Ni–Li anti-site defect induced intragranular cracking in Ni-rich layer-structured cathode

Abstract High packing density of Ni-rich lithium transition metal oxide (LTMO) cathodes contribute to high energy density of lithium-ion batteries, however, resulting in severe intergranular and intragranular cracking issues. Most of previous works are focused on understanding the behaviors of intergranular cracks. However, the incubation mechanism of intragranular crack, especially at atomic scale, is still unclear though they are one of the main obstacles for practical application of Ni-rich LTMO cathode. Here, we reveal at atomic scale the intragranular cracking mechanism of LiNi0.8Mn0.1Co0.1O2 cathode during cycling processes. Ni–Li anti-site defect enrichment region with lattice distortion has been identified as the nucleation site for intragranular crack in the primary particle. The growth of intragranular crack can be ascribed to the strain difference between layered phase and electrochemical inactive phase and the Columbic repulsion in cation-rich area, which originates from the Ni–Li anti-site defect in transformed structure. The golden strategy to acquire stable high-energy cathode lies in suppressing the migration of cations before cracks occur, providing new insights for the design of high-performance Ni-rich LTMO cathodes.