Mitigating Lattice Distortion of High-Voltage LiCoO 2 via Core-Shell Structure Induced by Cationic Heterogeneous Co-Doping for Lithium-Ion Batteries

Highlights A simple two-step multi-element co-doping strategy is proposed to fabricate core-shell structured LiCoO 2 based on the different diffusivities of dopant ions. The high diffusivity Al 3+ /Mg 2+ ions occupy the core of single-crystal grain while the low diffusivity Ti 4+ ions enrich the shell layer. In-situ XRD demonstrates the mitigated structural distortion under a high cut-off voltage of 4.6 V, resulting in a significantly improved cycling stability.