Local structure modification in lithium rich layered Li-Mn-O cathode material

X-ray absorption spectroscopy (XAS) is applied to study the local geometry of Co, Ni, and Mn sites in a new high voltage cathode for lithium batteries. The material is a solid solution between Li2MnO3 and Li(x)Mn0.4Ni0.4Co0.2O2. The XAS technique has permitted to check the local atomic structure and charge associated with the metals in a series of electrodes with different lithium concentration x, obtained during the first charge operation, and compared to the first discharge and a successive charge. The ex-situ XAS investigation on the initial activation of the cathode material (first charge) can be described by two separated reaction of LiMO2 (M = Ni and Co) and Li2MnO3. The strength and limitations of the EXAFS approach in these materials is underlined