1, H 2 O/EA-1:2, H 2 O/EA-2:1) are applied. It's obvious that not only the growth of zinc dendrites is suppressed, but also the electrochemical performances of the batteries are further improved. Overall, a dendrite-free and high-performance Zn/KZnHCF battery is obtained by using a mixed electrolyte solvent (H 2 O/EA-1:1), presenting average specific capacities of 50.0, 49.0, 46.3, and 43.2 mAh g−1 at current densities of 50, 100, 150, and 200 mA g−1, and remaining a specific capacity of 29.1 mAh g−1 at a current density of 200 mA g−1 after 500 cycles. • A dendrite-free and high-performance Zn/KZnHCF battery is created. • The inhibition effect of ethanol on the growth of Zn dendrites is clarified. • The effect of different electrolyte solvents is investigated by ex-situ XRD tests. • As-prepared Zn/KZnHCF batteries are superior to the reported aqueous zinc batteries. [ABSTRACT FROM AUTHOR]

Rechargeable Zn-based batteries (RZBs) have garnered a great interest and are thought to be among the most promising options for next-generation energy storage technologies due to their low price, high levels of safety, adequate energy density and environmental friendliness. However, dendrite formation during stripping/plating prevents rechargeable zinc-based batteries from being used in real-world applications. Dendrite formation is still a concern, despite the fact that inhibitory strategies have been put up recently to eliminate the harmful effects of zinc dendrites. Thus, in order to direct the strategies for inhibiting zinc dendrite growth, it is vital to understand the formation mechanism of zinc dendrites. Hence, for the practical application of zinc-based batteries, is essential to use techniques that effectively prevent the creation and growth of zinc dendrites. The development and growth principles of zinc dendrites are first made clear in this review. The recent advances of solutions to the zinc dendrite problem are then discussed, including strategies to prevent dendrite growth and subsequent creation as much as possible, reduce the negative impacts of dendrites, and create dendrite-free deposition processes. Finally, the challenges and perspective for the development of zinc-based batteries are discussed., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Worku.)

The issue of Zn dendrites has been limiting the further application of aqueous Zn ion batteries. In this work, the three-dimensional trench interface on the surface of the Zn foil is constructed by a simple etching method to buffer the formation of the Zn dendrite. Importantly, the relationship between stripping/plating behavior and dendrite formation, especially stripping behavior, is systematically analyzed using Ex-situ scanning electron microscope and finite element method. The low current density interface designed by etching a three-dimensional trench structure plays a key role in controlling the formation of the Zn dendrite. Therefore, the resultant Zn anode can be stably cycled up to 1800h at the current density of 1 mA cm−2 in the symmetric cell and displays a discharge capacity of 120.1 mAh g−1 after 1000 cycles at a current density of 1 A g−1 in a full cell. This strategy affords a generic approach for large-scale applications of metal anodes in aqueous systems. •The low current density interface is designed by the etched Zn foil. •The effects of stripping/plating behavior on the dendrite formation are analyzed. •The resultant Zn anode displays superior electrochemical performance in the cell. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable Zn batteries have gathered supreme significance and importance in the recent times as promising energy storage devices. Zn batteries possess prodigious potential for safer and large-scale energy storage applications. However, the critical challenges associated with both Zn anode and cathode adversely affects their widespread commercialization that needs urgent methodologies to tackle these issues governed by thermodynamic instability of Zn anode in traditional aqueous electrolytes. The water induced unwanted side reactions include Zn dendrites, corrosion, shape change, passivation, H 2 evolution that leads to poor Zn utilization and reversibility. Surface engineering of Zn anode through artificial protective layers/coatings is an emerging and promising research direction towards stabilization of Zn metal anodes. In this review, we summarize briefly the critical issues of Zn anode in aqueous environment and then switching to the up-to-date developments in surface coatings for Zn anode, with comprehensive explanations of their working principles. This review will provide latest and summarized literature for Zn battery community assisting them to design novel Zn anode protective approaches. [Display omitted] • Fundamental challenges of Zn anode in aqueous environment are highlighted. • Latest interfacial protection strategies for Zn anode has been summarized. • Role of different coating materials and their effectiveness has been revealed. • Future perspectives has been discussed towards realization of reliable Zn anodes. [ABSTRACT FROM AUTHOR]

• A dense Zn-Al-LDHs anode protection layer can efficiently avoid the additional reaction and growth of zinc dendrites. • The hydrophilic and anticorrosive property of Zn-Al-LDHs protection layer has a lower nucleation/dissolution energy barrier. • The lower surface area and adsorption capability of the dense protection layer can effectively shorten the ion transport path and improve kinetic. Rechargeable aqueous zinc ion batteries have attracted increasing attention for large-scale energy storage system. Restricted by the zinc deposition and dendrite growth, the practical application was hindered seriously by the poor rechargeability and instability. The strategy of utilizing Zn-Al-layered double hydroxides hexagonal nanoplates modifying zinc metal anode was employed by a scalable method of spinning coating. This integrated electrode can not only realize ions well-distributed reaction on the electrode surface due to the dense protection layer weak adsorption behavior and low surface area, but also can efficiently avoid excessive zinc deposition and growth of zinc dendrites. The nucleation and dissolution energy barriers in the phase transition between zinc ions and the integrated electrode are decreased as well. The integrated electrode harvests a long-term stability of 1000 h at 1.0 mA h cm-2 and effectively suppresses side reactions in the Zn//Zn symmetric cells. In addition, coupled with MnO 2 as full cell, the capacity remains 195 mA h g-1 with the retention of 81.2% after 200 cycles. It is promising that the employed scalable strategy will provide new pathway into Zn metal anode protection and accelerate the practical application of aqueous zinc ion batteries. [ABSTRACT FROM AUTHOR]

• Uniform nano-sized SiO 2 spheres are successfully coated on Zn surface as metal protective layer. • The coating layer facilitates electrolyte wettability of Zn foil to achieve better ions assessments. • The layer drives ions to uniformly deposit as ions shunt, avoiding the dendrites growing. • The modified electrode enhances the electrochemical performance in both symmetric and full cells. Aqueous Zn ion batteries (AZIBs) have been widely studied due to their high safety, suitable redox potential and high theoretical capacity. As the most commonly used anode for AZIBs, Zn foil suffers from severe dendrites growth and undesired side reactions, causing battery failure. In this work, a coating layer of stacked SiO 2 spheres is designed on a Zn metal surface (SiO 2 @Zn). The hydrophilic coating layer improves the electrolyte wettability of the Zn anode. Besides, it acts as ions shunt to lead Zn ions evenly plating between the coating layer and the metal anode, avoiding dendrites growth. With electrochemical characterizations and in-situ optical microscopy observations, the electrode presents a stable voltage profile and a long cycling life (2000 h at 0.5 mA cm−2), and the capacity decay in a full cell is significantly alleviated. [ABSTRACT FROM AUTHOR]

Zinc anode is promising for various aqueous batteries due to its low cost and high theoretical specific capacity. However, poor cycling stability caused by dendritic growth seriously hampered its widespread application. Herein, we demonstrate that by using an anion-exchange membrane, quaternary ammonia poly (N -methyl-piperidine- co - p -terphenyl) (QAPPT), as the separator, the damage from short circuits can be completely prevented. More details reveal that when approaching the QAPPT membrane, Zn dendrites perform a bending growth rather than pierce through it, which helps achieve a superior cycling stability without any short. The bending growth can be ascribed to a variation of electrolyte concentration at the electrode/membrane interface where Zn electrodeposited at a very low rate in the direction perpendicular to the membrane. By using QAPPT membrane, an ultra-stable Ni–Zn full cell is then realized. This finding may pave a facile way to solve the problems associated with dendrites for diverse alkaline Zn-based batteries. Image 1 • A highly base-stable anion-exchange membrane was employed as battery separator. • The separator exhibits zincate ion-conducting property. • The unique electrode/electrolyte interface prevents the short caused by dendrites. • Providing a practical strategy for rechargeable alkaline Zn-based batteries. [ABSTRACT FROM AUTHOR]

Zinc aqueous batteries have attracted great attention due to the earth abundance and the low redox potential of Zn metal. Utilizing Zn metal as an anode, however, causes low coulombic efficiency stemming from a dendritic Zn plating and formation of byproducts such as hydrogen gas, solid zinc hydroxide and salt-related compounds. One effective way of mitigating the issues is to modify the solvation structure of the electrolyte to increase the energy barrier of the water molecules for hydrolysis and electrolysis. Nevertheless, Zn aqueous batteries still indiscriminately utilize several types of electrolytes without elucidating the correlation between electrolyte composition and the electrochemistry of Zn metal. Here, we use operando optical microscopy to visualize the microstructural evolution of Zn metal, which strongly affects the electrochemical reversibility. In ZnSO 4 electrolyte, large Zn platelets grow and form loose agglomerates vulnerable to unexpected delamination from the electrodes. In Zn(OTf) 2 electrolyte, Zn platelets nucleate more homogeneously and grow smaller, which forms denser agglomerates enabling more stable cycling. We further reveal that the formation of a stable solid-electrolyte interphase layer holds the key to the excellent performance of acetonitrile-hybrid water-in-salt electrolytes. Our results show the necessity of designing proper electrolytes to develop long-life Zn aqueous batteries. Image 1 • Operando optical microscopic observation of Zn plating/stripping is demonstrated. • Correlation between electrolyte and microstructure of Zn metal is established. • Denser Zn agglomerates with finer Zn particles enables the better cyclability. • Stable SEI layer plays a key role for reversible deposition/stripping of Zn. [ABSTRACT FROM AUTHOR]