Fe_3O_4纳米晶的形貌可控制备及其电化学性能研究

Morphology-controlled preparation and electrochemical performance of Fe_3O_4 nanocrystal as anode material for lithium-ion battery

以油酸和癸酸作为表面活性剂调控Fe_3O_4纳米晶的生长过程制备了由不同比例{100}与{111}面构成的Fe_3O_4纳米晶。利用X射线衍射(XRD),场发射扫描电子显微镜(FESEM)等分析方法对Fe_3O_4纳米晶进行了物相测定和微结构观察,并分析了Fe_3O_4纳米晶的生长机制。在高电流密度(1A/g)条件下,八面体形貌Fe_3O_4纳米晶作为锂电池负极材料表现出比立方八面体和立方形貌Fe_3O_4纳米晶更加优异的电化学性能。实验结果证明Fe_3O_4多面体的表面结构显著影响Fe_3O_4活性材料在电化学循环过程中的电化学反应活性。

Monodisperse Fe3O4 polyhedrons enclosed by{100}/{111}facets with different area ratios were synthesized by effectively using oleic acid and decanoic acid to mediate the crystal growth process,and utilized as high rate（1A/g）anode materials for lithium ion batteries（LIBs）.XRD and FESEM were employed for the phase identification and microstructural observations of obtained Fe3O4 polyhedrons and the formation mechanism of Fe3O4 polyhedrons was studied.The electrochemical results showed that Fe3O4 octahedrons with highly reactive{111}facets possessed the best high rate cycling performance compared to that of cuboctahedrons and cubes.These results proved that the surface structure of Fe3O4 polyhedrons significantly affected the property of Fe3O4 nanocrystal materials and hence their electrochemical performance.