How About Vanadium-Based Compounds as Cathode Materials for Aqueous Zinc Ion 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.

Synergistic Theoretical and Experimental Insights into NH4+-Enhanced Vanadium Oxide Cathodes for Aqueous Zinc-Ion Batteries

This study explores the enhancement of aqueous zinc-ion batteries (AZIBs) using ammonium-enhanced vanadium oxide cathodes. Density Functional Theory (DFT) calculations reveal that NH4+ incorporation into V6O16 lattices significantly facilitates Zn2+ ion diffusion by reducing electrostatic interactions, acting as a structural lubricant. Subsequent experimental validation using (NH4)2V6O16 cathodes synthesized via a hydrothermal method corroborates the DFT findings, demonstrating remarkable electrochemical stability with a capacity retention of 90% after 2000 cycles at 5 A g-1. These results underscore the potential of NH4+ in improving the performance and longevity of AZIBs, providing a pathway for sustainable energy storage solutions.

Hollow VO2 microspheres anchored on graphene as advanced cathodes for aqueous zinc-ion batteries

Vanadium dioxide-based materials have been proved to be promising cathodes for aqueous zinc ion batteries (AZIBs) due to their cost-effectiveness and high theoretical specific capacity; nevertheless, the low electronic conductivity and poor cycle stability restrict their application. Herein, hollow VO2 microspheres anchored on graphene oxide (H-VO2@GO) are synthesized via a facile simple hydrothermal reaction as high-performance cathodes for AZIBs. The hollow micromorphology of the material provides a large specific surface area and effectively alleviates the volume changes during cycling, while the anchoring of VO2 on graphene oxide greatly improves the electronic conductivity and inhibits the agglomeration and pulverization of the material. Resulting from the combination of unique micromorphology and graphene oxide anchoring, the as-prepared H-VO2@GO exhibits the impressive specific capacity of 400.1 mAh/g at 0.5 A/g and excellent cycling performance with 96.1 % of capacity retention after 1500 cycles at 10 A/g. This investigation provides a use reference for designing high-performance cathodes materials for AZIBs by optimizing the microstructure of electrode materials.

Amorphous Vanadium Oxides with Dual ion Storage Mechanism for High-Performance Aqueous Zinc ion Batteries

Owing to the extremely limited structural deformation caused by the introduction of guest ions that their rigid structure can sustain, crystalline materials typically fail owing to structural collapse when utilized as electrode materials. Amorphous materials, conversely, are more resistant to volume expansion during dynamic ion transport and can introduce a lot of defects as active sites. Here, The amorphous polyaniline-coated/intercalated V2O5·nH2O (PVOH) nanowires are prepared by in situ chemical oxidation combined with self-assembly strategy, which exhibited impressive electrochemical properties because of its short-range ordered crystal structure, oxygen vacancy/defect-rich, improved electronic channels, and ionic channels. Through in situ techniques, the energy storage mechanism of its Zn2+/H+ co-storage is investigated and elucidated. Additionally, this work provides new insights and perspectives for the investigation and application of amorphous cathodes for aqueous zinc ion batteries.

Ethylene Glycol-Choline Chloride Based Hydrated Deep Eutectic Electrolytes Enabled High-Performance Zinc-Ion Battery

Aqueous rechargeable zinc-ion batteries (ARZIBs) are considered as an emerging energy storage technology owing to their low cost, inherent safety, and reasonable energy density. However, significant challenges associated with electrodes, and aqueous electrolytes restrict their rapid development. Herein, ethylene glycol-choline chloride (Eg-ChCl) based hydrated deep-eutectic electrolytes (HDEEs) are proposed for RZIBs. Also, a novel V10O24·nH2O@rGO composite is prepared and investigated in combination with HDEEs. The formulated HDEEs, particularly the composition of 1 ml of EG, 0.5 g of ChCl, 4 ml of H2O, and 2 M ZnTFS (1-0.5-4-2 HDEE), not only exhibit the lowest viscosity, highest Zn2+ conductivity (20.38 mS cm-1), and the highest zinc (Zn) transference number (t+ = 0.937), but also provide a wide electrochemical stability window (>3.2 V vs ZnǁZn2+) and enabledendrite-free Zn stripping/plating cycling over 1000 hours. The resulting ZnǁV10O24·nH2O@rGO cell with 1-0.5-4-2 HDEE manifests high reversible capacity of ≈365 mAh g-1 at 0.1 A g-1, high rate-performance (delivered ≈365/223 mAh g-1 at 0.1/10 mA g-1) and enhanced cycling performance (≈63.10% capacity retention in the 4000th cycle at 10 A g-1). Furthermore, 1-0.5-4-2 HDEE support feasible Zn-ion storage performance across a wide temperature range (0-80 °C) FInally, a ZnǁV10O24·nH2O@rGO pouch-cell prototype fabricated with 1-0.5-4-2 HDEE demonstrates good flexibility, safety, and durability.

One-Stone-for-Two-Birds Strategy for VSe2 to Enable High Capacity and Long-Life Zinc Storage

Based on a specific zinc storage mechanism and excellent electronic conductivity, transition metal dichalcogenides, represented by vanadium diselenide, are widely used in aqueous zinc-ion battery (AZIB) energy storage systems. However, most vanadium diselenide cathode materials are presently limited by low specific capacity and poor cycling life. Herein, a simple hydrothermal process has been proposed for obtaining a vanadium diselenide cathode for an AZIB. The interaction of defects and crystal planes enhances zinc storage capacity and reduces the migration energy barrier. Moreover, abundant lamellar structure greatly increases reaction sites and alleviates volume expansion during the electrochemical process. Thus, the as-obtained vanadium diselenide AZIB exhibits an excellent reversible specific capacity of 377 mAh g-1 at 1 A g-1, and ultralong cycle stability of 291 mAh g-1 after 3200 cycles, with a nearly negligible capacity loss. This one-stone-for-two-birds strategy would be expected to be applied to large-scale synthesis of a high-performance zinc-ion battery cathode in the future.

Low-current-density stability of vanadium-based cathodes for aqueous zinc-ion batteries

Vanadium-based cathodes have received widespread attention in the field of aqueous zinc-ion batteries, presenting a promising prospect for stationary energy storage applications. However, the rapid capacity decay at low current densities has hampered their development. In particular, capacity stability at low current densities is a requisite in numerous practical applications, typically encompassing peak load regulation of the electricity grid, household energy storage systems, and uninterrupted power supplies. Despite possessing notably high specific capacities, vanadium-based materials exhibit severe instability at low current densities. Moreover, the issue of stabilizing electrode reactions at these densities for vanadium-based materials has been explored insufficiently in existing research. This review aims to investigate the matter of stability in vanadium-based materials at low current densities by concentrating on the mechanisms of capacity fading and optimization strategies. It proposes a comprehensive approach that includes electrolyte optimization, electrode modulation, and electrochemical operational conditions. Finally, we presented several crucial prospects for advancing the practical development of vanadium-based aqueous zinc-ion batteries.

"Three-in-One" Multifunctional Hollow Nanocages with Colorimetric Photothermal Catalytic Activity for Enhancing Sensitivity in Biosensing

Immunochromatographic assays (ICAs) have been widely used in the field detection of mycotoxin contaminants. Nevertheless, the lack of multisignal readout capability and the ability of signaling tags to maintain their biological activity while efficiently loading antibodies remain a great challenge in satisfying diverse testing demands. Herein, we proposed a novel three-in-one multifunctional hollow vanadium nanomicrosphere (high brightness-catalytic-photothermal properties)-mediated triple-readout ICA (VHMS-ICA) for sensitive detection of T-2. As the key to this biosensing strategy, vanadium was used as the catalytic-photothermal characterization center, and natural polyphenols were utilized as the bridging ligands for coupling with the antibody while self-assembling with formaldehyde cross-linking into a hollow nanocage-like structure, which offers the possibility of realizing a three-signal readout strategy and improving the coupling efficiency to the antibody while preserving its biological activity. The constructed sensors showed a detection limit (LOD) of 2 pg/mL for T-2, which was about 345-fold higher than that of conventional gold nanoparticle-based ICA (0.596 ng/mL). As anticipated, the detection range of VHMS-ICA was extended about 8-fold compared with the colorimetric signal alone. Ultimately, the proposed immunosensor performed well in maize and oat samples, with satisfactory recoveries. Owing to the synergistic and complementary interactions between distinct signaling modes, the establishment of multimodal immunosensors with multifunctional tags is an efficient strategy to satisfy diversified detection demands.

Two Birds with One Stone: V4 C3 MXene Synergistically Promoted VS2 Cathode and Zinc Anode for High-Performance Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries (AZIBs) are considered to be a rising star in the large-scale energy storage area because of their low cost and environmental friendliness properties. However, the limited electrochemical performance of the cathode and severe zinc dendrite of the anode severely hinder the practical application of AZIBs. Herein, a novel 3D interconnected VS2 ⊥V4 C3 Tx heterostructure material is prepared via one-step solvothermal method. Morphological and structural characterizations show that VS2 nanosheets are uniformly and dispersedly distributed on the surface of the V4 C3 MXene substrate, which can effectively suppress volume change of the VS2 . Owing to the open heterostructure along with the high conductivity of V4 C3 MXene, the VS2 ⊥V4 C3 Tx cathode shows a high specific capacity of 273.9 mAh g-1 at 1 A g-1 and an excellent rate capability of 143.2 mAh g-1 at 20 A g-1 . The V4 C3 MXene can also effectively suppress zinc dendrite growth when used as protective layer for the Zn anode, making the V4 C3 Tx @Zn symmetric cell with a stable voltage profile for ≈1700 h. Benefitting from the synergistic modification effect of V4 C3 MXene on both the cathode and anode, the VS2 ⊥V4 C3 Tx ||V4 C3 Tx @Zn battery exhibits a long cycling lifespan of 5000 cycles with a capacity of 157.1 mAh g-1 at 5A g-1 .

Oxygen defects engineering and structural strengthening of hydrated vanadium oxide cathode by coating glucose hydrothermal carbon and pre-embedding Mn (II) ion for high-capacity aqueous zinc ion batteries

Vanadium oxide-based cathode with unique layered structure is considered as a candidate for aqueous zinc ion batteries (AZIBs). Unfortunately, considering poor electronic conductivity, sluggish diffusion kinetics, and the destruction of layered structures in the cycling process, the actual capacity and rate capability are constrained. Herein, the glucose hydrothermal carbon (GHC) and transition metal Mn2+ ion have been utilized to incorporate hydrated vanadium oxide (Mn-VOH@GHC). The oxygen vacancies defects of VOH, induced by GHC anchored on surface and Mn2+ inserted between interlayers, provides more active sites, higher electronic conductivity, and faster ion diffusion. In addition, GHC reinforces the integrity of external structure, while Mn2+ ion acts as structural pillars to support the interlayer structure. The Mn-VOH@GHC electrode can produce a high capacity of 530 mAh/g at the current density of 0.2 A/g thanks to these crucial properties, and after 2000 cycles at a high current density of 2 A/g, it can also produce a reversible capacity of 344 mAh/g. The results suggest that the synergistic effect of defect engineering and metal ion pre-insertion provides a new idea in enhancement of the electrochemical performance of AZIBs cathode materials.

Interface engineering of heterostructured vanadium oxides for enhanced energy storage in Zinc-Ion batteries

Rechargeable aqueous Zn-ion batteries (RAZIBs) with the merits of cost effectiveness and high safety have been rejuvenated as tantalizing energy storage systems to meet the demand for grid-scale applications. Currently, the energy storage capability of the positive electrode (cathode) holds the key for the overall performance of RAZIBs. In this work, we reveal VO2, V10O24·12H2O (HVO), and VO2/HVO can be prepared via hydrothermal reaction by using different reducing agents. VO2 exhibits high capacity of 237 mAh/g at 4 A/g, while it suffers from quick capacity decay with 48 % retention after 2000 charge/discharge cycles. On the contrary, HVO demonstrates moderate capacity but meritorious cycle stability (i.e., 173 mAh/g at 4 A/g and 82 % after 2000 cycles). By integrating the merits of high-capacity VO2 and high-stability HVO, the biphasic VO2/HVO sample exhibits promising electrochemical performance with high capacity (317 and 239 mAh/g at 1 and 4 A/g, respectively) and good cycle stability (80 % after 2000 cycles). As examined by band structure analysis, the superior electrochemical performance of VO2/HVO is attributed to the presence of a heterojunction between VO2 and HVO enabling a built-in electric field to boost electron transport kinetics, leading to high attainable capacity and reliable cycle performance in RAZIBs.

Hydrogen Peroxide Tuned Morphology and Crystal Structure of Barium Vanadate-Based Nanostructures for Aqueous Zinc-Ion Storage Properties

Improving the layered-structure stability and suppressing vanadium (V) dissolution during repeated Zn2+ insertion/extraction processes are key to promoting the electrochemical stability of V-based cathodes for aqueous zinc (Zn)-ion batteries (AZIBs). In this study, barium vanadate (Ba2 V2 O7 , BVO) nanostructures (NSs) are synthesized using a facile hydrothermal method. The formation process of the BVO NSs is controlled by adjusting the concentration of hydrogen peroxide (H2 O2 ), and these NSs are employed as potential cathode materials for AZIBs. As the H2 O2 content increases, the corresponding electrochemical properties demonstrate a discernible parabolic trend, with an initial increase, followed by a subsequent decrease. Benefiting from the effect of H2 O2 concentration, the optimized BVO electrode with 20 mL H2 O2 delivers a specific capacity of 180.15 mA h g-1 at 1 A g-1 with good rate capability and a long-term cyclability of 158.34 mA h g-1 at 3 A g-1 over 2000 cycles. Thus, this study provides a method for designing cathode materials with robust structures to boost the electrochemical performance of AZIBs.

Spent shell as a calcium source for constructing calcium vanadate for high-performance Zn-ion batteries

In this article, waste shell is directly used as a raw material to synthesize CaV3O7 as a cathode for aqueous zinc ion batteries. The obtained cathode material exhibits better performance than that of CaV3O7 prepared from pure calcium carbonate as a raw material. At 0.1 A g-1, the CaV3O7 prepared by spent shell as a calcium source displays a highly reversible discharge capacity of 373 mA h g-1. A high initial discharge capacity of 177.7 mA h g-1 can be gained at 5.0 A g-1, and the specific capacity remains at 133.3 mA h g-1 with a capacity retention of 75% after 3000 cycles. This work may spark inspiration for energy storage and generate more effective routes for recycling solid waste.

In-Situ Construction of V2 O5 Nanosheet/Nitrogen-Doped Carbon Nanosheet Heterostructures with Interfacial C─O Bridging Bonds as the Cathode Material for Zn Ion Batteries

Layered oxides are widely used as the electrode materials for metal ion batteries. However, for large radius size ions, such as Zn2+ and Al3+ , the tightly stacked layers and poor electrical conductivity of layered oxides result in restricted number of active sites and sluggish reaction kinetics. In this work, a facile in-situ construction strategy is provided to synthesize layered oxide nanosheets/nitrogen-doped carbon nanosheet (NC) heterostructure, which shows larger interlayer spacing and better electrical conductivity than the layered oxides. As a result, the Zn2+ ion diffusion inside the interlayer gallery is greatly enhanced and the storage sites inside the gallery can be better used. Meanwhile, the NC layers and oxide nanosheets are bridged by the C─O bonds to form a stable structure, which contributes to a better cycling stability than the pure layered oxides. The optimal V2 O5 @NC-400 cathode shows a capacity of 467 mA h g-1 at 0.1 A g-1 for 300 cycles, and long-term cyclic stability of 4000 cycles at 5 A g-1 with a capacity retention of 92%. All these performance parameters are among the best for vanadium oxide-based cathode materials.

Butterfly-tie like MnCO3@Mn3O4 heterostructure enhanced the electrochemical performances of aqueous zinc ion batteries

Due to the limited exploitation and utilization of fossil energy resources in recent years, it is imperative to explore and develop new energy materials. As an electrode material for batteries, MnCO3 has the advantages of safety, non-toxicity, and wide availability of raw materials. But it also has some disadvantages, such as short cycle period and low conductivity. In order to improve these deficiencies, we designed a MnCO3@Mn3O4 heterostructure material by a simple solvothermal method, which possessed a microstructure of "butterfly-tie". Owing to the introduction of Mn3O4 and the layered structure of "butterfly-tie", MnCO3@Mn3O4 possessed a discharge capacity of 165 mAh/g when the current density was 0.2 A/g and exhibited satisfactory rate performance. The MnCO3@Mn3O4 heterostructure was optimized by density functional theory (DFT), and the deformation charge density was calculated. It was found that the MnCO3@Mn3O4 heterostructure is stable owing to the molecular interaction between the O atoms from MnCO3 and the Mn atoms from Mn3O4 at the interface of heterojunction. Therefore, the MnCO3@Mn3O4 heterostructure material has promising applications as safe and efficient cathode material for energy batteries.

Tuning [VO6 ] Octahedron of Ammonium Vanadates via F Incorporation for High-Performance Aqueous Zinc Ion Batteries

The electrochemical properties of vanadium-based materials as cathode materials for aqueous zinc ion batteries are still restricted by low conductivity, sluggish reaction kinetics, and poor structural stability. Herein, the [VO6 ] octahedron, as the basic unit of vanadium-oxide layer of ammonium vanadates (NH4 V4 O10 , denoted as NVO), is incorporated by F atoms to regulate the coordinated environment of vanadium. Density functional theory (DFT) calculations and experimental results show that both physicochemical and electrochemical properties of NVO are improved by F-doping. The enhanced electronic conductivity accelerates the electron transfer and the expanded interlayer spacing expedites the diffusion kinetics of zinc ions. As a result, the F-doped NVO (F-NVO) electrode shows a high discharge capacity (465 mAh g-1 at 0.1 A g-1 ), good rate capability (260 mAh g-1 at 5 A g-1 ), and long-term cycling stability (88% capacity retention over 2000 cycles at 4 A g-1 ). The reaction kinetics and energy storage mechanism of F-NVO are further validated by in situ and ex situ characterizations.

Modifying Electronic Structure of Bismuth Telluride Through S Doping and Te Vacancy Engineering for Enhanced Zn-Ion Storage Ability in Aqueous Zn-proton Hybrid Ion Batteries

Bismuth chalcogenides are used as cathode materials in Zn-proton hybrid ion batteries, which exhibit an ultraflat discharge plateau that is favorable for practical applications. Unfortunately, their capacity is not competitive, and their charge storage mechanisms are ambiguous, both of which hinder their further development. In this study, S-doped Bi2 Te3- x (SBT) nanosheets are prepared by tellurizing a Bi2 O2 S precursor using a hydrothermal process. As revealed by density functional theory analyses, the S dopant and its induced Te vacancies can distinctly manipulate the electronic structure of SBT, resulting in decent electrical conductivity and more negative adsorption energy to Zn2+ . These advantages boost the Zn2+ storage ability of SBT materials. Consequently, compared with defect-free Bi2 Te3 , the SBT cathodes have superior specific capacity, rate capability, and cycling stability.

An imine-rich polymer with enlarged π-conjugated planes for aqueous zinc-ion batteries

Two imine-rich polymers (planar P3Q and linear TDB) were synthesized through a facile method. P3Q demonstrates an enlarged π-conjugated structure, increasing the coordination and conversion of Zn2+. As a result, for aqueous zinc-ion batteries, P3Q exhibits more excellent electrochemical performance than TDB with a discharge capacity of 226 mA h g-1 at 0.3 A g-1 and relatively high capacity retention of 70% after 100 cycles at 0.5 A g-1. The redox energy storage mechanism is also explored by ex situ characterization and density functional theory calculation.

Preparation of Li3V2(PO4)3 as cathode material for aqueous zinc ion batteries by a hydrothermal assisted sol-gel method and its properties

To alleviate the depletion of lithium resources and improve battery capacity and rate capacity, the development of aqueous zinc-ion batteries (AZIBs) is crucial. The open channels monoclinic structure Li3V2(PO4)3 is conducive to the transfer and diffusion of guest ions, making it a promising cathode material for AZIBs. Therefore, in this study, nanoneedles and particles Li3V2(PO4)3 cathode materials for AZIBs were prepared by a hydrothermal assisted sol-gel method, and the effect of synthesized pH values was studied. XRD results show that all samples had the monoclinic structure, and the Li3V2(PO4)3 sample prepared at pH = 7 exhibits (LVP-pH7) the highest peak tips and narrowest peak widths. SEM images demonstrate that all samples have the morphology character of randomly oriented needles and irregular particles, with the LVP-pH7 sample having more needle-like particles that contribute to ion diffusion. EDS results show uniform distribution of P, V, and O elements in the LVP-pH7 sample, and no obvious aggregation phenomenon is observed. Electrochemical tests have shown that the LVP-pH7 sample exhibits excellent cycling performance (97.37% after 50 cycles at 200 mA g-1) and rate ability compared to other samples. The CV test results showed that compared with other samples, the LVP-pH7 sample had the most excellent ionic diffusion coefficient (2.44 × 10-12 cm2 s-1). Additionally, the Rct of LVP-pH7 is the lowest (319.83 Ω) according to the findings of EIS and Nyquist plot fitting, showing a decreased charge transfer resistance and raising the kinetics of the reaction.