Silica/montmorillonite nanoarchitectures and layered double hydroxide-SPEEK based composite membranes for fuel cells applications

Anionic and cationic clays were here evaluated as nanofillers of low sulfonated polyetheretherketone (SPEEK, DS = 56%) for preparation of nanocomposite electrolyte membranes for PEMFC (Proton Exchange Membrane Fuel Cells) applications. A synthetic Mg-Al layered double hydroxide (LDH) exchanged with sulfate anions and a porous SiO2-montmorillonite heterostructured material containing delaminated clay particles, were added to SPEEK polymer for preparation of composite membranes with different nanofiller content (3, 6 and 9%). The resulting membranes were characterized concerning their structure, morphology and electrical conductivity performance. The incorporation of the Mg-Al LDH and the SiO2-motmorillonite fillers into the SPEEK seems to enhance water retention and the thermal stability of the resulting composite electrolyte membranes. Moreover, the composite electrolyte membranes show higher proton conductivity than the neat SPEEK membrane (0.023 S cm(-1)) after incorporation of the LDH and the SiO2-motmorillonite fillers (0.070 and 0.158 S cm(-1) respectively) at 120 degrees C and 100% relative humidity, which can be relevant for increasing the performance at high temperature of this type of membranes in fuel cell applications.