Probing the initiation of voltage decay in Li-rich layered cathode materials at the atomic scale

Through a correlative investigation of electrochemical characterization and atomic-scale scanning transmission electron microscopy, the voltage decay in Li-rich layered cathode materials is found to originate between 4.4 and 4.8 V, and the most dramatic structural change associated is the layered-to-spinel transition that nucleates in the initial cycle.