Li2MO3 (M: transition metal), which has a similar layer structure to LiCoO2
, is interesting for use as another layered rocksalt-type oxide cathode for
Li-ion batteries. We found that Li2PtO3 in Li2MO3 system is the first full
4 V class cathode material among 5d metal compounds. We investigated the e
lectrochemical, structural and kinetic characteristics of the 4 V region. T
he volumetric capacity of the 4 V plateau on discharge is comparable to tha
t of LiCoO2. Moreover, the reversibility of the structural change in the 4
V region was confirmed by X-ray diffractometry. (C) 1999 Elsevier Science S
.A. All rights reserved.