Abstract
The solid solution series Li[CrxLi(1/3−x/3)Mn(2/3−2x/3)]O2Li[CrxLi(1/3−x/3)Mn(2/3−2x/3)]O2 (0<x<1)(0Li[Co]O2,Li[Co]O2, except with their transition metal layers composed of [CrxLi(1/3−x/3)Mn(2/3−2x/3)].[CrxLi(1/3−x/3)Mn(2/3−2x/3)]. We believe the oxidation states of the elements in the transition metal layer are Li+,Li+, Cr3+,Cr3+, and Mn4+.Mn4+. Li/Li[CrxLi(1/3−x/3)Mn(2/3−2x/3)]O2Li/Li[CrxLi(1/3−x/3)Mn(2/3−2x/3)]O2 electrochemical cells were made to study the changes in voltage profiles with composition, x. The cell with x=1/3x=1/3 delivers a reversible capacity of about 130 mAh/g between 2.0 and 4.35 V vs. Li/Li+. Between 2.0 and 4.8 V, the cell with x=1/6x=1/6 delivers a reversible capacity of about 230 mAh/g via a partial loss of oxygen during the first charge process. All the Li[CrxLi(1/3−x/3)Mn(2/3−2x/3)]O2Li[CrxLi(1/3−x/3)Mn(2/3−2x/3)]O2 samples have very large irreversible capacities during the first cycle. © 2002 The Electrochemical Society. All rights reserved.