Hollow Fe₃O₄ microspheres as anode materials for lithium-ion batteries

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• 作者：Hyung-Seok Lim^a ; Byoung-Young Jung^a ; Yang-Kook Sun^b ; ^{yksun@hanyang.ac.kr} ; Kyung-Do Suh^a ; ^{kdsuh@hanyang.ac.kr}
• 关键词：Li-ion battery ; Anode materials ; Iron oxide ; Hollow structure ; Transition metal oxide
• 刊名：Electrochimica Acta
• 出版年：2012
• 期刊代码：30_00134686
• 类别：ch
• 出版时间：30 July, 2012
• 卷：75
• 期：Complete
• 页码：123-130
• 文件大小：2567 K

摘要

In this study, we proposed a unique method for hollow Fe₃O₄ microspheres and confirmed their electrochemical properties as anode materials for lithium-ion batteries. Poly(MAA/EGDMA)/Fe₃O₄ core-shell microspheres were prepared by simple ionic attraction between hydrogel microspheres with negative charge and magnetic Fe₃O₄ nanoparticles under alkaline conditions. The poly(MAA/EGDMA) core spheres were removed by heat treatment in order to form the hollow structure of Fe₃O₄ microspheres. Their hollow structure prevents cracking of the electrode during the volume change of repetitive Li-ion insertion and extraction reactions and improves the Li-ion transfer during cycling. The morphologies and structure of the hollow Fe₃O₄ microspheres were confirmed by scanning electron microscopy, focused ion beam-scanning electron microscopy, transmission electron microscopy, optical microscopy and X-ray diffraction. The electrochemical performance of the composite electrode was evaluated by constant current charging and discharging, cyclic voltammetry and cycling performance at various cycling rates. The results showed excellent cycle stability compared with a composite electrode containing bare Fe₃O₄ nanoparticles. These results indicate that the unique structures of Fe₃O₄ microspheres contribute to the excellent life and high reversible capacity of the battery when they are used as an anode of a lithium-ion battery.