Interfacial interaction of graphene oxide with montmorillonite in tailoring the structure and proton transport phenomena of alginate/PVA membrane for DMFC applications

Abstract

AbstractPolymer electrolyte membrane that has high proton conductivity and low methanol permeability are necessary for direct methanol fuel cells (DMFCs). A sodium alginate (SA)/polyvinyl alcohol (PVA)/montmorillonite (MMT)/graphene oxide (GO) quaternary composite membrane was effectively developed in this study. The homogeneous distribution of MMT and GO nanosheets in the SA/PVA/MMT/GO composite membrane was exhibited by scanning electron microscopy (SEM). Intriguingly, it has been established that the SA/PVA membrane contains chemical crosslinks between MMT and GO, which significantly contribute to the rise in proton conductivity. The SA/PVA/MMT/GO hybrid membrane has minimum loss modulus of 47.91% and storage modulus of up to 2.689 × 109 Pa, which are 3.8 times greater than those of SA/PVA‐MMT membrane without GO. This value indicates the viscosity and elasticity of the produced membrane. The quaternary composite membrane also exhibits outstanding oxidative stability and methanol barrier characteristics. The methanol permeability of SA/PVA/MMT/GO films 0.524 × 10−9 cm2 s−1, with methanol absorption as low as 9.72%. The best membrane performs at a high‐power density (1.761 mW/cm2) of DMFC at a GO content of 1.3 wt% because it obtains the maximum selectivity value (7.0529 × 106 S scm−3). Future commercial membranes may be replaced by the innovative quaternary membrane created in this work, which has significant potential.