Novel Anode Electrode Structure with a Fuel Management Layer for High-Concentration Passive Direct Methanol Fuel Cells

Methanol crossover is one of the main reasons that direct methanol fuel cells (DMFCs) cannot take advantage of a high theoretical energy density. Meanwhile, methanol crossover affects cell performance and cell life, which is one of the major obstacles to the development and application of DMFCs. To solve this problem, a novel anode electrode structure with a fuel management layer (FML) has been proposed for high-concentration passive DMFCs. The FML located between the anode flow field and the anode gas diffusion layer is constructed using nitrogen-doped carbon aerogel with superb wettability properties and an abundant capillary structure. The hydrophilic FML prepared from nitrogen-doped carbon aerogel adsorbs and stores fuel, inhibiting methanol transfer to the anode. Therefore, the methanol mass-transfer resistance is increased, and the methanol concentration inside the anode is reduced, which alleviates serious methanol crossover under a high methanol concentration supply. Different from the conventional stand-alone structure with a certain thickness, the hydrophilic FML structure is simple, and the preparation process is easy and compatible with the preparation of membrane electrodes, which almost does not increase the volume and weight of the DMFC. The novel structure proposed in this paper can increase the energy density of DMFC and enhance its application potential.