FIRST-PRINCIPLES PREDICTION OF VOLTAGES OF LITHIATED OXIDES FOR LITHIUM-ION BATTERIES

The average intercalation voltages (AIV) of cathode materials for rech argeable lithium-ion batteries are calculated from first principles us ing the LAPW method for both trigonal layered (LiMO2) and cubic spinel (LiM2O4) structures. All calculated AIV are in good agreement with co rresponding plateaus of measured open circuit voltages. It is shown th at the AIV is directly related to the change of bonding occurring upon the intercalation of lithium. With increasing atomic number of the tr ansition metal up to Co the increase of the AIV is caused by the incre ase in Li-O stabilizing interaction, which in turn is induced by incre asing covalency of M-O bonding. The AIV is demonstrated not to depend on the structure but only on the oxidation state of the transition met al. (C) 1998 Elsevier Science B.V. All rights reserved.