Co-Intercalation of Dual Charge Carriers in Metal-Ion-Confining Layered Vanadium Oxide Nanobelts for Aqueous Zinc-Ion Batteries

Vanadium-based oxides with high theoretical specific capacities and open crystal structures are promising cathodes for aqueous zinc-ion batteries (AZIBs). In this work, the confined synthesis can insert metal ions into the interlayer spacing of layered vanadium oxide nanobelts without changing the original morphology. Furthermore, we obtain a series of nanomaterials based on metal-confined nanobelts, and describe the effect of interlayer spacing on the electrochemical performance. The electrochemical properties of the obtained Al_2.65V₆O₁₃ ⋅ 2.07H₂O as cathodes for AZIBs are remarkably improved with a high initial capacity of 571.7 mAh ⋅ g⁻¹ at 1.0 A g⁻¹. Even at a high current density of 5.0 A g⁻¹, the initial capacity can still reach 205.7 mAh g⁻¹, with a high capacity retention of 89.2 % after 2000 cycles. This study demonstrates that nanobelts confined with metal ions can significantly improve energy storage applications, revealing new avenues for enhancing the electrochemical performance of AZIBs.     

水系锌离子电池钒基氧化物正极材料研究进展

近年来,钒基氧化物因为种类众多、理论比容量高和倍率性能优异等优点,被认为是一类具有潜在应用价值的水系锌离子电池正极材料。本文综述了V2O5、VO2等钒基氧化物材料的结构特点及其作为水系锌离子电池正极材料的最近研究进展。重点概述了当前钒基氧化物在锌离子电池中所面临的关键问题以及应对策略;最后,对钒基氧化物储锌材料的发展方向进行了展望。     

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.     

Constructing 2D Sandwich-like MOF/MXene Heterostructures for Durable and Fast Aqueous Zinc-Ion Batteries

Two-dimensional metal–organic frameworks (2D MOFs) can be used as the cathodes for high-performance zinc-ion battery due to their large one-dimensional channels. However, the conventionally poor electrical conductivity and low structural stability hinder their advances. Herein, we report an alternately stacked MOF/MX heterostructure, exhibiting the 2D sandwich-like structure with abundant active sites, improved electrical conductivity and exceptional structural stability. Ex situ characterizations and theoretical calculations reveal a reversible intercalation mechanism of zinc ions and high electrical conductivity in the 2D heterostructure. Electrochemical tests confirm excellent Zn²⁺ migration kinetics and ideal pseudocapacitive behaviors. As a consequence, Cu-HHTP/MX shows a superior rate performance (260.1 mAh g⁻¹ at 0.1 A g⁻¹ and 173.1 mAh g⁻¹ at 4 A g⁻¹) and long-term cycling stability of 92.5 % capacity retention over 1000 cycles at 4 A g⁻¹.     

Gaseous Nitrogen Oxides Catholyte for Rechargeable Redox Flow Batteries

There is a strong interest in finding highly soluble redox compounds to improve the energy density of redox flow batteries (RFBs). However, the performance of electrolytes is often negatively influenced by high solute concentration. Herein, we designed a high-potential (0.5 V vs. Ag/Ag⁺) catholyte for RFBs, where the charged and discharged species are both gaseous nitrogen oxides (NO_x). These species can be liberated from the liquid electrolyte and stored in a separate gas container, allowing scale-up of storage capacity without increasing the concentration and volume of the electrolyte. The oxidation of NO in the presence of NO₃⁻ affords N₂O₃, and the reduction of N₂O₃ regenerates NO and NO₃⁻, together affording the electrochemical reaction: NO₃⁻+3 NO⇌2 N₂O₃+e⁻ with a low mass/charge ratio of 152 grams per mole of stored electron. A proof-of-concept NO_x symmetric H-cell shows 200 stable cycles over 400 hours with >97 % Coulombic efficiency and negligible capacity decay.     

Bio-Inspired Polyanionic Electrolytes for Highly Stable Zinc-Ion Batteries

For zinc-ion batteries (ZIBs), the non-uniform Zn plating/stripping results in a high polarization and low Coulombic efficiency (CE), hindering the large-scale application of ZIBs. Here, inspired by biomass seaweed plants, an anionic polyelectrolyte alginate acid (SA) was used to initiate the in situ formation of the high-performance solid electrolyte interphase (SEI) layer on the Zn anode. Attribute to the anionic groups of −COO⁻, the affinity of Zn²⁺ ions to alginate acid induces a well-aligned accelerating channel for uniform plating. This SEI regulates the desolvation structure of Zn²⁺ and facilitates the formation of compact Zn (002) crystal planes. Even under high depth of discharge conditions (DOD), the SA-coated Zn anode still maintains a stable Zn stripping/plating behavior with a low potential difference (0.114 V). According to the classical nucleation theory, the nucleation energy for SA-coated Zn is 97 % less than that of bare Zn, resulting in a faster nucleation rate. The Zn||Cu cell assembled with the SA-coated electrode exhibits an outstanding average CE of 99.8 % over 1,400 cycles. The design is successfully demonstrated in pouch cells, where the SA-coated Zn exhibits capacity retention of 96.9 % compared to 59.1 % for bare Zn anode, even under the high cathode mass loading (>10 mg/cm²).     

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

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

Facilitating the Electrochemical Oxidation of ZnS through Iodide Catalysis for Aqueous Zinc-Sulfur Batteries

Aqueous zinc-sulfur (Zn-S) batteries show great potential for unlocking high energy and safety aqueous batteries. Yet, the sluggish kinetic and poor redox reversibility of the sulfur conversion reaction in aqueous solution challenge the development of Zn-S batteries. Here, we fabricate a high-performance Zn-S battery using highly water-soluble ZnI₂ as an effective catalyst. In situ experimental characterizations and theoretical calculations reveal that the strong interaction between I⁻ and the ZnS nanoparticles (discharge product) leads to the atomic rearrangement of ZnS, weakening the Zn-S bonding, and thus facilitating the electrochemical oxidation reaction of ZnS to S. The aqueous Zn-S battery exhibited a high energy density of 742 Wh kg_(sulfur)⁻¹ at the power density of 210.8 W kg_(sulfur)⁻¹ and good cycling stability over 550 cycles. Our findings provide new insights about the iodide catalytic effect for cathode conversion reaction in Zn-S batteries, which is conducive to promoting the future development of high-performance aqueous batteries.     

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(5 854 mAh·cm^-3)。由于充放电过程中存在锌枝晶和不可逆副产物(如H₂、ZnO、Zn₄(OH)₆SO₄)等问题,造成锌负极的库仑效率较低,严重缩短了电池的循环寿命,限制了其实际应用。本文针对锌负极在实际应用中遇到的困难与瓶颈,从微观层面分析了锌负极沉积/溶解的动力学与热力学机理,并从锌电极表面改性、锌片内部结构优化、电解液改性和新型隔膜等方面,介绍了锌负极保护的各种策略,并通过具体实例,分析了其制备方法和改性机理以及最终对电池性能的改善效果,为实用高效的锌负极保护方法提供了思路。最后,文章讨论了锌负极在商业化过程中面临的机遇和挑战,并对未来的研究前景和热点进行了展望。     

关于水系锌离子电池中无氧钒基正极材料的综述

水系锌离子电池具有功率密度高、环境友好、安全性高、低成本和锌资源丰富等优点,被认为具有潜力成为下一代电化学储能系统。然而,正极材料较差的电化学性能制约了水系锌离子电池的未来发展。尽管氧化锰、氧化钒、普鲁士蓝类似物、有机材料等多种材料已被广泛研究,设计具有高性能的理想正极材料仍面临着巨大挑战。无氧钒基化合物由于具有高的电导率、大的层间距、低的离子扩散势垒和高的理论比容量,受到越来越多的关注。本文总结了无氧钒基化合物的研究进展,包括电极材料的设计、改善其电化学性能的有效途径以及复杂的储能机制,提出了无氧钒基化合物目前面临的挑战和未来的发展前景,为进一步制备新型高性能钒基正极材料提供指导。     

Constructing Solid Electrolyte Interphase for Aqueous Zinc Batteries

Problems of zinc anode including dendrite and hydrogen evolution seriously degrade the performance of zinc batteries. Solid electrolyte interphase (SEI), which plays a key role in achieving high reversibility of lithium anode in aprotic organic solvent, is also beneficial to performance improvement of zinc anode in aqueous electrolyte. However, various studies about interphase for zinc electrode is quite fragmented, and lack of deep understanding on root causes or general design rules for SEI construction. And water molecules with high reactivity brings serious challenge to the effective SEI construction. Here, we reviewed the brief development history of zinc batteries firstly, then summarized the approaches to construct SEI in aqueous electrolyte. Furthermore, the formation mechanisms behind approaches are systematically analyzed, together with discussion on the SEI components and evaluation on electrochemical performance of zinc anode with various types of SEI. Meanwhile, the challenge between lab and industrialization are also discussed.     

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.     

水系锌离子电池用钒基正极材料的研究进展

水系锌离子电池(aqueous zinc-ion batteries,AZIBs)具有高安全性、低生产成本、锌资源丰富和环境友好等优点,被认为是未来大规模储能系统中极具发展前景的储能装置。目前,AZIBs的研究关键之一在于开发具有稳定结构和高容量的锌离子可脱嵌正极材料。钒基化合物用作AZIBs正极时,表现出可逆容量高和结构丰富可变等特点,受到了广泛的关注和研究。然而,钒基化合物的储锌机理较复杂,不同材料通常表现出各异的电化学性能和储能机理。在本综述中,我们全面地阐述了钒基化合物的储能机制,并探讨了钒基材料在水系锌离子电池中的应用和发展近况,以及它们的性能优化策略。在此基础上,也进一步地展望了水系锌离子电池及其钒基正极材料的发展方向。     

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.     

Regulated Ion/Electron-Conducting Interphase Enables Stable Zinc-Metal Anodes for Aqueous Zinc-Ions Batteries

Metallic Zinc (Zn) is considered as a remarkably promising anode for aqueous Zn-ion batteries due to its high volumetric capacity and low redox potential. Unfortunately, dendritic growth and severe side reactions destabilizes the electrode/electrolyte interface, and ultimately reduce the electrochemical performance. Here, an artificial protective layer (APL) with a regulated ion and electron-conducting interphase is constructed on the Zn-metal anode to provide excellent interfacial stability in high-rate cycling. The superior ionic and moderate electronic conductivity of the APL derives from the co-embedding of MXene and Zn(CF₃SO₃)₂ salts into the polyvinyl alcohol hydrogel, which enables a synergistic effect of local current density reduction during plating and ion transport acceleration during stripping for Zn anode. Furthermore, the high Young's modulus of the protective layer and dendrite-free deposition morphology during cycling suppresses hydrogen evolution reactions (2.5 mmol h⁻¹ cm⁻²) and passivation. As a result, in symmetrical cell tests, the modified battery presents a stable life of over 2000 cycles at ultra-high current density of 20 mA cm⁻². This research presents a new insight into the formation and regulation of stable electrode-electrolyte interface for the Zn-metal anode.     

Bio-Inspired Trace Hydroxyl-Rich Electrolyte Additives for High-Rate and Stable Zn-Ion Batteries at Low Temperatures

High-rate and stable Zn-ion batteries working at low temperatures are highly desirable for practical applications, but are challenged by sluggish kinetics and severe corrosion. Herein, inspired by frost-resistant plants, we report trace hydroxyl-rich electrolyte additives that implement a dual remodeling effect for high-performance low-temperature Zn-ion batteries. The additive with high Zn absorbability not only remodels Zn²⁺ primary solvent shell by alternating H₂O molecules, but also forms a shielding layer thus remodeling the Zn surface, which effectively enhances fast Zn²⁺ de-solvation reaction kinetics and prohibits Zn anode corrosion. Taking trace α-D-glucose (αDG) as a demonstration, the electrolyte obtains a low freezing point of −55.3 °C, and the Zn//Zn cell can stably cycle for 2000 h at 5 mA cm⁻² under −25 °C, with a high cumulative capacity of 5000 mAh cm⁻². A full battery that stably operates for 10000 cycles at −50 °C is also demonstrated.     

磺化聚酰亚胺酸碱复合膜的制备及其在全钒液流电池中的应用

采用高温一步法合成了一系列不同磺化度的三元共聚磺化聚酰亚胺(SPI),通过控制磺化二胺与非磺化二胺的摩尔比来调节磺化度.选取碱性聚合物聚乙烯吡咯烷酮(PVP)与SPI按质量比1∶9进行共混,制成SPI/PVP酸碱复合膜.对复合膜的吸水率、离子交换容量、钒离子渗透率以及电池性能进行了测试.结果表明,随着磺化度的升高,复合膜的吸水率、离子交换容量、质子电导率升高以及钒离子渗透率升高.复合膜的隔膜选择性比Nafion117的选择性好,其中SPI/PVP-3的选择性是Nafion117的10倍.电池性能测试表明,随磺化度的升高,复合膜能量效率升高.其中SPI/PVP-3膜较Nafion117膜具有较高的库伦效率和能量效率,通过循环测试SPI/PVP-3膜性能稳定,充放电理想.     

Step by Step Induced Growth of Zinc-Metal Interface on Graphdiyne for Aqueous Zinc-Ion Batteries

Rechargeable aqueous zinc ion batteries (AZIBs) promise high energy density, low redox potential, low cost and safety; however, their cycle performances are seriously insufficient to restrict the progress in this field. We propose a new concept of atomic electrode formed on the graphdiyne (GDY). This new idea electrode was synthesized by selectively, uniformly, and stably anchoring Zn atoms on GDY at the beginning of plating. The Zn atoms are induced to grow into larger size Zn clusters, which continue to grow into nanoflat. Finally, a new heterojunction interface is formed on GDY without any Zn dendrites and side reactions, even at high current densities. Such stepwise induction of growth greatly suppresses the formation of Zn dendrites, resulting in high electroplating/stripping reversibility and lifespan of AZIBs.     

Triple-function Hydrated Eutectic Electrolyte for Enhanced Aqueous Zinc Batteries

Aqueous rechargeable zinc-ion batteries (ARZBs) are impeded by the mutual problems of unstable cathode, electrolyte parasitic reactions, and dendritic growth of zinc (Zn) anode. Herein, a triple-functional strategy by introducing the tetramethylene sulfone (TMS) to form a hydrated eutectic electrolyte is reported to ameliorate these issues. The activity of H₂O is inhibited by reconstructing hydrogen bonds due to the strong interaction between TMS and H₂O. Meanwhile, the preferentially adsorbed TMS on the Zn surface increases the thickness of double electric layer (EDL) structure, which provides a shielding buffer layer to suppress dendrite growth. Interestingly, TMS modulates the primary solvation shell of Zn²⁺ ultimately to achieve a novel solvent co-intercalation ((Zn-TMS)²⁺) mechanism, and the intercalated TMS works as a “pillar” that provides more zincophilic sites and stabilizes the structure of cathode (NH₄V₄O₁₀, (NVO)). Consequently, the Zn||NVO battery exhibits a remarkably high specific capacity of 515.6 mAh g⁻¹ at a low current density of 0.2 A g⁻¹ for over 40 days. This multi-functional electrolytes and solvent co-intercalation mechanism will significantly propel the practical development of aqueous batteries.