Multiscale insights into intragranular cracking mechanisms in Ni-rich single-crystal layered oxide cathodes

Intragranular cracking has emerged as a dominant degradation pathway in Ni-rich single-crystal LiNi_xCo_yMn_1-x-yO₂ (SC-NCM) cathodes, driving structural fragmentation and irreversible capacity fading. Despite its critical impact on long-term performance, the mechanistic origins of crack nucleation and growth—and their interplay with existing mitigation strategies—remain insufficiently understood, constituting a major barrier to further materials optimization. In this review, we provide a comprehensive analysis of the chemical, mechanical, and electro-chemo-mechanical factors that govern intragranular crack formation and propagation in Ni-rich SC-NCM. We critically examine current crack-suppression strategies and elucidate the mechanistic principles underlying their effectiveness. Remaining challenges are highlighted, and we outline opportunities for integrating advanced in situ/operando characterization with multiscale, non-destructive imaging, and artificial intelligence-enabled predictive modeling. Together, these approaches offer a promising pathway toward resolving intragranular cracking and accelerating the commercial realization of next-generation, high-energy-density lithium-ion batteries.