O2 Structure Li[sub 2/3][Ni[sub 1/3]Mn[sub 2/3]]O[sub 2]: A New Layered Cathode Material for Rechargeable Lithium Batteries III. Ion Exchange

The ion exchange of Li for Na in P2‐structure to make T2‐structure is studied. Electron micrographs show that the hexagonal plate‐like crystal habit is preserved during ion exchange. Ion exchange is successful and equivalent using both molten salts and concentrated aqueous solutions. By controlling the Li:Na ratio in the ion exchange, it is possible to prepare an intermediate phase of approximate composition , where filled alkali layers of Li and Na alternate, thus doubling the c axis of the material. A summary of ion‐exchange reactions of Li for Na in other layered Na‐bronzes, such as , , , , , , , , , and , is given. © 2000 The Electrochemical Society. All rights reserved.