Size-selective synthesis of mesoporous LiFePO4/C microspheres based on nucleation and growth rate control of primary particles

Abstract

Because of the on-going miniaturization of devices powered by lithium-ion batteries, the realization of a high tap density that sustains a high power output is crucial to enhancing the low intrinsic volumetric energy density of LiFePO₄ (LFP), one of the most extensively studied cathode materials. To increase the tap density of LFP, we report a synthetic method that allows microscale size control of a LiFePO₄ precursor with a mesoporous structure based on changes in the chemical potential and nucleation and growth rates by surfactant addition. The carbon-coated LiFePO₄ particles prepared from the precursors had diameters and tap densities in the range of 3–7 μm and 1.3–1.5 g cm⁻³, respectively, depending on the surfactant concentration. The particles exhibited negligible antisite defects (approximately 2%) and showed a high volumetric capacity of approximately 190 mA h cm⁻³ at a 0.1 C-rate and an excellent rate performance of 80 mA h g⁻¹ at a 30 C-rate.