Effects of degradation products of the silicone gasket material on electrochemical performance and durability of proton exchange membrane fuel cell

초록

Gasket is a sealing material in proton-exchange membrane fuel cells (PEMFC) to prevent leakage and to prevent mixing of hydrogen and oxygen. In PEMFC, since gaskets are exposed to acidic liquid solution and subjected to mechanical stress, long-term chemical and mechanical stability and durability are essential, which can greatly affect the electrochemical performance and sealing of PEMFC. Silicone is an ideal candidate for gasket of PEMFC because of its excellent chemical stability and broad temperature range. However, silicone may decompose into low molecular weight materials in the fuel cell environment, and those low molecular weight materials may flow into other parts of the fuel cell, reducing performance and durability. Therefore, in this work, a silicone gaskets were synthesized and analysis of the degradation products of silicone rubbers under the accelerated PEM fuel cell environment was investigated. Electrochemical performance tests were performed to investigate the effect of fluorine group content on the performance of PEMFC. Optical microscopy was used to observe the surface change of the sample under an acidic environment and the mechanical strength was measured to confirm the acid resistance. Atomic absorption spectrometer analysis was employed to investigate silicone leachants eluted from the sample. This work was supported by the Technology Innovation Program(20009983) funded by the Ministry of Trade, Industry and Energy (MOTIE, Korea)