Preparation and properties of organic–inorganic alkaline hybrid membranes for direct methanol fuel cell application

• Development of the alkaline hybrid membrane for DMFC application
• The dimensional and chemical stabilities were improved by hybrid structure.
• Alternate membranes in the near future

A series of organic–inorganic alkaline hybrid membranes were prepared based on crosslinked quaternized chitosan (QCS, the quaternization degree (DQ) of the QCS was 80.8 ± 3.5%) with different contents of tetraethoxysilanes (TEOS) for alkaline direct methanol fuel cells (ADMFC). These hybrid membranes were characterized by Fourier-transform infrared (FT-IR), thermo gravimetric analysis (TGA). The ion exchange capacity (IEC), water uptake, alkaline stability, methanol permeability and mechanical properties of the membranes were also investigated to evaluate their applicability in ADMFC. The results showed that the anionic conductivities of the hybrid membranes at a level of 10− 2 S cm− 1 were obtained at 80 °C. The methanol permeability of the membranes was in a range from 7.5 × 10− 6 to 1.5 × 10− 6 cm2 s− 1. The obtained anion exchange membranes (AEM) were stable up to 200 °C in atmosphere according to the TGA analysis. The tensile strength and elongation at break of the membranes were in a range from 15.78 to 27.56 MPa and 10.32% to 3.21% at room temperature, respectively. The results of alkaline stability show that a tensile strength about 20.0 MPa was maintained after immersing the hybrid membrane in a 10 mol L− 1 KOH solution at room temperature for more than 96 h.