Functionalized Graphene Nanofiber-Incorporated Fumion Anion-Exchange Membranes with Enhanced Alkaline Stability and Fuel-Cell Performances

Anion-exchange membranes (AEMs) with high hydroxide conductivity,strong alkaline stability, and outstanding single-cell performanceare in great demand for use in fuel cells and water electrolyzer applications.In this study, carboxylic acid-functionalized graphene nanofibers(c-GNF) were used as an effective filler to improve the electrochemicaland physicochemical characteristics of the commercial FAA3 for anion-exchangemembrane fuel-cell (AEMFC) application. The effects of c-GNF incorporationon the structural, morphological, and electrochemical performancesof the composite membrane were systematically investigated. Introducingc-GNF into the FAA3 matrix increased the electrochemical performanceand physicochemical stability of FAA3 membranes. Notably, the nanocompositemembrane containing 1.70 wt % of c-GNF reached a maximum hydroxideconductivity of 58.8 mS cm(-1) at 90 & DEG;C, whereasthe pristine FAA3 presented only 28.7 mS cm(-1). Inaddition, the maximum peak power density (PPD) of 115.9 mW cm(-2) was observed for the FAGNF at 1.70 wt % in a H-2/O-2 AEMFC at 60 & DEG;C. Moreover, the alkalinestability test demonstrated that c-GNF inclusion had a significantinfluence on membrane chemical stability by retaining the conductivityup to 71% after 500 h of immersion in 5 M NaOH at 60 & DEG;C. Overall,this study demonstrates the enhancement of properties of a commercialmembrane for AEMFC application.

Automated summary

This study demonstrates the improvement of electrochemical and physicochemical characteristics of anion-exchange membranes for fuel cell applications by incorporating carboxylic acid-functionalized graphene nanofibers as fillers. The addition of these fillers enhances the electrochemical performance and stability of the membranes, resulting in increased hydroxide conductivity and peak power density. This research highlights the importance of enhancing the properties of commercial membranes for anion-exchange membrane fuel cells.