Performance of sulfonated poly(vinyl alcohol)/graphene oxide polyelectrolytes for direct methanol fuel cells

Abstract

[EN] The use nanotechnology along with the consideration of a functionalization and stabilization approach to the poly(vinyl alcohol) (PVA) was considered useful for the preparation of cost-effective polyelectrolyte membranes. A set of nanocomposite and crosslinked membranes based in PVA/SSA/GO were prepared and analyzed as polyelectrolytes in direct methanol fuel cells (DMFCs). The crosslinking and sulfonation by the use of sulfosuccinic acid (SSA) enhanced the stability and increased the proton conducting sites in the PVA structure. The presence of graphene oxide (GO) augmented the stability, remarkably decreased the methanol crossover and enhanced power density curves. An optimum value for proton conductivity was found for the 0.50%wt of GO proportion, which decreased to higher concentrations of GO. Given the power density curve dependency on both the proton conductivity and the crossover reduction, the performance of these membranes as polyelectrolytes in DMFCs is strictly related to the balance between both factors. Therefore, a proportion of GO of 0.75%wt may assure suitable proton conductivity 3 mS·cm-1 and high resistance to methanol permeability, reaching promising power density of 16 mW·cm-2 with lower hydration levels.