First-Charge Instabilities of Layered-Layered Lithium-Ion-Battery Materials: Relationship of Oxygen Ion Displacement to Mn Migration

Layered-layered composites with composition xLi₂MnO₃•(1-x)LiMO₂ enable high capacity and energy density Li-ion batteries, but suffer from degradation with cycling. Evidence of atomic instabilities during the first charge are discussed based X-ray absorption spectroscopy, first principles simulation, and existing literature. EXAFS measurements on 0.3Li₂MnO₃•0.7LiMn_0.5Ni_0.5O₂ during the first charge were analyzed to determine the coordination number deficit of Mn and Ni.