The use of green energy for transport applications is becoming ever more important, with fuel cells showing the potential to be a highly competitive candidate in the automobile industry. Traditional low temperature polymer electrolyte fuel cells (LT-PEFCs) can only be operated at temperatures below 80°C. High temperature polymer electrolyte fuel cells (HT-PEFCs), based on phosphoric acid (H_3PO_4) doped polybenzimidazole membranes (PBI), can be operated in a temperature range of 160-180°C. Because of the higher operating temperature, HT-PEFCs have many advantages, such as a much easier water and heat management, a more compact cooling system and a higher CO tolerance in the feed gas. However, the major drawback of H_3PO_4 as an electrolyte is the poisoning effect on the redox catalyst and low O_2 solubility. This leads to a significant decrease in the cathodic oxygen reduction reaction (ORR) kinetics.
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