Ultrafast Laser structuring of thick NMC90 cathodes for enhanced high-rate performance and reduced tortuosity

Thick Ni-rich NMC (LiNi x Co y Mn z O 2 , x > 90 mol%) cathodes are a promising route towards high energy density lithium-ion batteries but suffer from poor ionic transport, resulting in limited rate capability and accelerated degradation. Although laser structuring has emerged as an effective strategy to improve electrolyte transport, its application to thick high-nickel cathodes has not been systematically investigated, particularly regarding the influence of structuring geometry on electrochemical performance and transport properties. Here, femtosecond laser structuring was applied to conventional and thick single-crystal NMC90 (LiNi x Co y Mn z O 2 , x = 90 mol%) cathodes using three different pattern spacings to establish the relationship between electrode architecture, rate capability, cycling stability, and effective through-plane tortuosity. Laser structuring significantly enhanced high-rate half-cell performance without inducing thermal damage to the active material. Structured thick electrodes exhibited high discharge capacity at 3C together with improved cycling stability, while electrochemical impedance spectroscopy revealed reductions in ionic resistance and effective tortuosity exceeding 65–70% compared with unstructured electrodes. These findings demonstrate that femtosecond laser structuring effectively overcomes the transport limitations of thick Ni-rich cathodes, providing practical design guidelines for high-energy lithium-ion batteries.