Dresden 2014 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 14: Functional Materials III - Li ion batteries
MM 14.6: Vortrag
Montag, 31. März 2014, 17:00–17:15, IFW A
Effect of Ni-doping on structural, magnetic and electrochemical properties of LiMn1−xNixPO4 — •Alexander Ottmann1, Carsten Jähne1, Hans-Peter Meyer2, and Rüdiger Klingeler1 — 1Kirchhoff-Institute for Physics, University of Heidelberg, Germany — 2Institute of Earth Sciences, University of Heidelberg, Germany
Nanoscaled polycrystalline LiMn1−xNixPO4 with a doping level of x up to 0.45 has been synthesized via a microwave-assisted hydrothermal route. Characterization of the materials by means of X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and SQUID-magnetometry confirm well controlled Ni-doping in LiMnPO4. The data show solid solution behaviour with the lattice parameters linearly decreasing upon increasing the nickel concentration, corresponding to Vegard’s law. Concomitantly, the room temperature magnetization decreases which implies substitution of Mn2+ by Ni2+ in the LiMnPO4 host structure. Electrochemical characterization by means of cyclic voltammetry reveals an active Mn3+/Mn2+ redox couple. The redox potential depends on the nickel concentration in LiMn1−xNixPO4 and increases with x. Quantitatively, the reduction potential vs. lithium increases from 3.97 V in LiMnPO4 to 4.09 V in LiMn0.55Ni0.45PO4.