A study on porous silicon as diffusion layers and catalyst support in micro-DMFC application

• Main Authors: Chang-Chung Lai, 賴昶均
• Other Authors: Chii-Rong Yang
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/xy9m44

碩士 === 國立臺灣師範大學 === 機電科技研究所 === 96 === With the state of the art and the raised environmental consciousness, humans need certain power sources which are clean and environmentally friendly applied on daily-used portable electronic devices. DMFCs (DMFC, direct methanol fuel cell) were thought as the most promising power suppliers to replace lithium battery in next generation and are characterized with low operation temperature, rapid activation, high energy density, ease of carry and acquirement. Therefore, this research tried to fabricate a DMFC(micro DMFC), simplified its constitution and lower the cost to realize the possibility of DMFC integrated with portable electronic devices. This research were divided into four items: (1) flow channels realization with convex corner protected were fabricated with etchant composed of TMAH and additive; (2) porous silicon layer connected with flow channel were considered to replace carbon paper as diffusion layer; (3) the comparison of different thickness of porous layer with performances of DMFCs; (4) comparisons of performances resulted from porous silicon and carbon paper as diffusion layers. Experiments show that the 375 m-deep channel were successfully realized using TMAH solution with specific surfactant added; furthermore, the interconnected, 300 m-deep porous silicon diffusion layer connected with flow channels was achieved by PAECE (photo-assist electrochemical etching) process and the constitution of the DMFC were simplified also. The designed DMFC with 225 m-thick PS. Layer showed the maximum OCP of 387m V; maximum current density of 1.828 mA/cm2; maximum power density of 0.142 mW/cm2 and nearly equal to the performance (0.150 mW/cm2) of DMFC with carbon diffusion layer. Experimental result showed that using PS. layer in replace of carbon paper would be the promising way in DMFC application. Keywords: fuel cell, methanol, porous silicon, diffusion layer