Scalable Double-Layer Cathode Design for Enhanced Performance, Safety, and Industrial Feasibility in Pouch Cells

As the demand for high-performance lithium-ion batteries continues to escalate, we propose an optimized double-layer electrode that combines polycrystalline (PC) and single-crystal (SC) materials to address trade-offs in thick electrode designs. PC electrodes suffer from severe cracking during calendaring, while SC electrodes exhibit high tortuosity, restricting lithium-ion transport. A bilayer structure incorporating a minimal SC fraction in the top layer mitigates pressure-induced cracking while maintaining the energy density. Systematic experiments across the full PC-to-SC ratio range (10:0 to 0:10) identified 9:1 (P9S1) as optimal, balancing mechanical integrity, ionic transport, and electrochemical stability. Pouch cell tests at 45 °C and 1 C for 300 cycles showed P9S1 retained a 12.05 mAh higher discharge capacity and exhibited 53.61% better cycling retention than PC-only electrodes (P10S0). Gas analysis revealed CO and CO2 reductions of 36.18% and 10.25%, confirming improved gas suppression behavior. These enhancements stem from SC's high mechanical strength and PC's superior lithium-ion diffusivity, minimizing crack propagation and internal resistance. This study demonstrates that a rationally engineered double-layer electrode enhances electrochemical performance while providing a scalable, commercially viable strategy for next-generation lithium-ion batteries. Our findings establish a clear pathway for optimizing cathode electrode architectures in advanced energy storage systems.