Novel organic-inorganic polyphosphate based composite material as highly dense and robust electrolyte for low temperature fuel cells

Abstract

Low temperature operating ceramic-based solid electrolytes are practical option to develop highly efficient energy conversion devices for next-generation energy demands. The present work provides a novel ceramic-polymer composite, where the host matrix of gadolinium doped cerium pyrophosphate (CGP) is reinforced by a non-toxic, biodegradable functionalized cellulose-based polymer (P), to achieve a highly dense and stable ionic conductor that can be applied in low temperature fuel cell (LTFC) application. This composite is examined for its phase identity, microstructure, and electrochemical properties. The composite is exposed to four different thermodynamic conditions i.e. dry air, humidified air (WA), D2O containing air (DA), and humidified H2 (WH2) to examine its ionic conductivity. To identify the responsible charge carrier and its mobility under different thermodynamic conditions complex impedance analysis has been used. A highly dense (apparent porosity~3%), and stable proton-conducting electrolyte was obtained by this reinforcement, with a remarkable proton conductivity of 13 and 29 mScm−1 under WA and WH2the atmosphere, respectively, where pH2O is maintained to 0.03 atm. The present composite is also found to be stable up to 100 h in terms of microstructure and ionic conductivity. Accounting all, the composite is suitable to be used as a solid electrolyte for LTFC application.