Mixed-ceria reinforced acid functionalized graphene oxide-Nafion electrolyte membrane with enhanced proton conductivity and chemical durability for PEMFCs

Abstract

Towards the next-gen energy solutions, Nafion, as a state-of-the-art polymer electrolyte to low temperature fuel cell (LTFC) application has been one of the most demanding hydrogen to clean energy conversion device ever achieved. However, the inherent issue of limiting chemical durability and restricted proton conductivity have always been a topic of concern with pure Nafion membranes. To tackle this, we report a mixed-ceria reinforced phosphorylated graphene oxide (sPGO)/Nafion membrane as a potential electrolyte to simultaneously improve the chemical durability and proton conductivity of bare Nafion by utilizing the redox property of ceria nanoparticles and acidic sites of sPGO for accelerated proton transfer. As a progressive method, the single-step phosphorylation of GO introduced short chain branching along with enhanced number of acidic sites in the Nafion matrix whereas incorporation of mixed-ceria nanoparticles improved the chemical durability of the membrane due to its superior radical scavenging property. As a result, mixed-ceria reinforced sPGO/Nafion (Ce-sPGO/NF) electrolyte membrane showed higher proton conductivity (1.2-times) and chemical durability (8.1-times) than bare Nafion. Furthermore, the polymer electrolyte membrane (PEM) was also showcased high enough thermomechanical and electrochemical stability at 80 °C and 100% relative humidity (RH).