h-BN Based Composite Materials for Proton Transport Membrane

Abstract

Two-dimensional (2D) materials are versatile tools for the use in the field of membrane application due to their outstanding mechanical strength, thermal and chemical inertness. Especially, a growing recognition focuses on the use of hexagonal boron nitride (h-BN) which is also called as white graphene and has an isolobal structure to graphene. h-BN is well known for its highest proton conductivity among 2D materials, which led many researchers to study h-BN as a proton exchange membrane (PEM). This thesis discussed our approaches to exploit h-BN for PEM. In detail, my thesis illustrates the use of h-BN flakes for fabrication of proton exchange membranes. h-BN flakes with different weight percent ratios (1, 5, and 10 wt %) were dispersed in a commercial Nafion solution (D2021, alcohol based 1100 EW at 20 wt %), mixed and exfoliated simultaneously. The morphology of h-BN based dispersion was then characterized using SEM and TEM measurement, and showed its trend in dimension and its thickness. Sequentially, the dispersion was impregnated into the pores of hydrophilic PTFE (hPTFE) where the impregnation method was created from this research. Following the morphological characterization of the fabricated composite membrane on its top-, bottom-, and cross-view, not only the confirmation of the homogeneous impregnation but also the trend as wt % of h-BN increases are shown. From the composite membrane, performance was checked by a proton conductivity measurement. The result tells us the trend of decrease in the proton conductivity as wt % of h-BN increases, signifying more energy of time be needed to exfoliate multi-layers of exfoliated h-BN flakes impregnated in hPTFE matrix.