Unravelling structural changes of the Li1.2Mn0.54Ni0.13Co0.13O2 lattice upon cycling in lithium cell

Li-rich layered oxide materials (LRLOs) are the most promising positive electrodes materials for the next-generation Li-ion batteries. Nevertheless, cycle life stability and capacity retention are still inadequate and hinder their use in the commercial Li-ion devices. In fact, LRLOs undergo structural rearrangements and phase transitions upon cycling that reduce their electrochemical performances. Li1.2Mn0.54Ni0.13Co0.13O2 is one of the most studied LRLO materials, thanks to its high initial specific capacity, exceeding 300 mAh/g in the first cycle, that fades monotonically upon cycling. In this work, after a complete characterization of the pristine material, we demonstrate the electrochemical performances both in half and full cells and we shed new light on the structural degradations occurring upon cycling. By combining ex-situ synchrotron diffraction and Raman spectroscopy, we outline the structural evolution of the LRLO phase occurring in the first 10 cycles of lithium de-intercalation/intercalation, thus extending the understanding of the origin of capacity fading beyond the first cycle.