Unraveling the Morphological Dependency of the LiNi0.6Mn0.2Co0.2O2 Layered Oxide Reactivity in Li-Ion Batteries

LiNi 0.6 Mn 0.2 Co 0.2 O 2 is one of the most promising positive electrode materials for Li-ion batteries (LIBs). Platelet-shaped particles of 17 and 86 nm thicknesses were obtained, with the required composition and a structure close to the ideal 2D layered structure (less than 5.2% Ni 2+ ions in Li + sites). The electrochemical performances and surface reactivity of the materials were characterized in LIBs and compared to that of 280 nm particles with a more conventional morphology. Post-cycling analyses revealed a particular reactivity at high potential for the platelets compared to the conventional particles. X-ray photoelectron spectroscopy and ex situ X-ray diffraction analyses were performed to characterize the composition of the positive electrode/electrolyte interface and the structural changes undergone by the three materials upon cycling, respectively. This study showed that, as well as the particles’ composition, their morphology plays a significant role regarding the reactivity and the structural changes occurring during cycling at high potential.