This paper reports the microstructure and electrochemical properties of Si-Al-Fe ternary amorphous alloys prepared by rapid solidification as an anode for lithium secondary batteries. The microstructure was analyzed using XRD and HR-TEM with EDS mapping. In accordance with DSC analysis, annealing was performed to crystallize the active nano-Si in the amorphous alloy. Thus, nano-Si forms (~80 nm) embedded in the matrix alloy, such as Fe2Al3Si3, FeSi2, and Fe0.42Si2.67, were successfully synthesized. The electrode based on the Si-Al-Fe ternary alloy delivered an initial discharge capacity of approximately 700 mAh g-1, and exhibited a high Coulombic efficiency of 99.0~99.6% from the 2nd to 70th cycles.
This work investigated the effects of different conductive agents on the electrochemical properties of anodes. SiOx possesses high theoretical capacity and shows excellent cycle performance; however, the low initial coulombic efficiency and poor electrical conductivity limit its applications in real batteries. In this study, electrodes were fabricated using two different conductive agents, and the resulting physical and electrochemical properties were analyzed. SEM observations confirmed the formation of a CNT conductive network throughout the electrodes, while the electrical conductivity contributed to the electrode was confirmed by impedance measurements. Thus, the electrode fabricated with the CNT conductive agent showed greater capacity and superior cycle performance than did the electrode fabricated using the DB conductive agent.