Graphene-integrated polymeric membrane as a flexible, multifunctional electrode

Herein, we report on the fabrication of a graphene-based, semi-permeable membrane electrode (gr-ME) using non-solvent phase inversion to confine a packed-layer of graphene nanosheets into a ≤1 µm thick surface layer that smoothly transitions into the microporous membrane, primarily using polysulfone. The gr-MEs have: (i) gas permeance on the order of 100–1000 GPU with ∼0.3 CO₂/N₂ ideal selectivity (lower than Knudsen diffusion expectations); (ii) salt water permeance (∼5 LMH/bar) with NaCl rejection 20–40%, on the order of nanofiltration membranes, as well as, (iii) high electronic surface conductivity, with a sheet resistance as low as ∼18 Ω/sq. We've characterized the durability using tensile testing and it retains electrical conductivity when stretched until fracture at 9.5%. Electrochemical activity for these gr-MEs have been demonstrated for both the hydrogen evolution reaction, and as electrochemical capacitors. Finally, we illustrate that the capacitance can be increased by UV surface treatment of the graphene layer.