Active layer of fuel cell electrode with polymer electrolyte: Modeling of support grains, calculation of overall cathode characteristics

作者：Chirkov Yu G^*; Rostokin V I

来源：Russian Journal of Electrochemistry, 2013, 49(2): 149-160.

DOI：10.1134/S1023193513020055

• fuel cell with polymer electrolyte
• active layer
• computer simulation
• model of equally sized grains of three types
• optimum structure of the carbon support grain
• combined percolation cluster
• Knudsen diffusion

The active layer of the cathode of a fuel cell with polymer electrolyte (Nafion) is considered. The optimum carbon support structure is constructed using computer simulation: its carbon "skeleton" possesses the maximum outer surface area and provides electronic conductivity of the grains, support cubes, along the three coordinate axes. Nafion is absent in the support grain, so that the grain is capable of participating only in the transport of oxygen molecules, it possesses no proton conductivity. An estimate of all parameters of an optimum support grain is provided; in particular, the value of the effective Knudsen diffusion coefficient of oxygen is established. After this, effective proton conductivity and effective Knudsen diffusion coefficient are calculated already on the whole active layer scale, according to the model of equally sized cube grains of three types. In conclusion, the overall current in the active layer of a cathode with a polymer electrolyte was calculated for the percolation cluster consisting only of Nafion grains and the Knudsen diffusion of oxygen created only by a combined gas percolation cluster consisting of void grains and all support grains. The overall current value for t = 80A degrees C and pressure of p* = 101 kPa proved to be low, hundreds of mA/cm(2). The current value can apparently be increased to several A/cm(2) if the support grains are developed that would simultaneously possess both proton conductivity and ability to sustain oxygen diffusion.

• 出版日期2013-2