Chemically sustainable fuel cells via layer-by-layer fabrication of sulfonated poly(arylene ether sulfone) membranes containing cerium oxide nanoparticles

Abstract To facilitate further commercialization of proton exchange membrane fuel cell, decomposition of the polymer electrolyte membrane needs to be solved. Functional sulfonic acid group grafted onto poly(arylene ether sulfone) by sulfide linkages to prevent degradation of functional groups was synthesized. On the other hand, cerium oxide particles were prepared by the sol–gel method with a size of 5–7 nm for its radical scavenging ability. The durable layer-by-layer membrane of 100 μm thickness containing cerium oxide spheres on both surface layers was successfully fabricated by the spray method. The proton conductivity and electrochemical impedance spectroscopy revealed that the cerium oxide nanoparticle size lower than 5–10 nm would not affect the proton conductivity of the layer-by-layer membrane. During the open-circuit voltage (OCV) degradation test, the voltage loss rate of the sulfonated poly(arylene ether sulfone) (SPAES140-4CeO2) membrane 0.21 mV h−1 was 5-fold lower than that of the recast Nafion membrane 1.035 mV h−1. The polarization curves after 100 h of OCV degradation test demonstrate that the maximum power density of SPAES140-4CeO2 membrane dropped from 363.67 to 295.43 mW cm−2, while that of the pristine SPAES140 membrane significantly decreased from 378.59 to 230.48 mW cm−2.