پديدآورندگان :
Zhiani Mohammad mohammad.zhiani@gmail.com Isfahan University of Technology , Ghasemi shervedani Ziba Isfahan University of Technology , Kamali Saeedeh Isfahan University of Technology
كليدواژه :
graphene oxide , multi walled carbon nanotube , solution casting procedure , nanocomposite membrane , aluminum air battery
چكيده فارسي :
The procedure of membrane synthesis and evaluation plays an important role in development of
new energy related technologies such as fuel cells, batteries and electrolyzer. The main challenge of
membrane technology is the synthesis of high efficient, environmental friendly and cost effective
membranes. In this work, a series of proton exchange membranes based on multi-functionalized
graphene oxide (GO) and multi walled carbon nanotube (MWCNT) were synthesized via a solution
casting procedure. The structure and morphology of the samples were investigated by Fourier
transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and optical polarizing
microscopy. Finally, the synthesized membranes were evaluated for proton conductivity from the
point of measured current versus time at a constant potential in a homemade aluminum air battery
cell setup and compared with the commercial nafion 112 membrane. For the synthesis of
membranes, at first GO was synthesized through modified hummer method [1], MWCNT
purchased from US research nanomaterials Inc. (OD: 20-30 nm) and purified via reflux treatment
in HCl: HNO3 solution at 90 ◦C for 30 min, Then they were sulfonated via chlorosulfonic acid [2]
and labeled as GO-SO3H and MWCNT-SO3H respectively. The membranes were prepared by
casting the polymer solution of polyacrylonitrile/dimethylformamide With GO, GO-SO3H and
MWCNT-SO3H to get modified membranes with the labels of GO-AN, GO-SO3H-AN and
MWCNT-SO3H-AN. Fig. 1 shows the FT-IR spectra of GO, GO-SO3H and MWCNT-SO3H. As it
can be seen in the figure, all of the characteristic peaks of C-O, C=C, C=O and C-OH are obvious
in all samples spectra. But GO-SO3H and MWCNT-SO3H spectra showed the additional O=S=O
stretching vibration, -SO3- symmetrical stretching vibration and S-OH stretching vibration which
can enhance the proton conductivity of membrane.
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Figure 6. FT-IR spectra of GO, of GO-SO3H and MWCNT-SO3H
Fig. 2 shows the optical polarizing microscopy of GO-SO3H. It confirms the transparity and
presence of sulfonated GO in the nanocomposite membrane. The average currents of GO-SO3HAN,
MWCNT-SO3H-AN and GO-AN were 705, 653 and 608 mA at 2.3 V whereas the measured
current for nafion 112 was 1200 mA at this voltage. It appears that of GO-SO3H-AN and MWCNTSO3H-
AN nanocomposite membranes can be good candidates for future battery applications
Figure 7. Typical optical polarizing microscopy of GO-SO3H