V2O5 Nanobelts Research Articles

Reconstruction Effects of Layered Vanadium Oxides by Nanoengineering and Preintercalation for High Zinc-Ion Storage Performance.

Layered vanadium oxides with preintercalated cations have been recognized to be among the most promising cathode materials for aqueous zinc-ion batteries (AZIBs). However, their underlying structure-property relationships are still poorly understood owing to the lack of systematic comparison. Herein, a series of layered V2O5 nanobelts including single-layer α-V2O5 and bilayer hydrated δ-V2O5 with preintercalation (MxV2O5·nH2O, M = Mg2+, Ca2+, or Ba2+) with similar morphology are fabricated through a controllable synthesis protocol as models. The side-by-side comparisons of the energy storage performances and related kinetics in these samples decouple the reconstruction effects of nanostructuring and preintercalation. Results demonstrate that nanostructuring tends to improve the capacity and rate retention of α-V2O5 but leaves the rapid capacity decay unsettled, whereas preintercalation can convert α-V2O5 into δ-V2O5 with simultaneously enhanced discharge capacity, rate retention, and cycling stability. Regulation of the cations' species/content and their associated structural water appears to accelerate the electron/ion transport in V2O5 and stabilize the framework of V2O5, thereby boosting the energy storage properties. The optimized sample with a stoichiometric formula of Mg0.255V2O5·0.809H2O exhibits outstanding comprehensive energy storage performance that is comparable to the most advanced vanadium oxide hydrate cathodes reported in the literature. The quantification and understanding of the reconstruction effects of nanostructuring and preintercalation in this work offer insights into the structural engineering of advanced cathodes for AZIBs and beyond.

Synthesis-in-place of V2O5 nanobelts for wide range humidity detection

Resistive type humidity sensors offer advantages in simplicity, low cost, compact size, and remote operation. Due to the benefits, they have great potential for use in a variety of environments and future applications, including the Internet of Everything (IoE). However, resistive humidity sensors have limitations in detecting extreme humidity levels below 10 % or above 90 % relative humidity (RH) and are also vulnerable to high temperatures, which hinders their use in harsh environments applications. For broader applications, humidity sensors with reliable performance across the full range of humidity levels and high stability at elevated temperatures need to be developed. Here, we report high performance resistive humidity sensors based on V2O5 nanobelts operating at high temperatures. The V2O5 nanobelts are directly deposited between Pt electrodes by O2-assisted physical vapor transport (PVT) method. The V2O5 nanobelt humidity sensor exhibits reliable humidity sensing properties over a wide range from 1 % to 100 % RH. Furthermore, long-term stability and reproducibility of V2O5 nanobelts are demonstrated through 25 consecutive humid air pulses and measurements obtained after 4 months of storage. The high performance of the V2O5 nanobelt humidity sensor is advantageous for practical use in applications ranging from IoE environments to harsh industrial conditions.

Highly selective and stable electrochemical reduction of nitrate to ammonia using VO2-x/CuF catalyst with oxygen vacancies

Electrocatalytic reduction poses significant challenges due to slow kinetics, limited selectivity, and instability, hindering its potential for sustainable nitrate (NO3−) removal and producing valuable N-containing compounds. This study develops a one-step hydrothermal approach for decorating copper foam (CuF) with VO2 nanobelts. Subsequently, N2 annealing is performed to generate oxygen vacancies (OVs) and yield a VO2-x/CuF sample for its application as an electrocatalyst in reducing NO3− to ammonia (NH3). Several characterization techniques are applied to study the structural and morphological features of the VO2-x/CuF sample, which shows a high crystalline and defective bundle-like structure of nanobelts attributed to the release of oxygen atoms that are beneficial for the electrochemical NO3− reduction processes. The VO2-x/CuF sample demonstrates impressive results, with a NO3− conversion of 78.7 %, an NH4+ yield rate of 1.833 mmol h−1 cm−2, an NH4+ FE of 77.9 %, and a remarkable NH4+ selectivity of 99.7 % at −1.3 V vs RHE. It is worth mentioning that the isotopic labeling findings reveal that the NH4+ originated from NO3− during the electrocatalytic NO3− reduction using a VO2-x/CuF sample. This confinement method effectively creates accessible metallic catalysts with OVs, enabling high-activity, selective and stable NO3− reduction to NH4+ electrocatalysts.

One-step hydrothermal synthesis of vanadium dioxide/carbon core–shell composite with improved ammonium ion storage for aqueous ammonium-ion battery

Aqueous nonmetallic ion batteries have garnered significant interest due to their cost-effectiveness, environmental sustainability, and inherent safety features. Specifically, ammonium ion (NH4+) as a charge carrier has garnered more and more attention recently. However, one of the persistent challenges is enhancing the electrochemical properties of vanadium dioxide (VO2) with a tunnel structure, which serves as a highly efficient NH4+ (de)intercalation host material. Herein, a novel architecture, wherein carbon-coated VO2 nanobelts (VO2@C) with a core–shell structure are engineered to augment NH4+ storage capabilities of VO2. In detail, VO2@C is synthesized via the glucose reduction of vanadium pentoxide under hydrothermal conditions. Experimental results manifest that the introduction of the carbon layer on VO2 nanobelts can enhance mass transfer, ion transport and electrochemical kinetics, thereby culminating in the improved NH4+ storage efficiency. VO2@C core–shell composite exhibits a remarkable specific capacity of ∼300 mAh/g at 0.1 A/g, which is superior to that of VO2 (∼238 mAh/g) and various other electrode materials used for NH4+ storage. The NH4+ storage mechanism can be elucidated by the reversible NH4+ (de)intercalation within the tunnel of VO2, facilitated by the dynamic formation and dissociation of hydrogen bonds. Furthermore, when integrated into a full battery with polyaniline (PANI) cathode, the VO2@C//PANI full battery demonstrates robust electrochemical performances, including a specific capacity of ∼185 mAh·g−1 at 0.2 A·g−1, remarkable durability of 93 % retention after 1500 cycles, as well as high energy density of 58 Wh·kg−1 at 5354 W·kg−1. This work provides a pioneering approach to design and explore composite materials for efficient NH4+ storage, offering significant implications for future battery technology enhancements.

Tunnel-Oriented VO2 (B) Cathode for High-Rate Aqueous Zinc-Ion Batteries.

Tunnel-type vanadium oxides are promising cathodes for aqueous zinc ion batteries. However, unlike layer-type cathodes with adjustable layer distances, enhancing ion-transport kinetics in tunnels characterized by fixed sizes poses a considerable challenge. This study highlights that the macroscopic arrangement of the electrode crucially determines tunnel orientation, thereby influencing ion transport. By changing the material morphology, the tunnel orientation can be optimized to facilitate rapid ion diffusion. In a proof-of-concept demonstration, it is revealed that (00l) facets-dominated VO2 (B) nanobelts with dispersive morphology (VO2-D) tend to adopt a stacking pattern with directional ion transport along the c-axis on the electrode and guarantee fast ion diffusion. Compared with the aggregated sample (VO2-A) that tends to random arrangement on the electrode with isotropic and slow ion transfer behavior, the electrode featuring dispersive (00l) facets-dominated VO2 (B) nanobelts displays directional and fast ion diffusion behavior, thus exhibits an ultrahigh-rate performance (420.8 and 344.8 mAh g-1 at 0.1 and 10 A g-1, respectively) and long cycling stability (84.3% capacity retention under 5000 cycles at 10 A g-1). The results suggest that simultaneous manipulation of exposed crystal facet and morphology-related electrode arrangement should be promising for boosting the ion-transport kinetics in tunnel-type vanadium oxide cathodes.

Graphene Oxide Wrapped VO2 Nanobelts for Calendar‐Life Zn Storage Devices

AbstractAqueous zinc ion batteries (AZIBs) are thought to be emerging energy storage systems due to their features with high safety, low cost, and eco‐friendliness. They possess potential applications in smart grids and wearable devices. However, it is still a challenge to design suitable cathode materials that matches well with anode. Herein, graphene oxide (GO) coated VO2 nanobelts are prepared through a facile hydrothermal route. The Zn//VO2@GO batteries deliver a specific capacity of 323 mA h g−1 at a current density of 0.1 A g−1. It maintains an 88% of capacity retention rate at 5 A g−1 after 1000 times cycling. Moreover, the assembled flexible cells demonstrate excellent mechanical stability under different folding conditions.

The introduction of gallium ions into V2O5 interlayers for highly reversible Zn ion batteries

We prepare Ga3+ intercalated V2O5 nanobelts by a simple hydrothermal route. The assembled Zn//V2O5–0.1Ga cell delivers a discharge capacity of 512.07 mA h g−1 at 0.1 A g−1. It maintains 91.43% of the original capacity at 10 A g−1 after 5000 cycles.

Enhancing Zn2+ Storage Performance by Constructing the Interfaces Between VO2 and Co-N-C Layers.

Vanadium oxides have aroused attention as cathode materials in aqueous zinc-ion batteries (AZIBs) due to their low cost and high safety. However, low ion diffusion and vanadium dissolution often lead to capacity decay and deteriorating stability during cycling. Herein, vanadium dioxides (VO2) nanobelts are coated with a single-atom cobalt dispersed N-doped carbon (Co-N-C) layer via a facile calcination strategy to form Co-N-C layer coated VO2 nanobelts (VO2@Co-N-C NBs) for cathodes in AZIBs. Various in-/ex situ characterizations demonstrate the interfaces between VO2 layers and Co-N-C layers can protect the VO2 NBs from collapsing, increase ion diffusion, and enhance the Zn2+ storage performance. Additional density functional theory (DFT) simulations demonstrate that Co─O─V bonds between VO2 and Co-N-C layers can enhance interfacial Zn2+ storage. Moreover, the VO2@Co-N-C NBs provided an ultrahigh capacity (418.7mAhg-1 at 1Ag-1), outstanding long-term stability (over 8000 cycles at 20Ag-1), and superior rate performance.

Oxygen vacancy defect engineering of porous single-crystal VO2 nanobelts for aqueous zinc ion battery cathodes

Aqueous zinc ion batteries (AZIBs) have received considerable attention due to their high safety, low cost, environmental friendliness, and high theoretical capacities. However, the energy/power density and cost efficiency of AZIBs are still limited by cathode materials, so the exploration of advanced cathode materials plays a key role in their further practical development. Herein, porous single-crystal VO2 nanobelts with adjustable oxygen vacancy defects (Od-VO2 NBs) are obtained by precise regulation of chemical synthesis. Collective results reveal that the defect engineering designed Od-VO2–2 NBs as the optimized cathode exhibit excellent electrochemical performance due to the suitable oxygen vacancy defects, showing a high discharging capacity of 202.8 mAh g–1 after 500 cycles at 0.5 A g–1, durable cycling stability over 1000 cycles at 1.0 A g–1, and impressive rate performance. The electrode design can effectively improve the electrical conductivity and structural stability of Od-VO2 cathodes to accelerate reaction kinetics, and provide more activated sites for reversible Zn2+ storage. Besides this, the porous single-crystal structure favors rapid ions/electrons transport and buffers the volume change. This work demonstrates a simple method to design vanadium-based cathodes for high-performance AZIBs, making it a promising candidate for next-generation energy storage devices.

Fast responding and highly selective chemoresistive humidity sensor based on hydrated V2O5 nanobelts for real-time breath monitoring

Chemoresistive humidity sensors have gained massive attraction owing to the high potential for application in real-time breath monitoring. Herein, we introduce a chemoresistive humidity sensor based on ultrathin V2O5·nH2O nanobelts (NBs) prepared by liquid-phase exfoliation. Due to the layered structure, water molecules were embedded between layers, increasing the active surface area. Moreover, the multivalent vanadium states and oxygen vacancies are highly beneficial to increasing the adsorption sites in gas sensing reactions. V2O5·nH2O NBs exhibited promising humidity sensing properties examined by exposure to 50% relative humidity (RH). The response and recovery time to 50% RH was 21 s and 356 s, respectively, with stable and reliable sensing behaviors to repetitive exposure to humid air. The response to 50% RH was 27 times higher than the response to interference gas, indicating the outstanding selectivity to humidity. The theoretical detection limit was 0.55% RH, showing linear response increase with humidity concentration. The response degradation was marginal even after 3 weeks of relaxation, showing high stability. The breath monitoring experiment reveals extremely rapid response and recovery to exhaled breath, enlarging the suitability for a real-time breath monitoring platform.

Boosting the electrochromic properties by large V2O5 nanobelts interlayer spacing tuned via PEDOT

Vanadium pentoxide (V2O5) with a layered structure is of great interest in the field of electrochromic (EC) due to its abundance of color variations. However, there are still a series of problems such as slow ion diffusion, poor electronic conductivity and cyclic stability in the reaction process. Herein, we successfully prepared a stable and fast multi-color electrochromic material V2O5-PEDOT by a simple “one-pot” method. The layer space of V2O5 could be tuned by 3,4-ethylenedioxythiophene (named V2O5-PEDOT) during the dissolution and recrystallization of vanadium oxide. The expanded layer spacing facilitates rapid ion insertion and extraction. PEDOT serves as an internal conductive pillar to improve the overall conductivity of the material. The obtained intercrossing structure of the nanobelts shortens the ion diffusion distance and ensures electrolyte penetration. The V2O5-PEDOT exhibits the fast response time (1.1 s for coloration and 3.5 s for bleaching at 422 nm), high optical contrast (ΔT = 45% at 422 nm and ΔT = 35.2% at 1000 nm), great coloration efficiency (CE = 97.1 cm2/C), and high cyclic stability (86% preserved after 3000 cycles). The electrochromic devices (ECD) were successfully assembled by using V2O5-PEDOT films as ion storage layers and electrochromic layers, demonstrating remarkable performance.

Preparation of V2O5 nanobelt arrays/NiO nanosheet arrays composite as supercapacitor electrode material

V2O5 nanobelt arrays (VNBAs) is fabricated on Ni foam by using an easy hydrothermal route and then NiO nanosheet arrays (NNSAs) is grown on VNBAs by using a simple chemical bath deposition approach to form VNBAs/NNSAs composite. It is found that the monocrystalline VNBAs with a lamellar structure is uniformly distributed on nickel foam and the polystalline NNSAs with a close packed structure is closely covered on the VNBAs. CV, GCD, EIS and CA electrochemical techniques are used to test the supercapacitive properties of the VNBAs/NNSAs composite. The single electrode displays a high specific capacity of 875 F g−1, a good cycling stability of 96.1%, a small charge transfer resistance of 1.32 Ω and a rapid ion diffusivity of 2.5 × 10−8 cm2 s−1. The symmetric supercapacitor combined by the VNBAs/NNSAs displays a large energy density of 120.1 W h kg−1 at 400 W kg−1 and it retains 68.3 W h kg−1 at 8000 W kg−1. The VNBAs/NNSAs composite with high electrochemical performance is a potential supercapacitor electrode material.

Engineered nitrogen doping on VO2(B) enables fast and reversible zinc-ion storage capability for aqueous zinc-ion batteries

Vanadium-based compounds with high theoretical capacities and relatively stable crystal structures are potential cathodes for aqueous zinc-ion batteries (AZIBs). Nevertheless, their low electronic conductivity and sluggish zinc-ion diffusion kinetics in the crystal lattice are greatly obstructing their practical application. Herein, a general and simple nitrogen doping strategy is proposed to construct nitrogen-doped VO2(B) nanobelts (denoted as VO2-N) by the ammonia heat treatment. Compared with pure VO2(B), VO2-N shows an expanded lattice, reduced grain size, and disordered structure, which facilitates ion transport, provides additional ion storage sites, and improves structural durability, thus presenting much-enhanced zinc-ion storage performance. Density functional theory calculations demonstrate that nitrogen doping in VO2(B) improves its electronic properties and reduces the zinc-ion diffusion barrier. The optimal VO2-N400 electrode exhibits a high specific capacity of 373.7 mA h g−1 after 100 cycles at 0.1 A g−1 and stable cycling performance after 2000 cycles at 5 A g−1. The zinc-ion storage mechanism of VO2-N is identified as a typical intercalation/de-intercalation process.

Graphene oxide-assisted fabrication of mesoporous oxygen-deficient VO2 nanobelts for enhanced Zn2+ storage

Rechargeable aqueous zinc-ion batteries (ZIBs) are regarded as promising devices for large-scale stationary energy storage. However, developing ideal cathode materials confronts great challenges. Herein, a novel graphene oxide (GO)-assisted strategy is proposed to synthesis mesoporous VO2/G nanobelts with abundant oxygen defects for high-performance Zn2+ storage. The oxygen vacancies and mesopores facilitate Zn2+ insertion/extraction process. After an in-situ electrochemical activation at around 1.5 V, the monoclinic VO2 transforms to layered V2O5·nH2O, delivering an extremely high reversible capacity of 731 mAh/g (0.1 A/g). In addition, superior high-rate and cycling performances are also achieved.

Construction of oxygen vacancies and heterostructure in VO2-x/NC with enhanced reversible capacity, accelerated redox kinetics, and stable cycling life for sodium ion storage

Developing anode materials with high reversible capacity, fast redox kinetics, and stable cycling life for Na+ storage remains a great challenge. Herein, the VO2 nanobelts with oxygen vacancies supported on nitrogen-doped carbon nanosheets (VO2-x/NC) were developed. Benefitting from the enhanced electrical conductivity, the accelerated kinetics, the increased active sites as well as the constructed 2D heterostructure, the VO2-x/NC delivered extraordinary Na+ storage performance in half/full battery. Theoretical calculations (DFT) demonstrated that oxygen vacancies could regulate the adsorption ability for Na+, enhance electronic conductivity, as well as achieve rapid and reversible Na+ adsorption/desorption. The VO2-x/NC exhibited high Na+ storage capacity of 270 mAh g−1 at 0.2 A g−1, and impressive cyclic stability with 258 mAh g−1 after 1800 cycles at 10 A g−1. The assembled sodium-ion hybrid capacitors (SIHCs) could achieve maximum energy density/power output of 122 Wh kg−1/9985 W kg−1, ultralong cycling life with 88.4% capacity retention after 25,000 cycles at 2 A g−1, and practical applications (55 LEDs could be actuated for 10 min), promising to be utilized in a practicable Na+ storage.

Charge kinetics evaluation of Fe3O4/V2O5 nanowires under visible light for energy conversion applications

In this study, surface-modified bundled V2O5 nanobelts with Fe3O4 nanoparticles were synthesized and their photoelectrochemical properties were recorded under illumination by light. The effects of the electrolyte on the heterostructured photoanode, structural and optical properties, as well as charge kinetic behavior of the photoelectrode were investigated. A combination of V2O5 and Fe3O4 nanostructures exhibited better light absorption than pristine V2O5 and Fe3O4 samples. With V2O5–Fe3O4, an electron-hole transfer resistance of 24.13 Ω and ion-path resistance of 109.8 Ω were achieved in a 0.1 M Na2SO3 electrolyte under irradiation. These values were lower than those obtained with pure V2O5 and Fe3O4 nanostructures. The photocurrent density of the V2O5–Fe3O4 photoanode considerably increased in Na2SO3 electrolytes compared to those of the others due to greater active sites in the photoanode and considerable improvements in the charge transfer resistance, limiting current density, and Tafel slope. Thus, V2O5–Fe3O4 photoanodes were established to be durable and stable materials for photoelectrochemical water splitting.

Oxygen vacancies and heterointerface co-boosted Zn2+ (De)intercalation kinetics in VO2 for ultra-efficient aqueous zinc-ion batteries

In this study, we demonstrated the co-modification of oxygen vacancies and heterojunctions in VO2(B) (VO–VO2/MXene) as a cathode material for zinc-ion batteries (ZIBs). VO2 nanobelts are uniformly distributed on MXene nanosheets, which providing complete electron transport channels during the insertion or de-insertion of Zn2+. The formation of oxygen vacancies provides additional active sites and enhances the conductivity of VO2. Density functional theory calculations reveal that the oxygen vacancies effectively facilitate reversible intercalation/deintercalation process, which results in rapid intra-crystal zinc ion diffusion. The combination of VO–VO2 with MXene introduces an interfacial electric field, ultimately leading to synergistic enhancement in electrochemical activity. The VO–VO2/MXene composite exhibits the highest specific capacity (287 mAh g−1) at 10 A g−1 and excellent cycling lifespan (253 mAh g−1 after 3000 cycles) for ZIBs. This work provides a reliable strategy for the co-modification of metal oxide electrodes with oxygen vacancies and heterostructures.

Construction of novel polyaniline-intercalated hierarchical porous V2O5 nanobelts with enhanced diffusion kinetics and ultra-stable cyclability for aqueous zinc-ion batteries

Rechargeable aqueous zinc-ion batteries (ZIBs) have received considerable attention for large-scale energy storage applications due to the unique merits of high energy density, eco-friendliness and reliable safety. However, the development of high performance cathodes is still hampered by their inferior reversibility and sluggish Zn2+ diffusion kinetics, resulting in insufficient rate capability and poor cycling performances. Herein, we employed a feasible “two-in-one” strategy to intercalate conductive polymer (polyaniline, PANI) as pillar molecules into the V-MOF-derived hierarchical porous V2O5 (designated as PVO) and used as cathode for high-performance ZIBs. The high specific surface area and nanobelt-like porous structure endowed PVO with abundant accessible electrochemical active sites and shortened the electrons/ions transfer pathways, further delivering a high discharge capacity (489 mAh g−1 at 0.1 A g−1 and 97.2% capacity retention after 100 cycles). Meanwhile, the intercalation of PANI not only effectively expanded the Zn2+ diffusion channels, but also improved the structural stability during cycling as “interlayer pillars”. More importantly, the introduction of PANI could enhance the conductivity of the overall structure and weaken the electrostatic interaction between Zn2+ and PVO host, thereby suppressing the collapse of the layered structure. Accordingly, the obtained PVO cathode exhibited excellent rate capability (375 mAh g−1 at 5.0 A g−1) and satisfactory cycling stability (91.8% capacity retention after 2000 cycles at 8.0 A g−1). Moreover, the reversible Zn2+ storage mechanism was further investigated by kinetics analysis and DFT calculations. These ideal results provide key insights into the design of MOF-based cathode materials for high-performance aqueous zinc ion batteries.

Structural transition and photoluminescence behavior of (V2O5)1-x (Ag0.33V2O5)x (x = 0 to 0.1) nanocomposites

The two phase (V2O5)1-x(Ag0.33V2O5)x (x = 0, 0.05, 0.075 and 0.1) nanocomposites were synthesized through one step hydrothermal process. The X-ray diffraction followed by two phase Rietveld refinement confirms the crystallization of V2O5 and Ag0.33V2O5 phases in the Pmmn (orthorhombic) and C21 (monoclinic) symmetry respectively without any impurity phase. Furthermore, the FE-SEM, EDX, PL, UV–vis and XPS characterization were carried out for microstructural, optical and chemical studies. The formation of Ag0.33V2O5 nano-belts with average length and width of 3–4 μm and 40–50 nm respectively, were observed in the electron micrograph. Moreover, the XPS study confirms the constituent element are in expected oxidation states with Vanadium in only + 5 (V+5) for V2O5 and in mixed states (V+5 and V+4) for 10 % Ag0.33V2O5 nanocomposite. The photoluminescence spectra of these nanocomposite depicts two broad emission peaks located around 570 nm and 707 nm due to indirect inter-band and mid-state energy states transitions, respectively. PL also prove the increase in oxygen vacancies by loading of Ag in V2O5 matrix. The optical absorption of Ag0.33V2O5 represents a decrease in the energy band gap (2.10–1.97 eV) by adding Ag concentration in the V2O5, which also proved the semiconductor to metal transition (SMT).

Polypyrrole-coated V2O5 nanobelts arrays on carbon cloth for high performance zinc energy storage

V2O5 is considered as a promising cathode material for zinc ion batteries due to its abundance, low-cost, layered structure and high capacity. However, low electronic conductivity, vanadium dissolution accompanied with sluggish ion transport kinetics, severely limit its electrochemical performance. Herein, the polypyrrole-coated V2O5 nanobelts arrays grown on carbon cloth (PPy@V2O5/CC) are rationally designed and prepared by combination of solvothermal and vapor-phase polymerization process. The resultant flexible PPy@V2O5/CC electrode delivers a high specific capacity of 276 mAh g−1 at 0.1 A g−1, an excellent rate capability of 185 mAh g−1 at 10 A g−1, and extraordinary long-term cycling stability with 76% capacity retention after 8000 cycles at 5 A g−1, better than V2O5/CC. The significant enhancement can be attributed to the PPy protective layer, which can simultaneously achieve higher electronic conduction, suppressed vanadium dissolution, enhanced surface pseudocapacitive behavior, and faster Zn2+ diffusion rate. This work offers a novel strategy for constructing high-performance micro/nano functional composites for electrochemical energy storage system.