Si/iron silicide nanocomposite anodes with furfuryl-alcohol-derived carbon coating for Li-ion batteries

Abstract

A new type of carbon-coated Si/iron silicide nanocomposite anode material for lithium ion batteries is made employing furfuryl alcohol as a carbon precursor. A wet coating technique is applied to cover the surface of ball-milled ferrosilicon powders with polyfurfuryl alcohol resin derived from furfuryl alcohol. To optimize the electrochemical performance of this anode material, the carbonization heat treatment temperature is systematically varied between 600 and 1000 A degrees C. The effects of the carbonization temperature on the physical properties of the carbon-coated nanocomposites, such as the specific surface area and phase composition, and on the electrochemical performance characteristics, such as the initial discharge/charge capacity and capacity retention ratio of coin half-cells made with these nanocomposite anodes, are investigated. The electrochemical performance of the anode during cycling is found to depend strongly on the characteristics of the carbon coating layer, which is significantly affected by the carbonization temperature. An initial discharge capacity of 720 mAh g(-1) and a capacity retention of 75% after 300 cycles at 1 C are obtained from the coin half-cell made with the Si/iron silicide nanocomposite carbonized at 1000 A degrees C.