US scientists boost batteries' lifespan, fix capacity degradation issue

Researchers from Argonne National Laboratory and the University of Chicago’s Pritzker School of Molecular Engineering have identified key causes of capacity degradation and shortened lifespan in lithium-ion batteries, particularly those using nickel-rich cathode materials. Their study, published in Nature Nanotechnology, reveals that the common assumption that single-crystal Ni-rich layered oxide (SC-NMC) cathodes degrade similarly to polycrystalline Ni-rich materials (PC-NMC) is incorrect. Unlike PC-NMC, where mechanical failure is linked to volume changes causing particle cracking, SC-NMC degradation is driven by multidimensional lattice distortions caused by reaction heterogeneity and chemical phase deactivation. The research redefines the roles of cobalt and manganese in battery stability: cobalt, previously seen as detrimental in PC-NMC, is crucial in SC-NMC for mitigating localized strain and enhancing longevity, while manganese worsens mechanical degradation. This insight challenges existing design strategies and materials used in cathodes, suggesting that new materials and approaches are necessary for optimizing single-cr