Synthesis of LiFePO<sub>4</sub> by Co-Precipitation and Optimization of its Performance

Abstract

As a positive electrode material for lithium-ion batteries, LiFePO4 should be composited with carbonaceous materials due to its poor electrical conductivity. In this study, LiFePO4/C (carbon) composite was synthesized with method of solution co-precipitation, in which glucose was used as a carbon source. The LiFePO4 material was systematically optimized by X-ray diffraction, scanning electron microscopy. The crystalline structures, morphology and electrochemical performance of LiFePO4 prepared by solution co-precipitation were compared with that obtained by solid-state reaction. It is found that LiFePO4 is a pure phase with olivine structure, and exhibits a 3.4V discharge voltage plateau. In our experimental conditions, LiFePO4/C including 10wt. % of residual carbon obtained by solution co-precipitation possess excellent electrochemical performance, whose first specific capacity was 131.4 mAh•g-1 at 0.1C rate, the specific capacity was 128.3 mAh•g-1 after 20 times cycling.