Revealing the disrupted Li/vacancy structure in Co, Mg, and Al co-doped ultra-high Ni-rich cathodes

Li atoms are believed to rearrange during Li insertion/removal in LiNiO₂ cathodes in lithium-ion batteries, forming certain Li/vacancy ordering structures. Substitution of Ni by dopants is considered to hinder such orderings, which is related to a quasi-solid-solution behavior in phase transitions and improved battery cyclability. Previous studies investigate the disruptions by theoretical calculations, however, direct experimental evidence is missing. Herein, the disturbed Li/vacancy structures are first observed based on the ex situ⁶Li nuclear magnetic resonance measurement.