Lithium Vanadium Phosphate Research Articles

Effects of nickel-doping on the microstructure and electrochemical performances of electrospun Li3V2(PO4)3/C fiber membrane cathode

Metal ion-doping and fibrosis treatment are important ways to improve the conductivity of lithium vanadium phosphate (Li3V2(PO4)3) electrode materials. However, the traditional casting preparation method could reduce the electronic and ionic conductivities of Li3V2(PO4)3 electrodes. In this work, the nickel (Ni)-doped Li3V2(PO4)3/C nanofiber membrane with a three-dimensional network structure was prepared by an electrospinning technique, which was directly used for self-standing cathodes in lithium-ion batteries. The effects of Ni-doping on the morphology, structure, and electrochemical properties of Li3V2(PO4)3/C nanofiber membrane were studied. The results show that the Ni-doping not only changes the crystal structure and morphology of Li3V2(PO4)3/C fibers, but also affects the electrochemical performances of the Li3V2(PO4)3/C electrodes. 1‰ Ni-doping has slightest effect on the crystal structure compared with other ratios, and the catalytic effect of Ni nanoparticles makes Li3V2(PO4)3/C grow directionally to form a hybrid membrane containing Li3V2(PO4)3/C nanofibers and Li3V2(PO4)3/C nanowires. The hybrid membrane electrode possesses good electrochemical performances at the current densities of 1C and 5C owing to the long-range continuous electron conductive networks, high porosity to favor the electrolyte permeation and Li-ion transport, and stable integrated-electrode structure to enhance the redox reaction. This self-standing Li3V2(PO4)3/C nanofiber membrane cathode is expected to be used in high-energy lithium-ion batteries.

A Mechanism Study of Structural Transition of Lithium Vanadium Phosphate during the 1st Charge/Discharge in Comparison to Ti-Doped One

Battery is one of the most attractive energy storage systems for its usefulness in energy conversion in these days. A great attention has been paid to the Li-ion batteries, and a lot of attempts to develop the system exhibiting higher energy density and higher safety have been tried for many years. However, the safety of Li-ion battery has been problems continuously while the energy density has developed largely. The safety issues of Li-ion battery generally come from thermal runaway, mainly derived from oxygen evolution from cathode materials. Phosphate materials including frames of PO4 polyanions such as LiFePO4 are regarded as a suitable cathode material in Li-ion battery in terms of the point of view. Lithium vanadium phosphate (LVP) has high expectations as a cathode material because of its higher operating voltage (~3.6V) and theoretical capacity(197mAh/g) compared to LiFePO4. While monoclinic LVP has a higher energy density, large hysteresis comes from asymmetric charge/discharge profile, and capacity fading are the main problems when three lithium ions are extracted by raising the voltage up to 4.8V. To overcome these limitations, fine studies about the mechanism have been carried out by a few groups. Although the mechanism studies were carried out by L. Nazar group about structural transition [1] and by Lee and Park about the possible pathway of lithium ion in the structure [2], representatively, the reasons for capacity fading on LVP should be studied more. In this work, we investigated the structural changes of LVP during the first charge and discharge process of voltage window of 3.0V to 4.8V by using Galvanostatic Intermittent Titration Technique (GITT), synchrotron radiation-based X-ray Absorption Spectroscopy (XAS) and in situ X-ray diffraction (XRD). The irreversible structural transitions between charge and discharge process are one of the possible reason for the capacity fading. Also, we conducted comparison study on the electrochemical and structural properties between LVP and Li3Ti0.03V1.97(PO4)3/graphene (LVP-Ti) to overcome limitations of LVP. In situ XRD patterns show four consecutive two-phase transitions on LVP during the charge process. During the reinsertion of lithium ion, the patterns of LVP look like a combined process of single solid solution and two-phase transitions between full charged LVP (FC-LVP) and Li2V2(PO4)3 (Li2 phase) without forming Li1V2(PO4)3. In GITT data, a two phase transition behavior which was previously reported as a solid solution behavior during the Li-ion insertion from full charged LVP to Li2 phase in the discharge process is observed. From these data, it can be said that transforming behavior from FC-LVP to Li2 phase is closer to two-phase reaction. In LVP-Ti case, the charge capacity was 185.84 mAh/g and the discharge capacity was 171.20 mAh/g in the first cycle, which were higher than those of LVP, 178.84 mAh/g and 162.99 mAh/g. And in situ XRD patterns show four consecutive two-phase transitions as in LVP. During the phase transition in charge/discharge, LVP-Ti faces less lattice mismatch than LVP, resulting in better electrochemical performance, and this phenomenon is originated from smaller particle size and enduring strain. The XAS result shows that the XANES peaks of LVP-Ti change gradually which is in line with the XRD result as same as in LVP case. However, the larger peak area of the pre-edge for LVP-Ti suggesting that more electrons were released upon charging. This means that the higher capacities of LVP-Ti is contributed by further utilization of the V redox reaction. [1] Yin, S-C., Hiltrud Grondey, Pierre Strobel, M. Anne, and Linda F. Nazar. "Electrochemical property: structure relationships in monoclinic Li3-yV2(PO4)3." Journal of the American Chemical Society 125, no. 34 (2003): 10402-10411. [2] Lee, S., & Park, S. S. (2012). Atomistic simulation study of monoclinic Li3V2(PO4)3 as a cathode material for lithium ion battery: structure, defect chemistry, lithium ion transport pathway, and dynamics. The Journal of Physical Chemistry C, 116(48), 25190-25197.

Possibility of Using Petroleum Coke As Reducing Agent for V2O5 in Solid-Phase Synthesis of Li3V2(PO4)3

Nowadays, electrochemical batteries are playing an important role in the development of technology in various fields – consumer electronics, electric transport, and stationary energy storage systems. The main requirements for modern batteries are high specific energy and low cost. State of art lithium-ion batteries have the highest specific energy, but their cost is quite high, and that limits their production volume. Therefore, a relevant problem is the development of new low-cost electrode materials with a high specific energy. One of the most promising compounds for positive electrodes of lithium-ion batteries is lithium vanadium phosphate Li3V2(PO4)3. It has the same safety in operation as LiFePO4, and at the same time has a higher specific capacity of 197 mA·h/g vs. 170 mA·h/g in LiFePO4, and provides lithium-ion batteries higher average discharge voltage. The lithium-ion batteries with positive electrodes based on Li3V2(PO4)3 have an average discharge voltage of 4.1 V and with LiFePO4 have 3.3 V [1]. The main raw material for lithium-vanadium phosphate is vanadium pentoxide (V2O5). V5+ reduces to V3+ in the process of synthesis Li3V2(PO4)3. The aim of the present work was to study the possibility of using petroleum electrode coke as a reducing agent in the solid-phase synthesis of lithium vanadium phosphate Li3V2(PO4)3. The following reagents were used: Li2CO3 (>99.9%), NH4H2PO4 (>98%), V2O5 (>99%), petroleum electrode coke. The reagents were milled to a homogeneous mixture in a mortar, then pressed into pellets in a hydraulic press at a pressure of 6 tons per cm2. The synthesis was carried out at a temperature of 800 °C in a tubular furnace in an argon atmosphere for 5 hours. Electrodes of the following composition (% wt.) were made of the synthesized material: 80% Li3V2(PO4)3, 10% Super P, 10% LA-132. 1M LiPF6 in mixture of DMC:EMC:EC:PA (1:1:2:1 by vol.) was used as an electrolyte, Celgard®3501 was used as a separator, lithium metal foil (100 µm) was used as the negative electrode. On the 1st cycle, the discharge capacity of the cells was 130 mA∙h/g(Li3V2(PO4)3) for cells being cycled in the potential range of 3.0-4.2 V and 160 mA∙h/g(Li3V2(PO4)3) in the range of 3.0-4.8 V. According to obtained results, it can be concluded that petroleum electrode coke can be used as a reducing agent in the solid-phase synthesis of Li3V2(PO4)3. In order to improve the characteristics of Li - Li3V2(PO4)3 cells, it is necessary to optimize the synthesis method. This work was performed as part of a Government Order to Ufa Institute of Chemistry of the Russian Academy of Sciences by the Ministry of Science and Higher Education of the Russian Federation (Theme No. AAAA-A17-117011910031-7), Russia.

Research progress in doping of lithium vanadium phosphate cathode materials

Research progress in doping of lithium vanadium phosphate cathode materials

Vesicular Li3V2(PO4)3/C hollow mesoporous microspheres as an efficient cathode material for lithium-ion batteries

Vesicular lithium vanadium phosphate/carbon hollow mesoporous microspheres were fabricated using a facile polyvinylpyrrolidone-assisted aerosol-spray-assisted method and subsequent heat-treatment. While changing the content of polyvinylpyrrolidone, we found that carbon content was adjustable on the surface of lithium vanadium phosphate. By optimizing the carbon content among the composites, the electrochemical performance can be enhanced significantly. The results of electrochemical performance tests suggested that the samples exhibited good cycle performance and high discharge capability in the voltages between 3.0–4.8 V. The observed excellent electrochemical performances could be attributed to the proper content of carbon coating and the vesicular hollow mesoporous microsphere structure, increasing the transmission rate of lithium ions and reducing the structural change during charging and discharging effectively.

Quantum-chemical study of 7Li NMR shifts in the context of delithiation of paramagnetic lithium vanadium phosphate, Li3V2(PO4)3 (LVP)

The lithium NMR shifts of three paramagnetic materials important in the charging/discharging processes of lithium vanadium phosphate cathode materials have been studied by large-scale quantum-chemical methodology. Namely, the 7Li NMR shifts of the fully lithiated Li3V2(PO4)3 (LVP3.0), and of the partly delithiated Li2.5V2(PO4)3 (LVP2.5) and Li2V2(PO4)3 (LVP2.0), have been computed and analyzed using a recently proposed approach (A. Mondal, M. Kaupp J. Phys. Chem. C 123 (2019) 8387-8405) that accounts for the Fermi-contact, pseudo-contact, as well as orbital shifts, combining periodic computations with an incremental cluster model. LVP3.0 and LVP2.0 exhibit three and two unique Li sites, respectively, which could be assigned to their experimental 7Li NMR signals. In case of LVP2.0, the computations clearly assigned the signals at 143 ppm and 77 ppm to the Li(1) and Li(2) sites, respectively, even though the latter is connected to Vb(+III d2 sites and the former to Va(+IV) d1 sites. LVP2.5 is the most complex of these three materials, exhibiting a 50% occupation of Li(3) sites, which generates much more complicated Li NMR spectra with seven peaks that partly are closely spaced. Exploring three different occupation patterns, the computations can clearly assign five of the seven signals to one type of Li site and give most probable assignments for the two remaining signals. Notably, the calculations support seven signals to be assigned to LVP2.5, while previous interpretations took two of the signals as being entirely due to contamination by LVP2.0. The accuracy of the computations could probably be improved further by full DFT optimization of large super-cell structures. This work suggests that first-principles computations of NMR shifts of extended paramagnetic solids provide an important tool for the analysis of even rather complex NMR spectra.

In-situ preparation of nitrogen-doped carbon-modified lithium vanadium phosphate fibers with mesoporous nanostructure for lithium energy storage

Abstract To significantly enhance the lithium storage performance of lithium vanadium phosphate (Li3V2(PO4)3), nitrogen-doped carbon-modified Li3V2(PO4)3 fibers with mesoporous structure have been designed and prepared for the first time via a simple electrospinning technology. The obtained results demonstrate that the nanosized Li3V2(PO4)3 crystals (10–25 nm) are embedded into the one-dimensional carbon fibers. Meanwhile, the electrochemical tests indicate that the prepared electrode possesses outstanding rate performance for energy storage with a high capacity of 129.2 mAh g−1 over 400 cycles at 20 C. The good battery property can be attributed to the nanosized crystals and conductive mesoporous carbon nanofibers, which can decrease the Li+ diffusion pathway and improve the apparent conductivity of the active material.

A thermodynamic investigation on the substitution mechanism of Mg-doped lithium vanadium phosphate

Monoclininc lithium vanadium phosphate, Li3V2(PO4)3, is regarded as a potential cathode material for the next generation of high-performance lithium ion batteries, since it exhibits a high discharge voltage (up to ∼4.1 V) and a large theoretical specific capacity (197 mAhg−1). However, the low intrinsic electronic conductivity of Li3V2(PO4)3, which is a prevailing challenge for olivine type compounds, inhibits its use in commercial applications. Although the substitution of V3+ by other cation species is a common procedure to increase the conductivity and electrochemical performance of Li3V2(PO4)3, the underlying mechanisms for the improved properties are not yet well understood. Therefore, a thermodynamic approach is used in this work to investigate the influence of dopant, i.e. Mg2+ as well as vacancies on the V3+ site on the stability of the resulting materials. On the basis of the measured partial molar Gibbs energies, entropies and enthalpies of the electrochemical reaction, a detailed discussion of the substitution mechanisms and their influence on the electrochemical performance is presented.

Rechargeable lithium-ion system based on lithium-vanadium(III) phosphate and lithium titanate and the peculiarity of it functioning

We propose a new electrochemical system based on a negative electrode based on lithium pentatitanate, a positive electrode based on the lithium-vanadium(III) phosphate, 0.67 mol dm−3 lithium chlorate(VII) solution in a mixture of propylene carbonate and 1,2-dimethoxyethane as an electrolyte and consider the peculiarities of its functioning. The paper cites the arguments and experimental data disclosing the influence of the products of the secondary oxidation of 1,2-dimethoxyethane at the Li3V2(PO4)3-electrode on the functional behavior of the Li4Ti5O12-electrode as the main reason for the observed decrease in the characteristics of the battery prototypes and suggests the ways to solve this problem.

Synthesis of Promising Cathode Material for Lithium Polymer Batteries

Original method for synthesis of lithium vanadium phosphate was developed. The method includes two stages: 1st, synthesis of iron phosphate from a mixture of ammonium dihydrophosphate and metal oxide; and 2st, synthesis of lithium vanadium phosphate by thermal lithiation of the product obtained in the 1st stage, with mechanical activation of the precursor in the course of plastic deformation. Our results would provide some basis for further improvement on the Li3V2(PO4)3 electrode materials for advance lithium-ion batteries.

Novel High-Rate Performance of Dual Carbon-Coated Li3V2(PO4)3 Materials Used in an Aqueous Electrolyte

Lithium vanadium phosphate (Li3V2(PO4)3) coated with dual carbon–citric acid and polyvinylpyrrolidone (PVP), are used as the cathode materials for the novel aqueous rechargeable lithium-ion batteries (ARLBs). Li+ diffusion coefficient of Li3V2(PO4)3/C (LVP/C) is first calculated and reported for the ARLBs. The primary discharge specific capacities of LVP/C reaches 125.8 mA h g–1 (1 C), 122.7 mA h g–1 (2 C), 113.6 mA h g–1 (5 C) and 101.6 mA h g–1 (10 C), respectively. Particularly, at 50 C (equivalent to an ampere density of 6.6 A g–1), the capacity has almost no decrease after 300 cycles. At a novel 100 C (13.2 A g–1), 94.9% of capacity retention is achieved after 1000 cycles, and the Coulombic efficiency approximates equal to 100%. Lithium vanadium phosphate with a NASCION structure is regarded as the great promising candidate material for power batteries owing to its high safety, superior structural stability, and excellent electrochemical performance.

Approaching Theoretical Capacities in Thick Lithium Vanadium Phosphate Electrodes at High Charge/Discharge Rates

It is a great challenge to engineer thick or bulk electrodes with well-maintained rate performance, since their charge-transport kinetics are severely worsened at large current densities. Here, hig...

Mechanism Study on Structural Transition of Lithium Vanadium Phosphate As Cathode for Lithium-Ion Batteries

To apply high energy material to generate devices like energy storage system (ESS) and electric vehicle (EV), a number of properties should be achieved such as energy density, cost, power and especially safety. There are numerous novel materials, but the lithium transition metal phosphates (LiFePO4 [1], LiCoPO4 [2], LiMnPO4 [3], Li3V2(PO4)3 [4]) are the most promising materials due to its structural and thermal safety. Among them, lithium vanadium phosphate brings out sharp relief as cathode material because of high energy density. In case of all three lithium ions are extracted, the theoretical capacity of LVP is 197mAh/g. The investigation of mechanism during the charge/discharge process and reducing irreversible capacity when it extract three lithium ions are the critical issues on the monoclinic Li3V2(PO4)3(LVP) material to solve In this work, we investigated the structural changes of the LVP material during the first charge and discharge process of voltage window 3.0 to 4.8 V. One of the key problems related to the electrochemical performance of electrode materials for lithium ion batteries was phase transitions and local structure changes during lithium insertion or extraction. Irreversible structural change between charge and discharge process is the possible reason of the capacity fading. In situ XRD study is an effective tool to track the real time phase transitions of the electrode material. Galvanostatic Intermittent Titration Technique (GITT) was carried out not only for the distinguish phase transition but also for calculating diffusivity and polarization. We followed the four successive two-phase transitions during extraction of lithium ion from Li3V2(PO4)3 to Li2.5V2(PO4)3, Li2V2(PO4)3, Li1V2(PO4)3 and V2(PO4)3. During the lithium ion intercalation process, the sample shows specific property that the phase change directly V2(PO4)3 to Li2V2(PO4)3 without forming Li1V2(PO4)3 as same as traditional mechanism. On the contrary to the report, the phase transition was observed as two phase reaction which was reported as solid solution [5]. In the GITT data, single drop of the diffusivity coefficient was observed where solid solution case should not shows. At the same part of XRD patterns shows the clear evidence that transforming V2(PO4)3 phase to Li2V2(PO4)3 phase of LVP cathode material is two-phase reaction. More details will be discussed in the meeting. Figure 1. Contour plots of in situ XRD patterns and Galvanostatic Intermittent Titration Technique data of LVP material during discharge Reference [1] A.K. Padhi, K.S. Nanjundaswamy, J.B. Goodenough, J. Electrochem. Soc. 144 (1997) 1188. [2] N.N. Bramnik, K. Nikolowski, C. Baehtz, K.G. Bramnik, H. Ehrenberg, Chem. Mater. 19 (2007) 908 [3] M. Pivko, M. Bele, E. Tchernychova, N.Z. Logar, R. Dominko, M. Gaberscek, Chem. Mater. 24 (2012) 1041. [4] M.Y. Saidi, J. Barker, H. Huang, J.L. Swoyer, G. Adamson, Electrochem. Solid State Lett. 5 (2002) A149. [5] S.C. Yin, H. Grondey, P. Strobel, M. Anne, L.F. Nazar, J. Am. Chem. Soc. 125 (2003) 10402 Figure 1

Combustion synthesis and electrochemical evaluation of Cr-substituted lithium vanadium (III) phosphate

In this work, the effect of Cr3+ partial substitution on vanadium site in monoclinic lithium vanadium(III) phosphate (LVP) structure resulting in compounds with general formula: Li3V2- xCr x(PO4)3-C ( x = 0, 0.05, 0.1, 0.15) was studied. A two-step sol-gel combustion method was employed in syntheses. The samples were characterized by X-ray powder diffraction, scanning electron microscopy, coupled plasma optical emission spectroscopy, and flash combustion. The electrochemical performance of the active materials was examined through rate capability tests and cyclic voltammetry. The unsubstituted compound LVPC delivers higher capacity compared to the Cr-containing samples due to chromium inactivity in the potential range 3.0–4.4 V vs. Li/Li+. However, the Cr-substituted materials show better overall capacity retention (97–97.6%) in contrast to Li3V2(PO4)3-C (96%) in long cycling.

Magnesium/chloride co-doping of lithium vanadium phosphate cathodes for enhanced stable lifetime in lithium-ion batteries

Combining XRD with 31P NMR, it is demonstrated that the Mg and Cl atoms of the new Mg and Cl co-doped Li3V2(PO4)3/C material occupy V and O sites in its structure, respectively.

Effect of sulfur addition and nanocrystallization on the transport properties of lithium–vanadium–phosphate glasses

The glasses defined by the formula 37.5Li2O–25V2O5–37.5P2O5 mol% containing different sulfur (0, 10, 50 and 100 mol%) content were studied before and after nanocrystallization. X-ray diffraction and transmission electron micrograph of the heat treated samples indicated nanocrystals embedded in the glass matrix. The average crystallite size was found between 18 and 37 nm. Sulfur (S) behaved as a reducing agent for redox reaction during preparation of glass and affected the conductivity, i.e., the V4+–V5+ or V3+–V4+ion pairs increased with increasing S content and led to increasing conductivity of glasses. After creation of the nanocrystalline phase, S-free glass–ceramic nanocomposite exhibited improvement in electrical conductivity around three orders of magnitude than initial glass. This great improvement of electrical conductivity is related to increase in a concentration of V4+–V5+or V3+–V4+ ion pairs and also, forming of defective and well-conducting regions along the crystallite/glass interfaces. The decrease in electrical conductivity in the 50S glass–ceramic nanocomposite, which possessed the highest crystallite size, could be related to the increase of grain boundaries scattering because of the increasing crystallite size. The conduction was attributed to non-adiabatic small polaron hopping and mostly determined by hopping carrier mobility.

Encapsulation of Lithium Vanadium Phosphate in Reduced Graphene Oxide for a Lithium-ion Battery Cathode with Stable Elevated Temperature Performance

Polyanion-type cathode materials have received considerable attention for lithium-ion battery applications because of their excellent thermal stability compared to oxide compounds. Although the incorporation of carbonaceous materials can augment the cycling performance, the role of carbon structures in lithium vanadium phosphate (Li3V2(PO4)3, LVP) compounds remains unclear at an elevated temperature. Herein, carbon-coated Li3V2(PO4)3 (C-LVP) and reduced-graphene-oxide-wrapped Li3V2(PO4)3 (rGO-LVP) samples are prepared, their electrochemical performance is examined at room temperature and an elevated temperature. The rGO-LVP and C-LVP samples exhibit discharge capacities of ∼131mAhg−1 and ∼124mAhg−1, respectively, at charge and discharge rates of 10C in the range of 3.0–4.3V at 55°C after cycling at various rates. The capacity retentions of the rGO-LVP and C-LVP samples are ∼95% and ∼85%, respectively, after 150 cycles at charge and discharge rates of 1C in the range of 3.0–4.3V at 55°C. The excellent rate performance and cycling stability of the rGO-LVP sample are due to its capability in maintaining a low charge transfer resistance or a higher electrical conductivity and ionic conductivity as compared to the C-LVP sample during electrochemical cycling, as demonstrated by electrochemical impedance spectroscopy and cyclic voltammetry. The results have provided essential insight into designing inorganic–carbon hybrid materials for future batteries.

Wet-chemical coordination synthesized Li3V2(PO4)3/C for Li-ion battery cathodes

Lithium vanadium phosphate (Li3V2(PO4)3) is one of the most promising cathode materials for developing practical Li-ion batteries due to its advantages of structural stability, low cost, relatively high energy density. For this purpose, a wet-chemical coordination approach has been applied to synthesis of the Li3V2(PO4)3/C (LVP/C) cathode materials for Li-ion batteries. The structure, morphology, and electrochemical and kinetic behaviors of LVP/C samples calcined at different temperatures are studied. The optimized Li3V2(PO4)3 sample calculated at 850 °C (denoted as LVP-850) exhibits excellent rate performance: at high rate of 0.5, 1, 5, 10 and 20 C, impressive specific capacity of 110.9, 106, 91.2, 83 and 43.6 mAh g−1 can still be attainted, respectively. Even through it recovers back to 0.1 C, the cell can still deliver a capacity of 114.4 mAh g−1 (about 97.9% of the initial capacity). Combined with cyclic voltammetry technique and ex-situ X-ray photoemission spectroscopy (XPS), the Li+ insertion/extraction reaction mechanisms are also confirmed. Such an efficient method plays a critical role in improving rate performance and cyclic reversibility of Li3V2(PO4)3 particles, and should also be appropriate for other functional electrode materials.

A review for the synthesis methods of lithium vanadium phosphate cathode materials

Monoclinic Lithium vanadium phosphate [Li3V2(PO4)3, LVP] has been extensively studied because of its attractive electrochemical properties including high specific energy, high specific capacity (133 mAh g−1 in 3.0–4.3 V, 197 mAh g−1 in 3.0–4.8 V), high working voltage (4.0 V), good cycle stability and low price used in rechargeable lithium ion batteries (LIBs). However, the inherent defects such as low conductivity still restrict its practical application in high performance LIBs. Various synthesis methods have been developed in order to improve electrochemical performances of LVP. The results show that the different synthesis methods have great influence on the properties of LVP cathodes for LIBs, so the study on the synthesis method of high performance LVP will continue to be in great demand. This review briefly introduces the present synthesis methods of LVP, such as high-temperature solid-state method, sol–gel method, hydrothermal method, etc. Apart from already established conventional routes, the novel preparation technologies are also mentioned. Moreover, the synthesis mechanism and electrochemical performances of Li3V2(PO4)3 cathode materials synthesized by each synthetic method are reviewed. Finally, the directions for further research and prospective applications for the LVP materials are proposed.

Enhanced electrochemical performance of lithium ion battery cathode Li3V2(PO4)3/C

Li-ion battery cathode material lithium-vanadium-phosphate Li3V2(PO4)3 was synthesized by a carbon-thermal reduction method, using stearic acid, LiH2PO4, and V2O5 as raw materials. And stearic acid acted as reductant, carbon source, and surface active agent. The effect of its content on the crystal structure and electrochemical performance of Li3V2(PO4)3/C were characterized by XRD and electrochemical performance testing, respectively. The results showed that the content of carbon source has no significant effect on the crystal structure of lithium vanadium phosphate. Lihtium vanadium phosphate obtained with 12.3% stearic acid demonstrated the best electrochemical properties with a typical discharge capacity of 119.4 mAh/g at 0.1 C and capacity retention behavior of 98.5% after 50 cycles. And it has high reversible discharge capacity of 83 mAh/g at 5 C with the voltage window of 3 to 4.3 V.