Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - FEDMFC (DEVELOPMENT OF A HIGH PERFORMANCE FLOWING ELECTROLYTE-DIRECT METHANOL FUEL CELL STACK THROUGH MODELING AND EXPERIMENTAL STUDIES)

Teaser

Among the different fuel cell types, direct methanol fuel cells are considered to be a very promising energy technology for portable applications. Using liquid methanol as the fuel makes this fuel cell type favorable as methanol is easy to store and has low cost and high...

Summary

Among the different fuel cell types, direct methanol fuel cells are considered to be a very promising energy technology for portable applications. Using liquid methanol as the fuel makes this fuel cell type favorable as methanol is easy to store and has low cost and high energy density. One of the greatest challenges associated with this technology is methanol crossover problem. To overcome this challenge, a fuel cell design namely flowing electrolyte-direct methanol fuel cell (FE-DMFC) can be used. This fuel cell type is a novel energy technology in which the performance of the conventional DMFC is increased by eliminating the methanol crossover problem. To maximize the performance of this fuel cell, the design and operating parameters should be properly selected.

In this project, the main objective was to develop a high performance FE-DMFC stack through modeling and experimental studies. For this purpose, a three-dimensional and two-phase multiphysics model, which includes all the transport phenomena, was developed to predict the performance of the FE-DMFC stack accurately. In addition, a FE-DMFC based on alternative materials was manufactured in-house in cooperation with the partner organization in Europe (Forschungszentrum Jülich). Through the experimental and modeling studies, the effect of key design and operating parameters of the FE-DMFC on the output parameters was investigated; thus the parameters that increase the performance of this fuel cell mostly were determined. The specific objectives of the project are listed below.
• To develop a three-dimensional and two-phase multiphysics model of the FE-DMFC, which includes all the transport phenomena in all the layers
• To manufacture a FE-DMFC based on alternative materials
• To validate the model developed with experimental data
• To investigate the effect of significant design and operating parameters on the output parameters of the FE-DMFC
• To determine the parameters that increase the performance of this fuel cell mostly

This project is expected to contribute to the economy and prosperity of European Society as it was shown that FE-DMFC having alternative materials could have high performance and be used in portable devices in future. It was also shown that FE-DMFC can be used as a characterization tool to study the performance of cathodic electrodes and the influence of crossover in DMFCs. The result of this project can be beneficial for some of the fuel cell companies, universities, and research institutes that are interested in using methanol as the fuel to generate electricity.

Work performed

During this two-year project, the following steps were followed. Firstly, a comprehensive literature survey was carried to create a list of the alternative membrane electrode assembly (MEA) materials (and their properties) for DMFCs that have superior performance and durability. In addition to the literature survey, the effect of inclusion of zirconium phosphate to the membrane and cathode catalyst on the performance of DMFC was investigated. Secondly, a new FE-DMFC design based on alternative materials was formed and manufactured. This fuel cell was tested under different operating conditions (e.g. membrane type, methanol concentration, and flow rate of sulfuric acid solution). At this stage, multiphysics models (three-dimensional, two-phase model and non-isothermal) of a single FE-DMFC were also developed in Comsol Multiphysics environment. Using these models, the operating and design parameters that yield the highest performance of a DMFC were determined. Thirdly, mathematical modeling of a DMFC stack was performed to investigate the pressure, velocity, and methanol concentration distributions within the stack. Then, this stack model was used as a basis to develop a FE-DMFC stack model in Comsol Multiphysics environment. Finally, a 3D FE-DMFC short-stack model was developed to investigate the effect of key parameters on the performance of the stack as well as to find the methanol concentration and velocity distributions and the pressure drop in the stack. As a result of the research activities carried out during this project, a FE-DMFC having alternative materials was manufactured and it was shown that this fuel cell has much better performance than any previously manufactured FE-DMFCs reported in the literature. It was also shown experimentally that a FE-DMFC can reduce the methanol crossover considerably. The design and operating parameters that increase the performance of this fuel cell mostly were also identified. The main results achieved are listed below.

• High faradaic efficiencies up to 98 % are possible with the FE-DMFC at different current densities.
• Under the tested conditions, methanol crossover can be reduced by a factor of more than 10.
• Nafion® 115 based FE-DMFC has the best performance (0.38 V at 0.1 A/cm2) when it operates with 1 M methanol concentration and 5 ml/min sulfuric acid flow rate.
• The numerical studies showed that flowing electrolyte thickness, flowing electrolyte flow rate and methanol concentration are the most important parameters affecting the performance of the FE-DMFC.
• In a FE-DMFC stack, the cells furthest from the outlet manifold in a U-shaped configuration have the least amount of flow. This lead the anode methanol concentration distribution to have a low uniformity in these cells.

As a result of the activities carried out during this project, three journal papers and three conference papers were prepared. Five presentations were done in international conferences; and two seminars were given. Dr. Colpan created a webpage for the project, which included the objective, research highlights, and a list of the presentations and publications done from this project.

Final results

In this project, some innovation activities were carried out. For the first time in the literature, methanol crossover measurements were done experimentally for FE-DMFC; and it was shown that FE-DMFC is very effective in eliminating the unwanted methanol crossover from anode to cathode. In addition, new materials (Nafion 212 as the membrane and SS2205 as the flow field) were used to manufacture a FE-DMFC. It was shown that using these materials better performance and durability can be achieved. In addition, for the first time in the literature, a detailed investigation of a FE-DMFC stack was done through three-dimensional modeling technique.

This project has made significant impact in different dimensions. Dr. Colpan visited Forschungszentrum Jülich in Germany for 3 months. This visit improved Dr. Colpan’s knowledge on fuel cell experimentation. He was able to expand his network through his visit to Jülich and attendance to conferences. Some plans for future collaborative works have been made with some of the researchers met during these events. Dr. Colpan increased his number of publications as well as the infrastructure of his fuel cell laboratory. He purchased equipment such as automatic film applicator and fuel cell consumables using the budget allocated for these kinds of expenses. He was also be able to attract a first class researcher to his laboratory. This project also promoted the collaboration between the host, the partner, and a Canadian organization. Dr. Colpan was able to identify new areas to expand his research activities. He promoted his research field as well as Marie Skłodowska-Curie Actions when students from a high school and an university visited his laboratory.

Website & more info

More info: https://fedmfc.wordpress.com/.