Ricerc@Sapienza

Manufacturing new electrolytes with high ionic conductivity has been a crucial challenge
in the development and large-scale distribution of fuel cell devices. In this work, we present two
Nafion composite membranes containing a non-stoichiometric calcium titanate perovskite (CaTiO3-d)
as a filler. These membranes are proposed as a proton exchange electrolyte for Polymer Electrolyte
Membrane (PEM) fuel cell devices. More precisely, two different perovskite concentrations of 5 wt%

We comment on the interpretation put forward by Li et al. that their ceria particles involve sizable amounts of Ce3+ions. We propose that these nanoparticles consist of virtually pure ceria, and that they contain carbonated and hydrated species.