Bismuth Fluoride Nanocomposite as a Positive Electrode Material for Rechargeable Lithium Batteries

Abstract

The electrochemical activity of has been enabled in a nanocomposite prepared by high-energy milling. It has been demonstrated that a reversible conversion reaction occurs in the nanocomposite with the formation of Bi metal and LiF during lithiation and the reformation of during delithiation. When discharged at room temperature to at rates ranging from C/30 to C the nanocomposite exhibited a specific capacity of , which corresponds to 90% utilization of the active material. The composites retained a specific capacity of 65% of the theoretical capacity when the rate was elevated to 4C. Two polymorphs of were studied, a hexagonal P-3c1 high pressure form of Tysonite structure and the more common orthorhombic Pnma form isolated by an HF induced reaction. Both are shown to reconvert to the hexagonal P-3c1 structure after initial conversion.