DescriptionOne great advantage of the most common fuel cells, the polymer based fuel cells, is the low operating temperature which allows for easy and fast start-up and a variety of materials for construction and sealing. However, over the years the interest for increasing the working temperature has been growing. The motivation is diverse. A slight increase above 100-120°C is desired by the automotive industry to ease thermal control. This has been attempted via optimization of the perfluorosulphonic acid based membranes. A further increase to 140-200°C is desired to increase the tolerance to CO and thus to ease the integration with a reformer for carbonaceous fuels. This has been achieved by the phosphoric acid doped polymer membranes like polybenzimidazole with the added benefit that water management is unnecessary. The next step in temperature could be to go above 230-250°C in order to utilize the waste heat for methanol steam reforming. This is most realistic with solid inorganic proton conductors or molten salts and phosphate systems like CsH2PO4 have proven promising. At even higher temperature reforming of dimethyl ether and after that ethanol should be possible. Another advantage of increased temperature might be that a candidate for replacing platinum as catalyst is more easily found. From the other end of the fuel cell temperature window solid oxide fuel cells are developing in the direction of lower operating temperatures from initially 1000°C to 600-700°C or even lower. The limiting factor is oxide ion conductivity, but which temperature would ultimately be the optimum if one could chose freely? The presentation will elaborate on the benefits of the different working temperatures based on simple system requirements with and without fuel reformers. Overall criteria are energy efficiency and system simplicity.
J. O. Jensen, S. Martin and Q. Li. What is the ideal working temperature for proton conductors? Solid State Protonic Conductors (SSPC-17). Seoul, Korea, September 2014 (Invited talk)
|Period||14 Sep 2014 → 19 Sep 2014|
|Event title||Solid State Protonic Conductors - 17|
|Location||Seoul, Korea, Republic of|