Phosphoric acid sustained-release strategy boosting durability of high temperature proton exchange membrane fuel cells

High temperature proton exchange membrane fuel cells (HT-PEMFCs) based on phosphoric acid (PA) proton conductor operating from 130 to 180 °C have significant advantages of broader fuel flexibility, and simplified thermal and water management. However, HT-PEMFCs are beleaguered by water condensation-induced and electro-migrated PA loss, which makes them difficult to maintain the cell performance stability across a wide-temperature range and at high current loadings. Herein, a proton conducting phosphoric acid sustained-release layer (SRL) was constructed between catalyst layer and proton exchange membrane, which regulates PA distribution within membrane electrode assembly, inhibits PA loss and improves kinetic of electrode. Consequently, the resulting HT-PEMFC integrated with SRL exhibits a 1.6-fold higher peak power density increase in peak power density and only a 15 % reduction in performance after 30,000 cycles of accelerated stress testing. Notably, the voltage decay rates are significantly lower, at 1.35 % and 0.75 %, compared to cells without the SRL at temperatures of 160 °C and 40 °C, respectively.