Improving LiNi_0.9Co_0.08Mn_0.02O₂’s cyclic stability via abating mechanical damages

The cyclic plummet caused by mechanical-damage-induced particle cracking is one of the key challenges to hinder the practical application of nickel-rich cathodes. Mechanical stress, roughly estimated by Δc resulted from variation of O-(Li)–O propelling forces, could be tuned up by partially deflecting oxygen charges. Herein, we propose a strategy to abate the mechanical stress of LiNi_0.9Co_0.08Mn_0.02O₂ via adjusting electrons’ distribution with appropriate cations substitution. Among the investigated species, Ti- and Al-modifications alleviate the change of lattice c by drawing the neighbor-oxygen charges to transition metal (TM) layers, and Zn-substitution aggrandizes Δc indicating that pushing effect plays the dominant role. Since it renders the largest reduction of lattice c variation, ~40% less in both regions, Ti-substituted sample retains 93.4% of the initial capacity after 200 cycles, even without particle cracking, although the other samples also deliver ~220 mAhg⁻¹ under 0.1 ​C. Our approaches demonstrate the dependence of mechanical stress on electronic micro-structure, which is viable to develop long-life cathodes for power lithium ion batteries.