Experimental investigation of methanol crossover evolution during direct methanol fuel cell degradation tests

Methanol crossover and severe degradation are two of the most critical issues hindering the commercialization of direct methanol fuel cells. The experimental investigations found in the literature show that degradation has both permanent and temporary contributions; the latter can be recovered thanks to a suitable operation interruption. This work reports the experimental characterization of methanol crossover and water content in cathode exhaust during different degradation tests performed in continuous and cycling operation modes. Such investigation evidences a reduction of methanol crossover during the DMFC degradation tests that can be partially restored. Methanol crossover reduction presents both temporary and permanent contributions: the latter could be related to membrane degradation. Moreover the effect of both methanol crossover and electric power reduction on fuel cell efficiency are discussed.