Using a Sulfonated Silicon Dioxide Added Membrane Electrode Assembly to Improve the Performance of Self-humidifying Fuel Cell

• Main Authors: Shih-Chieh Hsu, 徐世杰
• Other Authors: Chien-Liang Lin
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/89092130350083863796

碩士 === 明道大學 === 材料科學與工程學系碩士班 === 100 === When a proton exchange membrane fuel cell (PEMFC) perfoms an electrochemical reaction, the moisture content of the proton exchange membrane has a substantial influence on proton transmission. To maintain the high moisture content of the membrane, a humidifier is typically placed in the system. This study, however, develops a self-humidifying fuel cell to reduce system weight and space, and to simplify the system. This experiment directly added SiO2 to the catalyst layer and enhanced the electrochemical reaction of the water diffusion between the cathode and the anode. In addition, SiO2 was modified by sulfonation to enhance the proton conductivity. A sulfonated mixture of SiO2 and the Pt/C catalyst was used as the anode catalyst layer. The preparation of the membrane electrode assembly was conducted using the traditional method, transfer method, and composite coating method. The single-cell operating temperatures were 50 and 70°C, anode/cathode humidification temperatures, 70oC/70oC, 50oC/50oC, 25oC/25oC, no humidification/25oC, and no humidification/no humidification at five types of humidification. The effects of various SiO2 and sulfonated SiO2 loadings, as well as various fabrication processes, were examined to determine the best method for enhancing the self-humidifying fuel cell performance. The results showed that adding minute quantities of sulfonated SiO2 into the 0.5 V enhanced the cell efficiency more so than not adding SiO2 by 34% when cell temperature 50oC the humidification temperature of 70oC and 50oC. Adding sulfonated SiO2 using the composite coating method effectively enhanced the self-humidifying fuel cell performance in low humidity conditions. The results for all tests showed that the transfer method had the best efficiency. A self-humidifying temperature of 50oC represented the optimal operating condition.