The Research Of Skin Effect To Catalysts In PEMFC

Proton exchange membrane fuel cell (PEMFC) will meet dynamic in operation at present, it will face 66%-80%of the dynamic situation when it as a car engine. The dynamic of PEMFC will cause the output of battery present dynamic current. This paper analysis the output current waveform of PEMFC, and simplified the output current waveform as sine wave. Then test the major structural materials of PEMFC (stainless steel material and graphite materials) into sine wave current, using electromagnetic method and mathematical induction strength calculation method to calculate the current density in material. In order to study the influence of skin effect to catalyst, this paper will be place catalyst into the stainless steel material with skin effect and testing the different positions of catalyst with electrode electrochemical properties and TEM. The main conclusions of experiments are as follows:(1) PEMFC will produce rectangle and sine wave dynamic current when it was in dynamic. The current density distribution of graphite and stainless steel material will be uneven in the sine wave power, and the current density distribution was effect by the qualitative of conductivity and the frequency of current. Compared with the current density distribution in tested materials and skin effect, it is known that dynamic current in PEMFC will cause skin effect in the materials.(2) The electrochemically active area, the size and distribution of Pt in different place of catalyst were tested. It is found that a higher current density will cause the down of electrochemically active area and the increase of Pt size.So, catalyst will be effected by the qualitative of conductivity and the frequency of current.