Revisiting the Structural Limitations of Layered Oxide Cathodes for Reversible Lithium-Ion Storage

O3-type layered oxides have long served as the backbone of lithium-ion battery cathodes, yet their practical capacities remain below theoretical limits. In this Perspective, we revisit the intrinsic structural limitations governing reversible Li storage in layered oxides and quantitatively delineate their electrochemical performance boundaries. Our analysis identifies high-voltage phase transitions, i.e., particularly the destructive O3–O1 slab gliding in Co-based oxides, as the primary structural bottleneck, whereas the more reversible H2–H3 transition in Ni-based counterparts enables higher capacity retention. We argue that future structural design should rationally harness these phase transitions without sacrificing energy density to achieve durable cycling. Beyond long-range order, local structural distortions and native crystallographic defects are revealed as critical weak points that trigger performance degradation. This work establishes a structural framework for defining the intrinsic stability boundary of layered oxides of O3 type and offers insights for developing defect-free, phase-transition-resilient layered oxide cathodes with stable high-capacity operation.