Environmental Study on Comparison of Four Different Methods on the Synthesis and Electrochemical Performance of LiMnPO4/C

LiMnPO4/C samples were synthesized by four different synthesis methods. Their influence on electrochemical performances of LiMnPO4/C as cathode materials for lithium-ion batteries was investigated. The structure and morphology of LiMnPO4/C samples were characterized by X-ray diffraction and scanning electron microscopy. Electrochemical performance in EC: DMC-LiPF6 of LiMnPO4/C was characterized by harge/discharge, cyclic voltammetry and alternating current (AC) impedance measurements. LiMnPO4/C with smaller grain size showed better performances in terms of the discharge capacity and cycle stability. The improved electrochemical properties of the LiMnPO4/C were attributed to the decreasing grain size and enhanced electrical conductivity produced via spray-drying followed by ball milling method. AC impedance measurements also showed that the LiMnPO4/C synthesized by spray-drying followed by ball milling method significantly decreased the charge-transfer resistance and shortened the migration distance of lithium ion. LiMnPO4/C synthesized by spray-drying followed by ball milling method exhibits the best electrochemical performance that the first specific discharge capacity is 114.9 mAh g(-1) in 25 degrees C and 132.14 mAh g(-1) in 50 degrees C at 0.1 degrees C rate, and the capacity retention is 89.8% after 50 cycles.