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 mu m 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.