Structural Changes of LiMn2 O 4 Spinel Electrodes during Electrochemical Cycling

Structural changes of spinel electrodes have been investigated in cells by X‐ray diffraction during prolonged electrochemical cycling between 4.5 and 3.4 V at room temperature. The capacity fade that is observed during cycling is attributed, at least partly, to disproportionation reactions at the particle surface of discharged electrodes, resulting in a soluble MnO component. The disproportionation reactions are described with respect to the Li‐Mn‐O phase diagram. The data support recent reports tha can be formed at the electrode surface slighty above 3 V when cells are discharged and charged at high rates. © 1999 The Electrochemical Society. All rights reserved.