Alkaline hybrid composite membrane for direct methanol fuel cells application

• A series of organic–inorganic alkaline hybrid membranes were prepared.
• Obtained hybrid membranes can be stable up to 150 °C in the air.
• A tensile stress at break of 41.2 MPa at room temperature was obtained.
• Membrane can keep the conductivity for more than 60 h in KOH solution.
• Swelling of the membrane obeyed the Schott's second-order swelling kinetic.

A series of organic–inorganic alkaline hybrid membranes were prepared based on crosslinked quaternized chitosan (QCS, the quaternization degree (DQ) was 63.5(± 2.5)%) with different contents of tetrabutyl titanate (TBT) for alkaline direct methanol fuel cells (ADMFCs). The result revealed that the obtained anion exchange membranes (AEMs) were stable up to 150.0 °C in the air atmosphere according to the TGA analysis and anionic conductivities of the hybrid membranes at a level of 10− 2 S cm− 1 were obtained at 70.0 °C. A tensile stress at a break of 41.19 MPa at room temperature was achieved for QCS-TBT20% membrane. The anionic conductivity of QCS-TBTx% (15 ≤ X ≤ 25) membrane in 1.0 mol L− 1 KOH solution was stable for more than 60.0 h. Corresponding to the increase in the content of TBT from 0 wt.% to 25 wt.% in the hybrid membrane, the methanol permeability was decreased from 7.55 × 10− 6 cm2 s− 1 to 1.85 × 10− 6 cm2 s− 1. The water swelling of QCS-TBTx% (X ≤ 30) membranes was discussed based on the stress relaxation model of polymer chains, and it obeyed the Schott's second-order swelling kinetics.