Interfacial Design of Dendrite‐Free Zinc Anodes for Aqueous Zinc‐Ion Batteries

Aqueous zinc‐ion batteries have rapidly developed recently as promising energy storage devices in large‐scale energy storage systems owing to their low cost and high safety. Research on suppressing zinc dendrite growth has meanwhile attracted widespread attention to improve the lifespan and reversibility of batteries. Herein, design methods for dendrite‐free zinc anodes and their internal mechanisms are reviewed from the perspective of optimizing the host–zinc interface and the zinc–electrolyte interface. Furthermore, a design strategy is proposed to homogenize zinc deposition by regulating the interfacial electric field and ion distribution during zinc nucleation and growth. This Minireview can offer potential directions for the rational design of dendrite‐free zinc anodes employed in aqueous zinc‐ion batteries.     

Bulk-Phase Reconstruction Enables Robust Zinc Metal Anodes for Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries are inherently safe, but the severe dendrite growth and corrosion reaction on zinc anodes greatly hinder their practical applications. Most of the strategies for zinc anode modification refer to the research of lithium metal anodes on surface regulation without considering the intrinsic mechanisms of zinc anode. Herein, we first point out that surface modification cannot permanently protect zinc anodes due to the unavoidable surface damage during the stripping process by solid–liquid conversion. A bulk-phase reconstruction strategy is proposed to introduce abundant zincophilic sites both on the surface and inside the commercial zinc foils. The bulk-phase reconstructed zinc foil anodes exhibit uniform surfaces with high zincophilicity even after deep stripping, significantly improving the resistance to dendrite growth and side reactions. Our proposed strategy suggests a promising direction for the development of dendrite-free metal anodes for practical rechargeable batteries with high sustainability.     

Recent Progress in Aqueous Zinc-Ion Batteries: From FundamentalScience to Structure Design

Rechargeable aqueous zinc-ion batteries (ZIB) sparked a considerable surge of research attention in energy storage systems due to its environment benignity and superior electrochemical performance. Up to now, less efforts to delve into mechanisms of zinc metal anode and their electrochemical performance. Zn metal anodes sustain thorny issues with Zn dendrite growth, hydrogen evolution reaction, and Zn corrosion irreversible byproduct formation, which results in low coulomb efficiency (CE) and poor cycle ability of the battery. Herein, we reveal the fundamental understanding of the above issue, outline four step, including mass transfer, desolvation process, charge transfer and Zn cluster formation. It can be clearly seen from reported strategies to promote Zn anode stability that deals with one or more steps, thereby boosting the understanding of the issues of Zn anodes and benefiting the rational design to surmount the issue. We also sum up advanced materials and structure design such as the design of the anode surface and internal structure, electrolyte strategies, and multifunctional separators. Finally, possible tactics and future innovation direction for Zn-based batteries are proposed to achieve high performance aqueous Zinc-ion batteries.     

Advanced Current Collectors for Alkali Metal Anodes

High-energy-density batteries are in urgent need to solve the ever-increasing energy storage demand for portable electronic devices, electric vehicles, and renewable solar and wind energy systems. Alkali metals, typically lithium(Li), sodium(Na) and potassium(K), are considered as the promising anode materials owing to their low electrochemical potential, low density, and high theoretical gravimetric capacities. However, the problem of dendrite growth of alkali metals during their plating/stripping process will lead to low Coulombic efficiencies, a short lifespan and huge volume expansion, eventually hindering their practical commercialization. To resolve this issue, a very effective approach is engineering the anodes on structured current collectors. This review summarizes the development of the alkali metal batteries and discusses the recent advances in rational design of anode current collectors. First, the challenges and strategies of suppressing alkali-metal dendrite growth are presented. Then the special attention is paid to the novel current collector design for dendrite-free alkali metal anodes. Finally, we give conclusions and perspective on the current challenges and future research directions toward advanced anode current collectors for alkali metal batteries.     

Discovering the Intrinsic Causes of Dendrite Formation in Zinc Metal Anodes: Lattice Defects and Residual Stress

Developing a highly stable and dendrite-free zinc anode is essential to the commercial application of zinc metal batteries. However, the understanding of zinc dendrites formation mechanism is still insufficient. Herein, for the first time, we discover that the interfacial heterogeneous deposition induced by lattice defects and epitaxial growth limited by residual stress are intrinsic and critical causes for zinc dendrite formation. Therefore, an annealing reconstruction strategy was proposed to eliminate lattice defects and stresses in zinc crystals, which achieve dense epitaxial electrodeposition of zinc anode. The as-prepared annealed zinc anodes exhibit dendrite-free morphology and enhanced electrochemical cycling stability. This work first proves that lattice defects and residual stresses are also very important factors for epitaxial electrodeposition of zinc in addition to crystal orientation, which can provide a new mechanism for future researches on zinc anode modification.     

Na-K liquid alloy:A review on wettability enhancement and ionic carrier selection mechanism

The intrinsic liquid interface of Na-K alloy allays concerns about dendrite growth on metal anodes that are thermodynamically within the room temperature(20-22℃).Nevertheless,it hinders the formation of a stable electrode structure due to the inferior wettability induced by considerable liquid tension.In addition,the dominant ionic carrier in the Na-K alloy is subject to multiple factors,which is not conducive to customized battery design.This review,based on recently reported frontier achievements on Na-K liquid anodes,summarizes practical strategies for promoting the wettability by hightemperature induction,capillary effect,vacuum infiltration,and solid interface protection.Furthermo re,four selection mechanisms of the dominant ionic carrier are presented:(1) ion property dominated,(2)cathode dominated,(3) separator dominated,and(4) solid electrolyte interface dominated.Notably,initial electrolytes in energy storage systems have been unable to play a decisive role in ionic selection.Utilizing a superior wettability strategy and simultaneously identifying the dominant ionic carrier can facilitate the tailored application of dendrite-free Na-K liquid anodes.     

A Semi-solid Zinc Powder-based Slurry Anode for Advanced Aqueous Zinc-ion Batteries

The booming of aqueous zinc-ion batteries (AZIBs) draws the researchers’ attention to issues of zinc metal anodes, such as uncontrollable dendrite growth, corrosion, and volume effects. Zinc powder anode is more suitable for the industrial application of AZIBs than the widely used zinc foil anode due to its low cost, tunability and processability. However, the related solutions are rarely studied because the above issues of zinc metal anode are more serious in zinc powder anode. Herein, for the first time, we design a semi-solid zinc slurry anode consisting of zinc powder and zincophilic tin additive dispersed in a conductive elastic rheological network. Zinc can be deposited homogeneously on the dispersed tin particles, which avoids agglomerative zinc deposition and alleviates volume change during repeated zinc stripping/plating. Moreover, the practical application of the full cell with slurry is very promising since its operating life can be easily extended by facile slurry renewal.     

锂金属负极人造保护膜的研究进展

金属锂因其具有极高的理论容量(3860 mAh·g^?1)、最低的电极电位(?3.04 V vs.标准氢电极)和低的密度(0.534 g·cm^?3),被认为是最具潜力的负极材料。但循环过程中不可控的枝晶生长及不稳定的固体电解质相界面膜所引起的安全隐患和电池库伦效率低等问题严重阻碍了锂金属负极的发展。通过在电极表面构建人造保护膜可以有效调控锂离子沉积行为,因此人造保护膜的构建是一种简单高效抑制锂枝晶生长的策略。本综述将从聚合物保护膜、无机保护膜、有机-无机复合保护膜和合金保护膜总结了人造保护膜的构建方法、抑制锂枝晶生长机理,为促进高比能锂金属电池的商业化应用提供借鉴参考作用。     

Bio-degradable zinc-ion battery based on a prussian blue analogue cathode and a bio-ionic liquid-based electrolyte

Rechargeable zinc-ion batteries are of high interest for electrical energy storage due to their low cost, high safety, and good energy density. The development of stable and high-performance cathode materials and environmentally friendly electrolytes is of interest for practical applications. Despite many efforts in pursuing batteries with high energy density and long cycle life, relatively little attention has been paid on the environmental aspects. Thus, bio-batteries that contain nontoxic materials and which are bio-degradable are an interesting alternative to conventional batteries. In the present paper, we present our first results on a highly reversible zinc/prussian blue analogue (PBA) bio-battery, where nanostructured PBA is used as a cathode material, a bio-degradable ionic liquid-water mixture as electrolyte, and zinc as anode. Both the PBA cathode and the zinc anode exhibit good compatibility with the bio-degradable electrolyte. The Zn/PBA battery shows good electrochemical performance including an open circuit voltage of 1.6 V, a specific capacity of ～54 mAh g^?1 (PBA), and a low self-discharge rate. The zinc anode also shows a good stability since no dendritic growth and shape change are observed after 50 charge-discharge cycles.     

Electrolyte Regulation towards Stable Lithium‐Metal Anodes in Lithium–Sulfur Batteries with Sulfurized Polyacrylonitrile Cathodes

Lithium–sulfur (Li–S) batteries are highly regarded as the next‐generation energy‐storage devices because of their ultrahigh theoretical energy density of 2600 Wh kg^?1. Sulfurized polyacrylonitrile (SPAN) is considered a promising sulfur cathode to substitute carbon/sulfur (C/S) composites to afford higher Coulombic efficiency, improved cycling stability, and potential high‐energy‐density Li–SPAN batteries. However, the instability of the Li‐metal anode threatens the performances of Li–SPAN batteries bringing limited lifespan and safety hazards. Li‐metal can react with most kinds of electrolyte to generate a protective solid electrolyte interphase (SEI), electrolyte regulation is a widely accepted strategy to protect Li‐metal anodes in rechargeable batteries. Herein, the basic principles and current challenges of Li–SPAN batteries are addressed. Recent advances on electrolyte regulation towards stable Li‐metal anodes in Li–SPAN batteries are summarized to suggest design strategies of solvents, lithium salts, additives, and gel electrolyte. Finally, prospects for future electrolyte design and Li anode protection in Li–SPAN batteries are discussed.     

Current status and challenges for practical flowless Zn–Br batteries

The fire hazard of lithium-ion batteries has influenced the development of more efficient and safer battery technology for energy storage systems (ESSs). A flowless zinc–bromine battery (FL-ZBB), one of the simplest versions of redox batteries, offers a possibility of a cost-effective and nonflammable ESS. However, toward the development of a practical battery, many critical issues should be addressed. In this contribution, we review the current FL-ZBB technologies and provide an assessment of them from a battery design perspective. The key cell design parameters and their influence on battery specifications are described. The challenges related to materials and cell structure are also discussed to motivate future research.     

Stabilizing Lithium into Cross‐Stacked Nanotube Sheets with an Ultra‐High Specific Capacity for Lithium Oxygen Batteries

Although lithium–oxygen batteries possess a high theoretical energy density and are considered as promising candidates for next‐generation power systems, the enhancement of safety and cycling efficiency of the lithium anodes while maintaining the high energy storage capability remains difficult. Here, we overcome this challenge by cross‐stacking aligned carbon nanotubes into porous networks for ultrahigh‐capacity lithium anodes to achieve high‐performance lithium–oxygen batteries. The novel anode shows a reversible specific capacity of 3656 mAh g^?1, approaching the theoretical capacity of 3861 mAh g^?1 of pure lithium. When this anode is employed in lithium–oxygen full batteries, the cycling stability is significantly enhanced, owing to the dendrite‐free morphology and stabilized solid–electrolyte interface. This work presents a new pathway to high performance lithium–oxygen batteries towards practical applications by designing cross‐stacked and aligned structures for one‐dimensional conducting nanomaterials.     

An Interface-Bridged Organic–Inorganic Layer that Suppresses Dendrite Formation and Side Reactions for Ultra-Long-Life Aqueous Zinc Metal Anodes

Aqueous zinc (Zn) batteries (AZBs) are widely considered as a promising candidate for next-generation energy storage owing to their excellent safety features. However, the application of a Zn anode is hindered by severe dendrite formation and side reactions. Herein, an interfacial bridged organic–inorganic hybrid protection layer (Nafion-Zn-X) is developed by complexing inorganic Zn-X zeolite nanoparticles with Nafion, which shifts ion transport from channel transport in Nafion to a hopping mechanism in the organic–inorganic interface. This unique organic–inorganic structure is found to effectively suppress dendrite growth and side reactions of the Zn anode. Consequently, the Zn@Nafion-Zn-X composite anode delivers high coulombic efficiency (ca. 97 %), deep Zn plating/stripping (10 mAh cm⁻²), and long cycle life (over 10 000 cycles). By tackling the intrinsic chemical/electrochemical issues, the proposed strategy provides a versatile remedy for the limited cycle life of the Zn anode.     

水系锌离子电池锌负极保护策略

水系锌离子电池采用金属锌作为负极材料,具有绿色环保、安全等优势,有望用于大规模储能.锌金属的储量比锂更加丰富,也更容易开采与提纯.同时,锌具有较低的氧化还原电位(-0.76V vs SHE)和较高的理论比容量(820 mAh·g-1)和体积容量密度(5854 mAh· cm-3).由于充放电过程中存在锌枝晶和不可逆副产...     

A ZIF-8 Host for Dendrite-Free Zinc Anodes and N,O Dual-doped Carbon Cathodes for High-Performance Zinc-Ion Hybrid Capacitors

Zn is a promising anode for aqueous energy storage owing to it intrinsic superior properties such as large capacity, abundant reserves, low potential and safety. But, the growth of dendrites during charge and discharge leads to a decrease in reversibility. In addition, further development of zinc-ion hybrid capacitors (ZICs) is seriously challenging because of the lack of an exceptional cathode. Herein, we use ZIF-8 annealed at 500 °C (annealed ZIF-8) as a host material for stable and dendrite-free Zn anodes. Utilization of annealed ZIF-8 results in dendrite-free Zn deposition and stripping as a result of its porous construction, which contains trace Zn. Furthermore, we firstly proposed innovative N,O dual-doped carbon which was designed by the derived ZIF-8 (ZIF-8 derived C) as cathode for high-energy and power-density ZICs. The new ZIC assembled by Zn@annealed ZIF-8 anode and ZIF-8 derived C cathode provides a capacity of 135.5 mAh g⁻¹ and an energy density of 108.4 Wh kg⁻¹ with a power density of 800 W kg⁻¹ at 1.0 A g⁻¹. In addition, it shows outstanding cycling stability of 91% capacity retention after 6000 cycles at 5.0 A g⁻¹. Moreover, the solid-state ZICs can drive LEDs and smart watches. This ZIC holds promise for the practical application of supercapacitors.     

High-Capacity Zinc Anode with 96 % Utilization Rate Enabled by Solvation Structure Design

Aqueous zinc-ion batteries (AZBs) show promises for large-scale energy storage. However, the zinc utilization rate (ZUR) is generally low due to side reactions in the aqueous electrolyte caused by the active water molecules. Here, we design a novel solvation structure in the electrolyte by introduction of sulfolane (SL). Theoretical calculations, molecular dynamics simulations and experimental tests show that SL remodels the primary solvation shell of Zn²⁺, which significantly reduces the side reactions of Zn anode and achieves high ZUR under large capacities. Specifically, the symmetric and asymmetric cells could achieve a maximum of ∼96 % ZUR at an areal capacity of 24 mAh cm⁻². In a ZUR of ∼67 %, the developed Zn−V₂O₅ full cell can be stably cycled for 500 cycles with an energy density of 180 Wh kg⁻¹ and Zn-AC capacitor is stable for 5000 cycles. This electrolyte structural engineering strategy provides new insight into achieving high ZUR of Zn anodes for high performance AZBs.     

Cauliflower-like nanostructured ZnV2S4 as a potential cathode material to boost-up high capacity and durability of the aqueous zinc-ion battery

Owing to their unique design and development, high safety and low-cost efficient cathode is still at the forefront of research for rechargeable zinc-ion batteries. However, the suitable cathode operating with ultrahigh capacity with a dendrite-free anode reaction mechanism remains challenging. In this, the first archetype of a high-rate and morphologically stabled cathode material is constructed from novel cauliflower-like nano-ZnV₂S₄ for aqueous zinc-ion batteries. Thus, nano-ZnV₂S₄ was prepared with an anion exchange reaction using ZnV₂(OH)₈ cauliflower-like nanostructured array as a template interestingly no morphological and shape changes were detected. The as-prepared nano-ZnV₂S₄ electrode reveals a specific discharge capacity of 348.2 mAh/g during 0.5 A/g with enhanced rate capability and excellent capacity retention of 89.2% at 4 A/g current density even after completing 1000 cycles.     

Toward Sustainable Metal-Iodine Batteries: Materials,Electrochemistry and Design Strategies

Due to the natural abundance of iodine, cost-effective, and sustainability, metal-iodine batteries are competitive for the next-generation energy storage systems with high energy density, and large power density. However, the inherent properties of iodine such as electronic insulation and shuttle behavior of soluble iodine species affect negatively rate performance, cyclability, and self-discharge behavior of metal-iodine batteries, while the dendrite growth and metal corrosion on the anode side brings potential safety hazards and inferior durability. These problems of metal-iodine system still exist and need to be solved urgently. Herein, we summarize the research progress of metal-iodine batteries in the past decades. Firstly, the classification, design strategy and reaction mechanism of iodine electrode are briefly outlined. Secondly, the current development and protection strategy of conventional metal anodes in metal-iodine batteries are highlighted, and some potential anode materials and their design strategies are proposed. Thirdly, the key electrochemical parameters of state-of-art metal-iodine batteries are compared and analyzed to solve critical issues for realizing next-generation iodine-based energy storage systems. Therefore, the aim of this review is to promote the development of metal-iodine batteries and provide guidelines for their design.     

水系锌离子二次电池锌负极的研究进展

锌离子二次电池具有优异的充放电性能、高功率密度和能量密度、低成本、高安全性和环境友好的特点,极具发展前景。金属锌,因优异的导电性、低的平衡电势、高的理论比容量和低成本等因素,是水系二次电池中理想的负极材料,然而也存在着枝晶生长、腐蚀和钝化等问题,限制了锌离子二次电池的可逆容量和循环寿命,通过优化调节锌负极的形貌与表面修饰等方法可以提高电池性能。本文综述了水系锌离子二次电池负极材料的研究进展,涵盖了金属锌负极、复合锌负极和锌合金,且展望了锌负极的发展前景。     

An Interface‐Bridged Organic–Inorganic Layer that Suppresses Dendrite Formation and Side Reactions for Ultra‐Long‐Life Aqueous Zinc Metal Anodes

Aqueous zinc (Zn) batteries (AZBs) are widely considered as a promising candidate for next‐generation energy storage owing to their excellent safety features. However, the application of a Zn anode is hindered by severe dendrite formation and side reactions. Herein, an interfacial bridged organic–inorganic hybrid protection layer (Nafion‐Zn‐X) is developed by complexing inorganic Zn‐X zeolite nanoparticles with Nafion, which shifts ion transport from channel transport in Nafion to a hopping mechanism in the organic–inorganic interface. This unique organic–inorganic structure is found to effectively suppress dendrite growth and side reactions of the Zn anode. Consequently, the Zn@Nafion‐Zn‐X composite anode delivers high coulombic efficiency (ca. 97 %), deep Zn plating/stripping (10 mAh cm^?2), and long cycle life (over 10 000 cycles). By tackling the intrinsic chemical/electrochemical issues, the proposed strategy provides a versatile remedy for the limited cycle life of the Zn anode.