Sol–gel processing and electrochemical characterization of monoclinic Li3FeF6

  • Georg Lieser
  • Melanie Schroeder
  • Holger Geßwein
  • Volker Winkler
  • Sven Glatthaar
  • Murat Yavuz
  • Joachim R. Binder
Original Paper


To find new cathode materials for future applications in lithium-ion batteries, lithium transition metal fluorides represent an interesting class of materials. In principle the Li intercalation voltage can be increased by replacing oxygen in the cathode host structure with the more electronegative fluorine. A facile pyrolytic sol–gel process with trifluoroacetic acid as fluorine source was established to synthesize monoclinic Li3FeF6 using nontoxic chemicals. The acicular Li3FeF6 powder was characterized with X-ray diffraction and a detailed structure model was calculated by Rietveld analysis. For the preparation of cathode films to cycle versus lithium monoclinic Li3FeF6 was ball milled with carbon and binder down to nanoscale. After 100 cycles galvanostatic cycling (C/20) 47 % fully reversible capacity of the initial capacity (129 mAh/g) could be retained. To the best of our knowledge the results presented in this work include the first rate performance test for monoclinic Li3FeF6 up to 1 C maintaining a capacity of 71 mAh/g. The redox reaction involving Fe3+/Fe2+ during Li insertion/extraction was confirmed by post-mortem XPS and cyclic voltammetry.


Sol–gel processing Trifluoroacetic acid Lithium-ion batteries Electrochemical performance Li3FeF6 Lithium transition metal fluoride Cathode material 



The authors thank the Helmholtz Association and the Helmholtz Initiative for funding the present work. This work was carried out with the support of the Karlsruhe Nano Micro Facility (KNMF), a Helmholtz Research Infrastructure at KIT. The authors thank Dr. Bergfeld (IAM-AWP, KIT) for the ICP measurements.

Conflict of interest

The authors declare no competing financial interest.

Supplementary material

10971_2014_3329_MOESM1_ESM.tif (754 kb)
As can be seen in the FTIR Spectra (Fig 12) the organic content of the pristine precursor is not fully pyrolysed at 275 °C. This organic content can be removed by washing with acetone or increasing the final reaction temperature up to 350 °C. (TIFF 753 kb)


  1. 1.
    Xu B, Qian D, Wang Z, Meng YS (2012) Recent progress in cathode materials research for advanced lithium ion batteries. Mater Sci Eng, R 73:51–65. doi: 10.1016/j.mser.2012.05.003 CrossRefGoogle Scholar
  2. 2.
    De Dompablo MEAY, Amador U, Tarascon J-M (2007) A computational investigation on fluorinated-polyanionic compounds as positive electrode for lithium batteries. J Power Sources 174:1251–1257. doi: 10.1016/j.jpowsour.2007.06.178 CrossRefGoogle Scholar
  3. 3.
    Okada S, Ueno M, Uebou Y, Yamaki J (2005) Fluoride phosphate Li2CoPO4F as a high-voltage cathode in Li-ion batteries. J Power Sources 146:565–569. doi: 10.1016/j.jpowsour.2005.03.149 CrossRefGoogle Scholar
  4. 4.
    Arai H, Okada S, Sakurai Y, Yamaki J (1997) Cathode performance and voltage estimation of metal trihalides. J Power Sources 68:716–719. doi: 10.1016/S0378-7753(96)02580-3 CrossRefGoogle Scholar
  5. 5.
    Amatucci GG, Pereira N, Badway F, Sina M, Cosandey F, Ruotolo M, Cao C (2011) Formation of lithium fluoride/metal nanocomposites for energy storage through solid state reduction of metal fluorides. J Fluor Chem 132:1086–1094. doi: 10.1016/j.jfluchem.2011.06.033 CrossRefGoogle Scholar
  6. 6.
    Amatucci GG, Pereira N (2007) Fluoride based electrode materials for advanced energy storage devices. J Fluor Chem 128:243–262. doi: 10.1016/j.jfluchem.2006.11.016 CrossRefGoogle Scholar
  7. 7.
    Žemva B, Chacon L, Lutar K, Shen C, Allman J, Bartlett N (1995) Syntheses and some properties of new nickel fluorides. J Fluor Chem 71:195–196. doi: 10.1016/0022-1139(94)06021-D CrossRefGoogle Scholar
  8. 8.
    Kohl J, Wiedemann D, Nakhal S, Bottke P, Ferro N, Bredow T, Kemnitz E, Wilkening M, Heitjans P, Lerch M (2012) Synthesis of ternary transition metal fluorides Li3MF6 via a sol–gel route as candidates for cathode materials in lithium-ion batteries. J Mater Chem 22:15819–15827. doi: 10.1039/c2jm32133e CrossRefGoogle Scholar
  9. 9.
    García Alvarado F, Kuhn A, Gonzalo M, Cándida E (2010) ES 2335854Google Scholar
  10. 10.
    Kimura A, Mikoshiba E (2010) U.S. 0248025Google Scholar
  11. 11.
    Schulz-Dobrick M, Lerch M, Ehrenberg H, Nakhal S, Koch J, Frieder S, Herklotz M (2011) U.S. 0227001Google Scholar
  12. 12.
    Okada S, Gocheva ID, Nishijima M, Takayuki D, Yamaki J (2009) JP 238687Google Scholar
  13. 13.
    Gocheva ID, Kamimura Y, Doi T, Okada S, Yamaki J, Nisihda T (2009) Direct synthesis of Cryolithe type Li3FeF6 and its charaterization as positive electrode in Li cell. Eng Sci Rep Kyushu Univ 31:7–11Google Scholar
  14. 14.
    Gonzalo E, Kuhn A, García-Alvarado F (2010) A comparative study of α- and β-Li3FeF6: structure and electrochemical behavior. J Electrochem Soc 157:A1002–A1006. doi: 10.1149/1.3454238 CrossRefGoogle Scholar
  15. 15.
    Kuhn A, Basa A, Gonzalo EC, Sobrados I, Sanz J (2011) Structure and electrochemical Li insertion properties of cryolite-type Li3FeF6 prepared by precipitation from aqueous-based solutions. Electrode Mater—Arcachon, Fr 5–6Google Scholar
  16. 16.
    Basa A, Gonzalo E, Kuhn A, García-Alvarado F (2012) Reaching the full capacity of the electrode material Li3FeF6 by decreasing the particle size to nanoscale. J Power Sources 197:260–266. doi: 10.1016/j.jpowsour.2011.09.048 CrossRefGoogle Scholar
  17. 17.
    Gonzalo E, Kuhn A, García-Alvarado F (2010) On the room temperature synthesis of monoclinic Li3FeF6: a new cathode material for rechargeable lithium batteries. J Power Sources 195:4990–4996. doi: 10.1016/j.jpowsour.2010.02.040 CrossRefGoogle Scholar
  18. 18.
    Basa A, Gonzalo E, Kuhn A, García-Alvarado F (2012) Facile synthesis of β-Li3VF6: a new electrochemically active lithium insertion material. J Power Sources 207:160–165. doi: 10.1016/j.jpowsour.2012.01.148 CrossRefGoogle Scholar
  19. 19.
    Gocheva ID, Doi T, Okada S, Yamaki J (2012) Electrochemcial properties of tritrutile-type Li2TiF6 as cathode active material in Li-ion batteries. Electrochemistry 5:471–474Google Scholar
  20. 20.
    Liao P, Li J, Dahn JR (2010) Lithium intercalation in LiFe2F6 and LiMgFeF6 disordered trirutile-type phases. J Electrochem Soc 157:A355–A361. doi: 10.1149/1.3294788 CrossRefGoogle Scholar
  21. 21.
    Liao P, Dunlap RA, Dahn JR (2010) In situ mössbauer effect study of lithium intercalation in LiFe2F6. J Electrochem Soc 157:A1080–A1084. doi: 10.1149/1.3473809 CrossRefGoogle Scholar
  22. 22.
    Baillie MJ, Brown DH, Moss KC, Sharp DWA (1968) Anhydrous metal trifluoroacetates. J Chem Soc A Inorganic, Phys Theor 3110–3114. doi:  10.1039/j19680003110
  23. 23.
    Dallenbach R, Tissot P (1981) Properties of molten alkali metal trifluoracetates. J Therm Anal 20:409–417. doi: 10.1007/BF01912890 CrossRefGoogle Scholar
  24. 24.
    Fujihara S, Ono S, Kishiki Y, Tada M, Kimura T (2000) Sol–gel synthesis of inorganic complex fluorides using trifluoroacetic acid. J Fluor Chem 105:65–70. doi: 10.1016/S0022-1139(00)00265-7 CrossRefGoogle Scholar
  25. 25.
    Fedorov PP, Luginina AA, Kuznetsov SV, Osiko VV (2011) Nanofluorides. J Fluor Chem 132:1012–1039. doi: 10.1016/j.jfluchem.2011.06.025 CrossRefGoogle Scholar
  26. 26.
    Du Y-P, Zhang Y-W, Sun L-D, Yan C-H (2009) Optically active uniform potassium and lithium rare earth fluoride nanocrystals derived from metal trifluroacetate precursors. Dalt Trans 8574–8581. doi:  10.1039/b909145a
  27. 27.
    Chalk SG, Miller JF (2006) Key challenges and recent progress in batteries, fuel cells, and hydrogen storage for clean energy systems. J Power Sources 159:73–80. doi: 10.1016/j.jpowsour.2006.04.058 CrossRefGoogle Scholar
  28. 28.
    Hammersley AP, Brown K, Burmeister W, Claustre L, Gonzalez A, McSweeney S, Mitchell E, Moy JP, Svensson SO, Thompson AW (1997) Calibration and application of an X-ray image intensifier/charge-coupled device detector for monochromatic macromolecular crystallography. J Synchrotron Radiat 4:67–77. doi: 10.1107/S0909049596015087 CrossRefGoogle Scholar
  29. 29.
    Fujihara S, Tada M, Kimura T (2000) Controlling factors for the conversion of trifluoroacetate sols into thin metal fluoride coatings. J Sol–Gel Sci Technol 19:311–314. doi: 10.1023/A:1008729531254 CrossRefGoogle Scholar
  30. 30.
    Mosiadz M, Juda KL, Hopkins SC, Soloducho J, Glowacki BA (2011) An in-depth in situ IR study of the thermal decomposition of barium trifluoroacetate hydrate. Thermochim Acta 513:33–37. doi: 10.1016/j.tca.2010.11.004 CrossRefGoogle Scholar
  31. 31.
    Kagarise RE (1957) Infrared spectrum of trifluoroacetic acid vapor. J Chem Phys 27:519–522. doi: 10.1063/1.1743760 CrossRefGoogle Scholar
  32. 32.
    Redington RL, Lin KC (1971) Infrared spectra of trifluoroacetic acid and trifluoroacetic anhydride. Spectrochim Acta Part A Mol Spectrosc 27:2445–2460. doi: 10.1016/0584-8539(71)80143-5 CrossRefGoogle Scholar
  33. 33.
    Jollie DM, Harrison PG (1997) An in situ IR study of the thermal decomposition of trifluoroacetic acid. J Chem Soc Perkin Trans 2:1571–1576. doi: 10.1039/a608233e CrossRefGoogle Scholar
  34. 34.
    Massa W (1980) Die Kristallstruktur von β-Li3VF6. Zeitschrift für Krist 153:201–210. doi: 10.1524/zkri.1980.153.3-4.201 CrossRefGoogle Scholar
  35. 35.
    Massa W, Rüdorff W (1971) Über alpha-und beta-Li3MeF6-Verbindungen.pdf. Zeitschrift für Naturforsch B 26:1216–1218Google Scholar
  36. 36.
    Schroeder M, Eames C, Tompsett DA, Lieser G, Islam MS, Islam MS (2013) LixFeF6 (x = 2, 3, 4) battery materials: structural, electronic and lithium diffusion properties. Phys Chem Chem Phys 15:20473–20479. doi: 10.1039/c3cp53606h CrossRefGoogle Scholar
  37. 37.
    Guo Y-G, Hu J-S, Wan L-J (2008) Nanostructured materials for electrochemical energy conversion and storage devices. Adv Mater 20:2878–2887. doi: 10.1002/adma.200800627 CrossRefGoogle Scholar
  38. 38.
    Park M, Zhang X, Chung M, Less GB, Marie A (2010) A review of conduction phenomena in Li-ion batteries. J Power Sources 195:7904–7929. doi: 10.1016/j.jpowsour.2010.06.060 CrossRefGoogle Scholar
  39. 39.
    Plitz I, Badway F, Al-Sharab J, DuPasquier A, Cosandey F, Amatucci GG (2005) Structure and electrochemistry of carbon-metal fluoride nanocomposites fabricated by solid-state redox conversion reaction. J Electrochem Soc 152:A307–A315. doi: 10.1149/1.1842035 CrossRefGoogle Scholar
  40. 40.
    Badway F, Pereira N, Cosandey F, Amatucci GG (2003) Carbon-metal fluoride nanocomposites. J Electrochem Soc 150:A1209–A1218. doi: 10.1149/1.1596162 CrossRefGoogle Scholar
  41. 41.
    Sides CR, Croce F, Young VY, Martin CR, Scrosati B (2005) A high-rate, nanocomposite lifepo4/carbon cathode. Electrochem Solid-State Lett 8:A484–A487. doi: 10.1149/1.1999916 CrossRefGoogle Scholar
  42. 42.
    Rahner D, Machill S, Schlörb H, Siury K, Kloss M, Plieth W (1998) Intercalation materials for lithium rechargeable batteries. J Solid State Electrochem 2:78–84. doi: 10.1007/s100080050068 CrossRefGoogle Scholar
  43. 43.
    West WC, Soler J, Smart MC, Ratnakumar BV, Firdosy S, Ravi V, Anderson MS, Hrbacek J, Lee ES, Manthiram A (2011) Electrochemical behavior of layered solid solution Li2MnO3 − LiMO2 (M = Ni, Mn, Co) Li-Ion cathodes with and without alumina coatings. J Electrochem Soc 158:A883–A889. doi: 10.1149/1.3597319 CrossRefGoogle Scholar
  44. 44.
    Grosvenor AP, Kobe BA, Biesinger MC, McIntyre NS (2004) Investigation of multiplet splitting of Fe 2p XPS spectra and bonding in iron compounds. Surf Interface Anal 36:1564–1574. doi: 10.1002/sia.1984 CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  • Georg Lieser
    • 1
  • Melanie Schroeder
    • 4
  • Holger Geßwein
    • 1
    • 3
  • Volker Winkler
    • 1
    • 2
  • Sven Glatthaar
    • 1
  • Murat Yavuz
    • 2
    • 3
  • Joachim R. Binder
    • 1
  1. 1.Institute for Applied Materials (IAM-WPT)Karlsruhe Institute of TechnologyEggenstein-LeopoldshafenGermany
  2. 2.Institute for Applied Materials (IAM-ESS)Karlsruhe Institute of TechnologyEggenstein-LeopoldshafenGermany
  3. 3.Electrochemical Energy StorageHelmholtz Institute UlmUlmGermany
  4. 4.MEET Battery Research CentreUniveristy of MünsterMünsterGermany

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