High-Performance Plasma-Polymerized Alkaline Anion-Exchange Membranes for Potential Application in Direct Alcohol Fuel Cells

Abstract

Alkaline anion-exchange membranes (AAEMs) are becoming significant materials for application in fuel cells. Considering the mobility of hydroxide ions is inherently slower than that of proton in dilute solution, AAEMs with high ion conductivity and several microns thickness are promising. In this study, ultra-thin AAEMs are successfully synthesized by plasma polymerization. The attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermo gravimetric analysis demonstrate that the benzyltrimethylammonium cationic groups are successfully introduced into the polymer matrix via plasma polymerization, quaternization, and alkalization. The physicochemical and electrochemical characteristics, including ionic exchange capacity, water uptake, thermal stability, chemical stability, and ionic conductivity, are measured. The plasma-polymerized AAEMs exhibit a satisfactory thermal stability, chemical stability, ionic exchange capacity (1.29 mmol · g−1), ionic conductivity (0.0331 S · cm−1), and activation energy (7.632 kJ · mol−1), suggesting a great potential for application in direct alcohol fuel cells.