Micrometer Scale X-ray CT-Informed Optimization of Heterogeneous Pore Distribution in Double Layered Thick LiNCM 811 Cathode

The pore structure of lithium-ion battery electrodes heavily influences ion transport and thus their deliverable capacity, especially at higher rates. Ideally, a gradient pore distribution favoring higher porosity near the separator side can enable faster ion transport at higher cycling rates. We present here a two-layer heterogenous cathode design using traditional NCM 811 material featuring a three-dimensional design space of this cathode design. An efficient characterization technique that combines fast micrometer-scale X-ray computed tomography and pore network modeling was developed, providing critical information regarding the ion transport pathways inside the cathode. Based on the X-ray CT data and performance characteristics obtained, we created a comprehensive profile of cathode rate performance as a function of their pore distribution with easily identifiable advantaged configurations for different cycling scenarios.