Synthesis, characterisation and electrochemical testing of multiwalled carbon nanotubes based nanocomposites for supercapacitor materials
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Date
2010-04
Authors
Valizadeh Kiamahalleh, Meisam
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Abstract
Electrochemical supercapacitors are becoming attractive energy storage
devices and fill the gap between conventional capacitors and batteries because they
have higher power density and a longer cycling life than batteries and have higher
energy density than conventional dielectric capacitors. In this study, in order to take
full of the capacitive behavior from different materials, hybrid supercapacitor
electrodes made from multiwalled carbon nanotubes (MWCNTs), transition metal
oxides and supported poly (3,4-ethylenedioxythiophene) (PEDOT) were
investigated. Different transition metal oxides, such as CuO, Fe203, NiO and Mn02,
were filled inside MWCNTs by wet chemical method. Transmission electron
microscope (TEM) images revealed that metal oxides particles encapsulated in the
cavities of MWCNTs. Energy-dispersive X-Ray (ED X) supported the chemical
composition of metal oxideslMWCNTs nanocomposites indicating that the particles
compositions comprised solely of carbon, metal and oxygen.The capacitive
behaviour of the prepared nanocomposites were investigated by using cyclic
voltammetery (CV) technique. It was found that the capacitive behaviour ofNiO and
Mn02 filled in MWCNTs were higher than that of Fe203 and CuO. Hence,
nanocomposites consisting ofNiO and Mn02 and MWCNTs were prepared in order
to obtain higher capacitive behaviour. The obtained NiOIMn02IMWCNTs
(NMOIMWCNTs) nanocomposite gave high capacitive behaviour. In addition,
charge/discharge (CD) test for this nanocomposite demonstrated high specific
capacitances (SC) value of 407.09 F/g due to the high pseudocapacitive behaviour of
NiO and Mn02. Moreover, in order to further enhance the capacitive behaviour of
the NMO/MWCNTs nanocomposite, it was coated with PEDOT as another type of
pseudocapacitive material. The obtained NMO/MWCNTslPEDOT nanocomposite
gave higher capacitive behaviour than NMO/MWCNTs nanocomposite and
demonstrated greater SC value of 535.00 Fig due to adding PEDOT. The TEM
images of NMO/MWCNTslPEDOT nanocomposite interestingly showed the
successful filling NMO particles inside MWCNTs and confirmed the uniform
coating of PEDOT layer on MWCNTs. EDX spectra and X-ray diffraction (XRD)
pattern, confirmed the composition and crystal phase of NMO particles inside
nanocomposite and the existence of PEDOT on NMO/MWCNTs nanocomposite.
Thermal gravimetric analysis (TGA) on NMO/MWCNTslPEDOT nanocomposite
showed that almost 20 wt% and 48 wt% of it were NMO particles and PEDOT,
respectively. The maximum SC value predicted by design of experiment (DOE) from
single response optimisation of NMO/MWCNTs and NMO/MWCNTslPEDOT
nanocomposites were 453.12 and 545.36 Fig, respectively.
Description
Keywords
Synthesis, characterisation and electrochemical testing of multiwalled carbon nanotubes based nanocomposites for supercapacitor materials , because they have higher power density and a longer cycling life