1 research outputs found
Single-Walled Carbon Nanotube-in-Binary-Polymer Nanofiber Structures and Their Use as Carbon Precursors for Electrochemical Applications
Hierarchical structuring
of materials in the nanometer regime provides
opportunities to achieve extraordinary characteristics of the resulting
products. Here, we report unique one-dimensional hierarchical nanostructures
consisting of single-walled carbon nanotubes (SWNTs), polyvinyl alcohol
(PVA), and polyacrylonitrile (PAN). First, SWNT-in-binary-polymer
nanofiber (SbPNF) structures were obtained through the incorporation
of PVA-wrapped SWNTs into PAN, followed by the electrospinning of
the SWNT/PVA/PAN solution. Importantly, the SbPNFs exhibited an aligned
SWNT-in-nanofiber structure and enhanced ordering of the polymer chains.
The SbPNFs were successfully converted to carbonized products [SWNT-in-carbon
nanofibers (SbCNFs)] with enhanced crystallinity and tunable electrochemical
properties. Compared to those of the control samples (no SWNT), the
charge-transfer resistance and the surface area of the SbCNFs were
two orders of magnitude lower and 11–20% higher, respectively,
which resulted in better electrochemical properties. The major factors
determining the properties of the SbCNFs included the SWNT content
and PVA/PAN microphase behavior. Furthermore, the removal of the PVA
phase from the SbPNFs provided another opportunity to control the
textural properties of the carbonized products. It was found that
meso- and macropores were more developed in the carbonized products
(SCNFs). The specific capacitance of the SCNFs increased to a maximum
of 577 F g<sup>–1</sup>, which was 3.7 times higher than that
of the SbCNFs. The SCNF with the best properties was successfully
applied to electrochemical capacitors as the electrode material. It
is believed that further optimization of the hierarchical nanostructures
will impart attractive properties for various applications