title: Macroporous Fe3O4/carbon composite microspheres with a short Li+ diffusion pathway for the fast charge/discharge of lithium ion batteries.
abstract: Macroporous Fe3O4/carbon composite and core-shell Fe3O4@carbon composite microspheres have been prepared by means of one-pot spray pyrolysis. The addition of polystyrene (PS) nanobeads to a spray solution containing an iron salt and poly(vinylpyrrolidone) (PVP) led to macroporous Fe3O4/carbon composite microspheres, the carbon and iron components of which are uniformly distributed over the entire composite microsphere. The pore-size distribution curve for the macroporous Fe3O4/carbon composite shows distinct peaks at around 10 and 80 nm. An electrode prepared from the macroporous Fe3O4/carbon composite microspheres showed better cycling and rate performances than an electrode formed from core-shell Fe3O4@carbon composite microspheres. The initial discharge and charge capacities of the macroporous Fe3O4/carbon composite microsphere electrode were determined to be 1258 and 908 mA h g(-1) at 2 A g(-1), respectively, and the corresponding initial coulombic efficiency was 72 %. The composite microsphere electrode cycled 500 times at 5 A g(-1) showed a high discharge capacity of 733 mA h g(-1).
authors: Department of Chemical Engineering, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701 (Korea), Fax: (+82) 2-458-3504.
authors: Seung Ho
authors: SH
authors: Choi
authors: You Na
authors: YN
authors: Ko
authors: Kyeong Youl
authors: KY
authors: Jung
authors: Yun Chan
authors: YC
authors: Kang
keywords: batteries; energy storage; iron; nanostructures; porous materials; spray pyrolysis