Improved cycling performances of binder-free macroporous silicon Li-ion negative electrodes using room temperature ionic liquid electrolyte
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The present article describes the innovative combination of freestanding macroporous silicon layers on copper foil collectors and room temperature ionic, liquid 1-propyl-1-methylpyrrolidinium bis(trifluosulfonyl)imide (Pyr13 FSI)-containing electrolyte (Pyr13 FSI mixed with 1 M LiTFSI) to produce highly stable negative electrodes for Li-ion batteries. A 20-μm-thick macroporous silicon layer was synthesized by anodization in hydrofluoric acid (HF)-based electrolyte followed by the deposition of a thick and mechanically stable copper layer acting as current collector. After peeling-off the parent substrate, the freestanding macroporous silicon layer was characterized as a negative electrode in a half-cell configuration. The electrode performances were determined under constant charge conditions (500, 750, and 1000 mA h g−1) and exhibited significantly higher stability for over 1800 charge and discharge cycles in 1 M LiTFSI dissolved in Pyr13 FSI.
KeywordsElectrochemical etching Freestanding macroporous silicon layers Negative electrode Lithium-ion batteries Room temperature ionic liquids
This study was supported by the Region Centre through the consecutive “BLaDES” and “μBaGS” projects.
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