Stacking Fault Slows Down Ionic Transport Kinetics in Lithium-Rich Layered Oxides

Stacking faults, as common native crystallographic planar defects, have a significant negative impact on lithium (Li) ion diffision in layered oxide cathode materials, which must be considered to design and construct high-performance Li-ion batteries. Herein, we disclose that the stacking fault is one of the important factors contributing to the sluggish diffusion kinetics of Li-rich layered oxides (LLOs). Multidimensional and multiscale structural analyses, combined with theoretical calculations, reveal that the stacking fault in LLOs interrupts the straight out-of-plane pathway and forces Li ions to take high-energy barrier diffusion pathways. Furthermore, by reducing the defect density of stacking faults in LLOs, the Li⁺ diffusion coefficient is enhanced, facilitating the rate performance of Li-ion batteries. Our results provide insight into comprehending the role of stacking faults in layered cathode materials and demonstrate an available crystallographic engineering route to improve the ionic diffusion capability.