Rechargeable lithium-ion battery cathodes: In-situ XAS

Lithium-ion batteries with high energy and power density are needed for a variety of new technologies. The materials that are used in the cathodes and anodes of these batteries have crystal structures that can accommodate and release lithium over a fairly large composition range. Over 95% of commercial lithium-ion batteries use LiCoO2 cathodes, but the high cost of cobalt makes cheaper alternatives desirable. Knowledge of the redox chemistry and changes in structure during electrochemical cycling is of paramount importance in designing new cathode materials with superior properties. The authors explored the changes in the atomic and electronic structure of nickel- and manganese-based cathode materials using in-situ x-ray absorption spectroscopy (XAS). The element-specific nature of the XAS technique and its sensitivity to the local chemical environment make it an ideal tool to study this class of materials.