New Fluoride Cathodes for Rechargeable Lithium Batteries

Abstract

We predict battery voltages close to 6 V when or are used as cathode materials based on our first principles band‐structure calculations. Although these fluorides use the same redox reaction as that of , i.e., , the fluorides are expected to show approximately 2 V greater voltages. This may be simply explained by the greater electronegativity of fluorine than oxygen; thereby the redox potential of can be better utilized. Theoretical volume changes associated with the delithiation of these fluorides are estimated to be +0.4 and −2.5%, which may be advantageous in achieving a long cycle lifetime. A series of fluorides, with and ions, can be expected to show similar voltages. Thus the materials can be optimized according to other properties such as lithium mobility. © 2000 The Electrochemical Society. All rights reserved.