Fabrication of dense cerium pyrophosphate-polystyrene composite for application as low-temperature proton-conducting electrolytes

Abstract

The goal of this study is to improve the applicability of cerium pyrophosphates as dense electrolytes in proton-conducting ceramicelectrolyte fuel cells (PCFCs) in 100-230°C, by using polystyrene as a pore-filler in partially sintered cerium pyrophosphate substrates. In this study an inorganic-organic composite membrane composed of Gd3+-doped cerium pyrophosphate (Ce0.9Gd0.1P2O7, CGP) and highly cross-linked polystyrene is prepared by polymerization of divinylbenzene monomers in partially sintered CGP substrates. The microstructure and electrochemical behavior of the CGP-polystyrene (CGP-PS) composites are characterized to understand their proton conductivity and long-term stability. The ionic conductivity measurement using electrochemical impedance spectroscopy (EIS) shows that the CGP-PS membranes have high ionic conductivity (>10 mS cm-1) in 110-200°C range under humidified condition (water vapor pressure, pH2O = 0.04-0.16 atm); where CGP-PS1 shows maximum conductivities of 16.1 and 14.8 mS·cm-1 in pH2O of 0.16 and 0.12 atm, respectively, at 190°C. The scanning electron microscopy (SEM) analysis of the as-prepared CGP-PS composites shows that they are dense and free of pores. The stability of the CGP-PS composites is analyzed after the long-term electrical conductivity measurement in humidified atmosphere. © 2015 The Electrochemical Society.