Abstract
High‐resolution electron microscopy of electrochemically cycled 
and 
shows that both the orthorhombic and monoclinic (layered) polymorphs form antiphase domain microstructures of 
size upon transforming to cubic spinel. During the subsequent cubic → tetragonal transformation, the antiphase domains become ferroelastic domains that are able to accommodate the large Jahn‐Teller induced strain. Electron diffraction patterns show that much cubic spinel is retained at high overall lithiation. A partially inverse structure with some 
occupying 
tetrahedral sites is likely. These features of the transformed spinels provide for improved capacity retention upon cycling compared to conventional 
. ©1999 The Electrochemical Society