Berlin 2012 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 17: Poster Session

MM 17.55: Poster

Montag, 26. März 2012, 17:00–19:00, Poster B

In-situ observation of structural changes accompanying lithium intercalation in silicon TEM lamellas — •Timo Wuttke, Burkhard Roos, Carsten Nowak, and Cynthia Volkert — Georg-August-Universität Göttingen, Institut für Materialphysik

In-situ studies of electrochemically driven lithiation and delithiation of materials for lithium-ion-batteries promise an improved understanding of the underlying intercalation mechanisms. We report the construction of a miniature lithium-ion-battery inside a transmission electron microscope using a STM-TEM holder. The cathode consists of a LiMn₂O₄-particle, while a silicon TEM lamella is used as anode. A liquid electrolyte ensures a high ionic conductivity between both components. It is based on an organic conducting salt dissolved in an organic ionic liquid and has a very small vapor pressure, enabling its use in the high vacuum of a TEM.

Crystalline silicon experiences several phase transitions with increasing amount of lithium and is amorphous once fully lithiated. Structural changes of both cathode and anode during lithiation are studied. Current-voltage characteristics, volume expansion and amorphization during lithiation are discussed.