Improved cycling performances of binder-free macroporous silicon Li-ion negative electrodes using room temperature ionic liquid electrolyte
Résumé
The present article describes the innovative combination of freestanding macroporous silicon layers on copper foil collectors androom temperature ionic, liquid1-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-thickmacroporous silicon layer was synthesized by anodization in hydrofluoric acid (HF)-based electrolyte followed by the depositionof a thick and mechanically stable copper layer acting as current collector. After peeling-off the parent substrate, the freestandingmacroporous silicon layer was characterized as a negative electrode in a half-cell configuration. The electrode performances weredetermined under constant charge conditions (500, 750, and 1000 mA h g−1) and exhibited significantly higher stability for over1800 charge and discharge cycles in 1 M LiTFSI dissolved inPyr13 FSI.