Stabilized cycling performance of silicon oxide anode in ionic liquid electrolyte for rechargeable lithium batteries

Abstract

Control of electrode–electrolyte interfacial stability and the composition of the solid electrolyte interphase (SEI) layer is a promising approach for improved cycling performance of silicon-based anode material for rechargeable lithium batteries. Here we demonstrate that a room temperature ionic liquid electrolyte effectively passivates the surface of the SiO_1.3 electrode and significantly enhances cycling ability in contrast to the commercial liquid electrolyte. The SiO_1.3 electrode, prepared by pulsed laser deposition, showed 88% capacity retention in the ionic liquid electrolyte of 1 M LiTFSI/Py₁₃TFSI delivering 1058–930 mA h g⁻¹ over 200 cycles. Results from infrared and X-ray photoelectron spectroscopic analyses suggest that the presence of organic SEI compounds consisting of the pyrrolidinium cation and TFSI anion and their decomposition products on the oxygen-abundant SiO_1.3 surface confers interfacial stability and cycling stability.