High-Energy-Density Li-Ion Batteries Employing Gradient Porosity LiFePO4 Electrode for Enhancing Li-Ion Kinetics and Electron Transfer

Abstract

Lithium iron phosphate (LFP) cathodes are promising materials for energy storage device applications due to their thermal stability, chemical robustness, cost-effectiveness, and long lifespan. However, their low electronic and ionic conductivity, as well as challenges in achieving high packing density in thick electrodes, limit their practical implementation. In this study, a gradient porosity LFP electrode with a high areal capacity of 6.3 mAh cm−2 and an electrode density of 2.5 g cc−1 is proposed. In electrodes with gradient porosity, binder migration is mitigated, ensuring a uniform binder distribution that enhances Li-ion kinetics and adhesion strength between the electrode and aluminum current collector. Furthermore, by employing a particle with short charge carrier pathways in the bottom layer and a particle with a high tap density in the top layer, facile Li-ion and electron transfer and easier electrode processing can be achieved. The resulting gradient porosity electrode with a high areal capacity of 6.3 mAh cm−2 exhibits excellent cycle stability over 100 cycles in full-cell operation. These findings provide valuable insight into scalable strategies for high-energy-density, cost-effective LFP-based Li-ion batteries.