Department of Mechanical Engineering and Materials Science, Washington University in St. Louis , St. Louis, Missouri 63130, United States.
Department of Nanotechnology and Advanced Materials Engineering, Sejong University , Seoul, 05006, Korea.
ACS Appl Mater Interfaces. 2017 Apr 26;9(16):14187-14196. doi: 10.1021/acsami.6b16822. Epub 2017 Apr 13.
Cation substitution of Bi with Fe in BiOCl leads to the formation of ionically layered BiFeOCl nanosheets. The synthesis follows a hydrolysis route using bismuth(III) nitrate and iron(III) chloride, followed by postannealing at 500 °C. Room temperature electrical conductivity improves from 6.11 × 10 S/m for BiOCl to 6.80 × 10 S/m for BiFeOCl. Correspondingly, the activation energy for electrical conduction reduces from 862 meV for pure BiOCl to 310 meV for BiFeOCl. These data suggest improved charge mobility in BiFeOCl nanosheets. Density functional theory calculations confirm this behavior by predicting a high density of states near the Fermi level for BiFeOCl. The improvement in electrical conductivity is exploited in the electrochemical performance of BiFeOCl nanosheets. The insertion capacity of Li ions shows an increase of 2.5×, from 215 mAh·.g for undoped BiOCl to 542 mAh·g for BiFeOCl after 50 cycles at a current density of 50 mA·g. Thus, the direct substitution of Bi sites with Fe in BiOCl results in nanosheets of an ionically layered ternary semiconductor compound which is attractive for Li ion battery anode applications.
在 BiOCl 中用 Fe 取代 Bi 导致形成离子层状 BiFeOCl 纳米片。该合成采用水解路线，使用三硝酸铋和三氯化铁，然后在 500°C 下进行后退火。室温电导率从 BiOCl 的 6.11×10 S/m 提高到 BiFeOCl 的 6.80×10 S/m。相应地，BiFeOCl 的电传导活化能从纯 BiOCl 的 862 meV 降低到 310 meV。这些数据表明 BiFeOCl 纳米片中的电荷迁移率得到了提高。密度泛函理论计算通过预测 BiFeOCl 近费米能级的高态密度证实了这种行为。电导率的提高在 BiFeOCl 纳米片的电化学性能中得到了利用。Li 离子的嵌入容量从未掺杂 BiOCl 的 215 mAh·g 增加到 50 次循环后在 50 mA·g 的电流密度下的 542 mAh·g，增加了 2.5×。因此，在 BiOCl 中用 Fe 直接取代 Bi 位导致形成离子层状三元半导体化合物的纳米片，这对于 Li 离子电池阳极应用具有吸引力。
