Durable Polysulfones with Densely Sulfonated Segments for Highly Proton Conducting Membranes
Sammanfattning: Popular Abstract in English Fuel cells have been considered as alternative power source to petroleum oil. Especially, fuel cells have potentials to provide no pollutant emission (e.g., CO2, NOx, SOx) out of the power generation. For instance, once the fuel cells are installed instead of combustion engine in the cars used for commuting, transportation and leisure, the amount of pollutant emission causing the global warming will be significantly reduced. One important indication to the market of fuel cells is that automotive manufacturers announced their commercialization of fuel cell vehicles in 2015, using proton-exchange membrane fuel cells (PEMFCs). Importantly for Scandinavian countries, Honda, Nissan, Toyota and Hyundai have all joined in signing the project with hydrogen infrastructure companies and Nordic NGOs which plans the market introduction of fuel cell vehicles and hydrogen refuelling infrastructure during the period 2014-2017. A key for success of the fuel cell market is the performance, durability and cost of the used material components. Importantly, polymer membrane plays a key role as the central to dominate the performance and durability of PEMFCs. State-of-the-art perfluorosulfonic acid (PFSA) membranes such as Nafion® developed by DuPont are today the most widely employed membrane material in PEMFC applications, because of their high performance and durability. However, PFSA membranes typically show some limitations for commercialization, and the main are the expensive material cost and environmentally unfriendliness due to their fluorinated structure. This has motivated an intensive research over the past decade for alternative membrane based on inexpensive and environmentally-friendly materials. Then, the engineering plastics, the thermally/chemically/mechanically stable polymer materials with cheap potential cost and environmentally friendliness, are intensively investigated as alternatives to PFSAs for membrane applications including not only fuel cells, but also desalination by reverse osmosis to purify water for drinking, gasification via electrolyte to produce fuel gases H2/O2 out of water and vanadium redox flow batteries for energy storage. In fact, the performance of such materials is still inferior to that of the PFSA membranes in terms of the membrane performance and durability. Therefore, the thesis work focused on extensive study of the preparation of polymers with high performance and durability. As a result, the polymers gave quite comparable proton conductivities to that of PFSAs. One remarkable finding is that they have potentials to perform over 10 times as much as that of PFSAs at cold climate. They were ultimately designed to give the most stable chemical property in relation to any conventional HC polymer. Finally, a new concept, microblock copolymers, was suggested as potential candidates for ion-exchange membrane applications towards commercialization in light of cost performance and reliable production, in addition to performance and durability.
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