Advanced Study of Aging of LiNi0.80Co0.15Al0.05O2 Cathode Material for Lithium-ion Batteries

LiNi0.80Co0.15Al0.05O2 (NCA), which is one of the promising Nickel-rich layered cathode materials for lithium ion battery (LIB) system, will play a key role in the coming vehicle electrification revolution. A comprehensive understanding of degradation mechanisms is important to prolong the lifespan of NCA-based LIB by optimizing its battery management system or achieving further improvements on material aspects. Recently, several studies revealed the inhomogeneous reactivity on composite porous electrodes, which could lead to a uneven degradation from electrode surface perpendicular towards current collector (through-plane). Since surface-focused characterization plays a major role in LIB aging studies, ignoring the porous heterogeneity can lead to deviate from actual aging scenarios resulting in spurious conclusions. This work tackles this issue by conducting a comprehensive aging study on the power-optimized commercial cells with thin-coated electrodes, which present minor through-plane porous inhomogeneity. Besides, the advanced characterization techniques are applied in this aging study to assess the aging phenomena in an innovative way. Our findings greatly stress the crucial role of electrode inhomogeneity
playing in the cycling aging. The discussions provide valuable insights into the new strategies of achieving better cycling life on NCA material or other type of Nickel-rich layered cathode materials.