title: A new concept for obtaining SnO2 fiber-in-tube nanostructures with superior electrochemical properties.
abstract: Tin oxide (SnO2 ) nanotubes with a fiber-in-tube structure have been prepared by electrospinning and the mechanism of their formation has been investigated. Tin oxide-carbon composite nanofibers with a filled structure were formed as an intermediate product, which were then transformed into SnO2 nanotubes with a fiber-in-tube structure during heat treatment at 500 °C. Nanofibers with a diameter of 85 nm were found to be located inside hollow nanotubes with an outer diameter of 260 nm. The prepared SnO2 nanotubes had well-developed mesopores. The discharge capacities of the SnO2 nanotubes at the 2nd and 300th cycles at a current density of 1 A g(-1) were measured as 720 and 640 mA h g(-1), respectively, and the corresponding capacity retention measured from the 2nd cycle was 88 %. The discharge capacities of the SnO2 nanotubes at incrementally increased current densities of 0.5, 1.5, 3, and 5 A g(-1) were 774, 711, 652, and 591 mA h g(-1), respectively. The SnO2 nanotubes with a fiber-in-tube structure showed superior cycling and rate performances compared to those of SnO2 nanopowder. The unique structure of the SnO2 nanotubes with a fiber@void@tube configuration improves their electrochemical properties by reducing the diffusion length of the lithium ions, and also imparts greater stability during electrochemical cycling.
authors.affiliation: Department of Materials Science and Engineering, Korea University, Anam-dong, Seongbuk-gu, Seoul 136-713 (Republic of Korea).
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: Hong
authors.forename: Ji-Wook
authors.initials: JW
authors.lastname: Yoon
authors.forename: Jong-Heun
authors.initials: JH
authors.lastname: Lee
authors.forename: Yun Chan
authors.initials: YC
authors.lastname: Kang
keywords: anode materials; cyclic voltammetry; electrospinning; lithium-ion batteries; nanotubes; tin oxide