V2O5 Nanospheres Research Articles

Pomegranate‐Inspired Cathodes Mitigate the Mismatch Between Carrier Transport and High Loading for Aqueous Zinc‐Ion Batteries

AbstractThe development of high‐energy‐density aqueous zinc‐ion batteries requires the preparation of cathodes with a thick layer of active material. However, the insulating nature and dissolution of vanadium‐based oxides lead to low areal capacity (0.1,1 mA h cm−2) during the charge/discharge cycle. Herein, V2O5 nanospheres are generated by anchoring onto the laser‐induced graphene (LIG) conductive network through defect‐induced adsorption, resulting in the formation of pomegranate‐like V2O5@LIG composites. The unique and abundant defect structure in the honeycomb LIG can trigger the formation of uniform V2O5 nanospheres with high specific surface area and interact electronically with V2O5 to enhance the electrical conductivity of the cathode materials up to four orders of magnitude. In contrast to conventional carbon materials that can cause steric hindrance for ion transport, the micropores within LIG shorten the ion transport path through the cathode. Concurrently, the pomegranate‐like encapsulated structure effectively prevents cathode material corrosion. Under a high‐loading mass of 17.1 mg cm−2, the full cell is stably cycled for 200 cycles, possessing a 92.5% capacity retention, and achieving a high areal capacity of 6.05 mA h cm−2.

Temperature Study on Vanadium Oxide Nano-Spheres As an Efficient Electrodes for Supercapacitor

Due to the intermittence nature of renewable sources of energy, the research community has paid close attention to energy storage devices for ensuring the continuous supply of energy. Among the other transition metal oxides, V2O5 nanostructures have some inherent properties such as their layered structure, numerous oxidation states, low cost, ease of availability, and low toxicity, seems to fit to work as an electrode material for supercapacitor application. In the current study, V2O5 nanospheres were created using a solvothermal technique. To determine the ideal calcination temperature for the synthesis of V2O5 nanospheres, a thorough experimental examination was conducted. The resulting V2O5 nanospheres were thoroughly evaluated for their temperature-dependent morphological, structural, and compositional characteristics using a variety of cutting-edge analytical techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron dispersive spectroscopy (EDS). The diameters of the nanospheres range from 1-2 micrometers, but their widths are only a few nm. The generated nanospheres electrochemical examination was performed using an aqueous LiCl electrolyte. The generated nanospheres exhibit a cyclic stability of 66% capacitance retention after 500 cycles and the maximum specific capacitance of about 360 F/g at 0.5 A/g. The exceptional reversibility and cyclic stability of the nanospheres were caused by the surface alteration brought on by calcination. The slower kinetics of electrode dissolving can be used to explain the improved cycle performance seen in this study as a result of the reduction in stress during the electrochemical reaction. Keyword: Supercapacitor, Vanadium Pentoxide, Energy storage, Electrochemistry.

Ppb-level detection of trimethylamine as biomarker in exhaled gas based on MoO3/V2O5 hierarchical heterostructure

The toxic gas trimethylamine (TMA) with fishy odor can not only be used as an indicator for evaluating seafood spoilage, but also as a biomarker for trimethylaminuria and kidney disease. This paper constructs a ppb-level trimethylamine gas sensor that operates at room temperature based on MoO3/V2O5 nanocomposites, which were fabricated by hydrothermal synthesis process. The adsorption energy of TMA on sensitive materials was calculated through the density functional theory, and the sensing mechanism was explored by simulating the adsorption process of TMA on the sensitive materials. The response (11.37%) of MoO3/V2O5 composites to ultra-low concentration (20 ppb) TMA was better than that of pure MoO3 nanorods (5.49%) and V2O5 nanospheres (6.36%) at room temperature. Compared with pure MoO3 sensors, an n-n heterojunction is formed between MoO3 and V2O5, which enhances the sensing performance of pure sensing material for TMA. In addition, the detection of exhaled gas in simulated kidney disease patients indicates that this sensor has great potential as an effective TMA detection tool in the field of non-invasive disease diagnosis.

Hydrogenated V2O5 with fast Zn-ion migration kinetics as high-performance cathode material for aqueous zinc-ion batteries

The scarce inventory of cathode materials with mild interaction between Zn2+ and cathode lattice is the main obstacle to the development for aqueous rechargeable Zinc-ion batteries. In this paper, based on the first-principles calculations, we show that the insertion of protons in V2O5 effectively reduces the electrostatic interaction and the Zn-ion diffusion energy barrier in V2O5 substantially decreases after hydrogenation. Hence, the hydrogenated V2O5 (HV2O5) nanospheres are first proposed as a high capacity cathode for aqueous rechargeable Zinc-ion batteries by microwave-assisted chemical precipitation synthesis. It is demonstrated to exhibit high peak capacities of 602 mAh g−1 at 0.1 A g−1, high rate capacity as well an excellent cycle lifespan with a capacity retention of 86% after 5000 cycles at 10 A g−1. The mechanism of ions-diffusion in different charge and discharge states is also studied, and it proves dual-ion energy storage mechanism that HV2O5 can attract Zn ions and H ions at discharging.

Synthesis and characterization of vanadium pentoxide nanospheres by pulsed laser deposition: Effect of laser ablated energy on photodetectors properties

This paper introduces vanadium pentoxide films that were grown under the different laser pulse energy (440,640 and 840) mJ/pulse deposition conditions in order to observe the impact on the structural, optical, morphology, and electric properties and to specify the optimum condition. V2O5 nanospheres (V2O5NSs) are synthesized on porous silicon n-type Si (100) by pulsed laser deposition (PLD) method at room temperature. Q-switching Nd: YAG laser 1064 nm and the pulse duration of 10 ns and a repetition rate of 1 Hz use in the ablation process. X-ray diffraction (XRD), photoluminescence (PL), Raman spectroscopy, and field emission-scanning electron microscope (FE-SEM) were used to undertake structural and optical analysis. The findings the indicated that as-deposited films crystallized well in 840 mJ, in comparison to other forms of laser pulse energy. Photoluminescence spectra reveal intense and broad green light emission with a high intensity at around 545 nm. The PL intensity with an energy gap of the V2O5NSs (2.26, 2.27, and 2.28) eV with different laser pulse energies (440,640 and 840) mJ/pulse, respectively has been noted. Electrical properties determined from the current–voltage characteristics and Photocurrent density – voltage of Al/V2O5NPs/PS/n-Si/Al. The results showed that detectivity improves as laser pulse energy increases, 80% quantum efficiency was achieved in 840 mJ/pulse laser ablated energy. The results indicate that V2O5NSs are a promising candidate for high-performance photodetector applications in optoelectronics.

Conductive copper glue constructs a reversible and stable zinc metal anode interface for advanced aqueous zinc ion battery

Aqueous zinc (Zn) ion battery (AZIB) has become one of the research hotspot in the field of energy storage due to its low cost, green environmental protection, high theoretical capacity, and high safety. However, the unrestrained growth of the dendrites leads to the occurrence of side reactions, such as corrosion of the electrodes and generation of hydrogen, which reduces the coulombic efficiency and performance of the battery. Herein, a simple method reports pasting a conductive copper glue (CCG) coating on the surface of Zn anode to improve the serious dendrite growth. The coating has strong intermolecular interaction and high conductivity, which not only avoids the occurrence of side reactions but also facilitates the uniform deposition of Zn2+ ions, preventing dendrite formation. The symmetrical battery assembled with Zn anode modified by CCG coating delivers longer cycle life (167 h) and lower voltage hysteresis (≈26 mV), which is much better than that of bare Zn symmetrical battery (30 h, ≈67 mV). Furthermore, the full battery assembly with modified Zn anode and stainless steel (SS) supported V2O5 nanospheres (VO-SS) cathode exhibit high capacity and long cycle life (113.5 mAh g−1 after 4000 cycles at 4.8 A g−1).

Highly ordered mesoporous V2O5 nanospheres utilized chemiresistive sensors for selective detection of xylene

This work reports a simple, time efficient, template-free solvothermal and environmentally friendly method for the synthesis of V2O5 nanospheres (NSs) for xylene gas detection. The four types of V2O5-5, V2O5-7, V2O5-9 and V2O5-11 NSs have been synthesized and tested toward xylene in concentration ranging from 1 ppm to 300 ppm. The V2O5-7 sensor exhibits excellent sensing response of 2.75 toward 100 ppm xylene gas within fast response time of 21 s with obtained limit of detection (LOD) of 1 ppm at optimal operating temperature 290 °C. The sensing mechanism is based on an interaction of V2O5 NSs towards xylene through chemical reaction with adsorbed oxygen species present on V2O5 NSs, resulting in a thinner depletion layer and a lower potential barrier which further leads to decrease in sensor resistance. These experimental results suggest that the V2O5 NSs based sensors have potential to fulfill the demands in the gas sensing field.

Enhanced thermoelectric performance of V2O5 bulk-type pellet nanodevices by tungsten doping

Bulk-type pellet thermoelectric devices were fabricated by pressing tungsten (W)-doped V2O5 (WxV2-xO5) nanospheres that were synthesized by chemical reaction, and their performance was studied. The sizes of the synthesized WxV2-xO5 nanospheres (x = 0, 0.04, 0.08, and 0.12) were measured as 259 ± 25, 184 ± 16, 178 ± 16, and 180 ± 21 nm, respectively. The thermoelectric properties were analyzed by obtaining the thermoelectric figure of merit (ZT) using the measured thermal conductivity, electrical conductivity, and Seebeck coefficient in the temperature range of 300–773 K. The thermal conductivity was decreased by the W doping, while the electrical conductivity was increased. As a result, the ZT value increased with the doping concentration, and the maximum ZT value of the W0·08V1·92O5 pellet reached 4.73 × 10−3, which is 3.3 times larger than that of a pure V2O5 pellet at 773 K.

Hydrothermal synthesis of V2O5 nanospheres as catalyst for hydrogen sulfide removal from sour water

Vanadium pentoxide (V2O5) nanospheres were synthesized hydrothermally for the first time with high specific surface area. The effect of different parameters including pH level, H2O2/H2O volume ratio and reaction temperature on the precipitate yield was investigated, and the highest yield was attained at the pH level of 3, H2O2/H2O volume ratio of 0.01 and the reaction temperature of 160 °C. Freeze drying, oven drying and vacuum drying methods along with auxiliary processes were employed to improve the drying process and minimize the aggregation of the synthesized nanoparticles (NPs). Two auxiliary processes were used prior to drying in the oven to improve the performance of drying. Firstly, precipitates were immersed in ethanol to get replaced in place of water molecules in a week. The precipitates were then dried at room temperature for a week to evaporate their moisture. In vacuum drying method, only the second auxiliary process was employed. In freeze drying technique, the segregate and uniform nanospheres of V2O5 were produced with an average diameter of 37 nm. Generally, the employed additional treatments cause the drying techniques to enhance and the extent of particles aggregation to reduce. Finally, the application of the synthesized NPs as catalyst was investigated for the elimination of H2S from sour water with the initial concentration of 1300 ppm. The sour water was provided from Shiraz Oil Refinery Company. Results revealed that the synthesized NPs enable to completely eliminate hydrogen sulfide from sour water with 20% greater conversion at early contact seconds as compared to commercial V2O5 powder.

Hollow V2O5 nanospheres wrapped by activated carbon to confine polysulfides for lithium sulfur battery

The practical application of the Li-S battery is restrained by the severe lithium polysulfide shuttle and sulfur insulation. In this work, the hollow V2O5 nanospheres wrapped by activated carbon as the host material for sulfur were prepared. The results indicate that initial specific discharge capacity of the electrode is 972 mA h g−1 and it can be maintained at 730 mA h g−1 after 200 cycles at 0.2 C. The average decay rate of the capacity for the AC@V2O5/S only is 0.09% per cycle after 200 cycles at 0.5 C. This excellent performance could result from the polar hollow V2O5 nanospheres providing more adsorption sites, which are conducive to electrolyte diffusion and confine polysulfides during the reaction of sulfur and polysulfide. Furthermore, the activated carbon coated on the outer layer can provide the large specific surface as conductive network. Therefore, this design strategy could show significant prospects for Li-S battery.

Thermoelectric properties of V2O5 nanosphere pellet

This study investigates the thermoelectric performance of a bulk-type pellet nanodevice fabricated with pressed V2O5 nanospheres synthesized by chemical reaction and sized 258 ± 27 nm. The following thermoelectric properties in the 300–773 K temperature range were analyzed: thermal conductivity (λ), electrical conductivity (σ), Seebeck coefficient (S), and figure of merit (ZT). The bulk-type pellet thermoelectric device exhibited a higher S and lower σ compared to the film-type device at 300 K. With increasing temperature, the absolute value of S and λ slightly decreased but the σ value increased. The power factor (PF) and ZT value at 773 K were 1.43 × 10−6 Wm−1K−2 and 1.4 × 10−3, respectively.

Enhanced rate and cycling performances of hollow V2O5 nanospheres for aqueous zinc ion battery cathode

Vanadium pentoxides (V2O5) show potential in aqueous zinc ion batteries (AZIBs) originating from their layered structure and high theoretical capacity. However, most of the reported V2O5 cathodes suffer from rapid capacity decay and sluggish Zn2+ diffusion kinetics. Herein, hollow V2O5 nanospheres with a diameter of about 450 nm and shell thickness of 50 nm were constructed via a template-free solvothermal method combined with subsequent calcination treatment. The nano-sized hollow structure can not only alleviate the structural stress upon cycling, but also provide shortened ion and electron transport paths, and enhance the surface capacitive behavior. When applied as cathode for AZIBs, it delivers ultrahigh reversible capacity (327 mAh g−1 at 0.1 A g−1), superior rate performance (146 mAh g−1 at 20 A g−1), and excellent cyclic performance (147 mAh g−1 after 6000 cycles at 10 A g−1; 122 mAh g−1 after 10,000 cycles at 15 A g−1), showing clear superiority over commercial V2O5 with irregular appearance. Such attractive capabilities demonstrate that hollow V2O5 nanospheres are a prospective cathode material for AZIBs.

Morphology engineering, room-temperature photoluminescence behavior, and sunlight photocatalytic activity of V2O5 nanostructures

V2O5 nanostructures of nanoparticles (NPs), nanorods (NRs), nanowires (NWs), and nanospheres (NSs), were prepared by hydrothermal and chemical reaction methods. Their morphology, structures, oxidation states, room-temperature photoluminescence (PL) properties, and photocatalytic activity were then investigated. The morphology measurements showed well-shape nanostructures, the X-ray diffraction (XRD) and Raman results revealed that all nanostructures had an α-V2O5 phase with an orthorhombic structure. A large increase of the V4+ oxidation state in NSs compared to the other nanostructures was observed by X-ray photoelectron spectroscopy (XPS) measurements and confirmed by Raman spectroscopy. The results show that a larger number of V4+ oxidation states of V2O5 NSs strongly enhanced PL intensity compared with other structures that showed weak PL. In particular, V2O5 NSs showed intense ultraviolet (UV) PL near 395 nm (3.14 eV) due to strong excitation by UV light, while this PL peak was not observed from other nanostructures. A large amount of charge separation in V2O5 NSs and the large surface contact area in V2O5 NPs result in more efficient photocatalytic activity from these nanoparticles than from V2O5 NRs and NWs.

Asymmetric supercapacitors based on 3D graphene-wrapped V2O5 nanospheres and Fe3O4@3D graphene electrodes with high power and energy densities

Asymmetric supercapacitor (ASC) devices are emerging as effective high-performance energy storage systems. We report on the synthesis of novel and green electrode materials and their use to construct high performance ASCs. The assembled ASCs are based on 3D porous graphene-wrapped V2O5 nanospheres as the positive electrode and Fe3O4@graphene as the negative electrode. The optimal ratio of the V2O5 nanospheres intercalated graphene sheets in the composite electrodes was identified. Compared to all positive electrode formulations, the V2O5@3DGr (33%) hybrid electrode achieved the highest specific capacitance (612.5 Fg−1) at a current density of 1.0 A g−1. Based on the excellent electrochemical behavior of the fabricated electrodes, the assembled asymmetric supercapacitor devices of V2O5@3DGr//Fe3O4@3DGr exhibited a maximum energy density of 54.9 Wh kg−1 with a power density of 898 Wkg−1 with an extended voltage of 1.8 V in 1.0 M Na2SO4 aqueous electrolyte. Furthermore, the ASC device demonstrated excellent cycling stability with 89.6% capacitance retention over 10,000 cycles. The outstanding electrochemical performance of the fabricated electrodes can be attributed to the synergic effect between graphene sheets and metal oxides (V2O5, Fe3O4) sandwich network structures. Interestingly, the proposed asymmetric electrode materials provide a promising strategy for integrating low cost transition metal, green electrolyte, high energy, and power densities of supercapacitor devices and that can bridge the gap with commercial batteries.

V2O5 Nanospheres with Mixed Vanadium Valences as High Electrochemically Active Aqueous Zinc-Ion Battery Cathode

HighlightsHollow V4+-V2O5 nanospheres are prepared by a novel and simple method using VOOH as the precursor.V4+-V2O5 with mixed vanadium valences is firstly constructed as an electrochemically active cathode for aqueous zinc-ion batteries.The V4+-V2O5 cathode exhibits a prominent cycling performance up to 1000 cycles and an excellent rate capability.

Highly sensitive electrochemiluminescence detection of mucin1 based on V2O5 nanospheres as peroxidase mimetics to catalyze H2O2 for signal amplification

Here, an electrochemiluminescence (ECL) aptasensor was proposed for the detection of mucin1 (MUC1) using V2O5 nanospheres as peroxidase mimics and MUC1-aptamer binding triggered catalyzed hairpin assembly (CHA) for signal amplification. In this approach, V2O5 nanospheres were capable of immobilizing a large quantity of N-(4-aminobutyl)-N-(ethylisoluminol) (ABEI) functionalized silver nanoparticles (Ag-ABEI) to form the Ag-ABEI@V2O5 signal probe for its large specific surface areas and good stability. Moreover, V2O5 nanospheres not only overcame the intrinsic limitations of natural enzymes, but also could effectively catalyze H2O2 decomposition to generate superoxide anion (O2) for significantly enhancing the ECL intensity of ABEI. To further improve the sensitivity of the proposed aptasensor, the MUC1-aptamer binding triggered CHA was applied to achieve the direct protein recycling without the need of enzyme cleavage and polymerization. The developed approach displayed desirable dynamic range from 10 fg mL−1 to 10 ng mL−1 and the limit of detection down to 3.33 fg mL−1. Furthermore, the described approach showed excellent sensitivity for MUC1 detection with the assistance of V2O5 peroxidase mimics and enzyme-free CHA, indicating that the approach would hold potential applications in biological fields.

Highly intense room-temperature photoluminescence in V2O5 nanospheres

Room-temperature photoluminescence (PL) in V2O5 nanospheres with zero-like dimensional structure was investigated. A large number of V4+ oxidation states in the nanospheres were observed by X-ray photoelectron spectroscopy (XPS) measurements. The nanospheres revealed high PL intensity compared with previous studies. In particular, they showed intense ultraviolet (UV) PL near a wavelength of 396 nm (3.13 eV). The intense UV PL was attributed to the enhanced transition probability due to the large number of V4+ (3d1) oxidation states. The PL properties showed strong dependencies on the oxidation states and their distribution.

Electric Cu nanoparticles decorated V2O5 spheres as high performance cathodes for lithium ion batteries

In order to overcome the intrinsic drawbacks of V2O5, including the intrinsically low electrical conductivity and slow electrochemical kinetics, V2O5 nanospheres are uniformly mixed with the electric Cu nanoparticles for forming V2O5/Cu composites. As used as an cathode material for LIBs, the V2O5/Cu composite demonstrated obviously improved electrochemical performance including high reversible specific capacity, superior rate capability and outstanding cycling stability. The V2O5/Cu cathodes can afford a high reversible capacity of 186 mAh g−1 after 70 cycles under a current density of 300 mA g−1 and good rate performance. Even at a high current density of 5 A g−1, a high reversible capacity of 101 mAh g−1 after 350 cycles can still remain. The improved performance can be contributed from the decorated Cu nanoparticles, which can result in a good contact in active materials and facilitate transportation of the electron into the inner region of the electrode.

Rational Construction of a Functionalized V2O5 Nanosphere/MWCNT Layer‐by‐Layer Nanoarchitecture as Cathode for Enhanced Performance of Lithium‐Ion Batteries

Vanadium pentoxide (V2O5) has received considerable attention owing to its potential application in energy storage with high specific capacity (294 mAh g−1). However, the development of V2O5 cathodes has been limited by the intrinsically low electrical conductivity and slow electrochemical kinetics resulting in a significant capacity decay. In this article, in order to overcome the issues, V2O5 nanospheres and multiwalled carbon nanotubes (MWCNTs) are used to fabricate layer‐by‐layer composited paper as the cathode, which is prepared via electrostatic interaction and vacuum filtration by alternating the positively charged V2O5 nanospheres and the negatively charged terminated MWCNT solutions. As a result, the V2O5 nanospheres are closely intercalated between the adjacent MWCNT layers leading to minimize the disadvantage voids and enhance the overall conductivity of the composited electrode, which exhibits an enhanced cycling durability as well as improved rate capability.

Low temperature growth of vanadium pentoxide nanomaterials by chemical vapour deposition using VO(acac)2 as precursor

Vanadium pentoxide (V2O5) nanomaterials with various morphologies were prepared by chemical vapour deposition at a relatively low temperature (evaporation temperature of 250 °C and growth temperature of 500 °C) using vanadyl acetylacetonate (VO(acac)2) powder as the vanadium precursor. The obtained samples were characterized by scanning electron microscopy, x-ray diffraction, Raman scattering and photoluminescence spectra. The results revealed that the samples including a V2O5 nanocluster film, V2O5 nanowires and V2O5 nanospheres were synthesized at different distances from the source material. For our chemical vapour transport system, we suggested that VOx vapour and VO(acac)2 vapour existed simultaneously during the growth process, which resulted in different morphologies of V2O5 nanomaterials. The quite different supersaturation distributions of VOx vapour and VO(acac)2 vapour led to three main growth areas. The V2O5 film was grown in the region where the supersaturation of the VOx vapour was high, V2O5 nanowires were obtained where the supersaturation of the VOx vapour was relatively low and V2O5 nanospheres were synthesized in the region where the supersaturation of the VO(acac)2 vapour was high. The growth pressure that influenced the vapour concentration controlled the morphologies of the nanowires. It was found that a specific level of low concentration was necessary to ensure the growth of V2O5 nanowires.