Conquering Heavy-Loading Decay of High-Temperature Polymer Electrolyte Membrane Fuel Cells with a Conductive Polymer-Based Phosphoric Acid Reservoir

Phosphoric acid migration and loss under heavy loading of high-temperature polymer electrolyte membrane fuel cells result in severe performance degradation. Herein, a buffering strategy with strong acid anchoring effect of conductive polymer as the electrode decoration layer is proposed. The newly designed electrode shows remarkable stability during rigorous acceleration stress tests without performance loss, whereas 54.9% decrease in peak power density is observed for a conventional one. Combining 3D X-ray microscopy (3D-XRM) reconstruction and analysis of the phosphoric acid redistribution within different electrodes, we believe that the leaching and loss of acid and consequent decay of the catalyst layer should be the major reasons for the degradation of performance during high-current operation. This buffering strategy with an acid reservoir provides opportunities for high-temperature polymer electrolyte fuel cells in power sources for heavy-duty applications.