摘要
Hydroxyl anion conducting membrane composed of poly(vinyl alcohol)(PVA),poly(diallyldimethylammonium chloride)(PDDA),and hydroxylated multiwalled carbon nanotubes(MWCNTs-OH)have been synthesized via a facile blending-casting method assisted by a hot-chemical cross-linking process.Fourier-transform infrared spectroscopy(FTIR)and scanning electron microscopy(SEM)showed that PDDA and MWCNTs-OH were successfully introduced into the PVA matrix and MWCNTs-OH could effectively improve the network structure of the membrane.With the addition of MWCNTs-OH,many properties of the membranes such as thermal,chemical,mechanical stability and swelling property were improved significantly.Most prominent is the improvement of mechanical property,where the PVA/PDDA/MWCNTs-OH(1:0.5/3 wt.%)membrane showed high tensile strength of 40.3 MPa,tensile elongation of 12.3%and high Young's modulus of 782.8 MPa.Moreover,MWCNTs-OH bound the polymer chains in the membranes more compactly,resulting in decreased water uptake.By tuning the mass fraction of PVA,PDDA,and MWCNTs-OH in the membrane,the maximum OH-conductivity(0.030 S cm^(-1)at room temperature)was achieved for the composition of 0.5 wt.%MWCNTs-OH doped with the PVA:PDDA(1:0.5 by mass)blend.The membranes showed excellent oxidative stability when treated with both a solution of H_(2)O_(2)(30 wt.%)at room temperature and in a hot KOH solution(8 M)at 80℃.Based on the full aliphatic structure membrane(PVA/PDDA-OH/1 wt.%MWCNTs-OH),membrane electrode assemblies(MEAs)fabricated with Pt/C cathode catalyst can achieve power densities of 41.3 mW cm^(-2)and 66.4 mW cm^(-2)in a H_(2)/O_(2)system at room temperature and 40℃,respectively.Using CoPc as the Pt-free cathode catalyst,power densities of 9.1 mW cm^(-2)and 14.0 mW cm^(-2)at room temperature and 40℃ were obtained,respectively.
基金
This work was financially supported by Chinese National Natural Science Foundation(grant no.51803175)。
