Experimental and Computational Study of the Structure and Electrochemical Properties of LixM2(PO4)3 Compounds with the Monoclinic and Rhombohedral Structure

Anisotropically grown Li 3 V 2 (PO 4 ) 3 nanocrystals, which are highly dispersed and directly impregnated on the surface of a carbon nanofiber (CNF), were successfully synthesized via a two-step synthesis process: i) precipitation of nanoplated V 2 O 3 precursors (20-200 nm); ii) transformation of the V 2 O 3 precursor into Li 3 V 2 (PO 4 ) 3 nanoplates without size change. The direct attachment of the Li 3 V 2 (PO 4 ) 3 nanocrystals to the carbon surface improves the electronic conductivity and Li + diffusivity of the entire Li 3 V 2 (PO 4 ) 3 /CNF composite, simultaneously producing a mesoporous network (pore size of approximately 10 nm) that acts as an electrolyte reservoir owing to the pillar effect of the impregnated Li 3 V 2 (PO 4 ) 3 crystals. This ideal Li 3 V 2 (PO 4 ) 3 /CNF nanostructure enabled a 480C rate (7.5 seconds) discharge with 83 mA h g −1 , and 69% of capacity retention at the slowest discharge rate (1C). Such an ultrafast charge-discharge performance opens the possibility of using Li 3 V 2 (PO 4 ) 3 as a cathode material for ultrafast lithium ion batteries with a stable cycle performance over 10,000 cycles at a 10C rate, maintaining 85% of the initial capacity. In the current society, the storage of electrical energy at high charge and discharge rate is an important technological issue as it enables hybrid and plug-in hybrid electric vehicles and provides a back-up to wind and solar energies.1,2 Rechargeable lithium-ion batteries (LIBs) are considered the most advanced energy storage systems; they possess high energy but limited power compared to high-power devices such as supercapacitors.1 To further improve the performance of the LIBs, several electrode materials have been proposed and investigated so far.2-11 Commercial cells utilize the layer-structured LiCoO 2 as the positive electrode, 3 but the high cost and toxicity of cobalt prohibit its use on a large scale. Spinel-type LiMn 2 O 4 is one of the alternative materials to cobalt for high-rate use. 4 Several reports on such materials for high-rate use have been published; however, the reported discharge performance are limited within 50-150C. Owing to their easy release of oxygen, LiCoO 2 and LiMn 2 O 4 also have safety issues at overcharged states or high temperatures.3,4 Thus, to achieve a long-term and safe use of the LIBs, cathode materials other than those including layer-structured or spinel-type materials have received significant attention. Researchers have identified polyanion-type cathode materials-such as phosphate cathode materials like LiFePO 4 (LFP) 5 and Li 3 V 2 (PO 4 ) 3 (LVP)-as attractive active materials because of their high thermal stability, high cyclability, and superior safety properties provided by the stable (PO 4 ) 3− unit. 6 The presence of a phosphate with a strong P-O covalency stabilizes the antibonding M-O (M = V or Fe) energy level through an M-O-P inductive effect and generates a conveniently high redox potential for M 3+ /M 2+ . 7 In particular, monoclinic LVP has attracted much attention because o...

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“…2. Overall, the XRD patterns of monoclinic LVP 36 (see the inset of Fig. 3, left) were found on the broad peak of the CNF (2θ = 20-30…”

Section: Resultsmentioning

confidence: 93%

Ultrafast Cathode Characteristics of Nanocrystalline-Li₃V₂(PO₄)₃/Carbon Nanofiber Composites

Naoi

Kisu

Iwama

et al. 2015

J. Electrochem. Soc.

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“…[52][53][54][55][56][57] They are of the general formula A x MM'(XO 4 ) 3 and comprise a three-dimensional framework of MO 6 and M'O 6 octahedra sharing corners with XO 4 tetrahedra. This framework forms large interstitial channels, which can accommodate alkali cations.…”

Section: Structure Selectionmentioning

confidence: 99%

“…In agreement with previous experimental and theoretical work, the Na 3 V 2 (PO 4 ) 3 NASICON is predicted to be stable in the rhombohedral phase, 54 while the Li 3 V 2 (PO 4 ) 3 NASICON is predicted to be stable in the monoclinic phase. 56 Diffusion barriers From Figure 3, we may observe that the nature of the host structure has a significant impact on the relative difference between the Na and Li migration barriers. While the barriers for the divacancy diffusion in layered ACoO 2 are similar for both Na and Li, they are significantly different for both alkali and vacancy diffusion in the close-packed olivine structure.…”

Section: Voltagesmentioning

confidence: 99%

Voltage, stability and diffusion barrier differences between sodium-ion and lithium-ion intercalation materials

Ong

Chevrier

Hautier

et al. 2011

Energy Environ. Sci.

1,273

1,046

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To evaluate the potential of Na-ion batteries, we contrast in this work the difference between Na-ion and Li-ion based intercalation chemistries in terms of three key battery properties -voltage, phase stability and diffusion barriers. The compounds investigated comprise the layered AMO 2 and AMS 2 structures, the olivine and maricite AMPO 4 structures, and the NA-SICON A 3 V 2 (PO 4 ) 3 structures. The calculated Na voltages for the compounds investigated are 0.18-0.57 V lower than that of the corresponding Li voltages, in agreement with previous experimental data. We believe the observed lower voltages for Na compounds are predominantly a cathodic effect related to the much smaller energy gain from inserting Na into the host structure compared to inserting Li. We also found a relatively strong dependence of battery properties with structural features. In general, the difference between the Na and Li voltage of the same compound, ∆V Na-Li , is less negative for the maricite structures preferred by Na, and * To whom correspondence should be addressed 1 more negative for the olivine structures preferred by Li. The layered compounds have the most negative ∆V Na-Li . In terms of phase stability, we found that open structures, such as the layered and NASICON structures that are better able to accommodate the larger Na + ion generally have both Na and Li versions of the same compound. For the close-packed AMPO 4 structures, our results show that Na generally prefers the maricite structure, while Li prefers the olivine structure, in agreement with previous experimental work. We also found surprising evidence that the barriers for Na + migration can potentially be lower than that for Li + migration in the layered structures. Overall, our findings indicate that Na-ion systems can be competitive with Li-ion systems.

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“…The concentration of magnetic clusters also depends on the preparation process and varies from small concentrations (1. Among the lithium metal polyphosphate family, the compounds described by formula Li x M 2 (PO 4 ) x (M=Fe, V, Mo and x=3, 5, 6, respectively) crystallize with the Nasicon-like structure [41]. Plots of the magnetic susceptibility, as a function of temperature for Fe-and Vcontaining compounds, are shown in Fig.…”

Section: Limpo 4 Olivine-related Compoundsmentioning

confidence: 99%

Magnetic properties of lithium intercalation compounds

Julien

Ait-Salah

Mauger

et al. 2006

Ionics

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Magnetic experiments are powerful tools to study fundamental properties and to check the qualities of samples. Temperature, stress, and impurities of materials can all affect magnetic properties and play an important role in the utilization of these materials for engineering applications. The estimation and analysis of the spontaneous magnetization can reveal ferromagnetic particles as impurities in samples. The shape of the temperature dependence of magnetization is indicative of the origin of the magnetic properties. However, it is necessary to correlate the χ m (T) curves and isothermal M(H) plots to achieve a complete analysis of the electronic properties of the materials. Highlights of magnetic properties of lithium intercalation compounds are briefly described. Intrinsic and extrinsic properties are considered as useful parameters to determine the purity of electrode materials for rechargeable Li-ion batteries.

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Experimental and Computational Study of the Structure and Electrochemical Properties of Li_xM₂(PO₄)₃ Compounds with the Monoclinic and Rhombohedral Structure

Cited by 172 publications

References 29 publications

Ultrafast Cathode Characteristics of Nanocrystalline-Li₃V₂(PO₄)₃/Carbon Nanofiber Composites

Ultrafast Cathode Characteristics of Nanocrystalline-Li₃V₂(PO₄)₃/Carbon Nanofiber Composites

Voltage, stability and diffusion barrier differences between sodium-ion and lithium-ion intercalation materials

Magnetic properties of lithium intercalation compounds

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Experimental and Computational Study of the Structure and Electrochemical Properties of LixM2(PO4)3 Compounds with the Monoclinic and Rhombohedral Structure

Cited by 172 publications

References 29 publications

Ultrafast Cathode Characteristics of Nanocrystalline-Li3V2(PO4)3/Carbon Nanofiber Composites

Ultrafast Cathode Characteristics of Nanocrystalline-Li3V2(PO4)3/Carbon Nanofiber Composites

Voltage, stability and diffusion barrier differences between sodium-ion and lithium-ion intercalation materials

Magnetic properties of lithium intercalation compounds

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Product

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Experimental and Computational Study of the Structure and Electrochemical Properties of Li_xM₂(PO₄)₃ Compounds with the Monoclinic and Rhombohedral Structure

Ultrafast Cathode Characteristics of Nanocrystalline-Li₃V₂(PO₄)₃/Carbon Nanofiber Composites

Ultrafast Cathode Characteristics of Nanocrystalline-Li₃V₂(PO₄)₃/Carbon Nanofiber Composites