O[sub 2]-Type Li[sub 2/3][Ni[sub 1/3]Mn[sub 2/3]]O[sub 2]: A New Layered Cathode Material for Rechargeable Lithium Batteries II. Structure, Composition, and Properties

is prepared from the corresponding by ion exchange. This work investigates the correlation between structure, composition, and electrochemical properties. Crystalline is a layered oxide with the T2 structure. Small deviations from the stoichiometry cause less ordered samples showing T2‐O2 intergrowth structures. Larger deviations or doping with 15% Co lead to stacking‐faulted O2 structures instead of T2. Best electrochemical results are obtained if the sample has a slightly disordered T2 structure. The electrochemical properties of are compared to those of related phases with the alternative O3 structure. Only O2‐type can be cycled with little loss of capacity as a function of cycle number. © 2000 The Electrochemical Society. All rights reserved.