Some aspects of the behavior of as a cathode for nonaqueous Li cells have been reconsidered. As found in the extensive investigation carried out at Sanyo's laboratories, the most active form is obtained by heating electrolytic in the range 350°–400°C. However, the basic support found in the present work for this behavior is quite different and excludes a γ‐β transition which, instead, has adverse effects on cathode performance. Indeed, has been found to be as poor a cathode material in Li cells as in aqueous cells. In the disordered orthorhombic structure of EMD (substantially retained upon moderate heating), Li+ is topochemically incorporated. This process causes structural alterations at relatively low Li+ contents. The remarkably flat discharge curves suggest formation of a pseudo two‐phase compound. Reversibility is incomplete because of these features and only shows up in mild conditions.