Twinning mediated intralayer frustration governs structural degradation in layered Li-rich oxide cathode

migration and transition metal rearrangement during cycling. Especially after the first full charge, the interlayer (001) twining-like structures and local intralayer frustrations formed. Over cycling, the intralayer frustrations further develop into pore-like microstructures along the {012} twinning boundary in the bulk of the particles, which contributes significantly to performance reduction. The results clarify the link between microstructure degradation and performance loss and provide valuable insights into the optimization of high-performance cathodes.