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Influence of the anode graphite particle size on the SEI film formation in lithium-ion cells

 
: Reinke, Christian; Nikolowski, Kristian; Wolter, Mareike; Michaelis, Alexander

:

Kanoun, O.:
Progress Reports on Impedance Spectroscopy : Measurements, Modeling, and Application
Berlin: De Gruyter, 2017
ISBN: 978-3-11-044983-9
ISBN: 978-3-11-044756-9
ISBN: 978-3-11-044982-2
ISBN: 978-3-11-044767-5
S.35-43
Englisch
Aufsatz in Buch
Fraunhofer IKTS ()
electrochemical impedance spectroscopy; lithium-ion cell; SEI formation

Abstract
Electrochemical impedance spectroscopy (EIS) is used as a tool to investigate the formation process of a lithium-ion cell. The usability of EIS was demonstrated for two anode active materials with different particle sizes. The initial charging of the cell was interrupted when a defined anode-half cell potential (vs. Li/Li+) was reached, in order to measure an impedance spectrum. This was fitted with a common equivalent circuit model and the SEI film resistance (RSEI) was extracted. Results show that for both active materials RSEI initially increases until an anode half-cell potential of approximately 0.2 V is reached. Subsequently the RSEI shows a sharp decline for both active materials. The SEI film resistance is significantly higher for smaller particles, indicating that a less conductive SEI is built on smaller particles during formation.

: http://publica.fraunhofer.de/dokumente/N-462144.html