Research of CNT and Acetylene Black within microporous layer coating for Alkaline Anion Exchange Membrane Fuel Cell

• Main Authors: Li-Wei Zheng, 鄭力瑋
• Other Authors: 楊錫杭
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107NCHU5693013%22.&searchmode=basic

碩士 === 國立中興大學 === 精密工程學系所 === 107 === In this research, the effect of the microporous layer composition on the anion exchange membrane fuel cell performance has been systematically investigated. In particular, two types of commercial carbon materials, acetylene black and multi-walled carbon nanotubes (MWCNT), were used to fabricate the microporous layer with polytetrafluoroethylene (PTFE) content. Different weight ratios of acetylene to MWCNT ratios of acetylene to MWCNT have been prepared and coated on the gas diffusion substrate which made up carbon fiber paper with hydrophobic treatment. Furthermore, the better air permeability and lower in-plane electric resistance were obtained from the samples with more MWCNT addition, which are due to the higher mud crack density and dimension formed on the MPL and higher electrical conductivity of MWCNT, respectively. From the surface morphology analysis, the SEM results showed that the rougher MPL surface with more and larger mud cracks was observed on the samples with higher amount of MWCNT. This can be attributed to the agglomeration of carbon nanotubes in the MPL slurry. For single AEMFC testing, the results showed that the power densities of an H2/O2 AEMFC using GDLs with coated MPL prepared by various weight ratios of acetylene to MWCNT being 1:0, 4:1, 1:1, and 1:2 were 396, 411, 518, and 354 mW/cm2, respectively. This indicated that, among prepared MPL samples, the GDL with MPL containing the 1:1 ratio of acetylene to MWCNT exhibited the best cell performance which can be ascribed to the better air permeability and electric conductivity. However, higher MWCNT addition in the MPL compared to acetylene (1:2 ratio) will form too big mud cracks on the MPL surface, which impact on the water removal and catalyst layer coating, and thereby, significantly reduce the cell performance. Thus, although the MWCNT can be beneficial for both air permeability and electric conductivity of the GDL, due to the easy agglomeration of MWCNT, the amount of MWCNT in the MPL should be carefully optimized to achieve higher cell performance.