V2O5 Electrodes Research Articles

Ag decorated V2O5 electrodes as a promising option for electrochromic, photovoltaic, and energy-saving applications

This study reports the fabrication of electrochromic Ag decorated V2O5 thin film by thermal evaporation method at 10−5 torr vacuum medium and the effects of the Ag doping to the V2O5 matrix. Besides, the electrochromic capabilities and energy-saving characteristics of the films are also in the scope of this study. Structural and morphological properties are investigated by XRD, FESEM, and AFM. The films have a polycrystalline structure and a porous surface. FTIR and Raman spectra verify the molecular formation of the films. The performance of the electrochromic films is characterized by a variety of techniques such as cyclic voltammetry, chronoamperometry, chronocolumetry, and electrochemical impedance spectroscopy. The color of the films changes from yellow to green and then from green to blue in the range of −1.2 and + 1.0 V vs Ag/AgCl with a reversibility of 92.9 %. With the response times of tb = 13.6 s and tc = 9.4 s, an optical modulation of 51.7 % (from yellow to blue), and a coloration efficiency of 93.7 cm2 C−1, Ag:V2O5 becomes an impressive electrochromic material produced by physical methods. Linear sweep voltammetry studies show that the photocurrent of both V2O5/ITO and Ag:V2O5/ITO electrodes increases under solar illumination. The supercapacitive performance of the film is investigated by cyclic voltammetry, and Ag:V2O5 is an encouraging electrode material with a specific capacitance of 720.9 F g−1 at 5 mV s−1 scan rate. An equivalent circuit is fitted from the film Nyquist data and the results also confirm the positive contribution of Ag doping on the response times, energy saving, and photoresponse of V2O5 thin film. In this regard, the produced electrodes are highly promising for potential applications in electrochromic, energy storage, and photovoltaic devices.

Samarium-doped vanadium pentoxide nanorods anchored reduced graphene oxide nanocomposite as a bi-functional electrode material for supercapacitor and direct methanol oxidation fuel cell applications

In this work, we demonstrate a novel, facile synthesis of reduced graphene oxide nanosheets decorated samarium-doped vanadium pentoxide (RGO/Sm:V2O5) nanocomposite material and explore its application toward supercapacitor and direct methanol oxidation process. As-fabricated material and electrode were well-characterized to evaluate its surface morphology and functionalities. Results indicate a maximum capacitance value of 544 F/g for RGO/Sm:V2O5 modified electrode than the 2% Sm:V2O5 (346 F/g) and V2O5 (133 F/g) modified electrodes. In addition, an excellent Rct value (3.2 Ω) was achieved for the RGO-loaded Sm:V2O5 electrode than the 2% Sm:V2O5 electrode (4.7Ω). The RGO/Sm:V2O5 electrode also shows higher cyclic efficiency (98 %) at the 1000th cycle than the non-RGO loaded Sm:V2O5 electrodes. Furthermore, the fabricated electrodes were also examined for the direct methanol oxidation performances, and the results indicate a higher current density value of 181 mA/cm2 for RGO/Sm:V2O5 electrode than 2% Sm:V2O5 electrode (139 mA/cm2). The excellent electrochemical performance of the RGO/Sm: V2O5 electrode is mainly due to the presence of RGO nanosheet in the synthesized nanocomposite material. Therefore, as-prepared material can be applied as an excellent alternative electrode material for energy storage and conversion systems.

Hydrothermal transforming phase structure and chemical composition of V2O5 for elevating electrochemical property of zinc ion batteries

V2O5 was hydrothermally modified in NaOH or KOH solutions at 180 °C for 24 h. The NaOH-modified powders had a nanorod-like structure with a crystal structure matching Na2V6O16·nH2O. The TG/DTA results of Na2V6O16·nH2O powders show a mass reduction of 4.24 % at 300 °C, corresponding to n of 1.496. KOH-modified powders have large rods and irregular structures with a crystal structure matching KV3O8. Its TG/DTA spectrum shows a very small percentage change, just 0.37 % at 600 °C. Cyclic voltammetry (CV) curves of a Na2V6O16·nH2O cathode in a 2 M ZnSO4 electrolyte exhibit higher oxidation and reduction current densities than those of pure V2O5 and KV3O8 electrodes.The best capacity of a Na2V6O16·nH2O electrode is 296.10 mAh g-1 at a current density of 50 mA g−1, which is higher than those of pure V2O5 (102.90 mAh g-1) and KV3O8 (91.07 mAh g-1) electrodes. EDS and XPS results reveal that the charge and discharge states involve de-insertion and insertion of Zn2+ ions out of/into the electrodes. Computational analysis of Zn intercalation into V2O5, Na2V6O16·nH2O, and KV3O8 structures displays increasing electron density on neighboring V atoms, which explains the increasing V4+/V5+ ratio in the discharged state as evidenced by XPS spectra.

Hierarchically Structured 3D Nanoporous Vanadium Oxide Transparent Electrodes for Next‐Generation Supercapacitors

AbstractThis article describes the automatic spray pyrolysis deposition (ASPD) process for the synthesis of hierarchically structured 3D nanoporous vanadium oxide (V2O5) transparent material on a fluorine‐doped tin oxide (FTO) substrate. The deposition of material occurs at 673 K using an aqueous solution of NH4VO3, with a constant solution spray rate of 10 mL min−1 and airflow rate of 10 L min−1. Structural analysis confirms the pure orthorhombic structure formation of the V2O5 material, while FE‐SEM images show a well‐organized 3D spongy‐like porous architecture. The excellent conformality of the ASPD enables the deposition of high‐aspect‐ratio 3D structured nanoporous V2O5 electrodes for next‐generation supercapacitor applications. The hierarchical structured 3D nanoporous V2O5 electrode exhibits superior electrochemical performance in a 1M Na2SO3 electrolyte. Within the potential window 0 to ‐1.3 V, the electrode archives the highest specific capacitance (SC) of 453.32 F g−1 and also retains 86% of its capacitance after 5000 cycles. These properties mainly originate from the crystallinity, 3D nanoporous structure, and fast and easy ionic intercalation through the material. Furthermore, a symmetric supercapacitor device using this electrode is fabricated and which yields outstanding electrochemical performance. Overall, the results highlight the potential of 3D nanoporous V2O5 as an outstanding electrode material for next‐generation supercapacitor applications.

Effect of Applied Stress on the Interfacial Kinetics, Ionic Conductivity, and Other Phenomena in Thin-Film Solid-State Batteries

Controlled stress is critical to both fabrication and operation of solid-state batteries to ensure pristine, low-impedance interfaces. The effects of externally applied stresses on overall cell performance and degradation due to altered thermodynamics, interfacial kinetics, and bulk transport of the active species have been studied in several prior works. In addition to the applied stack pressure which can vary up to 100s MPa, internal and localized stresses up to a few ~1 GPa can be generated from volume changes during charge and discharge. Electrode volume changes can result in cracking and delamination, causing loss of conductive pathways and active electrode-electrolyte area, and electrolyte fracture in the case of dendrite growth. The extent of these stress-electrochemistry couplings depends on the material and geometry of interfaces that affects the local stress distribution. To decouple some of these stress-potential, stress-kinetics, and stress-transport coupling phenomena, we use a nanoindenter platform to apply controlled uniaxial compressive forces to a thin-film electrochemical devices and batteries1. Interfaces in a thin-film sample can be uniform and planar over large areas, helping us study the effect of stress on the interfacial electrochemistry more directly and with greater quantitative accuracy. In this work we present our observations and analysis on the direct electrochemical-mechanical coupling in thin-film TiO2 and V2O5 metal oxide thin films as the working electrode with the single-ion Li+ conductor solid electrolyte LiPON. Preliminary results show that external uniaxial compressive load affects the electrochemistry observed through cyclic voltammetry and electrochemical impedance spectroscopy (EIS) measurements on thin-film batteries with TiO2 and V2O5 electrodes.

Electrochemical investigation of neodymium doped vanadium pentoxide anchored on reduced graphene oxide nanocomposites for hybrid symmetric capacitor devices

The modern world is highly dependent on portable electronic gadgets, so high-performance energy storage devices are a major demand for human beings. Here, we construct neodymium-doped vanadium pentoxide anchored with reduced graphene oxide nanocomposite (rGO/Nd:V2O5) as the electrode material for a high-performance symmetric capacitor device. The prepared electrodes showed pseudocapacitor behaviour and double layer capacitor behaviour, indicating the hybrid nature of the rGO/Nd:V2O5 electrode. Also, the V2O5, Nd:V2O5 and rGO/Nd:V2O5 electrodes show higher capacitance behaviour of 447, 677 and 1122 F/g at 1 A/g and 89 %, 94 % and 98 % cyclic efficiency at the 1000th cycle. However, the rGO/Nd:V2O5 symmetric capacitor device exhibits a higher capacitance value of 218 F/g at 1 A/g and a cyclic efficiency of 82 % at the 10000th cycle. Also, this electrode shows a low charge transfer resistance value of 12.67 Ω. This result shows the prepared rGO/Nd:V2O5 electrode as the high-performance electrode material for the supercapacitor devices.

Dynamic Electrode–Electrolyte Intermixing in Solid-State Sodium Nano-Batteries

Nanostructured solid-state batteries (SSBs) are poised to meet the demands of next-generation energy storage technologies by realizing performance competitive to their liquid-based counterparts while simultaneously offering improved safety and expanded form factors. Atomic layer deposition (ALD) is among the tools essential to fabricate nanostructured devices with challenging aspect ratios. Here, we report the fabrication and electrochemical testing of the first nanoscale sodium all-solid-state battery (SSB) using ALD to deposit both the V2O5 cathode and NaPON solid electrolyte followed by evaporation of a thin-film Na metal anode. NaPON exhibits remarkable stability against evaporated Na metal, showing no electrolyte breakdown or significant interphase formation in the voltage range of 0.05-6.0 V vs Na/Na+. Electrochemical analysis of the SSB suggests intermixing of the NaPON/V2O5 layers during fabrication, which we investigate in three ways: in situ spectroscopic ellipsometry, time-resolved X-ray photoelectron spectroscopy (XPS) depth profiling, and cross-sectional cryo-scanning transmission electron microscopy (cryo-STEM) coupled with electron energy loss spectroscopy (EELS). We characterize the interfacial reaction during the ALD NaPON deposition on V2O5 to be twofold: (1) reduction of V2O5 to VO2 and (2) Na+ insertion into VO2 to form NaxVO2. Despite the intermixing of NaPON-V2O5, we demonstrate that NaPON-coated V2O5 electrodes display enhanced electrochemical cycling stability in liquid-electrolyte coin cells through the formation of a stable electrolyte interphase. In all-SSBs, the Na metal evaporation process is found to intensify the intermixing reaction, resulting in the irreversible formation of mixed interphases between discrete battery layers. Despite this graded composition, the SSB can operate for over 100 charge-discharge cycles at room temperature and represents the first demonstration of a functional thin-film solid-state sodium-ion battery.

Polyaniline‐coated V2O5 as a high‐performance cathode material for Zn‐ion batteries

AbstractIntroductionDue to the advantages of environmental compatibility, low cost, and safety, aqueous zinc‐ion batteries (ZIBs) have stood out as the emerging energy storage devices among metal‐ion batteries. However, most cathode materials suffer from slow Zn2+ diffusion rates, resulting in poor charge–discharge rates and cycle life of state‐of‐the‐art ZIBs.Objective and MethodIn this work, a polyaniline (PANI) coating method is proposed to improve the Zn2+ diffusion kinetics and stability of the V2O5 cathode. The coating of PANI can maintain the structural stability of V2O5. Moreover, PANI is conducive to improving the electronic conductivity and increasing the intercalation/deintercalation capacity of V2O5 by promoting the diffusion process of Zn2+ ions, thereby increasing the charge–discharge capacity of ZIBs.ResultsEventually, the electrochemical performance of the PANI‐coated V2O5 electrode is significantly improved, delivering a high discharge specific capacity of 0.374 mAh cm−2 at the current density of 2 mA cm−2 and improved capacity retention of 83% after 500 cycles. This work demonstrates the positive effect of the PANI‐coating strategy on improving the electrochemical performance of V2O5 electrodes.

Electrochemical evaluation of reduced graphene oxide anchored with ruthenium doped vanadium pentoxide nanostructures for supercapacitor applications

Ru doped vanadium pentoxide and reduced graphene oxide loaded Ru doped vanadium pentoxide nanostructures have been synthesized through the sol–gel route. The orthorhombic structure of rGO@Ru:V2O5 nanocomposite has been confirmed by using X-ray diffraction analysis and the appearance of O-V-O vibrational mode was confirmed by FTIR and Raman analysis. Furthermore, the scanning electron microscope and high-resolution transmission electron microscope images illustrate the formation of rGO@Ru:V2O5 nanomaterials as sheet-particles-rod shaped nature. Finally, the electrochemical performance of the rGO@Ru:V2O5 electrode exhibits outstanding electrochemical performance which illustrates the maximum capacitance value 1185 F/g at 1.25 A/g compared with the 2 %Ru:V2O5 electrode. Also, it shows high energy and power densities of 20.92 Wh/Kg and 570 W/Kg for Ru:V2O5 electrode and 66.65 Wh/Kg and 810.89 W/Kg for rGO@Ru:V2O5 electrode. Both electrodes are shows the maximum cyclic stability of 98 % & 94 % for Ru:V2O5 and rGO@Ru:V2O5 electrodes, respectively.

Recent advancement in doped vanadium pentoxide for energy storage devices

The search for high-performing supercapacitors is a major area of energy storage and conversion research due to the increasing demand for portable electronics, electric vehicles, and green energy solutions. To improve upon traditional batteries and capacitors, researchers have focused on designing different electrode materials made of vanadium pentoxide (V2O5), which has a high capacitive potential and is non-toxic. However, poor conductivity, low porosity, and charge/discharge dissolution limit the performance of bulk V2O5. To overcome these limitations, researchers have added dopants to V2O5, which increase electron mobility, surface area, and structural stability. This review focuses on the effects of different synthesis methods and physical treatment strategies on the structure and electrochemical performance of doped V2O5 electrodes.

Multi-Scale Electrochemo-Mechanical Experiments on Thin Film Battery Materials

The application of a solid-electrolyte may enable the use of certain high energy density anodes like Li and Si and also circumvents the flammable liquid-electrolyte. However, all solid components introduce multiple solid-solid interfaces whose responses are strongly affected by the mechanical state of the region on both sides, which can be affected by a combination of applied stack pressure and cycling induced volumetric change1. Electrochemo-mechanical coupling (ECM) studies2 are a relatively new area for this society, especially with thin film structures,3 which provide high purity, uniformity, and controlled geometries for the reaction to take place. However, correctly interpreting ECM experimental results as well as explaining the fundamental failure mechanisms (i.e. cracking and dendrite propagation) requires careful experimental study of material mechanical properties and how electrochemical characteristics change with mechanical state4.In this work, we describe two experimental studies on sputter-deposited thin-film LixV2O5 electrodes, with a thickness of 1 µm on a Si wafer. A lateral cell design that has the two electrodes on a single plane on a substrate, is described to focus on a single electrode. An ionic liquid electrolyte (ILE) on the Si substrate is used instead of a solid electrolyte pellet to avoid high ohmic losses , and to focus on the mechanics of the LixV2O5. The ILE covers the two electrodes and serves as the ionic pathway. Lithium foil (or vapor-deposited Li metal) is placed on the wafer and serves as the Li source. The first study is conducted with a liquid electrolyte and compares the cell behaviors between stressed and unstressed states. An external mechanical load is applied to the whole electrode surface for a uniform force distribution. An important thermodynamic contribution of stress is the change in equilibrium potential, which can be measured as a function of applied stress on the electrode and may also affect charge transfer kinetics at the interface. The second experiment will focus on the composition modulated mechanical properties of LixV2O5 which is crucial for ECM modeling work. Here, we lithiate V2O5 electrodes to different amounts, remove the electrolyte to stop ionic transport, and then perform nanoindentation in an inert argon environment. The correlation between elastic moduli and x in LixV2O5 as well as the variation of equilibrium potential provide important parameters for building accurate ECM numerical models. Pasta, M., Armstrong, D., Brown, Z.L., Bu, J., Castell, M.R., Chen, P., Cocks, A., Corr, S.A., Cussen, E.J., Darnbrough, E., et al. (2020). 2020 roadmap on solid-state batteries. JPhys Energy 2, 032008.Wan, T.H., and Ciucci, F. (2020). Electro-chemo-mechanical modeling of solid-state batteries. Electrochim. Acta 331, 135355.Spencer Jolly, D., Ning, Z., Darnbrough, J.E., Kasemchainan, J., Hartley, G.O., Adamson, P., Armstrong, D.E.J., Marrow, J., and Bruce, P.G. (2020). Sodium/Na β″ Alumina Interface: Effect of Pressure on Voids. ACS Appl. Mater. Interfaces 12, 678–685.Cao, D., Sun, X., Li, Q., Natan, A., Xiang, P., and Zhu, H. (2020). Lithium Dendrite in All-Solid-State Batteries: Growth Mechanisms, Suppression Strategies, and Characterizations. Matter 3, 57–94.

Unraveling a cathode/anode compatible electrolyte for high-performance aqueous rechargeable zinc batteries

A cathode/anode compatible aqueous zinc triflate electrolyte is proposed by reorganizing the solvation structure of the electrolyte using an acetonitrile co-solvent. Acetonitrile notably alters the hydrogen bonds of the electrolyte, reducing the activity of water. Using this electrolyte, a ZnǁV2O5 full-cell exhibits high Coulombic efficiency, long cycle life and high rate capability. The interactions between electrolyte, cathode and Zn anode are clarified based on comprehensive in operando and ex situ experiments and molecular dynamics simulations. The addition of acetonitrile does not change the bulk ion storage of V2O5, but the unique electrode-electrolyte interfacial films with specific compositions and spatial distribution protect the Zn and V2O5 electrodes and improve the interfacial kinetics of the electrodes, thus significantly promoting the cycling performance of the full cell. This cathode/anode compatible electrolyte can overcome the challenges of both the cathode and anode which would promote aqueous rechargeable zinc batteries into practical application.

Electrospun V2O5 nanofibers as high-capacity cathode materials for zinc-ion batteries

Vanadium pentoxide (V2O5) has attracted significant attention in recent years as a cathode material for aqueous zinc-ion batteries (AZIBs). Its unique layered structure allows for reversible intercalation of various multivalent ions, including Zn2+.This paper proposes a sol–gel electrospinning method for preparation of vanadium pentoxide nanofibers, followed by thermal treatment in air. The composition and structure of the obtained powders were verified by X-ray diffraction, energy-dispersive X-ray elemental analysis, and X-ray photoelectron spectroscopy, while the morphology of the samples was investigated by scanning electron microscopy. The electrochemical properties and performance of the electrode materials based on V2O5 nanofibers were studied using cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy methods. V2O5 electrodes demonstrate high specific capacity (357 mA h g−1 at 0.05Ag−1) and good long-term cyclic stability.

High performance of V2O5 thin film electrodes for lithium-ion intercalation

A reduced toxicity production route of vanadium pentoxide thin films together with the study of the fabrication parameters that allow optimizing the performance of this material as a cathode for lithium-ion batteries is presented. V2O5 films were fabricated on silicon and stainless-steel substrates by combining electron beam evaporation of metallic vanadium film followed by an oxidation process. A strong dependence on their performance as cathodes for LiBs to the film thickness and microstructure was found, the later depending mainly on the oxidation temperature. Particularly, V2O5 electrodes with 150 nm of thickness fabricated from 50 nm of metallic vanadium oxidized at 500 °C, exhibit excellent performance with a reversible and fast Li storage capability, a high average discharge capacity up to 271 mAh/g at 0.5C, very close to the theoretical capacity (294 mAh/g), with near to 100% of coulombic efficiency. First-principles calculations of Li+ diffusion in three main V2O5 crystallographic directions using density functional theory (DFT) were performed to explain how this remarkable performance is related to the film microstructure.

Structured confinement effects of hierarchical V2O5 cathodes to suppress flow of molten salt in high specific energy thermal batteries with binder-free MgO

Despite the excellent thermal/air stability and high discharge voltage of V2O5 cathodes in thermal batteries, their poor conductivity must be overcome by adding molten salt. To ensure the mechanical integrity of V2O5 electrodes, MgO is used as a binder to suppress flow of molten salt. The poor conductivity of MgO increases the resistance, and leads to rapid attenuation of the voltage. Hence, we design a hierarchical V2O5/molten salt cathode with binder-free MgO by using a novel liquid mixing method. The molten salt is anchored on the interspace of hierarchical V2O5 with structured confinement effects. Cathodes synthesized with 20 wt.% of molten salt exhibit a short active time and high specific energy. To further improve electronic conductivity, 10 wt.% Ni is added into the aforementioned cathodes. The optimum specific capacity (255.80 mAh g−1) and specific energy (559.74 Wh Kg−1) can be obtained with 0.1 A cm−2 at 500 °C and a cut-off voltage of 1.6 V. Excellent discharge performance is achieved because of the low resistance (high Li+ diffusion and well-organized electron transport path), good mechanical integrity, and complete chemical reaction. This strategy provides a new way to regulate the conductivity of binder-free solid-state batteries.

Novel edge-capped ZrO2 nanoparticles onto V2O5 nanowires for efficient photosensitized reduction of chromium (Cr (VI)), photoelectrochemical solar water splitting, and electrochemical energy storage applications

Novel edge-capped ZrO2 nanoparticles on V2O5 nanowires were successfully synthesized through a simple, eco-friendly, and inexpensive hydrothermal technique. The as-prepared nanostructures were characterized using various measurements to study their structural, morphological, optical, and surface properties. Furthermore, photoelectrochemical water oxidation, photocatalytic performance for Cr(VI) reduction, and electrochemical energy storage were studied. The surface morphology analysis revealed the edge-capped ZrO2 nanoparticles on the V2O5 nanowires. The optical analysis showed that the heterostructure formation between ZrO2 and V2O5 could tune the bandgap (2.05 eV) of the composite. Due to the improved separation efficacy of the photoexcited charge carriers and greater surface area, compared to the pure materials, the ZrO2/V2O5 (ZV) composite displayed considerable improvement in photocatalytic Cr(VI) reduction performance, as well as excellent reusability performance (70.5 % after 4 cycles), thus facilitating its wastewater treatment. The ZV electrode displayed approximately 1.6- and 5.8-fold improvement in specific capacitance over the ZrO2 and V2O5 electrodes, respectively. Furthermore, the ZV electrode exhibited the lowest charge resistance under light illumination conditions. From the linear sweep voltammetry curve analysis, the ZV electrode possessed an improved photocurrent density (5.363 mA cm−2), demonstrating approximately 33- and 3.5-times improvement in photocurrent density over the pristine electrodes.

Characterization of two-way fabricated hybrid metal-oxide nanostructured electrode materials for photovoltaic and miniaturized supercapacitor applications

Portable electronic devices require a small volume self-powered energy system that can combine fabrication of energy harvesting and storage devices in one plane. This study focuses on fabricating novel all-oxide photovoltaic and supercapacitor devices based on MoO3, V2O5, and CoxOy thin electrodes prepared by a two-electrode cell arrangement. The fabricated devices were tested using solar simulator and potentiostat at ambient temperature. The power conversion efficiencies of the fabricated photovoltaic devices were found in the range of 0.17–0.39% depending on buffer layer characteristics. It therefore suggests that V2O5 and MoO3 can buffer photovoltaic processes by lowering the conduction band offset in the proximate CoxOy absorber. Pseudocapacitive behavior of MoO3/CoxOy||MoO3/CoxOy and V2O5/CoxOy||V2O5/CoxOy planar devices showed that they delivered maximum specific areal capacity values of 0.694 and 0.778 μAhcm−2 respectively at discharge current density of 0.1 mAcm−2. They also showed considerably low reduction in energy density (about 38.7%) even at a remarkable increase in power density of about 450% (at a high current density of 1.0 mAcm−2). In addition, the symmetric microsupercapacitors showed excellent retention of capacity even after 5000 cycles. These results generally indicate the reliability of the fabricated devices in the development of portable electronic components for energy application.

Film strains enhance the reversible cycling of intercalation electrodes

A key cause of chemo-mechanical degradation in battery electrodes is that they undergo abrupt phase transformation during the charging/discharging cycle. This phase transformation is accompanied by lattice misfit strains that nucleate microcracks, induce fracture and, in extreme cases, amorphize the intercalation electrode. In this work, we propose a strategy to prevent the chemo-mechanical degradation of intercalation electrodes: we show that by engineering suitable film strains we can regulate the phase transformations in thin-film intercalation electrodes and circumvent the large volume changes. We test this strategy using a combination of theory and experiment: we first analytically derive the effect of film strain on the electrochemical response of a thin-film intercalation electrode and next apply our analytical model to a representative example (LixV2O5 with multiple phase transformations). We then test our theoretical predictions experimentally. Specifically, we electrochemically cycle thin-film V2O5 electrodes with different film strains and measure their structure, voltage, and stress responses. Our findings show that tensile film strains lower the voltage for phase transformations in thin-film V2O5 electrodes and facilitate their reversible cycling across a wider voltage window without chemo-mechanical degradation. These results suggest that film strain engineering is an alternative approach to preventing chemo-mechanical degradation in intercalation electrodes. Beyond thin-film electrodes, our findings from this study are applicable to the study of stress-induced phase transformations in particle-based electrodes and the thin surface layers forming on cathode particles.

High-rate performance magnesium batteries achieved by direct growth of honeycomb-like V2O5 electrodes with rich oxygen vacancies

High-rate performance magnesium batteries achieved by direct growth of honeycomb-like V2O5 electrodes with rich oxygen vacancies

RGO-encapsulated Sn-doped V2O5 nanorods for high-performance Supercapacitors

Reduced graphene oxide (rGO) anchored Sn doped V2O5 (Sn-V2O5/rGO) nanocomposite materials are produced by employing the sol-gel method. The Sn-V2O5/rGO nanocomposite is composed of Sn dopant homogeneously dispersed on V2O5 nanorods and rGO nanosheets. At the time of charge/discharge process, this peculiar structure mainly reduces the amount of Na+ inflation, enhances the electrolyte insertion into the electrode and also increases the conductivity of the Sn doped V2O5 electrode. As results, the Sn-V2O5/rGO, 4%Sn-V2O5 and V2O5 electrodes exhibits excellent electrochemical performance and it provides high reversible specific capacitance of about 159.37, 139.06 and 120.10 F g−1 at 1 Ag−1. Even at this high current density, this Sn-V2O5/rGO electrode also withstands the capacitance maximum of about 73 %. Concretely, the prepared Sn-V2O5/rGO electrode material exhibits the low charge transfer resistivity than 4%Sn-V2O5 and V2O5 electrodes. Moreover, the electrode obeys the excellent capacitance retention (95 %) at 5 Ag−1 for the 1000th cycle.