Doping Kinetics and Structural Studies for Lithium‐rich Mn‐based Lithium Ion Cathode Materials
Ying Zhang, Qi Song, Qinfu Zhao, Ronglan Zhang, Jianshe Zhao
Abstract
The doping kinetics and effects on the structures and electrochemical properties for xLi 2 MnO 3 ·(1 − x )LiMO 2 (M = Ti, Zr, and Sn) cathode materials are fully studied by theoretical calculation combined with experimental facts. The results indicate that the dissociation energy of doped atoms and intrinsic oxygen in the Li 2 MnO 3 layer affect the stability of the structure. Meanwhile, the path and direction of lithium ion migration become major factors affecting the cycle performance of the materials. Simultaneously, the results recommend that the change of the lowest energy barrier of the lithium ion migration path after doping may lead to a change of the optimum direction of lithium ion migration. Ti‐doped materials with the lowest lithium ion migration barrier have better electrochemical performance. Due to the larger Zr–O binding energy for Zr‐doped materials, which restrains structural deoxidation, the materials have a relatively high first Coulomb efficiency. This discovery provides a new research idea for the modification of x Li 2 MnO 3 ·(1− x )LiMO 2 cathode materials in the future.