Uncovering Electrochemical-Mechanical Interplay of Stable Ultrahigh-Nickel Cathode via Fine Structure Regulation.

Abstract

Ni-rich layered oxides with optimized primary particle structures are crucial for developing lithium-ion batteries with high energy density. Although conventional high-valence elements doping effectively refines grains for columnar alignment, the industrial understanding of the processing-structure-performance relationship is lacking, and thus limits large-scale production. Herein, we investigate how molybdenum incorporation routes alter microstructure and performance, revealing a link between early structural evolution and capacity increase trends. Unlike the solid-phase gradient, the co-precipitation strategy achieves ultra-dispersed Mo doping, leading to super-refined primary particles and a dense structure that reduces microcracking through internal stress dissipation. Notably, it also limits electrolyte penetration, thereby influencing the initial Li⁺ transport kinetics. Moreover, this process induces a Li/TM cation-ordered structure that permeates the entire bulk phase of LiNi_0.95Co_0.04Mo_0.01O₂, suppressing Li⁺/Ni²⁺ cation disorder and mitigating intragranular/intergranular strain. These combined effects significantly enhance the structural robustness, resulting in a high discharge capacity of 204.9 mAh g^- ¹ at 5C. This work offers a straightforward and scalable industrial solution for enhancing the overall electrochemical performance of Ni-rich cathodes.