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. •Initial Coulombic efficiency (ICE) of SnO is improved from 57.58% to 96.74% by a simple pre-lithiation method.•The complex behaviors of pre-lithiated SnO materials are elucidated by combining XAS with XRD.•The degree of pre-lithiation can alter the electrochemical performance of LixSn materials.