Influence of intermediate liquid electrolyte layer on the performance of passive direct methanol fuel cell

摘要

Liquid feed Passive Direct Methanol Fuel Cell (DMFC) is a promising option for charging low power application devices. In passive DMFC, Nafion membranes provide high proton conductivity, chemical, and thermal stability. However, the DMFC suffers from the disadvantage that the Nafion membrane allows the flow of methanol fuel from the anode side to cathode side (methanol crossover), and leads to mixed overpotential losses. In the present study, liquid electrolyte (LE) layer is introduced between two Nafion membranes to reduce the methanol crossover and to improve the performance of the passive DMFC. The LE layer consists of piled hydrophilic filter papers, which are soaked in diluted sulfuric acid solution. Three different LE layers of thickness 1.5 mm, 2 mm and 2.5 mm are considered. The fuel cell performance is studied by varying the methanol concentration also. Experimental studies are carried out to find out the best thickness of the LE layer, which gives better fuel cell performance for different methanol concentrations. The fuel cell performance is evaluated in terms of peak power density and maximum current density. Optimum LE layer thickness of 2 mm, which gives better passive DMFC performance for different methanol concentration ranges is identified. The corresponding peak power density and maximum current density are 3.872 mW cm(-2) and 33.6 mAcm(-2), which are around 30.71% and 13.51% greater than the corresponding conventional-DMFC values, respectively.