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

This paper introduces a distributed gas breather to remove the gas byproduct (CO₂) from the micro direct methanol fuel cell (μDMFC). The concept and device configuration of "distributed breathing" aim to improve the performance of the μDMFC 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 CO₂ 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 μDMFC system, are discussed.