High-performance Aqueous Zinc Research Articles

CeO2 anchored in VO2@C rambutan-like microsphere achieving advanced zinc storage

Low-cost and high-safety aqueous zinc ion batteries (AZIBs) show great potential in energy storage for the grid. We propose a strategy to construct the self-assembled microspheres with the cerium oxide nanocrystals anchored on B-phase vanadium dioxide nanobelts, which are encapsulated by carbon (CVC), as cathode for high capacity and cycle stability of AZIBs. The rambutan-like structure with large specific surface area provides more active sites for the overall improvement of reaction kinetics; the carbon layer relieves vanadium dioxide from dissolving in the electrolyte while enhancing electron transfer rate; and electrocatalytic activity of cerium oxide accelerates redox reaction to enhance the performance of the cells. Consequently, the CVC electrode exhibits excellent electrochemical properties, including a reversible specific capacity (490 mAh g−1 at 0.1 A g−1), incredible cycle (84 % capacity retention after 1000 cycles at 5 A g−1). The excellent performance demonstrates the correctness of the combined internal and external modification strategy, while the simple hydrothermal method and inexpensive raw materials point to a new direction for the large-scale preparation of high-performance aqueous zinc ion batteries.

Modified structure of vanadium oxide via cadmium doping and in-situ activation for high-performance aqueous zinc ion storage

Vanadium oxides are promising cathode materials for aqueous zinc-ion batteries, but they suffer from severe crystal collapse and poor electrical/ionic conductivity. Herein, we successfully synthesized the designed cadmium-doped, carbon-coated vanadium oxide precursor with abundant oxygen vacancies (Cd0.015V2O3-x@C) using a straightforward one-pot thermal reduction method, followed by in-situ activation to form a high-performance cathode material, Cd0.004V2O5-y·nH2O@C. We find that the interlayered water dramatically reduces the electrostatic force between zinc ions and V2O5-y layers, meanwhile, abundant oxygen vacancies and cadmium doping alter the material’s band structure, resulting in enhanced electronic and ionic conductivities. Leveraging these advantages, the phase transitioned Cd0.004V2O5-y·nH2O@C cathode delivers a remarkably high capacity of 420 mAh/g (0.2 A/g), an excellent rate capability of 198 mAh/g (20.0 A/g), and an outstanding capacity retention of 78.5 % after 3500 cycles (20 A/g). This synergistic structure modification strategy of elemental doping and in-situ activation offers a novel approach to design high-performance vanadium oxide-based cathodes for advanced aqueous batteries.

Unraveling Energy Storage Performance and Mechanism of Metal-Organic Framework-Derived Copper Vanadium Oxides with Tunable Composition for Aqueous Zinc-Ion Batteries.

Achieving high-performance aqueous zinc (Zn)-ion batteries (AZIBs) requires stable and efficient cathode materials capable of reversible Zn-ion intercalation. Although layered vanadium oxides possess high Zn-ion storage capacity, their sluggish kinetics and poor conductivity present significant hurdles for further enhancing the performance of AZIBs. In response to this challenge, a dissolution-regrowth and conversion approach is formulated using metal-organic frameworks (MOFs) as a sacrificial template, which enables the in situ creation of copper vanadium oxides (CuVOx) with porous 1D channels and distinctive nanoarchitectures. Owing to their distinctive structure, the optimized CuVOx cathode experiences a reaction involving the synergistic insertion/extraction of Zn2+, resulting in rapid Zn2+ diffusion kinetics and enhanced electrochemical activity postactivation. Specifically, the activated electrode delivers a reversible capacity of 519mAhg-1 at 0.5Ag-1 for AZIBs. It is noteworthy that the electrode exhibits a remarkable reversible rate capacity of 220mAhg-1 at 5Ag-1 with excellent durable cycleability, retaining 88% of its capacity even after 3000 cycles. Various ex situ testing methods endorse the reversible insertion/extraction of Zn2+ in the CuVOx cathode. This study provides a novel insight into high-performance MOF-derived unique structure designs for AZIB electrodes.

Panthenol Additives with Multiple Coordination Sites Induce Uniform Zinc Deposition and Inhibited Side Reactions for High Performance Aqueous Zinc Metal Battery.

Application of aqueous zinc metal batteries (AZMBs) in large-scale new energy systems (NESs) is challenging owing to the growth of dendrites and frequent side reactions. Here, this study proposes the use of Panthenol (PB) as an electrolyte additive in AZMBs to achieve highly reversible zinc plating/stripping processes and suppressed side reactions. The PB structure is rich in polar groups, which led to the formation of a strong hydrogen bonding network of PB-H2O, while the PB molecule also builds a multi-coordination solvated structure, which inhibits water activity and reduces side reactions. Simultaneously, PB and OTF- decomposition, in situ formation of SEI layer with stable organic-inorganic hybrid ZnF2-ZnS interphase on Zn anode electrode, can inhibit water penetration into Zn and homogenize the Zn2+ plating. The effect of the thickness of the SEI layer on the deposition of Zn ions in the battery is also investigated. Hence, this comprehensive regulation strategy contributes to a long cycle life of 2300h for Zn//Zn cells assembled with electrolytes containing PB additives. And the assembled Zn//NH4V4O10 pouch cells with homemade modules exhibit stable cycling performance and high capacity retention. Therefore, the proposed electrolyte modification strategy provides new ideas for AZMBs and other metal batteries.

Inorganic-organic hybrid heterogeneous membrane for zinc protective layers in high-performance aqueous zinc ion batteries

Aqueous zinc-ion Batteries (AZIBs) suffer from stability and performance limitations due to challenges related to the zinc (Zn) metal anode, including hydrogen evolution reaction (HER), metal corrosion, and Zn dendrite formation. To mitigate these issues, researchers are developing innovative coatings and protective layers for Zn anodes, focusing on enhancing ion conductivity, electrochemical inertness, mechanical strength, and processability. Hybrid organic-inorganic heterostructure coating materials with silver nanowires (Ag NWs) encapsulated with Polypyrrole (Ag/PPy) have shown promise in addressing these challenges. The Zn anode coated with Ag/PPy layers and paired with an α-MnO2 cathode, achieved an impressive initial capacity of 302 mAh/g at a current density of 0.5 A/g. Remarkably, it retained a substantial capacity of 283 mAh/g after 300 cycles at a current density of 0.5 A/g, demonstrating a 94 % capacity retention rate. Moreover, the symmetry cell using this anode maintains stable Zn deposition/stripping overpotentials even at a high current density (a rate of 10C) for over 175 h. These findings highlight the potential of Ag/PPy coatings as a viable approach for enhancing the surface chemistry and physical properties of the Zn metal anode, paving the way for a wider use of AZIBs.

Dual-Ion-Doped Hydrated Vanadium Oxides Nanowires As Cathode Materials for High-Rate Aqueous Zinc Ion Batteries

Due to environmental-friendliness, high safety and stability, high theoretical capacity as well as low cost, aqueous zinc ion batteries (AZIBs) are budding as attractive alternatives for large-scale energy storage applications. However, the lack of suitable positive electrode materials becomes the main issue for AZIBs to pursue high energy density and excellent rate capability. Herein, the dual-ion-doped hydrated vanadium oxide nanowires (VOH) are synthesized through hydrothermal method, which is suitable to be cathode materials for AZIBs. Through metal ions and crystal water pre-intercalation, the interlayer spacing of (001) becomes larger, which is proposed to have better capability to accommodate Zn2+. Moreover, the pre-intercalated metal ions can serve as structural pillars between layers, providing excellent stability during discharging/charging process. In this study, the novel dual-ion-doped VOH exhibits more than 420 mA h g−1 at 0.1 A g−1 as well as more than 260 mA h g−1 at 5 A g−1. In addition, it can retain more than 80% capacity after 500 cycles at 5 A g−1. The energy storage mechanism of dual-ion-doped VOH is revealed via operando x-ray absorption near edge spectroscopy. This study implies that this dual-ion-doped VOH nanowires can serve as suitable positive electrode materials for high-performance aqueous zinc ion batteries.

MXene Supported Electrodeposition Engineering of Layer Double Hydroxide for Alkaline Zinc Batteries.

The main challenges faced by aqueous rechargeable nickel-zinc batteries are their comparatively low energy density and poor cycling stability, mainly due to the limited capacity and reversibility of existing Ni-based cathodes. Moreover, the preparation procedures of these cathodes are complex and not easily scalable, which makes them less promising for large-scale energy storage. Herein, we utilized MXene as a functional additive to effectively improve the electrodeposition preparation of NiCo layered double hydroxides (LDH). Benefiting from the improved interfacial contact between nickel foam (NF) and platting solution and the enhanced ionic conductivity of platting product based on MXene additives, the resulting binder-free NiCo LDH electrode can achieve ultrahigh areal loading (~65 mg cm-2) with abundant active surface for redox reactions and maintained short transport pathway for ion diffusion and charge transfer. Furthermore, the as-fabricated alkaline NiCo LDH-based battery delivers high discharge capacity, up to 20.2 mAh cm-2 (311 mAh g-1), accompanied by remarkable rate performance (9.6 mAh cm-2 or 148 mAh g-1 at 120 mA cm-2). Due to the high structural and chemical stability of MXenes/LDH-based electrode, excellent cycling life can also be achieved with 88.6 % capacity retention after 10000 cycles. In addition, ultrahigh areal energy density (31.2 mWh cm-2) and gravimetric energy density (465 Wh kg-1) can be simultaneously achieved. This work has inspired the design of advanced cathode materials to develop high-performance aqueous zinc batteries.

Pre-removing partial ammonium ion induces vanadium vacancy assist NH4V4O10 as a high-performance aqueous zinc ion battery cathode

Ammonium vanadate (NH4V4O10) is regarded as a promising cathode material for aqueous zinc-ion batteries, given its considerable theoretical capacity and tunable interlayer spacing. However, due to its inherent low electrical conductivity and the excessive presence of ammonium ions between layers, NH4V4O10 exhibits unsatisfactory electrochemical performance. In this study, it is proposed that the electrochemical performance of NH4V4O10 can be significantly enhanced by removing part of the ammonium cation and increasing the vanadium vacancy. The decrease of ammonium further increases the layer spacing, reduces the irreversible deamination and accelerates the diffusion of Zn2+. Density functional theory (DFT) calculations reveal that increasing vanadium vacancies significantly diminishes the strong electrostatic interactions between the V-O layers and Zn2+, enhances the material’s electrical conductivity, and stabilizes the crystal structure during zinc ion (de)intercalation, thus obtaining excellent electrochemical properties. As a result, the Vd-NVO cathode demonstrates a high reversible capacity of 371 mAh g−1, excellent rate performance, and remarkable cyclic stability, maintaining a reversible capacity of 131 mAh g−1 even after 1000 cycles at 5 A g−1.

Zincophilic and low-active metallic particles-induced alloying/dealloying behavior for high-performance aqueous zinc metal batteries

Aqueous zinc metal batteries (AZMBs) represent one of the most promising next-generation energy storage devices in terms of competitiveness. However, the commercialization of AZMBs has been significantly impeded by the occurrence of random dendrite growth and inevitable parasitic reactions on Zn metal anodes. In order to address this issue, we propose a solution wherein the surface of Zn foil is retouched through a replacement reaction with zincophilic and low-active Cu particles (designated as CuRZn). The CuRZn electrode exhibits exceptional corrosion resistance and enables stable Zn plating/stripping via alloying/dealloying processes. Consequently, the CuRZn||CuRZn symmetric battery exhibits stable operation for over 3200 h under 1 or 5 mA cm−2 and 1 mA h cm−2, and the CuRZn||Cu asymmetric battery achieves an excellent coulombic efficiency of 99.86 % under 2 mA cm−2 and 1 mA h cm−2 for over 2300 cycles. When coupled to an ammonium vanadate (NVO) cathode, the performance of the CuRZn||NVO full battery, which has a larger capacity (183.4 mA h g−1) than that of the bare Zn||NVO full battery (94.8 mA h g−1) at 2 A g−1, greatly improves after 1000 cycles. This study provides a simple and efficient surface retouching strategy for Zn metal anodes to achieve high-performance AZMBs.

Unlocking zinc storage in silver vanadate structures for high-performance aqueous zinc batteries

Zinc-ion batteries (ZIBs) are being increasingly recognized as promising candidates for large-scale energy-storage systems owing to their stability in air, abundance of elemental zinc, low cost, and ease of handling. Although various cathode materials have been explored for ZIBs, silver vanadate stands out for its highly stable structure. However, the presence of silver in silver vanadate may hinder its electrochemical performance, necessitating activation over several cycles. In this study, we introduce an ion-exchange reaction to directly activate silver vanadate. The resulting ion-exchanged zinc vanadate demonstrates superior performance compared with silver vanadate, showcasing stable cycling behavior and high-rate capability. Remarkably, it maintains a capacity retention of 71 % even after 400 cycles. Analysis of the zinc intercalation mechanism reveals a combination of capacitive and diffusion-based processes contributing to energy storage in ZIBs. Post-cycling examinations reveal the presence of dendritic zinc anodes and confirm the stability and safety of the framework, with no silver migration to the anode side. These findings highlight the potential of ZIBs as next-generation energy-storage solutions and underscore the need for continued research in optimizing electrode materials and electrolytes for practical applications.

Regulating Protons to Tailor the Enol Conversion of Quinone for High-Performance Aqueous Zinc Batteries.

Quinone-based electrodes using carbonyl redox reactions are promising candidates for aqueous energy storage due to their high theoretical specific capacity and high-rate performance. However, the proton storage manners and their influences on the electrochemical performance of quinone are still not clear. Herein, we reveal that proton storage could determine the products of the enol conversion and the electrochemical stability of the organic electrode. Specifically, the protons preferentially coordinated with the prototypical pyrene-4,5,9,10-tetraone (PTO) cathode, and increasing the proton concentration in the electrolyte can improve its working potentials and cycling stability by tailoring the enol conversion reaction. We also found that exploiting Al2(SO4)3 as a pH buffer can increase the energy density of the Zn||PTO batteries from 242.8 to 284.6 Wh kg-1. Our research has a guiding significance for emphasizing proton storage of organic electrodes based on enol conversion reactions and improving their electrochemical performance.

Enhancing the electrochemical activation kinetics of V2O3 for high-performance aqueous zinc-ion battery cathode materials

The discharge capacity and lifespan of zinc ion batteries currently remain impractical due to limitations in the cathode. Low-valence vanadium oxides are promising cathode material precursors that can be electrochemically converted into highly active hydrated amorphous oxides. However, the activation process itself suffers from structural instability or high local strain, due to the low electronic conductivity and the limited ion diffusion kinetics. To tackle this issue, herein, we synthesize porous carbon-coated nitrogen-doped V2O3 (p-NVO@C) microparticles utilizing a nitrogen-containing vanadium-based metal–organic framework (MOF) as the precursor. The uniform N doping and carbon coating improve the electronic conductivity of the active material particles. The carbon coating also traps the active material to reduce its dissolution loss; the high porosity of the p-NVO@C alleviates the stress from Zn2+-intercalation-induced expansion and shortens the ion transport paths. Moreover, first-principles calculations indicate that the doped N atoms in vanadium oxides generate a locally enhanced electric field, which accelerates the diffusion of Zn2+. Given the above advantages, the p-NVO@C particles demonstrate an outstanding specific capacity of 501 mAh/g at a current density of 0.2 A/g and a remarkable rate performance after the initial activation. The capacity retention rate remains as high as 95.7 % after 2000 cycles at a current density of 10 A/g. Ex-situ characterizations confirm the robust structural stability during phase transition cycles. This work provides an excellent solution to developing cathode materials for high-performance aqueous zinc ion batteries.

Steric-hindrance Effect Tuned Ion Solvation Enabling High Performance Aqueous Zinc Ion Batteries.

Despite many additives have been reported for aqueous zinc ion batteries, steric-hindrance effect of additives and its correlation with Zn2+ solvation structure have been rarely reported. Herein, large-sized sucrose biomolecule is selected as a paradigm additive, and steric-hindrance electrolytes (STEs) are developed to investigate the steric-hindrance effect for solvation structure regulation. Sucrose molecules do not participate in Zn2+ solvation shell, but significantly homogenize the distribution of solvated Zn2+ and enlarge Zn2+ solvation shell with weakened Zn2+-H2O interaction due to the steric-hindrance effect. More importantly, STEs afford the water-shielding electric double layer and in situ construct the organic and inorganic hybrid solid electrolyte interface, which effectively boost Zn anode reversibility. Remarkably, Zn//NVO battery presents high capacity of 3.9 mAh ⋅ cm-2 with long cycling stability for over 650 cycles at lean electrolyte of 4.5 μL ⋅ mg-1 and low N/P ratio of 1.5, and the stable operation at wide temperature (-20 °C~+40 °C).

Interfacial Engineering for Oriented Crystal Growth toward Dendrite-Free Zn Anode for Aqueous Zinc Metal Battery.

Zn deposition with a surface-preferred (002) crystal plane has attracted extensive attention due to its inhibited dendrite growth and side reactions. However, the nucleation and growth of the Zn(002) crystal plane are closely related to the interfacial properties. Herein, oriented growth of Zn(002) crystal plane is realized on Ag-modified surface that is directly visualized by in situ atomic force microscopy. A solid solution HCP-Zn (~1.10 at. % solubility of Ag, 30 °C) is formed on the Ag coated Zn foil (Zn@Ag) and possesses the same crystal structure as Zn to reduce its nucleation barrier caused by their lattice mismatch. It merits oriented Zn deposition and corrosion-resistant surface, and presents long cycling stability in symmetric cells and full cells coupled with V2O5 cathode. This work provides insights into interfacial regulation of Zn anodes for high-performance aqueous zinc metal batteries.

Heterojunction tunnelled vanadium-based cathode materials for high-performance aqueous zinc ion batteries

Rechargeable aqueous zinc ion batteries (ZIBs) have emerged as a promising alternative to lithium-ion batteries due to their inherent safety, abundant availability, environmental friendliness and cost-effectiveness. However, the cathodes in ZIBs encounter challenges such as structural instability, low capacity, and sluggish kinetics. In this study, we constructed BiVO4@VO2 (BVO@VO) heterojunction cathode material with bismuth vanadate and vanadium dioxide phases for ZIBs, which demonstrate significant advancements in both aqueous and quasi-solid-state ZIBs. Benefitting from the heterojunction structure, the materials present a high capacity of 262 mAh g−1 at 0.1 A g−1, superb cyclic stability with 96% capacity retention after 1000 cycles at 2 A g−1, and outstanding rate property with a specific capacity of 218 mAh g−1 even at a high rate of 5.0 A g−1. Furthermore, the flexible quasi-solid-state ZIBs incorporating the BVO@VO cathode demonstrate prolonged cyclic life performance with a remarkable specific capacity of 234 mAh g−1 over 100 cycles at a current density of 0.1 A g−1. This study potentially paves the way for the utilization of heterointerface-enhanced zinc ion diffusion for vanadium-based materials in ZIBs, thereby providing a new approach for the design and investigation of high-performance zinc-ion systems.

A dual-functional rare earth halide additive for high-performance aqueous zinc ion batteries

Aqueous zinc ion batteries have received much attention due to their high theoretical capacity, inherent safety, and low cost. However, the growth of zinc dendrites and side reactions hinder its practical application. In this study, a rare-earth metal salt, europium chloride (EuCl3), is used as a new electrolyte additive to regulate the uniform deposition of zinc and inhibit the interfacial side reactions. The EuCl3 additive benefits for preferentially Zn2+ deposition along the (002) crystal plane, as well as suppress the hydrogen evolution reaction (HER) at electrode-electrolyte interface. As a result, the capacity retention of the Zn//NaV3O8 full cell assembled with the modified electrolyte much better than that without additives, showing a long-term cycling life and high coulombic efficiency at a current density of 10 A g−1. This new dual-functional rare earth halide additive strategy provides great potential for the development of practical aqueous zinc ion batteries and other battery systems.

Heat activated VO2 (R) cathodes for high-performance aqueous zinc ion batteries

We introduce a novel approach for design and production of vanadium dioxide (VO2) cathodes activated by heat, specifically tailored for use in aqueous zinc-ion batteries (ZIBs). Our cathodes exhibit distinctive metal-insulator transition (MIT) characterized by the shift between monoclinic (M) and tetragonal rutile (R) phases. The employment of an aqueous electrolyte in ZIBs enables successful operation of VO2 cathodes, showcasing phase transition and enhanced electrochemical performance above a readily attainable temperature of approximately 68 °C. The MIT feature enhances the charge transfer properties at electrode-electrolyte interfaces, resulting in notable improvements in specific capacity and energy densities. Fabricated VO2(M) cathodes underwent heat-triggered transformation to VO2(R), resulting in a remarkable increase (400 %) in capacity. At 0.1 A g−1, VO2(R) cathodes show specific capacity of 354.6 mAh g−1, yielding an impressive energy density of 461.0 Wh kg−1 for aqueous ZIBs. This exceptional performance can be attributed to abrupt change in electrical conductivity upon thermal activation of MIT. This work underscores pivotal role of thermally activated MIT in finely tuning electrochemical performance of energy storage systems, prospecting a promising avenue for further advancements.

Zinc ion modulation of hydrated vanadium pentoxide for high-performance aqueous zinc ion batteries

The structure of V2O5 as a cathode material is prone to collapse during repeated embedding/de-embedding of Zn2+, and the instability of the material limits its application. Introducing metal ions into the V2O5 layer provides larger ion channels, improves cycling kinetics, and acts as a pillar to enhance the structure stability during the charge/discharge process. In this study, Zn0·2V2O5·0.51H2O (ZVOH) is prepared by the hydrothermal method by embedding both Zn2+ and structural water molecules in the V2O5 interlayer. ZVOH is used as the cathode in zinc-ion batteries (ZIBs) with high power and energy densities (∼6779.3 W kg−1 and 289.6 Wh kg−1) and outstanding cycling stability. Furthermore, the valence changes of vanadium in ZVOH during charging and discharging as well as the morphological changes on the surface of the electrode material are investigated by ex-situ methods. The binding energy of Zn2+ at the sites within ZVOH and the migration energy barrier for Zn2+ migration on the ZVOH surface are also investigated by density functional theory.

Defect engineering and morphology adjustment assist NH4V4O10 to be a high-performance aqueous zinc ion battery cathode

The ultrathin size of SNVO with oxygen vacancies and more active sites improved the diffusion ability of Zn2+ ions. SNVO exhibits excellent cycle stability, retaining 94.6% of its capacity after 1000 cycles at 10 A g−1.

Nicotinic acid additive with a double regulating mechanism for high-performance aqueous zinc ion batteries

Trace nicotinic acid (NA) can not only change the solvation structure of Zn2+, but also preferentially adsorbs on the Zn anode to reduce the side reactions and inhibit Zn dendrites. Zn‖Zn cells with NA can operate for 5200 h at 1 mA cm−2.