[001]晶向定向刻蚀介导α-Fe_2O_3纳米咖啡豆的一步合成及其高储锂性能研究（英文）

Facile one-pot fabrication of α-Fe_2O_3 nano-coffee beans by etching along [001] direction for high lithium storage

目前,对铁氧化物的形貌进行有效调控,并使其更好地应用于能量储存领域,是一项巨大的挑战.本工作成功地利用醋酸通过简单有效的水热合成法,得到了单晶赤铁矿α-Fe_2O_3纳米咖啡豆.这种特殊的纳米结构是在奥斯瓦尔德熟化(Ostwald ripening)和氢离子沿着[001]晶向定向刻蚀的共同作用下形成的.利用扫描电子显微镜、透射电子显微镜和X射线衍射测试等手段证明了这一假设的可信性.通过高温煅烧之后,作为负极材料,这些纳米咖啡豆展现了良好的锂离子性能.其在0.2 C倍率下的可逆容量为810 mA h g^(-1),且具有良好的循环稳定性能和倍率性能.因此,该纳米材料的结构设计将为合成具有更好表现的锂离子电池正极材料提供借鉴.

It is a great challenge to finely tune the morphology of iron oxides for energy storage. In this work, we introduced a facile hydrothermal method to obtain single crystalline hematite （α-Fe2O3） nano-coffee beans （NCBs） with the assistance of acetic acid. Interestingly, α-Fe2O3 nanos- tructures with this special morphology were formed under the effect of Ostwald ripening and oriented etching of H^＋ ions along [001] direction, which could be proved by the scanning electron microscope/transmission electron microscope and X-ray diffraction. After calcination at high temperature, the as-prepared α-Fe2O3 NCBs were used as potential anode ma- terials, showing a very high reversible capacity of 810 mA h g^-1 （0.2 C）, excellent cycling stability, and high-rate performance for lithium storage. Hence, in virtue of the good performances, the structural design of nanomaterials would be promoted in the fabrication of electrode materials for lithiumion batteries.