Experimental Study on Performance Improvement of Laminar Flow-Based Fuel Cell

The polymer electrolyte fuel cell (PEFC) is one of the promising candidates for the next generation power sources, however, there have still remained some issues such as manufacturing cost, material durability, fuel crossover and difficulty in water management. Almost all of these issues are attributed to the membrane used. The laminar flow-based fuel cell (LFFC), which is actually membraneless, has recently been proposed to overcome these issues. In LFFC, liquid fuel and liquid oxidant are supplied, flowing parallel with a thin boundary of diffusion zone, across which protons travel and electricity is generated.

This study aimed to improve the performance of LFFC and identify the factors that significantly influence the fuel cell performance. Here, the basic performance of a single cell LFFC, such as OCV and I-V characteristics, was investigated experimentally in conjunction with the internal flow visualization. Methanol solution was used as fuel and hydrogen peroxide solution or air was used as oxidant. Solutions were supported by sulfuric acid to enhance ionic conductivity. In I-V characteristics measurements, experimental parameters such as flow rate, oxidant concentration, operating temperature were varied to see how these parameters influenced the performance.

The results showed that the fuel cell performance was improved at higher operating temperature and oxidant concentration, however, performance improvement was not achieved at higher fuel flow rate. The results also showed that reduction of the electrode length along the flow direction decreased the influence of the boundary layer depletion and thereby improved the fuel cell performance. It was also revealed that the fuel cell performance was improved by reducing the distance between the electrodes. In conclusion, oxidant was more important than fuel in LFFC.