A highly proton-conducting, methanol-blocking Nafion composite membrane enabled by surface-coating crosslinked sulfonated graphene oxide

Coating an ultrathin crosslinked graphene oxide film onto a Nafion support enables the tradeoff effect to be successfully overcome by the resulting composite membrane: 93% decrease of methanol permeability while retaining the high proton conductivity of Nafion, owing to the synergistic modulation of methanol-transport and proton-transport channels within the graphene oxide film.