Inorganic-organic composite membranes containing amino-functionalized mesoporous silica loaded phosphotungstic acid with enhanced fuel cell performance and stability

Abstract

In this work, phosphotungstic acid (HPW) modified amino-functionalized mesoporous silica (AMS) as an inorganic filler (AMS@HPW) is incorporated into sulfonated poly (aryl ether sulfone) (SPAES) to prepare inorganic-organic composite membrane. The fabricated silica possesses a mesoporous structure with a surface area of 488.74 m2/g. The amino modification of silica acting as a “bridge” loads more HPW and promotes the compatibility between inorganic fillers and SPAES. The obtained SPAES/AMS@HPW composite membranes effectively inhibit HPW leakage and display better stability and fuel cell property due to the acid-base interaction and hydrogen-bond networks. Especially, the SPAES/AMS@HPW-1.0 membrane displays 18.4% higher proton conductivity (175.5 mS/cm) at 90 °C and 22.3–28.5% higher power density (470.4–678.4 mW/cm2) at 60%–100% RH than the original membrane. In addition, the SPAES/AMS@HPW-1.0 membrane still maintains stable voltage output and shows lower voltage decay (0.331 mV/h) and hydrogen permeation current density (8.28 mA/cm2) than Nafion 112 after the durability test.