Lithiation Mechanism of Methylated Amorphous Silicon Unveiled by Operando ATR‐FTIR Spectroscopy |
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Authors: | Bon Min Koo Jean‐Noël Chazalviel Fouad Maroun Michel Rosso François Ozanam |
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Affiliation: | Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, Université Paris‐Saclay, Palaiseau, France |
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Abstract: | The lithiation mechanism of methylated amorphous silicon, a‐Si1?x(CH3)x:H, with various methyl contents (x = 0 ‐ 0.12) is investigated using operando attenuated total reflection Fourier transform infrared spectroscopy. As in hydrogenated amorphous silicon, a‐Si:H, the first lithiation proceeds via a two‐phase mechanism. The concentration of the invading Li‐rich phase nonmonotonously depends on the methyl content of the active material. This behavior is tentatively explained by two distinct effects: a softening of the material due to a methyl‐induced lowering of its reticulation degree and its cohesion, and the presence of nanovoids at high enough methyl content. |
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Keywords: | amorphous silicon Li‐ion batteries lithiation mechanisms operando ATR‐FTIR silicon anodes |
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