Supercritical synthesis in combination with a spray process for 3D porous microsphere lithium iron phosphate

Abstract

A short synthesis time and high tap density are key conditions for the commercialization of electrode materials. Carbon coated three-dimensional porous LiFePO4 microspheres are synthesized by a supercritical and spray-dry combination method in a significantly short processing time (about 10 min). The three-dimensional (3D) porous morphology is composed of nanocrystallites tightly compacted to form three-dimensional electronic and ionic channels, which enhances their electrochemical properties. The obtained porous LiFePO4 microspheres are intensively analyzed by XRD, SEM, TGA, and FT-IR techniques. The porous microspheres, which are 60 μm in size, show uniform morphology with the carbon coating. Moreover, at a 0.1 C rate the 3D porous microspheres of LiFePO4 exhibit a high initial capacity with a high tap density (1.7 g cm-3) and high active material content (~90% without carbon), which corresponds to 94% and 79% of the theoretical capacity at 0.1 and 1 C.