“…The physical properties of a DL, as a reactant/product transfer channel and a support structure for the CL, have a very profound effect on the electrochemical reactions in the cell [ 14 , 18 ], such as gas–liquid two-phase mass transfer [ 10 , 12 , 13 , 15 , 17 ], ohmic polarization [ 12 , 13 , 19 ], and methanol crossover [ 10 , 15 , 16 , 17 ]. Graphene is highly conductive and mechanically and chemically stable; thus, it is widely used in DLs in DMFCs [ 10 , 12 , 13 , 15 , 20 ]. However, its processability and manufacturing costs are the main obstacles to its large-scale commercialization [ 12 ].…”