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EELS Spectroscopy of Iron Fluorides and FeFx/C Nanocomposite Electrodes Used in Li-Ion Batteries

Published online by Cambridge University Press:  15 February 2007

Frederic Cosandey
Affiliation:
Department of Materials Science and Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8065, USA
Jafar F. Al-Sharab
Affiliation:
Department of Materials Science and Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8065, USA
Fadwa Badway
Affiliation:
Department of Materials Science and Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8065, USA Energy Storage Research Group, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8065, USA
Glenn G. Amatucci
Affiliation:
Department of Materials Science and Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8065, USA Energy Storage Research Group, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8065, USA
Pierre Stadelmann
Affiliation:
Centre Interdepartemental de Microscopie Electronique, Ecole Polytechnique Federale de Lausanne, Switzerland
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Abstract

A new type of positive electrode for Li-ion batteries has been developed recently based on FeF3/C and FeF2/C nanocomposites. The microstructural and redox evolution during discharge and recharge processes was followed by electron energy loss spectroscopy (EELS) to determine the valence state of Fe by measuring the Fe L3 line energy shift and from Fe L3/L2 line intensity ratios. In addition, transition metal fluorides were found to be electron beam sensitive, and the effect of beam exposure on EELS spectra was also investigated. The EELS results indicate that for both FeF3/C and FeF2/C nanocomposite systems, a complete reduction of iron to FeO is observed upon discharge to 1.5 V with the formation of a finer FeO/LiF subnanocomposite (∼7 nm). Upon complete recharging to 4.5 V, EELS data reveal a reoxidation process to a Fe2+ state with the formation of a carbon metal fluoride nanocomposite related to the FeF2 structure.

Type
MATERIALS APPLICATIONS
Copyright
© 2007 Microscopy Society of America

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References

REFERENCES

Aken, P.A.V. & Liebscher, B. (2002). Quantification or ferrous/ferric ratios in minerals: New evaluation schemes of Fe L23 electron energy-loss near-edge spectra. Phys Chem Min 29, 188200.Google Scholar
Aken, P.A.V., Liebschen, B. & Styrsa, V.J. (1998). Quantitative determination of iron oxidation states in minerals using Fe L2,3-edge electron energy-loss near-edge spectroscopy. Phys Chem Min 25, 323327.Google Scholar
Amatucci, G.G., Tarascon, J.M. & Klein, L.C. (1996). CoO2, the end member of the LixCoO2 solid solution. J Electrochem Soc 143, 11141123.Google Scholar
Armstrong, A.R., Robertson, A.D. & Bruce, P.G. (1999). Structural transformation on cycling layered Li(Mn1−yCoy)O2 cathode materials. Electrochimica Acta 45, 285294.Google Scholar
Badway, F., Cosandey, F., Pereira, N. & Amatucci, G.G. (2003a). Carbon metal fluoride nanocomposites: High capacity reversible metal fluoride conversion materials as rechargeable positive electrodes for Li batteries. J Electrochem Soc 150, A1318A1327.Google Scholar
Badway, F., Pereira, N., Cosandey, F. & Amatucci, G.G. (2003b). Carbon metal fluoride nanocomposites: Structure and electrochemistry of FeF3:C. J Electrochem Soc 150, A1209A1218.Google Scholar
Botton, G.A., Appell, C.C., Horsewell, A. & Stobbs, W.M. (1995). Quantification of the EELS near-edge structure to study Mn doping in oxides. J Microsc 180, 211216.Google Scholar
Calvert, C.C., Brown, A. & Brydson, R. (2005). Determination of the local chemistry of iron in inorganic and organic materials. J Elect Spectrosc Rel Phen 143, 173187.Google Scholar
Chen, G.S., Boothroyd, C.B. & Humphreys, C.J. (1996). Electron-beam induced crystallization transition in self-developing amorphous AlF3 resists. Appl Phys Lett 69, 170172.Google Scholar
Chen, G.S. & Humphreys, C.J. (1997). Investigation of the proximity effect in amorphous AlF3 electron-beam resists. J Vac Sci Technol B 15, 19541960.Google Scholar
Colliex, C., Manoubi, T. & Ortiz, C. (1991). Electron-energy-loss-spectroscopy near-edge fine stuctures in the iron–oxygen system. Phys Rev B 44, 1140311411.Google Scholar
Cosandey, F., Al-Sharab, J., Badway, F. & Amatucci, G.G. (2004). HRTEM imaging and EELS spectroscopy of lithiation process in FeFx:C nanocomposites. Ceram Trans 161, 111119.Google Scholar
Egerton, R.F. (1996). Electron Energy-Loss Spectroscopy in the Electron Microscope. New York: Plenum Press.
Garvie, L.A.J. & Buseck, P.R. (1998). Ratios of ferrous to ferric iron from nanometer-sized areas in minerals. Nature 396, 667670.Google Scholar
Golla, U. & Putnis, A. (2001). Valence state mapping and quantitative electron spectroscopic imaging of exsolution in titanohematite by energy-filtered TEM. Phys Chem Min 28, 119129.Google Scholar
Golla-Schindler, U., Benner, G. & Putnis, A. (2003). Laterally resolved EELS for ELNES mapping Fe L2,3− and O K-edge. Ultramicroscopy 96, 573582.Google Scholar
Greneche, J.M., Bail, A.L., Leblanc, M., Mosset, A., Varret, F., Galy, J. & Ferey, G. (1988). Structural aspects of amorphous iron (III) fluorides. J Phys C 21, 13511361.Google Scholar
Jiang, N., Qiu, J. & Silcox, J. (2004). Effects of high-energy electron irradiation on heavy-metal flouride glass. J Appl Phys 96, 62306233.Google Scholar
Jiang, N. & Spence, J.C.H. (2006). Interpretation of oxygen K pre-edge peak in complex oxides. Ultramicroscopy 106, 215219.Google Scholar
Krishnan, K.M. (1990). Iron L3,2 near-edge fine structure studies. Ultramicroscopy 32, 309311.Google Scholar
Leapman, R.D., Grunes, L.A. & Fejes, P.L. (1982). Study of the L23 edges in the 3d transition metals and their oxides by electron-energy-loss spectroscopy with comparisons to theory. Phys Rev B 26, 614635.Google Scholar
Malac, M., Schoefield, M., Zhu, Y. & Egerton, R. (2002). Exposure characteristics of cobalt fluoride (CoF2) self-developing electron-beam resist on sub-100 nm scale. J Appl Phys 92, 11121121.Google Scholar
Mizushima, K., Jones, P.C., Wiseman, P.J. & Goodenough, J.B. (1980). LixCoO2: A new cathode material for bateries of high energy density. Mater Res Bull 15, 783789.Google Scholar
Padhi, A.K., Nanjundaswamy, K.S. & Goodenough, J.B. (1997). Phospho-olivine as positive-electrode materials in rechargeable lithium batteries. J Electrochem Soc 144, 11881194.Google Scholar
Paterson, J.H. & Krivanek, O.L. (1990). ELNES of 3d transition-metal oxides II. Variation with oxidation state and crystal structure. Ultramicroscopy 32, 319325.Google Scholar
Pearson, D.H., Fultz, B. & Ahn, C.C. (1988). Measurements of 3d state occupancy in transition metals using electron energy loss spectrometry. Appl Phys Lett 53, 14051407.Google Scholar
Plitz, I., Badway, F., Al-Sharab, J., Dupasquier, A., Cosandey, F. & Amatucci, G.G. (2005). Carbon metal fluoride nanocomposites: Structure and electrochemistry of carbon–metal fluoride nanocomposites fabricated by a solid state redox conversion reaction. J Electrochem Soc 152, A114A125.Google Scholar
Saifullah, M.S.M., Botton, G.A., Boothroyd, C.B. & Humphreys, C.J. (1999). Electron energy loss spectroscopy studies of the amorphous to crystalline transition in FeF3. J Appl Phys 86, 24992504.Google Scholar
Scheinfein, M. & Isaacson, M. (1986). Electronic and chemical analysis of fluoride interface structures at subnanometer spatial resolution. J Vac Sci Technol B 4, 326332.Google Scholar
Streblechenko, D. & Scheinfein, M.R. (1998). Magnetic nanostructures produced by electron beam patterning of direct write transition metal fluoride resists. J Vac Sci Technol A 16, 13741379.Google Scholar
Vinogradov, A.S., Fedoseenko, S.I., Krasnikov, A.B., Preobrajenski, A.B., Sivkov, V.N., Vyalikh, D.V., Molodstov, S.L., Adamchuk, V.K., Laubschat, C. & Kaindl, G. (2005). Low-lying unoccupied electronic states in 3d transition-metal fluorides probed by NEXAFS at the F 1s threshold. Phys Rev B 71, 045127/1045127/11.Google Scholar
Wang, F., Malac, M. & Egerton, R.F. (2006). Energy-loss near-edge fine structures of iron nanoparticles. Micron 37, 316323.Google Scholar
Wang, Z.L., Bentley, J. & Evans, N.D. (1999). Mapping the valence states of transition-metal elements using energy-filtered transmission electron microscopy. J Phys Chem B 103, 751753.Google Scholar