V2O5 Nanobelts Research Articles

VO2(B) nanobelts and reduced graphene oxides composites as cathode materials for low-cost rechargeable aqueous zinc ion batteries

Low-cost and high-safety aqueous zinc ion batteries show their potential application for a large-scale energy storage system due to the high capacity and stable Zinc metal anode. Herein, VO2(B)/reduce graphene oxide (RGO) composite is designed and synthesized via a facile simple hydrothermal reaction. VO2(B) nanobelts uniformly deposited on RGO nanoflakes, which provide an electronic transport pathway and prevent the collapse of the structure during the zinc ion (de)intercalation process. VO2(B)/RGO composite exhibits a remarkable capacity of 456 mAh g−1 at 100 mA g−1, an impressive rate capability of 292 mAh g−1 at 5 A g−1 and capable cycling stability. The existence of capacitive contribution leads to fast zinc ions storage behavior. Moreover, the VO2(B)/RGO composite also offers a maximum energy density of 317 Wh kg−1 at a power density of 70 W kg−1 (based on the mass of the positive electrode). It suggests that VO2(B)/RGO composite is a suitable cathode for zinc ion batteries.

A Durable Na0.56V2O5 Nanobelt Cathode Material Assisted by Hybrid Cationic Electrolyte for High‐Performance Aqueous Zinc‐Ion Batteries

AbstractRechargeable aqueous Zn‐ion batteries (ZIBs) show attractive potential in energy storage devices on account of high safety and eco‐friendliness. Yet the lack of suitable cathode materials prevented the practical application of ZIBs. In our work, a Na0.56V2O5 (NVO) nanobelt cathode material has been fabricated via a hydrothermal reaction. The prepared NVO samples reveal an expanded layer spacing, assisted by the chemical intercalation of Na+ into the V2O5. Particularly, a mild hybrid cationic electrolyte (0.5HCE, containing 3 M ZnSO4 and 0.5 M Na2SO4) was employed to replace the traditional ZnSO4 electrolyte (ZE) in the Zn//NVO system. Owing to the enlarged interlayer spacing and the protective effect of 0.5HCE, the NVO cathode delivers a preferable capacity and good cyclic stability. More specifically, the NVO cathode in 0.5HCE displays a high initial discharge capacity of 317 mAh g−1 at 0.1 A g−1, and exhibits a good stability after 1000 cycles at the current density of 1 A g−1. Besides, the Zn//NVO battery also presents a favorable rate capability and a high reversibility. This study could provide new directions for the development of low‐cost zinc ion batteries.

Enhanced Catalytic Performance Via Optimized Structural Properties for Dichlorotoluene Ammoxidation

A series of VO2 (B) nanostructures with different morphologies including nanobelts, urchins, and carambolas were hydrothermally synthesized and explored as catalyst precursors for ammoxidation of dichlorotoluene to optimize the structural properties. The catalytic results show the performance decreases in the following order: nanobelts> urchins> carambolas. On this basis, Cr doped VO2 (B) nanobelts were prepared and showed the yields of 2,6-dichlorobenzonitrle reaching up to 71.5%. This study provides valuable guidance on the design and development of highly effective ammoxidation catalysts.

New Prelithiated V2O5 Superstructure for Lithium-Ion Batteries with Long Cycle Life and High Power

Vanadium pentoxide (V2O5) is an attractive high-capacity cathode material for lithium-ion batteries but is limited by the poor structural stability. In this work, we report the synthesis and properties of a new lithium-ordered superstructure of Li0.0625V2O5 through controlled prelithiation treatment. Compared to VO5 square pyramids in a pure α-V2O5 structure, the distorted VO5 square pyramid in this superstructure imparts an intrinsic layer structure with improved stability, expanded c-plane spacing, as well as expansion in the a-axis. In the voltage range of 2.5–4.0 V vs Li/Li+, Li0.0625V2O5 nanobelts with lithium-ordered superstructures exhibit a specific capacity up to 215 mAh g–1, ultrahigh cycling capability, and high rate capability. Cyclic voltammograms of lithium insertion into Li0.0625V2O5 nanobelts also demonstrate two new pairs of reversible pseudocapacitive peaks in addition to the ordinary peaks of Li+ insertion into the pure orthorhombic α-V2O5.

Lithiophilic V2O5 nanobelt arrays decorated 3D framework hosts for highly stable composite lithium metal anodes

The lithium metal anode has been considered to be an optimal anode material for high-energy-density battery system due to its ultrahigh specific capacity. However, the sharp dendrite growth and infinite volume expansion have significantly impeded its commercial application. Herein, we propose that V2O5 as the lithiophilic substance can be decorated onto 3D stable frameworks to fabricate dendrite-suppressed composite Li metal anodes via a molten Li infusion method. It is demonstrated that the energetic chemical reaction between V2O5 and molten Li together with the capillary effect based on the nanostructure of interconnected V2O5 nanobelt arrays contributes synergistically to the great Li affinity of the V2O5-Ni foam (V2O5-NF) host and facilitate the efficient and uniform intake of molten Li into the 3D framework. Benefitting from the homogeneous Li distribution in the framework, the decreased local current density of the electrode and the stable property of the host, dendrite-free Li stripping/plating behavior and alleviated volume fluctuation have been achieved for the Li-V2O5-NF composite anode. Compared with the bare Li anode, the as-obtained Li-V2O5-NF composite anode exhibits much stable stripping/plating profiles with low overpotential (~18 mV) for ultralong lifespan (1600 h) at a current density of 1 mA cm−2 in symmetric Li/Li cell. Furthermore, outstanding rate capability and long-term cycling performance (78.8% capacity retention after 500 cycles under 2 C) are obtained in full cells when coupled with Li4Ti5O12 (LTO) cathodes, indicating a promising potential for practical application. Moreover, this work demonstrates that using a new lithiophilic material, V2O5, should be an effective method to construct high stable 3D Li metal anode for Li metal battery.

Prepotassiated V2O5 as the Cathode Material for High‐Voltage Potassium‐Ion Batteries

The voltage and capacity of cathodes are critical factors for energy density of batteries. However, the cutoff voltage of cathode materials in potassium‐ion batteries (PIBs) is usually 4.0 V, causing structural transformations in the electrode materials in the course of repeated insertion/extraction of K+ ions with a large radius (1.38 Å). Materials with large interlayer spacing and short ion diffusion paths show promise to overcome this issue. K0.486V2O5 nanobelts, prepared by preinserting K+ ions into V2O5, are used as cathode materials in high‐voltage PIBs. Various analysis methods are used to understand the insertion/extraction behavior of K+ ions in K0.486V2O5 cathodes cycled between 1.5 and 4.2 V. The analyses reveal the highly reversible structural evolution of K0.486V2O5, in which the chemically inserted K+ ions partially remain between VO layers charged at high voltage serving as stabilizing species to prevent phase transformations. K0.486V2O5 cathodes exhibit a high specific capacity of 159 mAh g−1 at 20 mA g−1 with good cycling stability of 67.4% after 100 cycles at 100 mAh g−1 in the half K‐ion cell. The results provide guidelines for designing layered transition metal oxides to be used as cathode materials for high‐voltage PIBs with high energy density.

Nitrogen-doped carbon dots-V2O5 nanobelts sensing platform for sensitive detection of ascorbic acid and alkaline phosphatase activity

In this work, the as-prepared V2O5 nanobelts can sensitively quench the fluorescence of nitrogen-doped carbon dots (N-CDs) based on the inner filter effect (IFE). In the presence of ascorbic acid (AA), the fluorescence of N-CDs can recover through the redox reaction between V2O5 nanobelts and AA. Meanwhile, in the presence of both alkaline phosphatase (ALP) and ascorbyl-2-phosphate (AAP), the fluorescence of N-CDs can also restore since AAP can be hydrolyzed into AA by ALP. Under optimum conditions, the linear range for AA is from 0.01 to 2.5 μM with a detection limit of 3 nM and that for ALP is from 0.1 to 30 U/L with a detection limit of 0.04 U/L (S/N = 3). Particularly, the proposed probe could be successfully used to detect AA and ALP in human serum samples. Furthermore, N-CDs can be applied in fluorescence imaging of Human breast cancer cells with satisfactory results.

Facile synthesis and characterization of V2O5 nanobelt bundles containing plasmonic Ag for photoelectrochemical water splitting under visible light irradiation

V2O5 nanobelt bundle (NBB) photoanodes were synthesized from commercial V2O5 powder via a facile, room-temperature aqueous solution technique. The V2O5 NBBs were several micrometers long and 15–25 nm wide, with an orthorhombic V2O5 structure, a crystallite size of 63 nm, and an optical bandgap of 2.19 eV. The V2O5 NBBs containing plasmonic Ag showed significantly lower charge transfer resistance than the pure V2O5 NBBs. The charge transfer resistance was further reduced to 21.02 Ω by adding 10% methanol to the 0.1 M KOH electrolyte as a hole scavenger. The water-splitting activity of the V2O5 and V2O5/Ag photoanodes was tested in 0.1 M KOH; a very low photocurrent density of 0.5 μA/cm2 was observed under visible light illumination. The low photocurrent was ascribed to a build-up of photogenerated holes at the photoelectrode/aqueous electrolyte. The addition of methanol drastically increased the photocurrent of the V2O5 NBB photoelectrode. A maximum photocurrent density of 0.2 mA/cm2 was achieved for up to 230 s under light illumination for the V2O5 NBBs containing plasmonic Ag in KOH and methanol, which was 400 times higher than that of the photoanode without a hole scavenger.

VO2(B) nanobelts/reduced graphene oxide composites for high-performance flexible all-solid-state supercapacitors

Vanadium oxide has attracted extensive attention for electrochemical capacitors due to its wide range of versatility. However, due to the relative poor conductivity and chemical stability of vanadium oxide, severe losses of capacitance often occur during charge and discharge processes. Herein, a free-standing vanadium dioxide (VO2(B)) nanobelts/reduced graphene oxide (VO2/rGO) composite film was fabricated by assembly of VO2(B) nanobelts and rGO for supercapacitors. The flexible rGO sheets and VO2(B) nanobelts intertwined together to form a porous framework, which delivered a 353 F g−1 specific capacitance at 1 A g−1, and after 500 cycles, the specific capacitance retention rate was 80% due to the enhanced conductivity of the VO2(B) nanobelts by rGO and increased transport of ions and electrons by the porous structures. An all-solid-state symmetrical supercapacitor was assembled from the VO2/rGO composites, which exhibited good energy storage performance with a maximum voltage of 1.6 V. The maximum power density is 7152 W kg−1 at the energy density of 3.13 W h kg−1, ranking as one of the highest power densities for reported materials. In addition, after 10000 cycles, it still has a specific capacitance retention rate of 78% at 10 A g−1.

Hierarchical flower-like structures composed of cross-shaped vanadium dioxide nanobelts as superior performance anode for lithium and sodium ions batteries

Until now, both lithium ion batteries (LIBs) and sodium ion batteries (SIBs), have been broadly researched, which is either attractive or challenging. Among the transition metal oxides (TMOs), VO2 (B), with a high theoretical capacity and appealing rate capability, has been studied as anode materials. In our work, the flower-like structures composed of cross-shaped VO2 (B) nanobelts were synthesized via a simple solvothermal method. The electrochemical properties were investigated for lithium storage (with capacities of 529.2 mA h g−1 at current density of 0.2 A g−1 after 200 cycles and 683.1 mA h g−1 at 1 A g−1 after 1000 cycles) and sodium storage (225.2 mA h g−1 at 0.2 A g−1 after 200 cycles, 150 mA h g−1 at 5 A g−1). The reaction mechanisms were explored by ex-situ XRD and ex-situ TEM, which reveals the intercalation mechanism for both LIBs and intercalation combined with conversion mechanisms for SIBs.

TiO2 nanorods confined in porous V2O5 nanobelts and interconnected carbon channels for sodium ion batteries

The limited ionic diffusion and electron transport pathway confine the rate performance and stability of TiO2 based anode material for sodium ion batteries. As regards, a typical TiO2 nanorods with a heterojunction with V2O5 nanobelts encapsulated into continuous carbon frame work were designed to promote the transport of electrons and Na+ ions as well as mitigating the volume expansion during the sodiation/desodiation process. One-dimensional (1D) TiO2 hierarchical coupling with ultrathin V2O5 nanobelts confined in continuous carbon framework is designed by combining with hydro-thermal method and aqueous solution growth mechanism at room-temperature. Such structure advantages including three-dimensional (3D) building blocks, large surface area, and the optimum porous hybrid architecture afford rich accessible sites and multiple pathways for the transfer of charge carriers, which shorten the ion transport kinetics and facilitate the mass transfer as current expands to 200 times (from 0.1 Ag1 to 20 Ag−1) as well as the buffering volume expansion advantages during repeated cycles. Simultaneously, the composition synergistic effects including the oxygen vacancies due to the substitution of Ti by V introduce the enhancements in both electron conductivity and the preferred lower Na ion insertion/extraction energy barrier. In addition, these composite is benefited from superior capacity contribution from V2O5, the abundant active reaction sites because of the exposure of the large surfaces which are beneficial from the rich pores. Such three-dimensional TiO2-V2O5 composite can accelerate the electron transportation via the highly orientated interconnected structure as well as facilitating the ion diffusion because of the larger expanded interlayer. The approach supplies a promising material model for preferred orientation active planes and higher Na+ transport kinetics. Such composite with unique structural features presented remarkable high-rate performance when tested as a anode material for sodium-ion batteries (366 mA h g−1 at ∼20 A g−1), and showed very stable sodium-storage performance (a capacity retention nearly to 100% at 5 A g−1). When employed as anode for sodium-ion hybrid capacitors (SIHCs), it delivered a maximum power density of 6.84 kW kg−1 (with 114.07 Wh kg−1 energy density) and a maximum energy density of 244.15 Wh kg−1 (with 152.59 W kg−1 power density). This work with highlights in composition synergistic effects and typical structure design supplies a promising approach to enhance the electrochemical property of sodium ion batteries, which also can be applied to different metal oxides for energy storage devices.

Oxygen vacancies enhance lithium storage performance in ultralong vanadium pentoxide nanobelt cathodes

Ultralong V2O5 nanobelts have been successfully synthesized by a facile hydrothermal oxidation route. Oxygen vacancies are generated in the V2O5 nanobelts by annealing under N2 atmosphere at an elevated temperature. The microstructure and chemical composition of the pristine and annealed V2O5 nanobelts are studied by different methods. Compared to the pristine V2O5 nanobelts, the annealed V2O5 nanobelts sample possesses a higher reversible capacity of 177.8 mAhg−1 after 50 cycles at a current density of 0.3 Ag−1, corresponding to ∼0.27% capacity loss per cycle. At a higher current density of 1.2 Ag−1, the reversible capacity of annealed V2O5 electrode can reach 128.5 mAhg−1, which is two times larger than that of pristine V2O5 electrode. Ultralong flexible morphology together with oxygen vacancies in the annealed V2O5 electrode is considered to be responsible for the enhanced lithium storage properties.

Preparation and capacitance of V2O5/holey graphene hybrid aerogel electrode with high performance

V2O5/holey graphene hybrid aerogel electrode (VHGA) with 3D hierarchical porous structure is fabricated by hydrothermally treating a mixed suspension of holey graphene oxide (HGO) nanosheets, acetic acid, and NH4VO3 at 180 °C for 24 h and followed by freeze drying V2O5/holey reduced graphene oxide hydrogel (HRGO). The prepared VHGA electrodes show an interconnected and stable 3D porous network, and V2O5 nanobelts are randomly embedded in the aerogel, preventing the restacking of HRGO nanosheets. VHGA-2 hybrid aerogel electrode exhibit high specific capacitance (264 F g−1) at a current density of 0.25 A g−1, outstanding rate capability (77%) at various current densities from 0.5 to 10 A g−1 and good cycling performance (85%) after 1000 cycles in 0.5 M K2SO4 aqueous electrolyte. HRGO nanosheets provide an electronic conduction channel, and the 3D hierarchical porous structure shortens the diffusion length of electrolyte ions. The structural advantages of VHGA hybrid aerogel electrode are beneficial to the capacitive behavior. This facile and efficient preparation method for VHGA electrode can be further developed for preparing other transition metal oxide/holey graphene hybrid aerogel electrodes with desired structure and superior properties.

Reconstructed Orthorhombic V2O5 Polyhedra for Fast Ion Diffusion in K-Ion Batteries

Summary Potassium-ion batteries (KIBs) are a promising alternative to lithium-ion batteries because of the abundance, low cost, and redox potential of K; however, the significantly larger radius of K+ inevitably destabilizes the crystal structure of the cathode material, impeding the diffusion of K+. Here, to lower the insertion energetics and diffusion barriers of K+, we synthesizedδ-K0.51V2O5 nanobelts (KVOs) with a large interlayered structure and optimized growth orientation by reconstructing the V–O polyhedra of orthorhombic V2O5; these exhibited a high average voltage (3.2 V), high capacity (131 mAh g−1), and superior rate capability even at 10 A g−1. By coupling the electrochemical experiments with theoretical calculations, we found that the excellent K-ion storage performance of KVO is attributed to its large interlayered structure and unique 1D morphology. Additionally, we assembled a full KIB composed of KVO and graphite with high energy and power densities, proving its feasibility as a promising new battery.

A cathode for Li-ion batteries made of vanadium oxide on vertically aligned carbon nanotube arrays/graphene foam

A hierarchically structured free-standing V2O5/vertically aligned carbon nanotube/graphene foam (V2O5-VA-CNTs/GF) coated by PEDOT was designed. Instead of forming a thick coating layer around, the V2O5 nanobelts disperse uniformly among the CNTs forest without severe aggregations. The PEDOT-V2O5-VA-CNTs/GF delivered a reversible capacity of 296.8 mAh g−1 at 1C, and has capacity retention of 113.3 mAh g−1 at 5C after 1000 cycles. First principles calculations indicate the addition of VA-CNTs to V2O5 electrode could improve the electronic conductivity and facilitate Li-ion adsorption, which lead to the outstanding Li-ion storage and conversion behaviour.

Three-dimensional skeleton networks of reduced graphene oxide nanosheets/vanadium pentoxide nanobelts hybrid for high-performance supercapacitors

Supercapacitors based on two-dimensional (2D) ultrathin nanomaterials of reduced graphene oxide (rGO) and vanadium pentoxide (V2O5) are rapidly growing, but constructing three-dimensional (3D) skeleton networks structure with both high energy density and superior cycle stability remains challenging. In this work, supercapacitor based on 3D skeleton networks of rGO nanosheets/V2O5 nanobelts hybrids has been successfully constructed via a simple one-pot hydrothermal method. The resultant rGO/V2O5 hybrid aerogel electrodes show a high specific capacitance of 310.1 F g−1 (1 A g−1) and 195.2 F g−1 (10 A g−1). Moreover, the assembled symmetric supercapacitors based on as-fabricated hybrid electrodes deliver a high gravimetric capacitance of 225.6 F g−1 (0.5 A g−1), a high energy density of 31.3 Wh kg−1 (249.7 W kg−1) and excellent long-term cycle stability (remain 90.2% after 5000 cycles). Above all, the as-designed 3D skeleton networks, with rGO nanosheets and V2O5 nanobelts hybrids intimately stacked, can give a guidance for designing other high-performance graphene-based electrodes and hold a great potential for high-performance electrical energy storages.

Facile preparation of hierarchical vanadium pentoxide (V2O5)/titanium dioxide (TiO2) heterojunction composite nano-arrays for high performance supercapacitor

We report a heterojunction composite of V2O5 nanobelt arrays/TiO2 nanoflake arrays grown directly on nickel foam. The morphology evolution and growth mechanism of TiO2 nanoflake arrays on V2O5 nanobelt arrays are investigated in detail. The heterojunction composite nano-arrays have a large specific capacitance of 587 F g−1 at a current density of 0.5 A g−1, a high coulombic efficiency (>92%), an excellent cycle stability (92%) after 5000 cycles and a low charge transfer resistance of 2.6 Ω. When the heterojunction composite nano-arrays are assembled into symmetric supercapacitor, the device shows a high energy density of 100.8 W h kg−1 at a power density of 399 W kg−1. The high supercapacitive performance is attributed to their direct growth on conductive current collector and the synergistic effect of V2O5 and TiO2.

In-situ characterizations of chemo-mechanical behavior of free-standing vanadium pentoxide cathode for lithium-ion batteries during discharge-charge cycling using digital image correlation

The free-standing V2O5 nanobelts cathodes for lithium-ion batteries are synthesized through hydrothermal reaction followed by anneal treatments and vacuum filtration deposition. The well cycling performances of the electrode were verified by battery test system. The microstructure and surface morphologies of the V2O5 electrode before and after discharge-charge cycles were analyzed by X-ray diffraction and scanning electron microscope, respectively. The evolutions of strain fields of free-standing V2O5 electrodes are in-situ measured by digital image correlation technique. The heterogeneous features of in-plane strains of V2O5 electrode surface in macro-scales are characterized and systematically discussed as a function of test time (or voltage). Given the effect that the elastic modulus is dependent on the concentration and cycling number, the evolutions of in-plane stresses of V2O5 cathodes during discharge-charge cycling are estimated using a chemo-mechanical constitutive equation. The influences of chemical and mechanical components on in-plane stresses are extracted and discussed, respectively. The results are crucial to further reveal the chemo-mechanical coupling failure mechanism of V2O5 cathode and optimize the electrode structure of lithium-ion battery systems.

Building ultrathin polyaniline encapsulated V2O5 heterogeneous nanowires and its electrochromic performance

A novel V2O5@PANI composite nanowires were prepared by simply stirring in sodium nitrate solution and in-situ chemical oxidation polymerization methods. The V2O5@PANI composite nanowires display excellent optical and electrochemical properties, such as multicolor ranging from black, pale yellow, light yellow to dark green, outstanding cycling stability for 1000 cycles and fast switching time of bleaching and coloration (1.5 and 2.3 s, respectively). These outstanding performances are attributed to the synergistic effect between PANI encapsulated and original V2O5 nanobelts. The study offer a new synthesis strategy for fabricating inorganic-organic composite materials in optical and electrochemical fields. The morphology and structure of the composite were characterized by scanning electron microscopy, high-resolution transmission electron microscopy and X-Ray photoelectron spectroscopy.

Al-doped VO2(B) nanobelts as cathode material with enhanced electrochemical properties for lithium-ion batteries

Aluminium has shown its superiority in stabilization of the monoclinic VO2(B) in free-standing nanobelts. In this paper, aluminium-doped VO2(B) nanobelts are successfully fabricated by a facile one-step hydrothermal method and used as cathode for lithium-ion battery. XPS results show that Al-doping promotes the formation of high valence state of vanadium in VO2(B) nanobelts. Due to the accommodation of valence state of vanadium and lattice volume, Al-doped VO2(B) nanobelts used as the cathode material for lithium-ion batteries exhibit better lithium storage properties with high capacity of 172[Formula: see text]mAh[Formula: see text]g[Formula: see text] and cycling stability than undoped VO2(B) nanobelts. This work demonstrates that the doping of aluminium can significantly enhance the electrochemical performance of VO2(B), suggesting that appropriate cationic doping is an efficient path to improve the electrochemical performance of electrode materials.