Passive vapor-feed direct methanol fuel cell using sintered porous metals to realize high-concentration operation

The use of methanol vapor is helpful to reduce the effect of methanol crossover in a direct methanol fuel cell. This study develops a passive vapor-feed direct methanol fuel cell (VF-DMFC) based on a pervaporation membrane and sintered porous metals which act as functional layers for effective control of the mass transfer process. The feasibility of using this method is experimentally validated. For the cathode, a sintered porous metal-fiber plate (SPMFP) with great hydrophobicity is used as a water management layer to enhance water back diffusion from the cathode to the anode. Results indicate that the use of a SPMFP promotes a higher cell performance especially when a higher methanol concentration is used. The highest peak power density of 19.3mW/cm2 is achieved at an ambient temperature when 12M methanol is supplied. Neat-methanol operation is also viable under this condition. The cathode current collector (CC) with a window-like pattern yields a higher cell performance than the parallel-channel. For the anode, the use of a hydrophilic sintered porous metal-powder plate (SPMPP) embedded in the anode CC reduces the cell performance due to limitation of methanol delivery. This work also reports the influences of methanol concentration and vapor chamber temperature.