Fabrication of anion-exchange composite membranes for alkaline direct methanol fuel cells

摘要

The quaternized poly(vinyl alcohol)/3-(trimethyl ammonium) propyl-functionalized silica (designated as QPVA/Q-SiO_2) composite polymer membrane is prepared by a solution casting method. The Q-PVA is polyvinyl alcohol (PVA) derivatized with glycidytrimethyl ammonium chloride (GTMAC) and the Q-SiO_2 is 3-(trimethyl ammonium) propyl-functionalized silica. The highest ionic conductivity of the QPVA/20 wt.%Q-SiO_2 composite polymer electrolyte is σ = 2.37mScm~(-1) at ambient temperature. The alkaline direct methanol fuel cell (ADMFC) comprised of an anion-exchange QPVA/Q-SiO_2 composite membrane is assembled and examined. The highest peak power density of the DMFC with 8 M KOH + 2 M CH3OH fuel is 35.13 mW cm~(-2) at 50℃ and 1 atm air. The peak power density is 0.27 mW cm~(-2) with a pure 2 M CH_3OH fuel at 25℃ and 1 atm air.