Nano Hexagonal Boron Nitride-Nafion Composite Membranes for Proton Exchange Membrane Fuel Cells

This study investigates the proton conductivity and characterization of nano hexagonal boron nitride-Nafion composite membranes. Proton conducting composite membranes are prepared by mixing Nafion and nano hexagonal boron nitride (NhBN) particles with 3, 5, 10, and 15% weight ratios. Particle size distribution analysis is made for BN nanoparticles and the homogeneity of the membranes is proved by SEM and AFM. FTIR confirms the interaction between NhBN and Nafion. Methanol permeation and water absorption tests are made and it shows that hydrophobic NhBN particles decrease the swelling property and methanol retention of the membranes. X-ray investigation of the composites supports semi-crystalline nature of the composite materials. At dry conditions, the maximum proton conductivity was measured as 0.005 S/cm at 150 degrees C for NafBN10, which is much higher than the pure Nafion. The results confirm that boron nitride nanoparticles have high contribution on the proton transfer, which may be explained with the formation of hydrogen bonds between amine and hydroxyl groups of boron nitride and sulfonic acid groups of Nafion. (C) 2014 Society of Plastics Engineers