Regulating Li Extraction in Transition Metal Layer for High‐Performance Li‐Excess Layered Oxide Cathode with Intergrowth Structure

ABSTRACT In lithium‐excess layered oxide cathodes, the extra lithium within transition metal (TM) layers (i.e., Li [TM] ) can trigger anionic redox to provide additional capacity. However, substantial extraction of Li [TM] may induce irreversible/detrimental local structural rearrangements. The conventional edge‐shared connecting configuration between LiO 6 and TMO 6 octahedra facilitates interlayer migration of Li [TM] . In contrast, the face‐shared configuration has the potential to limit the mobility of Li [TM] , but this metastable configuration cannot be harvested via traditional calcination. Herein, during Na‐to‐Li ion exchange in P2 phase Na 0.66 [Li 0.22 TM 0.78 ]O 2 precursor, we observe that the random gliding of TMO 2 layers yielding Li 0.66 [Li 0.22 TM 0.78 ]O 2 with O2/O6 intergrowth structure. Despite the random gliding, the functional face‐shared configuration is successfully obtained and proven to effectively restrict interlayer migration of Li [TM] during charging. Consequently, we observe the suppressed formation of aggregated vacancies and O–O dimers within the TM layers. Ultimately, our synthesized O2/O6 Li‐excess demonstrates enhanced structural reversibility and improved capacity/voltage retention. This oxygen‐stacking engineering provides a compelling strategy for developing cathodes with enhanced local structural reversibility.