Sn@SnOx/C nanocomposites prepared by oxygen plasma-assisted milling as cyclic durable anodes for lithium ion batteries

An advanced tin oxide-coated tin in graphite (Sn@SnOx/C) nanocomposite is synthesized with a one-step method of dielectric barrier discharge oxygen plasma-assisted milling (O2-P-milling). Synergetic effects of rapid plasma heating and impact stress act on the tin/graphite powder during O2-P-milling, and SnOx (1 ≤ x ≤ 2) is generated in situ on the Sn surface from the reaction between Sn and oxygen. The resulting composite possesses a unique microstructure, where Sn nanoparticles coated by an ultrathin amorphous/nanocrystalline SnOx layer are homogeneously embedded within a graphite matrix. As lithium ion anodes, the Sn@SnOx/C nanocomposites display superior electrochemical performance to Sn-C and Sn-SnO2-C nanocomposites milled under argon plasma. The SnOx/C nanocomposite obtained after O2-P-milling for 25 h that contains a high content of amorphous/nanocrystalline SnOx exhibits a high capacity retention of 500 mA h g−1 at 250 mA g−1 after 70 cycles, indicating that O2-P-milling is a promising method to prepare Sn-based multiphase nanocomposite anode materials.