Costs high temperature cells

Temperatures up to 1500 °C reduce the reversible thermodynamic potential for water decomposition from a room temperature value of 1.23 V to 0.7 V (43%). The cost of electrolytic hydrogen varies linearly with the potential of the cell at the current density being used, since cost of the electricity is the dominating item in the cost of electrolytic hydrogen, high-temperature steam electrolysis would greatly improve the economics. Heat is needed to maintain the temperature of the system, but heat costs only a third of the cost of electricity. So far, very high temperature cells are research items, but 1000 °C cells have been developed in Europe under the nickname Hot Elly. ... 

The modem reduction cell is a rather costly high-temperature device. The cost of reduction cell repairs has a sufficient effect on the production cost of A1 and smelter operation. Another reason for the special attention plant managers give to the service life of the cells is that sudden shutdowns means unreceived A1 and problems with operation. 

Pefkianakis, E. K. Morfopoulou, C. Deimede, V. Kallitsis, J. K., Blends of aromatic polyethers bearing polar pyridine units and their evalnation as high temperature polymer electrolytes, Macromol. Sympos., 219(1), 183-190 (2009). Deng, S. Mays, J. W. Hassan, M. K. Mauritz, K. A., Low cost high temperature fuel cell membranes based on poly(l,3-cyclohexadiene) homopolymers, polymer blends, and block copolymers, the 238th ACS National Meeting, ACS Division of Fuel Chemistry, Washington, DC, 16-20.08.2009. 

Current availability of individual lanthanides (plus Y and La) in a state of high purity and relatively low cost has stimulated research into potential new applications. These are mainly in the field of solid state chemistry and include solid oxide fuel cells, new phosphors and perhaps most significantly high temperature superconductors... 

For last few years, extensive studies have been carried out on proton conducting inorganic/organic hybrid membranes prepared by sol-gel process for PEMFC operating with either hydrogen or methanol as a fuel [23]. A major motivation for this intense interest on hybrid membranes is high cost, limitation in cell operation temperature, and methanol cross-... 

The fact that these cells can operate with many different fuels is one advantage of high-temperature operation. However, there is at present much research directed toward lowering the operating temperature for cost reasons. 

Operation of cells at higher temperatures such as 80°C, as in membrane fuel cells, is not encouraged here because of the corrosion instability of the hardware, manufactured from titanium or titanium alloy. Even without such constraints, however, this high temperature would be unwelcome as the water produced is present as steam - without the conductive bridge of the liquid phase it would be necessary to bond the catalytic particles to the membrane with all the associated problems of technology and cost. 

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