Phosphoric acid fuel cells manufacture

This survey focuses on recent developments in catalysts for phosphoric acid fuel cells (PAFC), proton-exchange membrane fuel cells (PEMFC), and the direct methanol fuel cell (DMFC). In PAFC, operating at 160-220°C, orthophosphoric acid is used as the electrolyte, the anode catalyst is Pt and the cathode can be a bimetallic system like Pt/Cr/Co. For this purpose, a bimetallic colloidal precursor of the composition Pt50Co30Cr20 (size 3.8 nm) was prepared by the co-reduction of the corresponding metal salts [184-186], From XRD analysis, the bimetallic particles were found alloyed in an ordered fct-structure. The elecbocatalytic performance in a standard half-cell was compared with an industrial standard catalyst (bimetallic crystallites of 5.7 nm size) manufactured by co-precipitation and subsequent annealing to 900°C. The advantage of the bimetallic colloid catalysts lies in its improved durability, which is essential for PAFC applicabons. After 22 h it was found that the potential had decayed by less than 10 mV [187],... 

Phosphoric acid fuel cells rely on expensive components and, like pems, use platinum catalysts to accelerate the chemical reactions at the electrodes. Finally, they have not achieved the level of sales needed to significantly reduce manufacturing costs. For these reasons, UTC Fuel Cells is phasing out production of phosphoric acid fuel cells in favor of pem fuel cell technology, which is likely to be significantly less expensive. 

During phosphoric acid fuel cell research and development, technical solutions were found, which later were adopted successfully in the development of other fuel cell types. This is true, in particular, for the use of platinum catalysts not in a pme form, but as deposits on carbonaceous supports (for instance, carbon black), leading to a considerable drop in the amounts of platinum needed to manufacture... 

PAFCs are the first fuel cells to be commercially available. The major manufacturers of these fuel cells are UTC Power, Toshiba Corporation, HydroGen Corporation, Fuji Electric Corporation and Mitsubishi Electric Corporation. UTC Power introduced for sale a 200 kW PAFC system in 1991, and over 260 units were delivered to various customers worldwide. The design operational lifetime for these units was 40,000 h and most of the fielded units have met or exceeded this requirement A number of these units are still operational today with fleet leader at Mohegun Sun in Uncasville, Connecticut, USA, accumulating more than 76,(X)0 h [48]. Fuji s phosphoric acid fuel cell power plants, launched in 1998 have also demonstrated 40,000 h of life in field and some units after overhaul have exceeded 77,000 h of operational lifetime [1]. 

Phosphoric acid fuel cells have successfully been commercialized. Second generation fuel cells include solid oxide fuel cells and molten carbonate fuel cells. Research is ongoing in areas such as fuel options and new ceramic materials. Different manufacturing techniques are also being sought to help reduce capital costs. Proton exchange membrane fuel cells are still in the development and testing phase. 

Polybenzimidazole (PBI) (initially manufactured by Hoechst-Celanese, now PE ME A) is one of the few polymers under consideration for high-temperature operation. The application of PBI [206, 207] and the noncommercial AB-PBI [208] in fuel cells was introduced by Savinell and coworkers. For that, the membrane was immersed in concentrated phosphoric acid to reach the needed proton conductivity. Operation up to 200 °C is reported [209]. A disadvantage of this class of membranes is the acid leaching out during operation, particularly problematic for cells directly fed with liquid fuels. Additionally, the phosphoric acid may adsorb on the platinum surface. A review on membranes for fuel cells operating above 100 °C has been recently published [209]. 

Polymer electrolyte, alkaline, phosphoric acid, molten carbonate, and solid oxide fuel cell technology descriptions have been updated from the previous edition. Manufacturers are focusing on reducing fuel cell life cycle costs. In this edition, we have included over 5,000 fuel cell patent abstracts and their claims. In addition, the handbook features a new fuel cell power conditioning section, and overviews on the hydrogen industry and rare earth minerals market. 

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