Electrochemical property: Structure relationships in monoclinic Li(3-y)V2(PO4)3

Effects of morphology on the electrochemical performances of Li3V2(PO4)3 cathode material for lithium ion batteries

The effects of various morphologies on the electrochemical performances of Li₃V₂(PO₄)₃ (LVP) were summarized and discussed.

Synthesis of biocarbon coated Li3V2(PO4)3/C cathode material for lithium ion batteries using recycled tea

A biocarbon coated Li₃V₂(PO₄)₃ (LVP-C) cathode with high electrochemical performance was synthesized by a sol–gel method using recycled tea as both structural template and carbon source.

Nanocomposite Li3V2(PO4)3/carbon as a cathode material with high rate performance and long-term cycling stability in lithium-ion batteries

Li₃V₂(PO₄)₃/carbon nanocomposite with high electrochemical performance has been successfully synthesized by combining sol–gel method and nanocasting route.

Vanadium phosphate as a promising high-voltage magnesium ion (de)-intercalation cathode host

Electrochemically de-lithiated Li₃V₂(PO₄)₃, are investigated as high-voltage (∼3.0 V vs. Mg/Mg²⁺) cathode hosts for Mg²⁺ (de)-intercalation. The exceptional high voltage surpasses the hitherto reported values of cathodes for magnesium batteries.

A better understanding of the capacity fading mechanisms of Li3V2(PO4)3

The main capacity decay of Li₃V₂(PO₄)₃ lies in the kinetic limitation between the LiV₂(PO₄)₃ ↔ V₂(PO₄)₃ phase transition, vanadium dissolution, rather than structure degradation.

The effect of titanium in Li3V2(PO4)3/graphene composites as cathode material for high capacity Li-ion batteries

We report high capacity and rate capability of titanium-added Li₃V₂(PO₄)₃ (LVP) as a cathode material for lithium ion batteries (LIBs).

Synthesis of Li3V2(PO4)3/C for use as the cathode material in lithium ion batteries using polyvinylidene fluoride as the source of carbon

The Li₃V₂(PO₄)₃/C cathode, prepared using PVDF as the source of carbon, is covered by a thin carbon film and has an excellent conductivity and electrochemical performance.

Li3V2(PO4)3 particles embedded in porous N-doped carbon as high-rate and long-life cathode material for Li-ion batteries

The porous N-doped carbon stabilized Li₃V₂(PO₄)₃ particles are obtained by using a modified sol–gel method, and the composite exhibits a high discharge capacity of 114.7 mA h g⁻¹ at 1 C in the voltage range of 3–4.3 V after 600 cycles.

A Bi-doped Li3V2(PO4)3/C cathode material with an enhanced high-rate capacity and long cycle stability for lithium ion batteries

A promising cathode material Li₃V_1.97Bi_0.03(PO₄)₃/C for high-power Li rechargeable batteries shows excellent electrochemical performance.

Morphology and surface properties of LiVOPO4: a first principles study

First principles calculations were used to investigate the surface energies, equilibrium morphology, surface redox potentials, and surface electrical conductivity of LiVOPO4. Relatively low-energy surfaces are found in the (100), (010), (001), (011), (111), and (201) orientations of the orthorhombic structure. Thermodynamic equilibrium shape of the LiVOPO4 crystal is built with the calculated surface energies through a Wulff construction. The (001) and (111) orientations are the dominating surfaces in the Wulff shape. Similar calculations for VOPO4 display a larger decrease in surface energies for the (100) surface rather than those in the other surfaces. It suggests that the Wulff shape of LiVOPO4 is closely related to the chemical environment around. Surfaces (100), (010) and (201) present lower Li surface redox potentials in comparison with the bulk material. Therefore, the Li migration rate on surfaces could be effectively increased by maximizing the exposure of these low redox potential surfaces. In addition, lower surface band gaps are found in all orientations compared to the bulk one, which indicates that electrical conductivity can be improved significantly by enlarging surfaces with relatively low band gaps in the particle. Therefore, synthesizing (201) and (100) nanosheets will greatly improve the electrochemical properties of the material.

Stable 4 V-class bicontinuous cathodes by hierarchically porous carbon coating on Li3V2(PO4)3 nanospheres

A high performance, durable cathode material for lithium ion batteries is achieved by incorporating ∼50 nm Li3V2(PO4)3/C core-shell nanospheres into a porous carbon framework. The Li3V2(PO4)3/C nanocomposite delivers an initial discharge capacity of 130 mA h g(-1), approaching its theoretical limit (133 mA h g(-1)). At a high current rate (10 C), the nanocomposite displays an impressive long cycle life and remarkable capacity retention (90% after 1200 cycles). Notably, the Coulombic efficiency is above 99% during the course of cycling. The remarkable power capability and cycle stability derived from our simple and scalable synthesis suggests that this 4 V-class material could be one of the most promising candidates for future batteries.

Manipulating size of Li3V2(PO4)3 with reduced graphene oxide: towards high-performance composite cathode for lithium ion batteries

Lithium vanadium phosphate (Li₃V₂(PO₄)₃, LVP)/reduced graphene oxide (rGO) composite is prepared with a rheological method followed by heat treatment. The size and interface of LVP particles, two important merits for a cathode material, can be effectively tuned by the rGO in the composite, which plays as surfactant to assist sol-gelation and simultaneously as conductive carbon coating. As a consequence, the composite with 7.0 ± 0.4 wt.% rGO shows a capacity of 141.6 mAh g⁻¹ at 0.075 C, and a rate capacity of 119.0 mAh g⁻¹ at 15 C with respect to the mass of LVP/rGO composite, and an excellent cycling stability that retains 98.7% of the initial discharge capacity after 50 cycles. The improved electrochemical performance is attributed to the well-controlled rGO content that yields synergic effects between LVP and rGO. Not only do the rGO sheets reduce the size of LVP particles that favor the Li⁺ ion migration and the electron transfer during charging and discharging, but also contribute to the reversible lithium ions storage.

Effect of carbon matrix dimensions on the electrochemical properties of Na3V2(PO4)3 nanograins for high-performance symmetric sodium-ion batteries

Na3V2(PO4)3 nanograins dispersed in different carbon matrices are rationally synthesized and systematically characterized. The acetylene carbon matrix provides the best conductive networks for electrons and sodium ions, which endows Na3V2(PO4)3 stable cyclability and high rate performance. The Na3V2 (PO4)3 -based symmetric sodium-ion batteries show outstanding electrochemical performance, which is promising for large-scale and low-cost energy storage applications.

Ionic-liquid-assisted synthesis of nanostructured and carbon-coated Li3V2(PO4)3 for high-power electrochemical storage devices

Carbon-coated Li3V2(PO4)3 (LVP) displaying nanostructured morphology can be easily prepared by using ionic-liquid-assisted sol-gel synthesis. The selection of highly viscous and thermally stable ionic liquids might promote the formation of nanostructures during the sol-gel synthesis. The presence of these structures shortens the diffusion paths and enlarges the contact area between the active material and the electrolyte; this leads to a significant improvement in lithium-ion diffusion. At the same time, the use of ionic liquids has a positive influence on the coating of the LVP particles, which improves the electronic conductivity of this material; this leads to enhanced charge-transfer properties. At a high current density of 40 C, the LVP/N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide material delivered a reversible capacity of approximately 100 mA h g(-1), and approximately 99 % of the initial capacity value was retained even after 100 cycles at 50 C. The excellent high rate and cycling stability performance make Li3V2(PO4)3 prepared by ionic-liquid-assisted sol-gel synthesis a very promising cathode material for high-power electrochemical storage devices.

Three-dimensionally ordered macroporous Li3V2(PO4)3/C nanocomposite cathode material for high-capacity and high-rate Li-ion batteries

A three-dimensionally ordered macroporous (3DOM) Li3V2(PO4)3/C cathode material with small-sized macropores (50-140 nm) is successfully synthesized using a colloidal crystal array. The 3DOM architecture is built up from fully densely sintered Li3V2(PO4)3/C nanocomposite ceramics particles. Such a 3DOM Li3V2(PO4)3/C micrometer sized particle combines the advantages of both Li3V2(PO4)3 nanocrystal and micrometer sized particle. The resultant 3DOM Li3V2(PO4)3/C nanocomposite exhibits a stable and highly reversible discharge capacity up to 151 mA g(-1) at 0.1 C, and an excellent high-rate capability of 132 mA g(-1) at 5 C in the voltage range of 3.0-4.4 V. Compared to the corresponding bulk nanocomposite, the 3DOM Li3V2(PO4)3/C cathode exhibits a significantly improved high-rate performance, which promises new opportunities in the development of high energy and high power lithium-ion batteries.

One-Pot synthesized bicontinuous hierarchical Li3V2(PO4)3/C mesoporous nanowires for high-rate and ultralong-life lithium-ion batteries

Lithium-ion batteries have attracted enormous attention for large-scale and sustainable energy storage applications. Here we present a design of hierarchical Li3V2(PO4)3/C mesoporous nanowires via one-pot synthesis process. The mesoporous structure is directly in situ carbonized from the surfactants (CTAB and oxalic acid) along with the crystallization of Li3V2(PO4)3 without using any hard templates. As a cathode for lithium-ion battery, the Li3V2(PO4)3/C mesoporous nanowires exhibit outstanding high-rate and ultralong-life performance with capacity retention of 80.0% after 3000 cycles at 5 C in 3-4.3 V. Even at 10 C, it still delivers 88.0% of its theoretical capacity. The ability to provide this level of performance is attributed to the hierarchical mesoporous nanowires with bicontinuous electron/ion pathways, large electrode-electrolyte contact area, low charge transfer resistance, and robust structure stability upon prolonged cycling. Our work demonstrates that the unique mesoporous nanowires structure is favorable for improving the cyclability and rate capability in energy storage applications.

Pyro-synthesis of a high rate nano-Li3V2(PO4)3/C cathode with mixed morphology for advanced Li-ion batteries

A monoclinic Li3V2(PO4)3/C (LVP/C) cathode for lithium battery applications was synthesized by a polyol-assisted pyro-synthesis. The polyol in the present synthesis acts not only as a solvent, reducing agent and a carbon source but also as a low-cost fuel that facilitates a combustion process combined with the release of ultrahigh exothermic energy useful for nucleation process. Subsequent annealing of the amorphous particles at 800°C for 5 h is sufficient to produce highly crystalline LVP/C nanoparticles. A combined analysis of X-ray diffraction (XRD) and neutron powder diffraction (NPD) patterns was used to determine the unit cell parameters of the prepared LVP/C. Electron microscopic studies revealed rod-type particles of length ranging from nanometer to micrometers dispersed among spherical particles with average particle-sizes in the range of 20-30 nm. When tested for Li-insertion properties in the potential windows of 3-4.3 and 3-4.8 V, the LVP/C cathode demonstrated initial discharge capacities of 131 and 196 mAh/g (~100% theoretical capacities) at 0.15 and 0.1 C current densities respectively with impressive capacity retentions for 50 cycles. Interestingly, the LVP/C cathode delivered average specific capacities of 125 and 90 mAh/g at current densities of 9.6 C and 15 C respectively within the lower potential window.

Lithium vanado(V)molybdate(VI), Li[VMoO6]

Brannerite-type Li[VMoO₆] has been synthesized by a solid state reaction route. The V and Mo atoms statistically occupy the same site with mirror symmetry and are octa­hedrally surrounded by O atoms. The framework is two-dimensional and is built up from edge-sharing (V,Mo)O₆ octa­hedra forming (VMoO₆)_∞ layers that run parallel to the (001) plane. Li⁺ ions are situated in position with symmetry 2/m in the inter­layer space. The bond-valence analysis reveals that the Li⁺ ionic conductivity is along the [010] and [110] directions, and shows that this material may have inter­esting conduction properties. This simulation proposes a model of the lithium conduction pathways.

Enhancement of the cycling performance of Li3V2(PO4)3/C by stabilizing the crystal structure through Zn2+ doping

Zn doping was proven to be helpful in stabilizing the crystal structure of Li₃V₂(PO₄)₃/C upon repeated cycles.

Novel synthesis of LiMnPO4·Li3V2(PO4)3/C composite cathode material

A carbon-coated LiMnPO₄·Li₃V₂(PO₄)₃ composite cathode material is synthesized from a rod-like MnV₂O₆·4H₂O precursor prepared via aqueous precipitation for the first time, followed by chemical reduction and lithiation with oxalic acid as the reducing agent and glucose as the carbon source.

Facile synthesis of nitrogen-doped carbon derived from polydopamine-coated Li3V2(PO4)3 as cathode material for lithium-ion batteries

Nitrogen-doped, carbon-coated Li₃V₂(PO₄)₃ cathode materials were prepared by the oxidative self-polymerization of dopamine on the Li₃V₂(PO₄)₃ surface and subsequent carbonization of polydopamine.

A Na3V2(PO4)3 cathode material for use in hybrid lithium ion batteries

A NASICON-structure Na3V2(PO4)3 cathode material prepared by carbothermal reduction method is employed in a hybrid-ion battery with Li-involved electrolyte and anode. The ion-transportation mechanism is firstly investigated in this complicated system for an open three-dimensional framework Na3V2(PO4)3. Ion-exchange is greatly influenced by the standing time, for example, the 1 hour battery presents a specific capacity of 128 mA h g(-1) while the 24 hour battery exhibits a value of 148 mA h g(-1) with improved rate and cycling performances over existing literature reported Li-ion batteries. In the hybrid-ion system, an ion-exchange process likely takes place between the two Na(2) sites in the rhombohedral structure. NaLi2V2(PO4)3 could be produced by ion-transportation since the Na(+) in the Na(1) site is stationary and the three Na(2) sites could be used to accommodate the incoming alkali ions; Li(x)Na(y)V2(PO4)3 would come out when the vacant site in Na(2) was occupied depending on the applied voltage range. The reported methodology and power characteristics are greater than those previously reported.

Li3V2(PO4)3@C core-shell nanocomposite as a superior cathode material for lithium-ion batteries

Li3V2(PO4)3@C core-shell nanoparticles with typical sizes of 20-40 nm were synthesized using a hydrothermal-assisted sol-gel method. Ascorbic acid and PEG-400 were adopted as carbon sources and reductants. The uniform Li3V2(PO4)3@C nanocomposite obtained was composed of a Li3V2(PO4)3 core with high-phase purity and a graphitized carbon shell, which was characterized using XRD, SEM, TEM, and Raman analysis. The nanocomposite exhibited a remarkably high rate capability and long cyclability, delivering a discharge capacity of 138 mA h g(-1) at 5 C within a voltage range of 3-4.8 V and the capacity retention was 86% after 1000 cycles. The superior electrochemical performance of Li3V2(PO4)3@C indicates that it has potential for application as a cathode material in advanced rechargeable lithium-ion batteries.

Long-life and high-rate Li3V2(PO4)3/C nanosphere cathode materials with three-dimensional continuous electron pathways

Lithium-ion batteries (LIBs) are receiving considerable attention as storage devices in the renewable and sustainable energy developments. However, facile fabrication of long-life and high-rate cathode materials for LIBs is required to facilitate practical application. Here we report a favourable way to synthesize a Li3V2(PO4)3/C nanosphere cathode with three-dimensional (3D) continuous electron pathways by synergistically utilizing polyethyleneglycol (PEG) and acetylene black for carbon coating and conductive network construction. The as-prepared cathode material has a discharge capacity of 142 mA h g(-1) at 1 C rate, approaching its theoretical value (150 mA h g(-1)), and can even be cycled at a rate as high as 30 C without capacity fading. After 1000 cycles at a rate of 5 C, the as-prepared material has a capacity retention of up to 83%, and can also tolerate 5000 cycles with a considerable capacity, demonstrating excellent cycling stability. Our work shows that this material has great potential for high-energy and high-power energy storage applications, and this rational method can be applied to synthesize high-performance cathode materials on a large scale.