Li interaction into a phyllomanganate of Rancieite type: Electrochemical behavior and XAS study

The present study deals with a layered lithiated manganese oxide belonging to the Rancieite structural type. The Li insertion mechanism and its reversibility, the origin of capacity limitation at high rate and the origin of capacity fading upon cycling are investigated with help of electrochemical studies and XAS experiments. It is shown that Li ions can be extracted in charge and can be used as an additional Li source to compensate the fading upon cycling. The good reversibility is explained on the basis of a reversible change of the local order around the Mn cations during the discharge and charge processes. The capacity fading upon cycling is coming from the partial blocking of the Li intercalation site. (c) 2006 Elsevier Ltd. All rights reserved.