Silicate-phosphate interactions in silicate glasses and melts: I. A multinuclear ( 27 Al, 29 Si, 31 P) MAS NMR and ab initio chemical shielding ( 31 P) study of phosphorous speciation in silicate glasses

Cody, George D.; Mysen, Bjørn O.; Sághi-Szabó, G.; Tossell, J. A.

doi:10.1016/s0016-7037(01)00597-x

Cited by 92 publications

(62 citation statements)

References 29 publications

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“…3b͒ yields an isotropic 31 P peak at Ϫ10 ppm, consistent with a partial oxygen bridging to the Fe site. 12,13 The spectrum also shows a broad sideband manifold, with nearly identical asymmetry to that observed for 7 Li in LiMnPO 4 , implying that the asymmetry arises from the same fundamental mechanism. The similarity is made apparent in the comparison of spectra shown in Fig.…”

Section: Resultssupporting

confidence: 53%

[sup 7]Li and [sup 31]P Magic Angle Spinning Nuclear Magnetic Resonance of LiFePO[sub 4]-Type Materials

Tucker

Doeff

Richardson

et al. 2002

Electrochem. Solid-State Lett.

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LiFePO 4 and LiMnPO 4 have been characterized using 7 Li and 31 P magic angle spinning ͑MAS͒ nuclear magnetic resonance spectroscopy. LiFePO 4 was synthesized by a hydrothermal route and LiMnPO 4 was synthesized at high temperature in an inert atmosphere. Both compositions give rise to single isotropic 7 Li resonances. The MAS isotropic peak linewidth for LiFePO 4 is considerably larger than that for LiMnPO 4 , suggesting the presence of local disorder in the Li coordination sphere for LiFePO 4 . In both samples, the isotropic peak is accompanied by a large, asymmetric spinning sideband manifold, arising from bulk magnetic susceptibility broadening and the paramagnetic interaction between the lithium nucleus and transition metal unpaired electrons. Recent research has focused on the possibility of using LiFePO 4 as a positive electrode material in lithium rechargeable batteries, especially those intended for transportation applications. Since the first reports of reversible lithium deintercalation from LiFePO 4 , 1,2 several research groups have developed methods of enhancing the electrochemical behavior of this material. Improvements have included coating the LiFePO 4 particles with a conductive carbonaceous layer to enhance utilization, 3,4 preparing the materials at low temperature to promote high surface area and preclude the formation of oxidized Fe 3ϩ impurities, 5 and replacing some of the Fe with Mn to increase the operating voltage at the beginning of discharge.6 Fundamental studies of LiFePO 4 -related materials, however, have been limited; a few research groups have used Mössbauer spectroscopy 6,7 and extended X-ray absorption fine structure ͑EXAFS͒ 8 to determine structural features pertaining to the Fe/Mn site. Magic angle spinning nuclear magnetic resonance ͑MAS NMR͒ spectroscopy is a complementary technique which is very sensitive to the atomic and electronic environment at the lithium site. Successful application of the MAS NMR technique would allow direct observation of Li in the bulk of these interesting materials. NMR studies of electrode materials are, however, often obfuscated by the effects of electronic, ionic, and magnetic properties of these materials. These effects can even preclude quantitative study without the use of specialized NMR techniques. We describe in this paper the direct observation of 7 Li and 31 P MAS NMR in the end members of the Li͑Fe,Mn͒PO 4 series, LiFePO 4 and LiMnPO 4 . This work provides the basis for future detailed NMR studies of the Li͑Fe,Mn͒PO 4 system. We anticipate such studies will elucidate the relationship between local structure and electrochemical properties such as operating voltage, rate capability, and capacity retention. Understanding this relationship will promote rational design of improved olivine-type battery materials. ExperimentalA modification of the hydrothermal method described by Whittingham et al.5 was used to synthesize LiFePO 4 . A mixture of FeSO 4 •7H 2 O, H 3 PO 4 , and LiOH ͑mole ratios 1:1:3͒ dissolved in water was heated at 120°C i...

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Section: Resultssupporting

confidence: 53%

[sup 7]Li and [sup 31]P Magic Angle Spinning Nuclear Magnetic Resonance of LiFePO[sub 4]-Type Materials

Tucker

Doeff

Richardson

et al. 2002

Electrochem. Solid-State Lett.

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“…Toplis and Schaller [30] reported that 31 P MAS-NMR spectra of xNa 2 O-(1Àx)Al 2 O 3 -2SiO 2 -yP 2 O 5 glasses were separated into four peaks at 13, 7, 2 and À5 ppm, which were assigned to a PO 3À 4 tetrahedra with n Al = 0, 1 and 2 except for a peak at 2 ppm assigned to P 2 O 4À 7 . Cody et al [31] also reported a systematic study on a multinuclear MAS-NMR and ab initio calculation of the chemical shielding of 31 P to speciate phosphorus in a sodium alumino-silicate glass containing a constant composition of phosphorus at various Na/Al ratios. The peaks at À12 and À19 ppm were assigned to Na 2 PO 4 (SiR 3 )-(AlR 3 ) and Na 2 PO 4 (SiR 3 )(AlR 3 ) 2 , respectively, where R denoted that the cluster was linked to the silicate network.…”

Section: P Mas Nmr Spectramentioning

confidence: 99%

Structural characterization of ionomer glasses by multinuclear solid state MAS-NMR spectroscopy

Matsuya

Stamboulis

Hill

et al. 2007

Journal of Non-Crystalline Solids

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“…One advantage that solid state NMR spectroscopy has over other analytical methods is that it is element specific, i.e., one may apply NMR spectroscopy to explore perturbations to the electronic environment of target nuclei (e.g., 29 Si) by other elements that may also be "NMR active," (e.g., 1 H, 19 F, 23 Na, 27 Al, and 31 P). In many NMR studies of glasses, the multi-element spectroscopic approach has been employed (e.g., Dupree et al, 1989;Kohn et al, 1989b;Brow et al, 1990;Kümmerlen et al, 1992;Sato et al, 1992;Zheng et al, 1999;Cody et al, 2001;Robert et al, 2001) and provides for multiple spectroscopic "points-of-view" that greatly benefit interpretation of glass structure.…”

Section: Introductionmentioning

confidence: 99%

Structure vs. composition: A solid-state 1H and 29Si NMR study of quenched glasses along the Na2O-SiO2-H2O join

Cody

Mysen

Lee

2005

Geochimica et Cosmochimica Acta

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Silicate-phosphate interactions in silicate glasses and melts: I. A multinuclear ( 27 Al, 29 Si, 31 P) MAS NMR and ab initio chemical shielding ( 31 P) study of phosphorous speciation in silicate glasses

Cited by 92 publications

References 29 publications

[sup 7]Li and [sup 31]P Magic Angle Spinning Nuclear Magnetic Resonance of LiFePO[sub 4]-Type Materials

[sup 7]Li and [sup 31]P Magic Angle Spinning Nuclear Magnetic Resonance of LiFePO[sub 4]-Type Materials

Structural characterization of ionomer glasses by multinuclear solid state MAS-NMR spectroscopy

Structure vs. composition: A solid-state 1H and 29Si NMR study of quenched glasses along the Na2O-SiO2-H2O join

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