Silicon carbide fiber-reinforced composite membrane for high-temperature and low-humidity polymer exchange membrane fuel cells

Currently, efforts are being made to commercialize a fuel cell system through research on fuel cell material enhancements. In particular, improvements in the membrane-electrode assembly, a key component of polymer electrolyte membrane (PEM) fuel cells, are essential to increase the performance of a fuel cell, in addition to accelerating its commercialization. Therefore, in this study, we used silicon carbide (SiC) fibers (web type) by electrospinning, which possess superior material, thermal, and chemical properties, as a structural material for the composite electrolyte membrane in the membrane-electrode assembly by impregnating it with the polymer electrolyte ionomer of short-side chain (SSC). In addition, we enhanced the ion-exchange capability of functionalized SiC fibers by introducing the hydroxyl (OH) group and phosphoric acid. The resulting functionalized composite electrolyte membrane exhibited a 70% better ion-exchange capability than the conventional cast electrolyte membrane and SiC webs composite electrolyte membranes was observed to excellent mechanical strength. We characterized and illustrative modeled the functionalized silicon carbide fibers, on the basis of which we further developed composite membrane. We then fabricated a unit cell of PEMFC based on this composite electrolyte membrane, and evaluated its single-cell performance, electrochemical properties, and accelerated voltage life-time durability test of operating 35 h according to the electro- and physic-chemical characteristics of the MEA under high-temperature and low humidity (120 °C/RH 40%).