Enthalpies of formation and heat capacity functions for maricite,NaFePO4(cr), and sodium iron(III) hydroxy phosphate,Na3Fe(PO4)2· (Na4/3H2/3O)(cr)

Tremaine, Peter R.; Xiao, Caibin

doi:10.1006/jcht.1999.0542

Cited by 13 publications

(5 citation statements)

References 15 publications

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“…Maricite, as opposed to olivine, is the thermodynamically stable structure for NaFePO 4 . 49,50 The maricite structure is similar to the olivine structure, except that the alkali occupies the M(2) site, and transition metal occupies the M(1) sites. Generally, they are of less interest for battery applications given that there are no obvious channels for fast alkali diffusion in these materials, unlike in the olivine structure.…”

Section: Structure Selectionmentioning

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.

1,309

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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Section: Structure Selectionmentioning

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.

1,309

1,046

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“…For our work, taking thermodynamic data from a sole source was possible only for well-known substances (α-Fe, Li 2 CO 3 , etc) whose characteristics completely coincide in few reference books. Table presents the standard thermodynamic values needed for our calculations and taken from various sources with a necessary indication of the references and comments on how the calculated thermodynamic values have been obtained by us, if absent in the source explicitly. − In every case, preference was given to the primary experimental papers containing fuller data, including the coefficients of eq .…”

Section: Results and Discussionmentioning

confidence: 99%

“…As a result of the application of a thermodynamic cycle, a close value Δ f H 298 °(FePO 4 ) = −1220.4 kJ•mol −1 was calculated on the basis of these numeric data.Due to the poorer experimental database, La Iglesia 68 describes the lithium−phosphate compounds with a lower accuracy than the soduim and potassium compounds:(h i (Li 2 O) = (−817.30 ± 12.97) kJ•mol −1 ; g i (Li 2 O) is not given). This enables us to evaluate, by this method, the standard enthalpy of formation only: Δ f H 298 °(LiFePO 4 ) = (−1591.23 ± 13) kJ•mol −1 , which is very near to the corresponding value for orthorhombic sodium iron phosphate:Δ f H 298 °(NaFePO 4 ) = −1571.8 kJ•mol −1 ,69 but is in contradiction with the value Δ f H 298 °(LiFePO 4 ) = −1392.45 kJ•mol −1 calculated from the data from ref 66. Taking various data sets and applying the quasi-additivity principle to compounds close by composition and structure, we have additionally found Δ f H 298 °(LiFePO 4 ) = −1514.8 kJ•mol −1 (from the standard enthalpies of formation of Li 3 PO 4 , NaFePO 4 , and Na 3 PO 4 ) and S 298 °(LiFePO 4 ) = 136.75 J•K −1 •mol −1 (from the standard entropies of the constituent oxides Li 2 O, P 2 O 5 , FeO).Table3presents the values of Δ f G 298 °(LiFePO 4 ) corresponding to different calculation techniques.…”

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confidence: 77%

Thermodynamics of LiFePO₄ Solid-Phase Synthesis Using Iron(II) Oxalate and Ammonium Dihydrophosphate as Precursors

et al. 2013

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A detailed thermodynamic analysis and an experimental study of the thermolysis mechanism of Li2CO3 + NH4H2PO4 + FeC2O4 blends were performed from the viewpoint of the usage of these compounds for the LiFePO4 solid-phase synthesis. Thermodynamic calculations of the assumed chemical reactions have been done within a practically important (for LiFePO4 synthesis) temperature range of (25 to 900) °C. The thermodynamic parameters of the related compounds (Li2O, Li3PO4, (NH4PO3)4, NaFePO4, FePO4 2H2O, FePO4, and LiFePO4) were determined more precisely than earlier. The temperature dependences of changes in the standard Gibbs energy, standard enthalpy, standard entropy, and standard molar heat capacity for the chemical reactions in LiFePO4 synthesis were calculated. Various paths of oxalate decomposition may well proceed concurrently with the predomination of this or that path under slight changes in the experimental conditions. The formation of orthorhombic lithium orthophosphate Li3PO4 was detected just in a blend grinded at room temperature. Heating up to 360 °C results in full destruction of the reaction mixture; Li3PO4 in its activated state is a crystal component at this synthesis stage. Lithium orthophosphate structurally belonging to the same spatial Pnma group as the target product LiFePO4 is the basis of its synthesis.

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“…Therefore, the molar ratio of Fe 2+ to Fe 3+ used in the present study was 1.4 ‫.2׃‬ In general, as long as the molar ratio of Fe 2+ to Fe 3+ is not greater than ‫,1׃1‬ the Fe 3 O 4 can be formed (He et al, 2003). Additionally, the process Fe 2+ →Fe 3+ +e -is an endothermic process and heating can accelerate oxidization of Fe 2+ into Fe 3+ , because the standard molar enthalpies of formation of Fe 2+ and Fe 3+ are −89.1 kJ mol -1 and −48.5 kJ mol -1 , respectively (Tremaine and Xiao, 1999). It was therefore necessary to keep relatively low temperature during the process of preparation of water-based ferromagnetic fluid.…”

Section: The Absolute Quantity and Relative Magneticmentioning

confidence: 99%

Preparation and characterization of magnetic resin made from chitosan and cerium

Wang

et al. 2010

J. Ocean Univ. China

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In this study, the water-based ferromagnetic fluid and magnetic resin made from chitosan and cerium complex (MRCCC) were successfully prepared by using the chemical co-precipitation technique and by the reversed-phase suspension cross-linking polymerization. MRCCC presented uniform and narrow particle size distribution as determined by the Laser Particles Sizer. The Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD) study demonstrated that there were iron and cerium existing in MRCCC. The movement of MRCCC under magnetic field proved its magnetic property. The swelling kinetics in water or solutions with different pH indicated that MRCCC could be applied in solutions with pH greater than 1.0. The ferromagnetic fluid particles were stable in MRCCC soaked in solutions with pH >2.0. In view of these results, MRCCC can be used as material for separation, clarification, adsorption, sustained release and hydrolysis activity.

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Enthalpies of formation and heat capacity functions for maricite,NaFePO4(cr), and sodium iron(III) hydroxy phosphate,Na3Fe(PO4)2· (Na4/3H2/3O)(cr)

Cited by 13 publications

References 15 publications

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

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

Thermodynamics of LiFePO₄ Solid-Phase Synthesis Using Iron(II) Oxalate and Ammonium Dihydrophosphate as Precursors

Preparation and characterization of magnetic resin made from chitosan and cerium

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Enthalpies of formation and heat capacity functions for maricite,NaFePO4(cr), and sodium iron(III) hydroxy phosphate,Na3Fe(PO4)2· (Na4/3H2/3O)(cr)

Cited by 13 publications

References 15 publications

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

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

Thermodynamics of LiFePO4 Solid-Phase Synthesis Using Iron(II) Oxalate and Ammonium Dihydrophosphate as Precursors

Preparation and characterization of magnetic resin made from chitosan and cerium

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Thermodynamics of LiFePO₄ Solid-Phase Synthesis Using Iron(II) Oxalate and Ammonium Dihydrophosphate as Precursors