A distributed gas breather for micro direct methanol fuel cell (μ-DMFC)

Abstract

This paper introduces a distributed gas breather to remove the gas byproduct (CO/sub 2/) from the micro direct methanol fuel cell (/spl mu/DMFC). The concept and device configuration of "distributed breathing" aim to improve the performance of the /spl mu/DMFC by (1) decreasing flow resistance, (2) increasing the active electrode area, and (3) reducing or possibly eliminating the discrete gas separator. Experimental verification is provided by a prototype breather with microscale hydrophobic breathing holes, which successfully removed CO/sub 2/ bubbles from a mixture of weak sulfuric acid and sodium bicarbonate aqueous solution. The techniques to fabricate sub-micron hydrophobic breathing holes with good stability, which would enable integration of the breather into the eventual /spl mu/DMFC system, are discussed.