Fabrication of the cross-linked PVA/TiO2/C nanocomposite membrane for alkaline direct methanol fuel cells

Abstract

A crosslinked Poly(vinyl alcohol) based composite membrane was developed through a phase inversion process for use in alkaline direct methanol fuel cells (ADMFCs). The titanium dioxide (TiO2) and carbon nanoparticles (NPs) have been incorporated into the PVA polymer matrix to improve the mechanical and thermal properties. The membrane samples were further modified with maleic acid, a carboxylic acid acting as the cross-linker, under controlled temperature and time conditions to enhance electrochemical properties. The mechanical strength and thermal stability of membranes were determined using a Universal testing machine (UTM) and thermogravimetric analysis (TGA), while the crystallographic and morphological features were examined through X-ray diffraction (XRD) and Scanning electron microscopy (SEM), respectively. The proton conductivity (σ), methanol permeability, and water uptake (%) were also assessed. The XRD curves, SEM images, and TGA trends confirmed the successful cross-linking of maleic acid, uniform dispersion of nanoparticles (NPs), and excellent thermal stability in the crosslinked PVA-TiO2-C membrane. This sample also exhibited the highest tensile strength (163 MPa), and lower permeability (45000 Ss/cm3). Moreover, the ionic conductivity was obtained in the order of 10−2 S/cm. These combined characteristics position the cross-linked PVA-TiO2-C membrane as a promising candidate for application in alkaline direct methanol fuel cells (ADMFCs).