Aligned Nanocomposite Membranes Containing Sulfonated Graphene Oxide with Superior Ionic Conductivity for Direct Methanol Fuel Cell Application

In this work, iron oxide (Fe3O4) nanoparticles are deposited onto sulfonated graphene oxide (SGO) nanosheets using a solvothermal method. By applying a magnetic field on the solution during casting, the SGO/Fe3O4 nanosheets are drawn to the through-plane direction of the membrane. The structures of the nanosheets and membranes are characterized. The aligned poly(vinyl alcohol) (PVA)/SGO/Fe3O4 membrane shows higher proton conductivity, water uptake, thermal stability, methanol permeability, and selectivity compared to a nonaligned membrane. By orientation of nanosheets, 5.7% improvement in the tensile stress of the membranes is observed. The aligned PVA/SGO/Fe3O4 nanocomposite membrane generates the highest power density of 25.57 mW cm–1 at 30 °C. As a result, the aligned PVA/SGO/Fe3O4 nanocomposite membrane appears to be a good candidate for direct methanol fuel cell application.