Optimized Interfaces\nfor PBI-Based High-Temperature\nDirect Ethanol Fuel Cells

The present study combines innovative strategies aiming\nat enhanced\nperformance of direct ethanol fuel cells (DEFC) by modifying interfaces\nat both electrodes and electrolyte. Increasing the operating temperature\nto 180 °C to promote faster kinetics and thermally activated\nprocesses taking place in DEFC was possible by using phosphoric-acid-doped\nPBI (polybenzimidazole) composite electrolytes. The properties of\nthe PBI electrolytes were improved by adding SiO<sub>2</sub> as an\ninorganic second phase, promoting an increase in the proton conductivity\nand inhibiting ethanol crossover. Optimizing electrode reactions by\nincreasing the triple-phase boundary was demonstrated by using a powdered-based\nPBI “ionomeric” concept to boost the performance of\nthe proton exchange membrane fuel cell. The electrochemical characterization\nof the high-temperature direct ethanol fuel cells (HT-DEFC) showed\nthat combining the strategies for the optimized electrode and electrolyte\nwas crucial for increasing the performance of membrane electrode assemblies\noperating at 180 °C.