Fluorine-Doped SnO<sub>2</sub>@Graphene Porous Composite
for High Capacity Lithium-Ion Batteries
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Abstract
For the first time, a composite of
fluorine-doped SnO<sub>2</sub> and reduced graphene oxide (F-SnO<sub>2</sub>@RGO) was synthesized
using a cheap F-containing Sn source, Sn(BF<sub>4</sub>)<sub>2</sub>, through a hydrothermal process. X-ray photoelectron spectroscopy
and X-ray diffraction results identified that F was doped in the unit
cells of the SnO<sub>2</sub> nanocrystals, instead of only on the
surfaces of the nanoparticles. F doping of SnO<sub>2</sub> led to
more uniform and higher loading of the F-SnO<sub>2</sub> nanoparticles
on the surfaces of RGO sheets, as well as enhanced electron transportation
and Li ion diffusion in the composite. As a result, the F-SnO<sub>2</sub>@RGO composite exhibited a remarkably high specific capacity
(1277 mA h g<sup>–1</sup> after 100 cycles), a long-term cycling
stability, and excellent high-rate capacity at large charge/discharge
current densities as anode material for lithium ion batteries. The
outstanding performance of the F-SnO<sub>2</sub>@RGO composite electrode
could be ascribed to the combined features of the composite electrode
that dealt with both the electrode dynamics (enhanced electron transportation
and Li ion diffusion due to F doping) and the electrode structure
(uniform decoration of the F-SnO<sub>2</sub> nanoparticles on the
surfaces of RGO sheets and the three-dimensional porous structures
of the F-SnO<sub>2</sub>@RGO composite)
