Regensburg 2010 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 26: Poster Session
MM 26.37: Poster
Dienstag, 23. März 2010, 14:45–16:30, Poster C
Nanocrystalline LiFePO4 Prepared by Mechanochemical Route — •Vladimir Šepelák1, Sylvio Indris1, Klaus Dieter Becker2, Wolfgang Bensch3, and Paul Heitjans4 — 1Karlsruhe Institute of Technology, Karlsruhe, Germany — 2Braunschweig University of Technology, Braunschweig, Germany — 3Christian-Albrechts-University Kiel, Kiel, Germany — 4Leibniz University Hannover, Hannover, Germany
Among the typical Li ion battery cathode materials, LiFePO4 of the phospho-olivine family is particularly interesting due to its high power density, low cost, and environmental compatibility. Taking into account a nonequilibrium state of complex oxides prepared by mechanochemical methods [1], an enhanced electrochemical performance may be anticipated in such ’interface-controlled’ materials.
In the present work, nanocrystalline LiFePO4 with an average particle size of about 10 nm was prepared via far-from-equilibrium mechanochemical processing of the bulk LiFePO4. HR-TEM studies revealed a nonuniform structure of LiFePO4 nanoparticles consisting of an ordered core surrounded by a disordered surface shell/interface region. A comparative 57Fe Mössbauer spectroscopic study of bulk and nanocrystalline LiFePO4 revealed that the near-surface layers of phosphate nanoparticles are disordered due to the strongly distorted geometry of the FeO6 octahedra. Quantitative information on hyperfine parameters of the nonequilibrium LiFePO4 nanophase is obtained.
The work is supported by the DFG (SPP 1415).
[1] V. Šepelák et al., Chem. Mater. 21 (2009) 2518.