Cracking the challenge: mechanisms of formation and mitigation of microcracks in Ni-rich cathodes for advanced lithium-ion batteries

Ni-rich layered cathodes are among the most promising candidates for next-generation lithium-ion batteries (LIBs), owing to their high reversible capacity, cost-effectiveness, and potential for large-scale applications such as electric vehicles. However, the high nickel content that enables superior energy density also accelerates structural degradation, particularly the formation of microcracks, which compromise both the mechanical stability and electrochemical performance of the batteries. This review systematically summarizes the mechanisms of microcrack initiation and propagation, including structural phase transformations, non-uniform lithium distribution, anisotropic lattice volume changes, and stress accumulation during the M–H2–H3 transition. On this basis, recent advances in inhibition strategies, including elemental doping, surface coating, structural design, and single crystallization, as well as multi-strategy and emerging approaches such as entropy stabilization and self-healing interfaces, are critically evaluated. The advantages, limitations, and technical bottlenecks of each method are highlighted, with emphasis on the necessity of synergistic regulation. Finally, perspectives on future directions are presented, aiming to guide the rational design of stable, crack-resistant Ni-rich cathodes for high-performance LIBs. This review provides new insights into the fundamental understanding of microcrack evolution and offers guidance for the rational design of durable Ni-rich cathode materials for advanced LIBs.