THE ELECTROCHEMICAL STABILITY OF LITHIUM-METAL OXIDES AGAINST METAL REDUCTION

The possibility of metal reduction during the charging of secondary li thium batteries with LixMO2 cathodes is investigated. Loss of active m aterial due to metal reduction can be one of the causes of capacity de cay in these batteries after repeated charging. First principles metho ds are used to calculate the metal reduction potentials in layered Lix MO2 compounds where M = Ti, V, Mn, Fe, Co or Ni. It is found that, for several of these compositions, the metal ions may preferably reduce b efore the lithium ion during charging. (C) 1998 Elsevier Science B.V. All rights reserved.