A sol–gel synthesis of polyether-based proton conducting electrolytes Original Research Article

Proton conducting electrolyte gels composed of short polyether “tails” bound to a sol–gel matrix ([MePEG350S(CH2)3SiO3]n) and sulfonated oligomeric methyl polyethylene glycol (MePEG350-SO3H) exhibit dry and unplasticized H+ conductivities of up to 2.3×10−5 S/cm at 50 °C under vacuum. Proton conductivities in these electrolyte gels increase with added acid (MePEG350-SO3H). Activation barriers to H+ conductivity were between 20 kJ/mol for 0.25 M MePEG350-SO3H in (MePEG350S(CH2)3SiO3)n, and 38 kJ/mol for the 1.26 M mixture. Air equilibrated conductivities in these materials reached a maximum of 3.4×10−4 S/cm for neat MePEG350-SO3H.