Synthesis and Electrochemical Characterization of LiMn_(0.6)Fe_(0.4)PO_4/C Cathode Material via a Modified-Solid State Reaction Method

摘要

LiMn_(0.6)Fe_(0.4)PO_4/C cathode material is synthesized via a modified-solid state reaction method. The calcination temperature is adjusted in the range of 500-700℃ for 10 h. The crystal structure, morphology, and carbon coating layer of the synthesized LiMn_(0.6)Fe_(0.4)PO_4/C are analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), respectively. The electrochemical performance of LiMn_(0.6)Fe_(0.4)PO_4/C, such as initial capacity, rate capability, cycling performance and EIS is also evaluated. The synthesized cathode material shows around 100～200 nm of primary particle size with no impurities. The highest initial discharge capacity of 162.1 mA h g~(-1) and columbic efficiency of 98.5% are obtained at a heat treatment temperature of 600℃. In addition, LiMn_(0.6)Fe_(0.4)PO_4/C active material shows the high capacity retention of 85% at 5 C compared to 0.2 C. It also shows the excellent capacity retention of 97.5% after the 50th charge/discharge.