Forced under-rib water removal by using expanded metal mesh as flow fields for air-breathing direct methanol fuel cells

Abstract Water management is a critical issue to be solved efficiently for an air-breathing direct methanol fuel cell (DMFC). The cell performance decreases sharply once the water flooding occurs. In this paper, a novel strategy of water removal is proposed by incorporating a functional self-made expanded metal mesh, which can be used as the cathode flow field in a DMFC. Experiments show that water can be directly discharged in the form of water film or water line from the water outlet to the bottom underneath the expanded mesh. The water management can be further improved by using absorbent cottons, suitable feed rates and an upright texture direction of the metal mesh. Results also show that only a few mesh openings are blocked by water when the tested device tilts from 60° to 120°. In a real DMFC, the expanded mesh displays an excellent ability in water removal compared to the traditional perforated flow fields. The cathode water only gathers at the bottom and covers very few mesh openings. This new method helps efficiently avoid the issue of water flooding at the cathode using the expanded mesh.