Phase Separation Tendencies of Aluminum‐Doped Transition‐Metal Oxides ( LiAl1 − x M x O 2 ) in the α ‐ NaFeO2 Crystal Structure

First‐principles methods are used to calculate the miscibility of eight aluminum‐doped transition‐metal oxides in the layered structure. This study finds that for all Li(Al,M) compounds investigated (M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu) the enthalpy of mixing is positive. In addition, detailed analyses were performed on and by calculating full temperature‐composition phase diagrams. For the Li(Al,Co) system, we find regions of immiscibility below −173°C and above 600°C. For both Li(Al,Co) and above 600°C, Al‐doping is limited by the formation of .