High Energy Density Large Particle LiFePO₄

Abstract

To improve the energy density of LiFePO 4 (LFP) cathode materials for Li-ion cells, we have utilized a modified mechanofusion method for preparing micrometer-sized LFP/C composite flake particles. The resulting flake particle morphology resulted in improved packing efficiency, enabling an electrode porosity of 14% to be achieved at high loadings, which represents a volumetric energy density increase of 28% compared to conventional LFP. Furthermore, LFP/C flake composites electrodes were found to have a higher coulombic efficiency, a reduced voltage− polarization, and a greatly reduced charge transfer resistance compared to conventional LFP electrodes. This is believed to be due to the low surface area of the LFP/C flake composite particles coupled to fast Li + ion grain boundary diffusion. The ability to make highly dense LFP and low surface area electrodes could have profound impacts, allowing for Li-ion cells to be made with low cost and low environmental impact LFP, while high achieving volumetric energy densities and high coulombic efficiencies.