Lithium Vanadium Oxide Research Articles

(Keynote) High Power Batteries Enabled by Disordered Rocksalt Anodes

Batteries with exceptional charge and discharge rates and cycle life can bridge the gap between high-energy-density batteries and supercapacitors. In traditional lithium-ion batteries, the limiting electrode is usually the carbon anode. Fast charging, for example, leads to deposition of lithium metal which triggers life and safety issues. Oxide anodes with higher operating potentials have been considered, e.g., lithium titanium oxide, titanium niobium oxide, to name a few.In recent years, we have been developing lithium vanadium oxide as an anode. Li3V2O5 (LVO) has a disordered rocksalt (DRS) structure. When 2 moles of lithium are inserted into this structure, the volume change is about 5.5%. The cubic structure, however, indicates that the linear change is only 1.8%. The material has an operating potential of 0.6 V vs Li/Li+, thus virtually eliminating the possibility of lithium plating. Lithium-ion cells pairing LVO with 4V oxide cathodes have demonstrated thousands of stable cycles and can be charged at a rate as high as 20C (Nature, 2020, 63). To further lower the potential (which translates to higher energy density for a cell), we have investigated the possibility of doping with Mg. Both theoretical and experimental evidence suggest that the DRS structure is preserved. More interestingly, we have found that the electrode potential can indeed be lowered while the fast charging and long life qualities are preserved.We have further extended this DRS design principle to sodium ion systems. Insertion of sodium into V2O5 results in the formation of a DRS structure, analogous to the case of lithium. Na3V2O5 (NVO) is found to accept two mole of Na reversibly within the DRS structure. Pairing NVO with a sodium vanadium phosphate cathode forms a sodium ion all vanadium battery. This battery has shown exceptional rate capabilities during both charging and discharging, with great potential for applications in power conditioning systems and grid storage.

Superior electrochemical performances of Lithium vanadium oxide with coconut shell-based porous carbon as the anode of the aqueous Li ion battery

Carbon materials, as the skeleton structure of electrode materials, are composited with lithium-ion anode materials, which not only increase the electrical conductivity of the materials, but also enhance the electrochemical performance of the electrode materials. In this paper, LiV3O8@C composites were prepared by using coconut shell-based porous carbon to structurally modulate aqueous lithium-ion anode materials. And three composites with different structures and sizes were successfully synthesized by hydrothermal method, hydrothermal stirring method and improved solid-phase method. After XRD and SEM analyses, it was found that all three composites maintained the monoclinic crystal system structure of LiV3O8, and the materials prepared by the hydrothermal method showed a smooth layer structure, while the materials prepared by the hydrothermal stirring method and the solid-phase method showed nanorods with different sizes. The prepared anode materials and LiFePO4 cathode materials were assembled into an aqueous lithium-ion full battery, and were subjected to charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The results indicate that the electrochemical performances of the three composites are significantly improved compared with the pure LiV3O8. Specifically, the discharge capacities of the two groups of nanorod-like composites were 112.2 mAh/g and 85.5 mAh/g at a rate of 0.2 C, which were improved by as much as two times compared with the pure LiV3O8. However, the composite material with layered structure not only reaches an initial discharge specific capacity of 148.39 mAh/g, which is 2.7 times higher than that of the pure LiV3O8, but also effectively slows down the dissolution effect of LiV3O8 by compositing with the carbon material, and at the same time, it shows excellent rate performance.

Highly safe lithium vanadium oxide anode for fast-charging dendrite-free lithium-ion batteries

Abstract Fast-charging technology is the inevitable trend for electric vehicles (EVs). Current EVs’ lithium-ion batteries (LIBs) cannot provide ultrafast power input due to the capacity fading and safety hazards of graphite anode at high rates. Lithium vanadate oxide (Li3VO4) has been widely studied as fast-charging anode material due to its high capacity and stability at high rates. However, its highly safe characteristic under fast-charging has not been studied. In this study, a fast-charging anode material is synthesized by inserting Li3VO4 in Ti3C2Tx MXene framework. The morphologies of Li3VO4/Ti3C2Tx electrode after cycling at different rates were studied to analyze the dendrites growth. Electrochemical testing results demonstrate that Li3VO4/Ti3C2Tx composite displays high capacities of 151.6 mA h g−1 at 5 C and 87.8 mA h g−1 at 10 C, which are much higher than that of commercial graphite anode (51.9 mA h g−1 at 5 C and 17.0 mA h g−1 at 10 C). Moreover, Li3VO4/Ti3C2Tx electrode does not generate Li dendrite at high rates (5 and 10 C) while commercial graphite electrode grows many Li dendrites under the same conditions, demonstrating fast-charging and high safety of Li3VO4/Ti3C2Tx composite. Our work inspires promising fast-charging anode material design for LIBs.

Effect of Li2O on Physical, Structural, Thermal and Electrical Properties of MgO-V2O5 Glasses

Three compositions 75V2O5-25MgO (MVL-0), 75V2O5-16MgO-9Li2O (MVL-9) and 75V2O5-13MgO-12Li2O (MVL-12) were synthesized by melt-quench technique. Addition of Li2O instead of MgO promoted the devitrification of magnesium vanadate glass. X-ray diffraction pattern showed the amorphous nature of MVL-0, while MVL-9 and MVL-12 were seen to exhibit a lithium vanadium oxide phase with the presence of some amorphous phase. Densities of the samples increased with the increase in Li2O concentration. Raman spectra of MVL-0 exhibited broad band as compared to the other samples; as Li2O concentration increased, the band became sharp including the appearance of some more new bands. High electrical conductivity was observed for MVL-12; ∼9.615×10–5 S.cm–1 at 50°C to 1.96×10–3 S.cm–1 at 250°C, which is comparable to the conductivity of standard cathode materials used in battery and electrochemical fuel cells. So, these samples may be used as cathode materials due to good conductivity at 250°C for battery and electrochemical fuel cells.

One-dimensional Li3VO4/carbon fiber composites for enhanced electrochemical performance as an anode material for lithium-ion batteries

Lithium vanadium oxide (Li3VO4) has gained attention as an alternative anode material because of its higher theoretical capacity (592 mAh g−1), moderate ionic conductivity (∼10−4 S cm−1), and lower working voltage range (∼0.5–1.0 V vs. Li/Li+) in comparison to other metal oxides. However, there are disadvantages to using Li3VO4 as an anode material, such as low initial Coulombic efficiency and poor rate performance that is attributed to its low electronic conductivity (<10−10 S cm−1). In the present study, the synthesis of one-dimensional Li3VO4 electrode was performed via a facile method by using oxidized vapor grown carbon fiber as a template and the formation of the outer shells of conductive carbon via chemical vapor deposition technique. In a half-cell configuration, the prepared Li3VO4 composites exhibited an enhanced electrochemical performance with a reversible capacity of 516.2 mAh g−1 after 100 cycles at a rate of 0.5 C within the voltage range of 0.01–3.0 V. At a high rate of 5 C, a large reversible capacity of 322.6 mAh g−1 was also observed after 500 cycles. The full cell (LVO/VGCF16-C||LiCoO2) using LiCoO2 as the cathode showed competitive electrochemical performance, which demonstrates its high potential in commercial applications.

Lithium Vanadium Oxide/Graphene Composite as a Promising Anode for Lithium-Ion Batteries

Lithium vanadium oxide (Li3VO4, LVO) is a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity (394 mAh g-1) and safe working potential (0.5-1.0 V vs. Li+/Li). However, its electrical conductivity is low which leads to poor electrochemical performance. Graphene (GN) shows excellent electrical conductivity and high specific surface area, holding great promise in improving the electrochemical performance of electrode materials for LIBs. In this paper, LVO was prepared by different methods. SEM results showed the obtained LVO by sol-gel method possesses uniform nanoparticle morphology. Next, LVO/GN composite was synthesized by sol-gel method. The flexible GN could improve the distribution of LVO, forming a high conductive network. Thus, the LVO/GN composite showed outstanding cycling performance and rate performance. The LVO/GN composite can provide a high initial capacity of 350.2 mAh g-1 at 0.5 C. After 200 cycles, the capacity of LVO/GN composite remains 86.8%. When the current density increased from 0.2 C to 2 C, the capacity of LVO/GN composite only reduced from 360.4 mAh g-1 to 250.4 mAh g-1, demonstrating an excellent performance rate.

Enhanced Li-ion migration behavior in Li3V2O5 rock-salt anode via stepwise lattice tailoring

Electrode exploration with the appropriate equilibrium voltage and facile cation diffusion kinetics is the key enabler towards realizing the extreme power output of the battery formats. With the aid of the stepwise lattice tailoring, herein, we present an alternative fast-charging anode of the rock-salt lithium vanadium oxide. Specifically, the pre-insertion of polyaniline (PANI) molecules unlocks the basal plane of the layered V2O5 precursor, while subsequent Na+ doping at the octahedral sites could stabilize the lattice breathing and mitigate Li-ion diffusion barrier along the tetrahedron-octahedron-tetrahedron pathway, as confirmed by the operando X-ray diffraction and kinetics simulation. The Na0.6Li2.4V2O5@PANI//LiFePO4 full cell prototype (3 mAh cm−2) exhibits 82% capacity retention at 20 C for 2000 cycles, as well as the cycling endurance within a wider temperature range of 0-60°C. This stepwise lattice engineering strategy opens a fresh impetus of the electrode innovations for the high-power energy storage devices.

Improved hydrogen storage properties of Li-Mg-N-H system by lithium vanadium oxides

The Mg(NH2)2-2LiH system is considered as one of the most potential hydrogen storage materials due to its high hydrogen storage capacity (5.6 wt%) and excellent reversible hydrogen adsorption and desorption performance. However, its poor kinetic characteristics of hydrogen absorption and desorption limit its practical application. In this work, Li3VO4 @LiVO2 was synthesized by a hydrothermal method, and was then introduced into Mg(NH2)2-2LiH system to enhance the hydrogen absorption and desorption kinetic characteristics. The results show that the hydrogen storage properties were greatly improved with addition of 10 wt% Li3VO4 @LiVO2 addition. As for the hydrogen absorption and desorption kinetics, the average hydrogen absorption rate of 10 wt% Li3VO4 @LiVO2 modified Li-Mg-N-H sample within 20 min at 200 ℃ increased by 95.2% compared with that of the pristine Li-Mg-N-H sample, and the average hydrogen desorption rate of 10 wt% Li3VO4 @LiVO2 modified sample within 30 min at 180 ℃ increased by 42% compared with that of the pristine sample. The Ea of hydrogen desorption decreased from 117.86 kJ/mol to 99.43 kJ/mol, which also indicates that Li3VO4 @LiVO2 catalyst effectively improved the kinetic performance of hydrogen desorption and desorption of Li-Mg-N-H. Moreover, the hydrogen desorption capacity and hydrogen absorption capacity of 10 wt% Li3VO4 @LiVO2 modified Li-Mg-N-H increased by 18.4% and 13.8% compared with that of the pristine sample. The catalytic mechanism of Li3VO4 @LiVO2was discussed based on XRD, XPS and FTIR analysis results.

Co-sputtering of lithium vanadium oxide thin films with variable lithium content to enable advanced solid-state batteries

A co-sputtering process for pre-lithiation of vanadium oxide was successfully developed. The performance is comparable to an electrochemical lithiation of vanadium oxide, which enables its use as a cathode layer in thin-film solid-state batteries.

Full Utilization of Lithium Trivandate (Li1.1V3O8) in Thick Porous Electrodes with High Rate Capacity upon Extended Cycling Elucidated Via Operando Energy Dispersive X-Ray Diffraction

Newer, more demanding energy storage systems require high energy density along with high power and fast charge rates. Conventional battery electrode fabrication techniques are often limited by how much active material they can hold in the case of slurry-cast electrodes and how much of the electrode can be utilized in the case of dense pelletized electrodes. Thick porous electrode fabrication techniques have been developed as a way to obtain a higher active mass loading and an architecture which enables ionic and electronic transport. The homogeneity of the phase distribution of lithiated LVO in thick (∼500 μm) porous electrodes (TPEs) designed to facilitate both ion and electron transport was determined using synchrotron-based operando energy dispersive X-ray diffraction (EDXRD). Probing 3 positions in the TPE while cycling at a fast rate of 1C revealed a homogeneous phase transition across the thickness of the electrode at the 1st and 95th cycles. Continuum modelling indicated homogenous lithiation across the electrode upon discharge at 1C consistent with the EDXRD results and ascribed decreasing accessible active material to be the cause of loss in delivered capacity between the 1st and 95th cycles. The model was supported by the observation of significant particle fracture by SEM consistent with loss of electrical contact. The absence of the beta phase peaks in the EDXRD over extended cycling are consistent with electrochemical accessibility of only part of the active material. Overall, the combination of operando EDXRD, continuum modeling, and ex situ measurements enabled a deeper understanding of lithium vanadium oxide transport properties under high rate extended cycling within a thick highly porous electrode architecture.

Lithium vanadium oxide (Li1.1V3O8) thick porous electrodes with high rate capacity: utilization and evolution upon extended cycling elucidated via operando energy dispersive X-ray diffraction and continuum simulation.

The phase distribution of lithiated LVO in thick (∼500 μm) porous electrodes (TPEs) designed to facilitate both ion and electron transport was determined using synchrotron-based operando energy dispersive X-ray diffraction (EDXRD). Probing 3 positions in the TPE while cycling at a 1C rate revealed a homogeneous phase transition across the thickness of the electrode at the 1st and 95th cycles. Continuum modelling indicated uniform lithiation across the TPE in agreement with the EDXRD results and ascribed decreasing accessible active material to be the cause of loss in delivered capacity between the 1st and 95th cycles. The model was supported by the observation of significant particle fracture by SEM consistent with loss of electrical contact. Overall, the combination of operando EDXRD, continuum modeling, and ex situ measurements enabled a deeper understanding of lithium vanadium oxide transport properties under high rate extended cycling within a thick highly porous electrode architecture.

Rare earth metal La-doped induced electrochemical evolution of LiV3O8 with an oxygen vacancy toward a high energy-storage capacity

Due to its high theoretical capacity (∼280 mA h g−1), lithium vanadium oxide (LiV3O8) is considered a promising electrode material for meeting the demands for a longer battery life.

Peering into Batteries: Electrochemical Insight Through In Situ and Operando Methods over Multiple Length Scales

Summary In order to overcome the limitations of static and destructive characterizations of Li-ion battery materials and components, comprehensive investigation peering into batteries over various length and time scales is essential. In this regard, emerging in situ and operando characterization methodologies focusing on multiple size domains become a powerful approach to resolve current challenges and navigate future directions. This perspective provides a series of illustrative examples of in situ and operando characterizations over atomic, crystallite/particle, electrode, and battery system length scales with a focus on two electrode material classes: insertion and conversion materials. The operating principles, features, analysis methods, and information gained from each characterization method are discussed. Herein, we present the necessity and opportunity for in situ and operando characterization of electrochemical energy storage materials and systems. Further, we suggest future directions to gain the insight needed to tackle currently intractable issues on Li-ion battery application, failure, and emerging design concepts.

Reversible V3+/V5+ double redox in lithium vanadium oxide cathode for zinc storage

Zn ion batteries show great potential for large-scale energy storage owing to their low-cost, safe and environment-friendly features. There is an urgent need for cathode material with high-energy-density and long-service-life. Vanadium-based cathodes would be particularly desirable due to the bi-electronic transfer reaction (V5+/V4+/V3+). Herein, we present a reversible V3+/V5+ double redox in lithium vanadium oxide (LiV3O8) with the insertion of Zn2+ for ZIBs. In this way, six-electron transition in LiV3O8 was achieved with only 7.64% volumetric expansion, yielding the highest capacity of 557.5 ​mA ​h ​g−1, and good cycling retention of 85% over 4000 cycles. The use of V3+/V5+ double redox will open-up new opportunities for designing vanadium-rich cathodes for high-performance Zn ion battery.

Boosting the rate and cycling performance of β-LixV2O5 nanorods for Li ion battery by electrode surface decoration

The β-phase lithium vanadium oxide bronze (β-LixV2O5) with high theoretic specific capacity up to 440 mAh g−1 is considered as promising cathode materials, however, their practical application is hindered by its poor ionic and electronic conductivity, resulting in unsatisfied cyclic stability and rate capability. Herein, we report the surface decoration of β-LixV2O5 cathode using both reduced oxide graphene (rGO) and ionic conductor LaPO4, which significantly promotes the electronic transfer and Li+ diffusion rate, respectively. As a result, the rGO/LaPO4/LixV2O5 composite exhibits excellent electrochemical performance in terms of high reversible specific capacity of 275.7 mAh g−1 with high capacity retention of 84.1% after 100 cycles at a current density of 60 mA g−1, and acceptable specific capacity of 170.3 mAh g−1 at high current density of 400 mA g−1. The cycled electrode is also analyzed by electrochemical impedance spectroscopy, ex-situ X-ray diffraction and scanning electron microscope, providing further insights into the improvement of electrochemical performance. Our work provides an effective approach to boost the electrochemical properties of lithium vanadates for practical application in lithium ion batteries.

Synthesis of LiMg1−xZnxVO4 with 0 ≤ x ≤ 1 for application to the negative electrode of lithium-ion batteries

Lithium vanadium oxides are attractive as a negative electrode material for lithium-ion batteries, because of the wide range of oxidation states in vanadium ions. We synthesized LiMgVO4 and LiZnVO4 using a two-step solid-state reaction technique and examined their electrochemical properties in a nonaqueous lithium cell. LiMgVO4 possesses a Na2CrO4-type structure with a cation distribution of [LiV]tet[Mg]oct, whereas LiZnVO4 possesses a phenacite structure with a cation distribution of [LiZnV]tet. The LiMgVO4 sample with a purity of 97.7 wt% exhibits a rechargeable capacity (Qrecha) of 214 mAh g−1 and stable cycling performance over 30 cycles. Meanwhile, the LiZnVO4 sample with a purity of 97.7 wt% indicates a Qrecha of 440 mAh g−1, but the Qrecha value rapidly decreases to ∼300 mAh g−1 within the first five cycles. We also synthesized a mixture of LiMgVO4 and LiZnVO4, namely, LiMg1−xZnxVO4 with 0 <x < 1, to provide both a large Qrecha value and good cycling stability. As expected, the x = 0.5 sample shows a Qrecha of 373 mAh g−1 and moderate cycling performance. Therefore, the LiMg1−xZnxVO4 compounds are found to be a possible alternative to known negative electrode materials such as Li[Li1/3Ti5/3]O4 and graphite.

The study of lithium vanadium oxide LiV3O8 as an electrode material for all-solid-state lithium-ion batteries with solid electrolyte Li3.4Si0.4P0.6O4

Lithium vanadium bronze LiV3O8 was synthesized by the method of aqueous solution and by solid state method. The synthesized materials were characterized using X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). Thermal stability and temperature dependences of conductivity for the bronze samples synthesized by both methods were studied. At room temperature the conductivity of the bronze obtained by solid state method is three times higher. LiV3O8| Li3.4Si0.4P0.6O4 |LiV3O8 solid state cell was analysed by pulse potentiometry and voltammetry at 320°С. It is shown that lithium vanadium bronze has a good adhesion to Li+ solid electrolyte, does not react with it below 330 оС and does not degrade with cycling. It was established that the microstructure of the active material of the cathode, which determines the kinetics of Li+ intercalation/deintercalation, dominates the characteristics of the investigated cell.

Differentiating Molecular and Solid‐State Vanadium Oxides as Active Materials in Battery Electrodes

AbstractMolecular vanadium oxides – polyoxovanadates (POVs) – have recently received widespread interest as new, high performance active materials in lithium ion and sodium ion battery electrodes. This is due to their low molecular weight and their high redox activity. However, little attention has been paid to the structural and chemical stability of the POVs under typical electrode fabrication processes. Here, we report how molecular polyoxovanadates can be differentiated from solid‐state vanadium oxides as active materials in battery electrodes using combined spectroscopic, X‐ray diffraction and element‐analytical data. Our study highlights that novel electrode fabrication processes are required as prototype POVs are not stable under classical fabrication conditions. We explore POV degradation pathways and show how thermal POV conversion leads to the formation of layered solid‐state lithium vanadium oxide phases. A facile protocol is presented to detect and prevent POV degradation. In future, this will enable energy materials science to unambiguously identify and use molecular or solid‐state vanadium oxides as next‐generation active materials in lithium or post‐lithium battery electrodes.

Use of Vanadium-Containing Slime for Preparing Cathodes for Lithium-Ion Current Sources

Crude vanadium-containing dump slimes can be used as a raw material for preparing lithium vanadium oxides suitable as cathode materials for lithium-ion chemical current sources. A simple procedure for preparing LiV3O8 from the slime was suggested. The synthesized compound was characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and synchronous thermal analysis. The material prepared from vanadium-containing dump slimes has uniform microstructure and high electronic conductivity of the order of 1.4 × 10–2 S cm–1; it is thermally stable in the interval 30–550°С and capable of intercalation/deintercalation of lithium ions in its structure in the course of cycling in lithium-ion current sources.

Physicochemical Properties of Li6V5O15 as the Cathode Material for Lithium-Ion Batteries

Lithium-vanadium oxide with the formal composition Li6V5O15, uniform microsctructure, and the particle size of 100 nm is synthesized by a solution method. The synthesized compound is characterized by the methods of X-ray diffraction analysis, Raman spectroscopy, and synchronous thermal analysis. The total electric conductivity is measured by the method of impedance spectroscopy and its electronic component is estimated by dc method. In the temperature range of 200–400°C, Li6V5O15 represents a mixed electronic- ionic conductor with predomination of the ionic component and is thermally stable up to 550°С. Preliminary tests of a laboratory model of electrochemical cell Li|LiPF6|Li6V5O15 are carried out.