Advanced performance and ultra-high, long-term durability of acid-base blended membranes over 900 hours containing sulfonated PEEK and quaternized poly(arylene ether sulfone) in H2/O2 fuel cells

In this study, quaternized poly (arylene ether sulfone) (QNPAES) was synthesized using conventional nucleophilic aromatic polycondensation. We then developed a blended membrane composed of sulfonated poly (ether ether ketone) (SPEEK) using facile solution casting. A series of mixed hybrid membranes of SPEEK/QNPAES were prepared by varying the wt% of QNPAES mixed with SPEEK. The results showed that an appropriate amount of QNPAES (i.e., 6 wt%) could significantly improve the mechanical strength, proton conductivity and physicochemical properties of a prepared mixed membrane, as well as the proton exchange membrane fuel cell (PEMFC) performance and durability at relative humidity (RH) of 20%. Specifically, a SPEEK/QNPAES at 6 wt% provides a current output, power output and endurance of 0.431 A cm-2, 0.15 W cm-2 and over 900 h, respectively, at an RH of 20% and 60 degrees C. These results can be attributed to acid-base ionic crosslinking, which offers effective interfacial compatibility between SPEEK and QNPAES. A PEMFC with SPEEK/QNPAES membranes when used at 20% RH achieved significantly advanced performance and ultra-high, long-term durability compared with those of PEMFCs with bare SPEEK, suggesting that SPEEK/QNPAES membranes can be used as polymer electrolyte membranes.

Automated summary

A quaternized poly (arylene ether sulfone) (QNPAES) was synthesized and a blended membrane composed of sulfonated poly (ether ether ketone) (SPEEK) was developed. The mechanical strength, proton conductivity, and physicochemical properties of the mixed membrane were significantly improved by adding an appropriate amount of QNPAES (6 wt%). The PEMFC performance and durability of the mixed membrane were also greatly enhanced at 20% RH.