Advancing the Performance of Lithium-Rich Oxides in Concert with Inherent Complexities: Domain-Selective Substitutions

Abstract

Historically, modifications to Li- and Mn-rich (LMR) cathodes have been studied in relation to their efficacy in solving challenges such as oxygen loss and voltage fade, which are inherent to the activation process of these electrodes. However, even in the presence of these phenomena, well-optimized LMR cathodes show considerable promise as earth-abundant options, particularly if other barriers to implementation can be overcome or mitigated. As the complex mechanisms of LMR electrodes are known to stem from the local, chemical inhomogeneities that define the nanocomposite domain nature of these oxides, strategies aimed at manipulating the performance of activated electrodes, irrespective of voltage fade, through domain-selective modifications, could prove instructive. Herein, we use a novel synthesis process aimed at influencing the site occupancy of substituted Sn⁴⁺, as an example 4+ cation, into a Co-free Li_1.13Mn_0.57(1–x)Sn_0.57xNi_0.3O₂ LMR oxide. We show that Sn⁴⁺ can be selectively substituted into Li-rich environments. The consequences are revealed to be both chemical and morphological, and the domain-selective doping strategy provides a knob for directed control of the low state-of-charge impedance behavior. These results reveal new clues and insights with respect to further advancing the practical relevance of LMR cathode particles and electrodes.