One-atom thick graphene is believed to be practically impermeable to any gas or liquid. On the other hand, the transport of molecules through graphene pores allows for size-dependent permeability of graphene membranes. Structural engineering of graphene therefore opens up the possibility to achieve selective molecular transport through macroscopic areas of graphene. In contrast to pristine graphene, graphene oxide (G-O) has different functional groups that affect its permeability. G-O membranes are permeable for water molecules while remaining impermeable for other gas and liquid molecules. Such selective permeability of G-O membranes is ascribed to the presence of functional groups that provide pathways for water molecules through the G-O platelets.Here we report experimental studies of permeability properties of G-O oxide and reduced graphene oxide (RG-O) films for Li+ ions. In our experiments, permeation of Li+ through G-O and RG-O membranes has been investigated using Li+ conductive solid electrolyte, G-O or RG-O film, and an oxide layer, all sandwiched between two electrodes. Permeability tests were performed by applying external electric field to the electrodes. We demonstrate that Li+ ions can reversibly move across the RG-O film demonstrating the permeability of RG-O membranes for Li+ ions. In contrast, G-O membranes are impermeable for Li+ ions. The obtained results show the possibility to tailor the permeability of graphene oxide membranes through modification its chemical structure. Detailed mechanism of metal ion permeation/impermeation through RG-O/G-O membrane films is discussed. The presented studies are promising for development of graphene-based membranes for electrochemical devices.We appreciate support from NSF (Grant #: DMR-1206986).

Permeation of metal ions through graphene-based membranes

246th National Meeting (2013)

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