Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 17: Poster Session
MM 17.18: Poster
Montag, 26. März 2012, 17:00–19:00, Poster B
Synthesis and electrochemical properties of tailored LiMPO4 (M= Mn, Co) — •Christoph Neef, Carsten Jähne, and Rüdiger Klingeler — Kirchhoff Institut für Physik, Universität Heidelberg, Germany
Due to their high stability and theoretical capacity, transition-metal olivine phosphates offer a large potential for application as positive electrodes in Li-Ion batteries. Among LiFePO4, which is already used in high power cells, LiMnPO4 and LiCoPO4 are interesting compounds because of their high open cell voltage vs. Lithium of 3.9V and 4.6V respectively. Here we report on the microwave assisted hydrothermal synthesis of LiMnPO4 and LiCoPO4 and their electrochemical characterisation by means of cyclic voltammetry and impedance spectroscopy. Variation of synthesis parameters as well as wet ball milling are used for size and shape tayloring of the particles. PEIS is used to study the morphology influence on high and low frequency impedance and thus on charge transfer resistances, ion diffusion and double layer capacitances. We found that size reduction of particles increases the electrochemical performance, however the extensive application of ball milling may cause a loss of crystal structure and thus reduces the ability of lithium intercalation / deintercalation.