Novel, self-standing membranes based on chitosan (CS), incorporating N-doped reduced graphene oxide nano-ribbons (N-rGONR) and crosslinked with the naturally derived genipin (GEN), were developed. FTIR confirmed successful GEN reaction with CS and the introduction of N-rGONRs, which reduced the overall crystallinity while improving its mechanical properties. The comprehensive physicochemical and electrochemical properties, including ethanol permeability, alkali uptake, dimensional stability, ionic conductivity, and durability, were evaluated. Membrane performance was assessed within the single-cell module under practical operating conditions in an alkaline direct ethanol fuel cell (ADEFC). CS-based membranes containing 0.01 wt% N-rGONR achieved a maximum power density of 6.8 mW cm-2 at 57 degrees C with 1 M ethanol/1 M KOH, increasing to 17.7 mW cm-2 at 3 M ethanol/5 M KOH, surpassing a commercial reference membrane. Membranes containing either NrGONR or GEN showed superior performance in single-cell experiments; however, their combined addition demonstrated better retention of ionic conductivity over 14 days of exposure to simulated ADEFC operating conditions. This synergistic stabilisation effect of both components on CS, which when not modified completely degrades in prolonged exposure experiments, emphasises the potential of the newly developed CS-based membranes for alkaline direct ethanol fuel cell applications.

Alkaline Polymer Electrolyte Fuel Cells (APEFCs) have emerged as a promising candidate for clean energy production. Anion exchange membrane (AEM) is an essential element of alkaline polymer electrolyte fuel cells for its role in facilitating hydroxide ion conduction. The objective of this study is to investigate the effect of a glutaraldehyde-based crosslinker solution on the performance of anion exchange membranes (AEMs) fabricated using quaternary ammonium poly (vinyl alcohol) (QPVA) as the backbone polymer and polyquaternium-7 as the second polymer. The introduction of a glutaraldehyde-based crosslinking agent was purposed to enhance membrane stability and reduce excessive swelling. The study evaluates the impact of varying glutaraldehyde concentrations on membrane performance. FTIR analysis confirms the presence of key functional groups of QPVA, polyquaternium-7, and the crosslinking agent. SEM images reveal that the membranes demonstrate dense and homogeneous physical structure. The results show that water uptake, swelling degree, ion exchange capacity (IEC), and hydroxide conductivity are influenced by the concentration of the glutaraldehyde solution. The QP-GA-13 AEM exhibited the best overall performance, achieving the highest tensile strength of 31.1 MPa and the highest hydroxide ion conductivity of 4.15 mS cm⁻¹ at 70°C. In single-cell tests, this membrane delivered a maximum power density of 85 mW cm⁻² and a current density of 350 mA cm⁻² at 80°C under humidified oxygen conditions.

Crosslinked anion exchange membranes (AEMs) made from poly(vinyl alcohol) (PVA) as a backbone polymer and different approaches to functional group introduction were prepared by means of solution casting with thermal and chemical crosslinking. Membrane characterization was performed by SEM, FTIR, and thermogravimetric analyses. The performance of AEMs was evaluated by water uptake, swelling degree, ion exchange capacity, OH - conductivity, and single cell tests. A combination of quaternized ammonium poly(vinyl alcohol ) (QPVA) and poly(diallyldimethylammonium chloride) (PDDMAC) showed the highest conductivity, water uptake, and swelling among other functional group sources. The AEM with a combined mass ratio of QPVA and PDDMAC of 1:0.5 (QPV/PDD 0.5 ) has the highest hydroxide conductivity of 54.46 mS cm -1 . The single fuel cell tests with QPV/PDD 0.5 membrane yield the maximum power density and current density of 8.6 mW cm -2 and 47.6 mA cm -2 at 57 °C. This study demonstrates that PVA-based AEMs have the potential for alkaline direct ethanol fuel cells (ADEFCs) application.