New Anode Material Based\non SiO–Sn_<i>x</i>Co_<i>y</i>C_<i>z</i> for Lithium Batteries

Abstract

A new family of composite materials as anode for lithium-ion\nbatteries,\nMO-Sn_<i>x</i>Co_<i>y</i>C_<i>z</i> (<i>x</i>:<i>y</i>:<i>z</i> molar ratio), was synthesized by custom-made ultrahigh\nenergy ball milling (UHEM) and conventional SPEX ball milling methods.\nIn the past, alloys such as SnCoC and metal oxides such as SiO, SnO₂, MoO₃, etc., have been studied extensively because\nof their long cycle life and/or high capacity. The composite metal\noxide-SnCoC combines both of these advantages. In this work, we took\n50 wt % SiO–50 wt % Sn₃₀Co₃₀C₄₀ as an example, and found that ultrahigh energy ball mill offers\nmore nanoparticles and higher capacity compared with conventional\nmilling. High-energy X-ray diffraction indicates the presence of CoSn₂ and Co Bragg phases and highly distorted phases in the mixture.\nExtended X-ray absorption fine structure analysis reveals a tremendous\ndifference between UHEM and SPEX samples. The pair distribution function\nshows the local structure and indicates that SiO and SnCoC are not\nonly a physical mixture, but have reacted chemically. Full-cell testing\nestablished the feasibility of the composite as an anode material\nfor high-energy, long-life Li-ion batteries. These results demonstrate\nthat the nanostructured SiO–Sn₃₀Co₃₀C₄₀ composite is a promising anode material for practical applications.