Combining XAS with XRD for elucidating the complex structural behavior of pre-lithiated SnO anode materials for Lithium-ion batteries

Tin-based oxides anode materials have been widely studied to aim at higher performance for next-generation lithium-ion batteries (LIBs) due to the high theoretical specific capacity of Sn (reaching 994 mAh.g−1). However, the volume variation of Sn/LixSn transformation changes during the lithiation prevents a common application of these materials in nowadays used batteries. To understand the lithiation pathways, in this work, the degree of pre-lithiation of tin-base anode materials was investigated via combined X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) techniques. The experimental results confirm the formation of LiSn, Li7Sn3, Li5Sn2, Li13Sn5, Li7Sn2, and Li22Sn5 phases. The degree of pre-lithiation plays a critical role in determining the electrochemical characteristics of LixSn alloy. This work provided useful and new insights in the future development of advanced anode materials for LIBs.