Structure–Transport Relationships in Microarchitected LiFePO ₄ –Carbon Li Ion Battery Electrodes

The interconnected pore structure and large surface-to-volume ratio of three-dimensional (3D) architected battery electrodes enable enhanced electrochemical performance through improved ionic transport. We developed a hydrogel infusion additive manufacturing (HIAM)-based approach to fabricate microarchitected LiFePO₄ (LFP)/C composite electrodes with feature dimensions of 18 μm, delivering a specific capacity of 160 mAh/g at C/10. Electrodes with tilted cube, honeycomb, and triply periodic minimal surface (TPMS) geometries were designed to probe geometric effects on electrochemical performance under various rates. Material characterization revealed homogeneous formation of LFP particles (201 ± 67 nm) within the lattices, while the concomitantly formed carbon network provided mechanical support and enabled high-fidelity architecture. An experimentally informed electrochemical model identified electrolyte Li⁺ transport and solid-state Li⁺ diffusion as the dominant factors governing active material utilization. This work introduces a versatile manufacturing platform for 3D battery components and provides insights into structure optimization for high-performance rechargeable batteries.