Disproportionated Tin Oxide and Its Nanocomposite for High-Performance Lithium-Ion Battery Anodes

Abstract

We exploited the unstable characteristics of solid SnO at all temperatures to develop a simple, fast, inexpensive, and scalable method based on high-energy ball milling to transform SnO into a disproportionated nanocomposite that consists of amorphized Sn and nanocrystalline SnO2. In the first step of this process, nanostructured disproportionated SnO (d-SnO) made up of nanosized Sn and SnO2 crystallites is produced by ball milling pure SnO powder. The electrochemical performance of the d-SnO is then enhanced by creating a d-SnO/C nanocomposite through additional ball milling. This d-SnO/C nanocomposite was analyzed by various techniques, such as XRD, high-resolution transmission electron microscopy, and extended X-ray absorption fine structure analysis, and consists of amorphized Sn (approximate to sub-3nm) and nanocrystalline SnO2 (approximate to 5-15nm) within an amorphous carbon matrix. This structure produces excellent electrochemical performances with a high initial energy density (first charge: 892 mAhg(-1) or 1436 mAhcm(-3)), a relatively good initial Coulombic efficiency (approximate to 73%), long cycling stability (above 642 mAhg(-1) or 1034 mAhcm(-3) over 300 cycles), and a fast rate capability (3C: 585 mAhg(-1) or 942 mAhcm(-3)). Based on these results, we believe that d-SnO/C nanocomposite electrodes have the potential to create a new area of research in the field of high-performance Li-alloy-based anode materials.