Design of Multilayer Cathodes with Graded Porosity and Their Impact on Lithium-Ion Battery Performance

Multilayer (ML) electrodes have emerged as a promising strategy to enhance the electrochemical performance of lithium-ion batteries (LIBs), which is essential for their efficient use in modern applications. A key advantage of ML designs is their ability to address specific limitations commonly observed in conventional single-layer electrodes. In this study, the impact of structural grading is investigated on electrochemical performance using ML cathodes with varying thicknesses of 82, 142, and 205 μm, corresponding to areal capacities of 4, 7, and 10 mAh cm-2, respectively. Each ML electrode is designed with higher porosity near the separator to facilitate ion transport and denser layers near the current collector to maintain energy storage. The mass ratio between layers, overall porosity, and electrode thickness are kept constant, and single-layer electrodes with identical parameters are used as references. The ML design resulted in reduced tortuosity and improved rate capability, especially at higher mass loadings. These results demonstrate the advantages of porosity grading and support the use of ML architectures as a scalable strategy for improving the power performance of next-generation LIBs.