直接甲醇燃料电池溶胶-凝胶流动相的制备与表征

Preparation and Characterization of Sol-Gel Flux Phase in Direct Methanol Fuel Cell

对直接甲醇燃料电池溶胶-凝胶流动相的制备工艺进行了分析,采用溶胶-凝胶法以正硅酸甲酯为前驱体制备出了溶胶-凝胶流动相。分别以溶胶-凝胶流动相和液体流动相为燃料对比研究了直接甲醇燃料电池的放电性能,测定了溶胶-凝胶流动相在Nafion117膜中的甲醇渗透率,研究了溶胶-凝胶流动相的质子电导率。实验结果表明,使用溶胶-凝胶流动相时,单电池性能比使用液体流动相时稍低,可以用作直接甲醇燃料电池的燃料;室温下溶胶-凝胶流动相在质子交换膜中的甲醇扩散系数为1.46×10-7 cm2·s-1,而液态流动相的甲醇扩散系数为1.43×10-6 cm2·s-1,与液态流动相相比溶胶-凝胶流动相的甲醇渗透率下降了约90%,其甲醇渗透率明显降低;溶胶-凝胶流动相的质子电导率与液态流动相基本一致,均达到165 mS·cm-1以上,说明溶胶-凝胶流动相质子导电性能良好。

The sol-gel flux phase used in direct methanol fuel cell （DMFC） was prepared by sol-gel method with methyl silicate as the precursor. The discharge performance comparison between the DMFC using sol-gel flux phase and that using liquid flux phase was conducted, the methanol crossover rate through the Nafion117 membrane was determined and the proton conductivity of the sol-gel flux phase was investigated. The results show that the cell performance of DMFC with sol-gel flux phase is a little lower than that of the DMFC with liquid flux phase, and the sol-gel flux phase can be used as the fuel of DMFC. It was found that the methanol diffusion coefficient of the sol-gel flux phase is about 1.46×10-7 cm2.s-1, while the methanol diffusion coefficient of the liquid flux phase is about 1.43×10-6 cm2·s-1; compared with the liquid flux phase, the methanol crossover rate of the sol-gel flux decreases about 90%. The proton conductivity of the sol-gel flux phase is as well as that of the liquid flux phase, and both of them are about 165 mS.cm-1, which means that the sol-gel flux phase has an excellent proton conductivity.