Fabrication and Characterization of Chitosan Nanoparticle-Incorporated Quaternized Poly(Vinyl Alcohol) Composite Membranes as Solid Electrolytes for Direct Methanol Alkaline Fuel Cells

•Preparation of chitosan nanoparticles from bulk to enhance the degree of deacetylation.•The incorporation of chitosan nanoparticles into a QPVA matrix to form a nanocomposite membrane.•The nanocomposite constructed into thin-film membranes using the solution casting method.•To improve permeability, glutaraldehyde was cross-linked with the nanocomposite membranes.•A direct methanol alkaline fuel cell was studied at different temperatures.

In this study, we designed a method for the preparation of chitosan nanoparticles incorporated into a quaternized poly(vinyl alcohol) (QPVA) matrix for direct methanol alkaline fuel cells (DMAFCs). The structural and morphological properties of the prepared nanocomposites were studied using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM) and dynamic laser-light scattering (DLS). The crystallinity of the nanocomposite solid electrolytes containing 0 and 10% chitosan nanoparticles were investigated using differential scanning calorimetry (DSC). The electrochemical measurement of resulting nanocomposite membranes were analyzed according to the following parameters: methanol permeability, liquid uptakes, ionic conductivity and cell performances. The composite membranes with 10% chitosan nanoparticles in a QPVA matrix (CQPVA) show suppressed methanol permeability and higher ionic conductivity than pristine QPVA. In addition, the glutaraldehyde cross-linked nanocomposite film exhibited improvement on the methanol barrier property at 80 °C. The peak power density of the DMAFCs reached 67 mW cm−2 when fed into 1 M of methanol in 6 M of KOH.

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