Research On Two-Phase Carbon Modified Li2fesio4 As Cathode Material

Two-phase carbon modified Li2FeSiO4 composites (Li2FeSiO4/(C + G)) were synthesized via solid-state reaction assisted with refluxing. Activated natural graphite was chosen as carbon source. The phase and the microstructure of Li2FeSiO4/(C + G) were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and Raman spectrometry (Raman). The effect of activated graphite content on the electrochemical performance of Li2FeSiO4/(C+G) was also investigated. The results show that activated graphite exists in Li2FeSiO4/(C+G) samples in the form of amorphous carbon as well as graphite crystallite. Li2FeSiO4/(C+G) composite prepared with 5wt% activated graphite achieved the excellent electrochemical performance with a higher initial discharge capacity of 170.3 mAh.g(-1) and with a capacity retention ratio of 88.7% after 50 cycles.