Microwave-assisted rheological phase synthesis of LiFe0.5Mn0.3Co0.2PO4/C cathode materials for lithium ion batteries

Abstract

LiFe0.5Mn0.3Co0.2PO4/C composites were fabricated via a facile microwave-assisted rheological phase method and investigated as cathode materials for lithium ion batteries. Herein the physical and chemical properties, and electrochemical performance of the samples synthetized by stearic acid or PEG400 as carbon source were compared. The as-prepared nanoparticles by stearic acid as carbon source are ideally covered fully and uniformly by carbon layer with thickness of about 2 nm. Galvanostatic charge/discharge test between 2.5–5.0 V indicate that it has enhanced electrochemical performances with a discharge capacity of 151.2 mAh g−1, 141.9 mAh g−1, 120.9 mAh g−1, 107.8 mAh g−1, 84.8 mAh g−1 and 69.0 mAh g−1 at a current rate of 0.05 C, 0.1 C, 0.5 C, 1 C, 3 C and 5 C, respectively. It also has excellent cycling performance with a capacity retention of 88.1% of still maintained after 100 cycles at 0.5 C. The results indicate that microwave-assisted rheological phase method is a fast and efficient way to obtain carbon-coated olivine structured composites with high-purity, desired structure and good electrochemical performance.