High-rate cathode materials for Li-ion batteries require fast Li transport kinetics, which typically rely on topotactic Li intercalation/de-intercalation because it minimally disrupts Li transport pathways. In contrast to this conventional view, here we demonstrate that the rate capability in a Li-rich cation-disordered rocksalt cathode can be significantly improved when the topotactic reaction is replaced by a non-topotactic reaction. The fast non-topotactic lithiation reaction is enabled by facile and reversible transition metal octahedral-to-tetrahedral migration, which improves rather than impedes Li transport. Using this concept, we show that high-rate performance can be achieved in Mn- and Ni-based cation-disordered rocksalt materials when some of the transition metal content can reversibly switch between octahedral and tetrahedral sites. This study provides a new perspective on the design of high-performance cathode materials by demonstrating how the interplay between Li and transition metal migration in materials can be conducive to fast non-topotactic Li intercalation/de-intercalations.

用于锂离子电池的高倍率正极材料需要快速的锂传输动力学，这通常依赖于拓扑结构的锂嵌入/脱嵌，因为它对锂传输路径的干扰最小。与这种传统观点相反，在这里我们证明了当拓扑反应被非拓扑反应取代时，富锂阳离子无序岩盐正极的倍率性能可以显着提高。快速的非拓扑锂化反应是通过过渡金属八面体到四面体迁移实现的，这改善而不是阻碍锂的传输。使用这个概念，我们表明当一些过渡金属含量可以在八面体和四面体位点之间可逆地转换时，可以在 Mn 和 Ni 基阳离子无序岩盐材料中实现高倍率性能。