Evolution of Ni/Li antisites under the phase transition of a layered LiNi1/3Co1/3Mn1/3O2 cathode

Abstract

At present, the expectation for batteries with an enhanced performance has accelerated the development of high-performance cathodes, among which the layered cathodes have drawn significant attention and probably hold the key to unlocking the capacity limitations of Li-ion batteries (LIBs). However, the capacity advantages of layered cathodes, especially in the high voltage delithiation region, cannot be effectively stabilized because of the uncontrollable generation of Li-transition metal antisites under the phase transition. Furthermore, few convincing results have been provided to elucidate their contribution to the electrochemical performance. To this end, we found, theoretically, that in a layered LiNi_1/3Co_1/3Mn_1/3O₂ cathode, the formation of Ni/Li antisites can occur spontaneously upon the Li–Ni linear exchange mechanism. After being introduced into the layered LiNi_1/3Co_1/3Mn_1/3O₂, these antisites are prone to clustering together within the (003) plane to introduce some discrete stage-like structures, which will cause serious Jahn–Teller distortions and influence the Li ion 2D diffusion and also relax the c axis, hence changing the phase transition process. These interesting findings provide deep and insightful view to further understand the cation disorder phenomenon and the high voltage features of layered cathodes, and also demonstrate a rewarding avenue for building better LIBs.