Structure and property of SiFe@C anode composites

The SiFe@C anode materials were prepared by mechanical ball milling and high-temperature pyrolysis method with SiFe and pitch as the raw materials, and the characteristics of a series of SiFe@C composites prepared at different pyrolysis temperatures were compared with those of uncoated SiFe. The phase composition, morphology and electrochemical performance of SiFe@C anode composites were detected by XRD, SEM, TEM, EDS and constant current charge-discharge test. The results reveal that the initial discharge specific capacity of SiFe@C composite electrode prepared at 850℃ is 1 376.25 mAh/g with the initial coulombic efficiency of 86.35%. After 70 cycles, the discharge specific capacity is 940.33 mAh/g, the coulombic efficiency is 98.78% and the capacity retention rate is 76.32%, which indicates that its cycling stability and rate capability is much higher than the SiFe and other SiFe@C electrode composites obtained at other temperatures.