Functionalized boron nitride embedded sulfonated poly (ether ether ketone) proton exchange membrane for direct methanol fuel cell applications

Nanostructured materials have been utilized in tailoring the proton exchange membrane (PEM) with the attempt to reduce the methanol transport and enhance proton conductivity in direct methanol fuel cell (DMFC) applications. In this study, polyaniline coated activated boron nitride (PANI-A-BN) was embedded in sulfonated poly (ether ether ketone) (SPEEK) membranes for DMFC applications. The influence of boron nitride (BN) and activated boron nitride (A-BN) was also compared. The crystallinity and morphological analyses revealed that structure of PANI-A-BN nanocomposites were altered. The dispersion of functionalized BN was clearly witnessed from the SEM and AFM images of SPEEK membranes PANI-A-BN/SPEEK membrane exhibited a higher water uptake (58.42%) and ion exchange capacity (IEC) (1.76 meq g⁻¹) compared to other membranes prepared in this work. The methanol permeability was significantly reduced in BN and functionalized BN embedded SPEEK nanocomposites membranes (3.08 × 10⁻⁷ cm⁻² S⁻¹). The proton conductivity and chemical stability of PANI-A-BN/SPEEK membrane were improved. The DMFC performance of nanocomposite membrane was compared with that of commercial Nafion membrane. 0.1 wt% PANI-A-BN/SPEEK membrane exhibited the highest open circuit voltage and power density of 0.158 V and 11.38 mW/cm², respectively.