Thermodynamic properties of sodium pyrovanadate (Na4V2O7) at high temperature (298.15–873 K)

Pei, Guishang; Xiang, Junyi; Yang, Lilian; Jin, Xin; Lv, Xuewei

doi:10.1016/j.calphad.2020.101802

Cited by 18 publications

(10 citation statements)

References 14 publications

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“…The enthalpy increments of CaMgV 2 O 7 at high temperatures were measured accurately using isothermal drop calorimetry. The average sensitivity of the drop calorimetry for each test was established and described elsewhere 28,29 . The sensitivity increased remarkably at high temperatures, consistently with the results of Beneš et al 30 .…”

Section: Resultssupporting

confidence: 71%

“…The average sensitivity of the drop calorimetry for each test was established and described elsewhere. 28,29 The sensitivity increased remarkably at high temperatures, consistently with the results of Beneš et al 30 In each experimental run, at least four drops of sample pellets and four drops of the sapphires were prepared to limit the experimental errors as soon as possible. The typical heat flow curves for the eight-drop tests at 773 K are presented in Figure 9, in which the blue line denotes the endothermic peaks for the sapphire reference pellets, whereas the green lines show the endothermic peaks for the CaMgV 2 O 7 pellets.…”

Section: Thermodynamic Propertysupporting

confidence: 78%

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Double pyrovanadates CaMgV₂O₇: Formation mechanism, phase structure, and thermodynamic properties

et al. 2022

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A double pyrovanadate CaMgV 2 O 7 sample was synthesized via a facile solidstate route under an air atmosphere. The nonequilibrium formation pathways of the CaMgV 2 O 7 were investigated via powder X-ray diffraction. A multistep reactions path (metavanadates-pyrovanadates-double pyrovanadate CaMgV 2 O 7 ) was proposed to describe the formation of the CaMgV 2 O 7 considering the thermodynamic and kinetic factors. The cell unit parameters of the CaMgV 2 O 7 sample indicated the crystallization according to a monoclinic system with space group P12/c1( 14), and the lattice parameters of a = 6.756 Å, b = 14.495 Å, c = 11.253 Å, β = 99.12, and V = 108.806 Å 3 . X-ray photoelectron spectroscopy also confirmed the +5 oxidation state vanadium in CaMgV 2 O 7 . The endothermic effects at 1033 and 1143 K were related to the incongruent melting and liquidus temperatures of CaMgV 2 O 7 , respectively. The comprehensive thermodynamic properties of CaMgV 2 O 7 were established in both low-and high-temperature regions, utilizing a physical property measurement system and multi-hightemperature calorimetry (96 lines). The heat capacity (200 J mol K −1 ) and entropy (198 J mol K −1 ) at 298.15 K were computed based on the low-temperature heat capacity values, and the enthalpy of formation at 298.15 K was also estimated. The fitted high-temperature capacity can be used to obtain the changes in the enthalpy, entropy, and Gibbs free energy. This study is part of building a reliable thermodynamic database of the CaO-MgO-V 2 O 5 system.

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Section: Resultssupporting

confidence: 71%

Section: Thermodynamic Propertysupporting

confidence: 78%

Double pyrovanadates CaMgV₂O₇: Formation mechanism, phase structure, and thermodynamic properties

et al. 2022

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“…A typical heat flow signal of four references (α‐Al 2 O 3 ) and four Na 2 Ti 3 O 7 samples at 1073 K was measured by drop calorimetry and presented in Figure 3. Each endothermic peak in the heat flow signal was individually integrated using the Calisto data analysis software 17 …”

Section: Resultsmentioning

confidence: 99%

Thermodynamic properties of sodium trititanate (Na₂Ti₃O₇) at high temperature (298.15‐1403 K)

et al. 2021

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Sodium‐ion batteries (NaIBs) have attracted extraordinary attentions as a promising scalable energy storage alternative to current lithium‐ion batteries (LIBs), owing to their natural abundance and low costs. Sodium trititanate (Na2Ti3O7) is a promising material as the material of NaIBs with low potential and high theoretical capacitance. In order to better understand their service performance when utilized in rechargeable NaIBs, studies on thermodynamic properties of Na2Ti3O7 are indispensable. However, an extensive literature review revealed that the heat capacity of Na2Ti3O7 is established with divergences, especially for high‐temperature region. Therefore, the 99.5% purity of Na2Ti3O7 powder was first Synthesized through solid‐state reaction with sodium carbonate (Na2CO3) and titanium dioxide (TiO2) as raw materials. The as‐prepared samples were used to measure the heat capacity from 573 to 1323 K which was carried out with multihigh temperature calorimeter (MHTC) 96 line. The temperature dependence of heat capacity was modeled as a function: Cp =255.51073 + 0.06059 T − 3.86912 × 106 T−2 (J mol−1 K−1) (298.15 ‐ 1403 K), and then used for computing changes in enthalpy, entropy, and Gibbs free energy. Heat capacity of Na2Ti3O7 from 0 to 1403 K was given for future application of Na2Ti3O7 in rechargeable batteries.

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“…Therefore, two heating cycles were taken, and the second cycle during the heating process was used in this study. The maximum uncertainties on the instrument of temperature measurements were equal to ±1 K and enthalpy change ±2.0%, which was calibrated using standard materials, such as aluminum, zinc, tin and indium, silver, nickel, respectively 24–26 …”

Section: Methodsmentioning

confidence: 99%

“…The maximum uncertainties on the instrument of temperature measurements were equal to ±1 K and enthalpy change ±2.0%, which was calibrated using standard materials, such as aluminum, zinc, tin and indium, silver, nickel, respectively. [24][25][26] The molar heat capacity of Ca 5 Mg 4 V 6 O 24 sample at high temperature was measured using a classic "three steps" method based on the DSC technique (NETZSCH STA 404 F3 Pegasus). Measurements were operated in a dynamic model with a heating rate of 10 K min −1 in the argon atmosphere (99.998%, 50 ml min −1 ), and the isothermal intervals of 15 and 10 min before and after the dynamic temperature profile were designed to stabilize the heat flow curve, respectively.…”

Section: Thermodynamic Property Measurementsmentioning

confidence: 99%

The phase structure, thermodynamic properties, and dissolution behavior of Ca₅Mg₄V₆O₂₄

et al. 2022

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A Ca5Mg4V6O24 compound was synthesized through solid‐state roasting routes under an air atmosphere, and its crystal structure and thermodynamic properties were determined using various methods. The cell parameters of Ca5Mg4V6O24 indicate that it crystallizes in cubic space group Ia3d with the unit cell parameters a = 12.442 ± 0.001 Å. X‐ray photoelectron spectroscopy also confirmed that the vanadium element in the Ca5Mg4V6O24 sample is present in the +5 state. The melting of Ca5Mg4V6O24 was detected at 1442 K. The molar heat capacity (374 J mol K−1) and entropy (688.2 J mol K−1) of Ca5Mg4V6O24 at 298.15 K were determined using physical properties measurement system, and simultaneous thermal analyzer for the first time. The solubility of Ca5Mg4V6O24 in water at different temperatures was measured and its dissolution behavior in sulfuric acid and kinetics was experimentally established.

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Thermodynamic properties of sodium pyrovanadate (Na4V2O7) at high temperature (298.15–873 K)

Cited by 18 publications

References 14 publications

Double pyrovanadates CaMgV₂O₇: Formation mechanism, phase structure, and thermodynamic properties

Double pyrovanadates CaMgV₂O₇: Formation mechanism, phase structure, and thermodynamic properties

Thermodynamic properties of sodium trititanate (Na₂Ti₃O₇) at high temperature (298.15‐1403 K)

The phase structure, thermodynamic properties, and dissolution behavior of Ca₅Mg₄V₆O₂₄

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Thermodynamic properties of sodium pyrovanadate (Na4V2O7) at high temperature (298.15–873 K)

Cited by 18 publications

References 14 publications

Double pyrovanadates CaMgV2O7: Formation mechanism, phase structure, and thermodynamic properties

Double pyrovanadates CaMgV2O7: Formation mechanism, phase structure, and thermodynamic properties

Thermodynamic properties of sodium trititanate (Na2Ti3O7) at high temperature (298.15‐1403 K)

The phase structure, thermodynamic properties, and dissolution behavior of Ca5Mg4V6O24

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Product

Resources

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Double pyrovanadates CaMgV₂O₇: Formation mechanism, phase structure, and thermodynamic properties

Double pyrovanadates CaMgV₂O₇: Formation mechanism, phase structure, and thermodynamic properties

Thermodynamic properties of sodium trititanate (Na₂Ti₃O₇) at high temperature (298.15‐1403 K)

The phase structure, thermodynamic properties, and dissolution behavior of Ca₅Mg₄V₆O₂₄