High Energy Density LiFePO4/C Cathode Material Synthesized by Wet Ball Milling Combined with Spray Drying Method

Abstract

Lithium iron phosphate with high energy density was synthesized by a combination of wet ball milling, spray drying and carbon thermal reduction technology using inexpensive FePO4 as starting material. The effect of morphology on structure and electrochemical properties of LiFePO4/C cathode material was systematically investigated. The as-obtained LiFePO4/C composite has ordered olivine structure and micro-spherical morphology assembled with nanosized primary particles. The lithium iron phosphate microsphere has a core-shell structure, not only does the surface of nanoparticles have a homogeneous and complete carbon coating but also does the surface of secondary particles form a carbon shell, which results in its uniform particle size distribution and enhanced electronic conductivity. All above-mentioned factors lead to its excellent room-temperature and low-temperature electrochemical performance in LiFePO4/Li half-cell, as well as good processabilty in 14500 cylindrical full-cell. More importantly, its high tap density and pole piece compaction density can effectively improve the volumetric specific energy of the battery.