Structural mechanism investigation on methanol crossover and stability of a passive direct methanol fuel cell performance via modified micro‐porous layer

Abstract

Methanol crossover affects the performance of a direct methanol fuel cell (DMFC). To overcome this problem, this study introduced a modified microporous diffusion layer (MPL) with addition of titanium dioxide (TiO 2 ) to the carbon nano-fibre (CNF) and carbon black (CB) material at the anode side of DMFC. The main objectives of this work were to present a surface characterization of the modified MPL via scanning electron microscopy (SEM) and discussed the detailed mechanism on the drop of the power density due to increment of methanol concentration. Secondly, this work also tested the performance and stability of the modified MPL. The SEM imaging showed a reduced surface crack at the anode diffusion layer in CB + TiO 2 , the pore network improved on the mixture of CNF-TiO 2 . Electrochemical impedance spectroscopy (EIS) showed that TiO 2 has low resistance and helps to reduce the resistance when added to the CNF and CB. These findings showed that the mixture of TiO 2 with CNF and CB presented a good effect in reducing the methanol crossover by presenting the lowest percentage for stability drop as 0.31% and 1.37% compared to other researchers. It also improved the stability of the DMFC power output over the long-term performance test. Highlights:• This study presents a surface characterization of the modified MPL of TiO 2 -CNF-CB • It also discusses in detail the mechanism on the power density drop due to increment of methanol concentration • This study will also test the performance and stability of the modified MPL.• The results show that the mixture of TiO 2 -CNF-CB improved the stability of the DMFC K E Y W O R D S anode diffusion layer, carbon nano-fibre, direct methanol fuel cell, titanium dioxide

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