Synthesis and Electrochemical Performance of LiMn0.6Fe0.4PO4/C Cathode for Lithium-ion Batteries

The LiMn0.6Fe0.4PO4/C cathode for lithium-ion batteries (LIBs) was synthesized by solvothermal, ball-milling combined with solid phase calcination method using sucrose as a carbon source and oxalic acid as an antioxidant. The final products with different morphologies were obtained by changing sintering temperatures. The structure and morphology of the target products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Cyclic voltammetry and galvanostatic charge and discharge tests were employed to characterize the electrochemical properties of the samples. The results manifest that well-crystallized olivine structure LiMn0.6Fe0.4PO4/C nano-rods and nano-spindles with no obvious impurity phase are obtained. The spindle-like LiMn0.6Fe0.4PO4/C sample S-650 (which was sintered at 650 degrees C) shows a highly monodisperse and homogeneous morphology. Electrochemical analysis results demonstrate that S-650 exhibits the best electrochemical performance with an initial discharge capacity of 119.1 mAh/g at the current density of 0.2 C (1 degrees C=170 mA/g), and a capacity of 148.8 mAh/g is achieved after 80 charge-discharge cycles, in comparison with S-600 (which was sintered at 600 degrees C) and S-700 (which was sintered at 700 degrees C). Meanwhile, S-650 also demonstrates excellent cycling stability even at a high current density of 2C.