Enhancing Cell Performance of Lithium-Rich Manganese-Based Materials via Tailoring Crystalline States of a Coating Layer.

Li-rich Mn-based-layered oxides are considered to be the most felicitous cathode material candidates for commercial application of lithium-ion batteries on account of high energy density. Nevertheless, defects containing an unsatisfactory initial Coulombic efficiency and rapid voltage decay seriously impede their practical utilization. Herein, a coating layer with three distinct crystalline states are employed as a coating layer to modify Li[Li _0.2 Mn _0.54 Ni _0.13 Co _0.13 ]O ₂ , respectively, and the effects of coating layers with distinct crystalline states on the crystal structure, diffusion kinetics, and cell performance of host materials are further explored. A coating layer with high crystallinity enables mitigatory voltage decay and better cyclic stability of materials, while a coating layer with planar defects facilitates Li ⁺ transfer and enhances the rate performance of materials. Consequently, optimizing the crystalline state of coating substances is critical for preferable surface modification.