Abstract:

Porous silicon (PS) due to its porous structure and large surface-to-volume ratio is prospective to substitute the traditional diffusion layer materials such as carbon paper or carbon cloth in miniaturized fuel cell based on MEMS technology. On singal-crystalline silicon n<100>(0.04--0.15Ω·cm) PS film was prepared. In order to make the preparation controllable, the effects of various experimental conditions including HF concentration, current density and anodization duration on porosity, pore depth and anodization rate were systematically examined. The C-V curves of PS film with 40% porosity, 500--700nm aperture and 60μm depth in 0.5mol/L H₂SO₄ solution indicate that PS electrode surfaces exhibit comparable catalytic activity with that of carbon paper. Therefore, the PS film shows potential application value in μPEMFCs .

Key words: miniaturized fuel cell, diffusion layer, porous silicon, controllable preparation