Silicon-Doped LiFePO4Single Crystals: Growth, Conductivity Behavior, and Diffusivity
| Autor: | Tolga Acartürk, Ulrich Starke, Katja Weichert, Ruhul Amin, Chengtian Lin, Jubo Peng, Joachim Maier |
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| Rok vydání: | 2009 |
| Předmět: |
Materials science
Silicon Doping Analytical chemistry chemistry.chemical_element Ionic bonding Conductivity Condensed Matter Physics Thermal diffusivity Electronic Optical and Magnetic Materials law.invention Dielectric spectroscopy Biomaterials chemistry law Electrochemistry Ionic conductivity Electron paramagnetic resonance |
| Zdroj: | Advanced Functional Materials. 19:1697-1704 |
| ISSN: | 1616-3028 1616-301X |
| DOI: | 10.1002/adfm.200801604 |
| Popis: | Single crystals of silicon doped LiFeP0 4 with a silicon content of 1% are grown successfully by the floating zone technique and characterized by single-crystal and powder X-ray diffraction, secondary ion mass spectroscopy, and chemical analysis. Electron paramagnetic resonance demonstrates the presence of only Fe 2+ ; no traces of Fe 3+ are found. Impedance spectroscopy as well as step-function polarization/depolarization (DC) measurements are carried out using the cells Ti/LiFe(Si)P04/ Ti and LiAl/Lil/LiFe(Si)PO 4 /Lil/LiAl. The electronic and ionic conductivities as well as the Li-diffusivity of the sample in the major crystallographic directions ([h00], [0k0], and [00l]) are determined. Within experimental error the transport properties along the band c-axes are found to be the same but differ significantly from the a-axis, which exhibits lower values. Compared to undoped LiFeP0 4 , Si-doping leads to an increase of the ionic conductivity while the electronic conductivity decreases, which is in agreement with a donor effect. The activation energies of conductivities and diffusivities are interpreted in terms of defect chemistry and relevant Brouwer diagrams are given. |
| Databáze: | OpenAIRE |
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