适用于微型燃料电池扩散层的多孔硅的可控制备工艺研究

多孔硅以其多孔结构及大的表面体积比等特点被认为是可在基于MEMS技术的微型燃料电池中代替碳 纸、碳布作为扩散层的材料. 本文考虑传统碳纸、碳布作为扩散层的要求, 并结合多孔硅材料的特点, 选用n<100>(0.04～0.15 Ω·cm)单晶硅进行了多孔硅制备工艺的研究; 考察了腐蚀液的浓度、电流密度和氧化处理时间对多孔硅的孔隙率、孔深度及氧化速率 的影响, 实现了多孔硅的可控制备. 孔隙率为40%、孔径为350～700nm、厚度为60μm的多孔硅膜电极经循环伏安测定, 在0.5mol/L H₂SO₄溶液中, 表现出与碳纸相近的电活性, 显示了潜在的应用价值.

Controlled Preparation of Porous Silicon as Diffusion Layer for Miniature Fuel Cell

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 .