Synthesis and characterization of anhydrous proton conducting inorganic-organic composite membranes for medium temperature proton exchange membrane fuel cells (PEMFCs)

摘要

We report on anhydrous proton conducting inorganic-organic composite membranes synthesized from tetraethoxysilane/poly(-dimethylsiloxane)/trimethylphosphate and 1 -ethyl-3 methylimidazolium-bis (trifluoromethanesulfonyl) imide ionic liquid as sol-gel precursors. The Fourier transform infrared spec-troscopy, ~(31)P, ~1H, and ~(13)C Nuclear magnetic resonance, thermo gravimetric and differential thermal analysis measurements confirmed that the prepared hybrid membranes possess good chemical stability and are thermally stable up to 350℃. Conductivity of all the fabricated hybrid membranes was measured under anhydrous conditions within the temperature range -20-150 ℃, and a value of 4.87 x 10~(-3) S/cm at 150℃ was achieved for 40 wt% [EMI][TFSI] ionic liquid doped 72TEOS-18PDMS-10PO (OCH_3)_3 (mol %) hybrid membrane. For 40 wt% ionic liquid doped composite membrane, the measured hydrogen permeability value at 150℃ was 4 x 10~(-12) mol/cm s Pa.