Activating ion transport channels of poly(styrene-b-(ethylene-co-butylene)-b-styrene) anion exchange membranes using ionic oligomeric polystyrene

Owing to structure advantages, poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) has garnered significant attention in the field of anion exchange membranes (AEMs) for fuel cell applications . However, its low ionic conductivity has remained a formidable obstacle for high-performance SEBS based AEMs. Herein, an innovative approach is employed, incorporating ionic oligomeric polystyrene (OPS) into physically crosslinked SEBS based AEMs, to fabricate two series of OPS/SEBS AEMs via precise control of the molecular weight and load ratio of OPS, respectively. The variables are theoretically capable of decreasing the glass transition temperature ( T g ) of the polystyrene phase below the operating temperature of fuel cells. The results demonstrate that the lower molecular weight and the higher load quantity of OPS not only broaden the ion transport channels but also lower the energy barrier of the conducting polystyrene phase. Remarkably, the membrane (1300-CHM–OH–35) with an IEC of 2.41 mmol g −1 significantly improved the ionic conductivity to 150.9 mS cm −1 at 80 °C, despite its low total polystyrene content (45.78%), and attained a peak power density of 506.26 mW cm −2 at 1100 mA cm −2 in a H 2 /O 2 single cell operating at 70 °C. This outstanding performance underscores the promising potential of our approach in the development of high-performance SEBS AEMs for fuel cell applications.