title: Hierarchical assembly of Ti(IV)/Sn(II) co-doped SnO₂ nanosheets along sacrificial titanate nanowires: synthesis, characterization and electrochemical properties.
abstract: Hierarchical assembly of Ti(IV)/Sn(II)-doped SnO₂ nanosheets along titanate nanowires serving as both sacrificial templates and a Ti(IV) source is demonstrated, using SnCl2 as a tin precursor and Sn(II) dopants and NaF as the morphology controlling agent. Excess fluoride inhibits the hydrolysis of SnCl2, promoting heterogeneous nucleation of Sn(II)-doped SnO₂ on the titanate nanowires due to the insufficient oxidization of Sn(II) to Sn(IV). Simultaneously, titanate nanowires are dissolved forming Ti(4+) species under the etching effect of in situ generated HF resulting in spontaneous Ti(4+) ion doping of SnO₂ nanosheets formed under hydrothermal conditions. Compositional analysis indicates that Ti(4+) ions are incorporated by substitution of Sn sites at a high level (16-18 at.%), with uniform distribution and no phase separation. Mössbauer spectroscopy quantified the relative content of Sn(II) and Sn(IV) in both Sn(II)-doped and Ti(IV)/Sn(II) co-doped SnO₂ samples. Electrochemical properties were investigated as an anode material in lithium ion batteries, demonstrating that Ti-doped SnO₂ nanosheets show improved cycle performance, which is attributed to the alleviation of inherent volume expansion of the SnO₂-based anode materials by substituting part of Sn sites with Ti dopants.
authors.affiliation: Department of Physics and Materials Science & Centre for Functional Photonics (CFP), City University of Hong Kong, Hong Kong SAR. andrey.rogach@cityu.edu.hk.
authors.forename: Hongkang
authors.initials: H
authors.lastname: Wang
authors.forename: Liujiang
authors.initials: L
authors.lastname: Xi
authors.forename: Jiri
authors.initials: J
authors.lastname: Tucek
authors.forename: Yawen
authors.initials: Y
authors.lastname: Zhan
authors.forename: Tak Fu
authors.initials: TF
authors.lastname: Hung
authors.forename: Stephen V
authors.initials: SV
authors.lastname: Kershaw
authors.forename: Radek
authors.initials: R
authors.lastname: Zboril
authors.forename: C Y
authors.initials: CY
authors.lastname: Chung
authors.forename: Andrey L
authors.initials: AL
authors.lastname: Rogach