caa a22 4500 463217233 CHVBK 20180405153200.0 cr unu---uuuuu 170326e20070901xx s 000 0 eng 10.1007/s00269-007-0164-8 doi (NATIONALLICENCE)springer-10.1007/s00269-007-0164-8 Mineralogy, Mössbauer spectra and electrical conductivity of triphylite Li(Fe2+,Mn2+) PO4 [Elektronische Daten] [K. Fehr, R. Hochleitner, E. Schmidbauer, J. Schneider] The electrical conductivity of monocrystalline triphylite, Li(Fe2+,Mn2+)PO4, with the orthorhombic olivine-type structure was measured parallel (∥) to the [010] direction and ∥ [001] (space group Pnma), between ∼400 and ∼700K. Electrical measurements on triphylite are of technological interest because LiFePO4 is a promising electrode material for rechargeable Li batteries. Triphylite was examined by electron microprobe, ICP atomic emission spectroscopy, X-ray diffraction, Mössbauer spectroscopy and microscopic analysis. The DC conductivity σDC was determined from AC impedance data (20Hz-1MHz) extrapolating to zero frequency. Triphylite shows σDC with activated behavior measured ∥ [010] between ∼500 and ∼700K during the first heating up, with activation energy of E A = 1.52eV; on cooling E A = 0.61eV was found down to ∼400K and extrapolated σDC (295K) ∼10−9Ω−1cm−1; ∥ [001] E A = 0.65eV and extrapolated σDC(295K) ∼10−9 to 10−10 Ω−1cm−1, measured during the second heating cycle. The enhanced AC conductivity relative to σDC at lower temperatures indicates a hopping-type charge transport between localized levels. Conduction during the first heating up is ascribed to ionic Li+ hopping. DC polarization experiments showed conduction after the first heating up to be electronic related to lowered activation energy. Electronic conduction appears to be coupled with the presence of Li+ vacancies and Fe3+, formed by triphylite alteration. For comparison, σDC was measured on the synthetic compound LiMgPO4 with olivine-type structure, where also an activated behavior of σDC with E A ∼1.45eV was observed during heating and cooling due to ionic Li+ conduction; here no oxidation can occur associated with formation of trivalent cations. Springer-Verlag, 2007 Triphylite nationallicence Impedance spectroscopy nationallicence Ionic and electronic conduction nationallicence 57Fe Mössbauer spectra nationallicence Fehr K. Department für Geo- und Umweltwissenschaften, Sektion Mineralogie, Petrologie und Geochemie, Universität München, Theresienstr 41, 80333, München, Germany aut Hochleitner R. Mineralogische Staatssammlung, Theresienstr 41, 80333, München, Germany aut Schmidbauer E. Department für Geo- und Umweltwissenschaften, Sektion Geophysik, Universität München, Theresienstr 41, 80333, München, Germany aut Schneider J. Department für Geo- und Umweltwissenschaften, Sektion Kristallographie, Universität München, Theresienstr 41, 80333, München, Germany aut Physics and Chemistry of Minerals Springer-Verlag 34/7(2007-09-01), 485-494 0342-1791 34:7<485 2007 34 269 https://doi.org/10.1007/s00269-007-0164-8 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00269-007-0164-8 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Fehr K. Department für Geo- und Umweltwissenschaften, Sektion Mineralogie, Petrologie und Geochemie, Universität München, Theresienstr 41, 80333, München, Germany aut NATIONALLICENCE 700 1- Hochleitner R. Mineralogische Staatssammlung, Theresienstr 41, 80333, München, Germany aut NATIONALLICENCE 700 1- Schmidbauer E. Department für Geo- und Umweltwissenschaften, Sektion Geophysik, Universität München, Theresienstr 41, 80333, München, Germany aut NATIONALLICENCE 700 1- Schneider J. Department für Geo- und Umweltwissenschaften, Sektion Kristallographie, Universität München, Theresienstr 41, 80333, München, Germany aut NATIONALLICENCE 773 0- Physics and Chemistry of Minerals Springer-Verlag 34/7(2007-09-01), 485-494 0342-1791 34:7<485 2007 34 269 Metadata rights reserved Springer special CC-BY-NC licence nationallicence SWISSBIB 454437587 BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer