Regensburg 2010 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 49: Topical Session Battery Materials I

MM 49.3: Vortrag

Donnerstag, 25. März 2010, 11:15–11:30, H6

Determination of the lithium diffusion coefficient in novel anode materials based on graphite/SiCN composites — •Andrzej P. Nowak, Magdalena Graczyk-Zajac, Claudia Fasel, and Ralf Riedel — Institute of Materials Science, Darmstadt University of Technology, Petersenstr. 23, 64287 Darmstadt, Germany

Commercially available anode materials for lithium ion secondary batteries are based on graphite due to its cycle stability, low price, easy to handle and reversible capacity of 372 mAh/g. This type of anode material is suitable for high energy application. However, there is still a need for new materials for high power applications. Here, we report on novel graphite/SiCN composite materials which exhibit promising electrochemical performances for high energy and high power density batteries. For high energy application the ratio graphite to preceramic polymer is 3:1 and the capacity reaches a value of 600 mAh/g. For high power application the starting materials ratio is 1:1 and the capacity after 200 cycles has been determined to be about 200 mAh/g. The correlation between electrode capacity and the graphite/SiCN ratio, the pyrolysis temperature and materials composition has been established. The relation between these parameters as well as the lithium diffusion coefficient in the novel electrode materials was calculated from the results obtained from EIS, CV and GITT studies. The direct dependence between the lithium diffusion coefficient and the materials electrochemical properties is discussed.