Facile preparation of a MXene-graphene oxide membrane and its voltage-gated ion transport behavior

Two-dimensional MXenes have become a crucial topic in the field of ion transportation owing to their excellent electrochemical performance. Herein, a strategy for preparing a layered MXene-graphene oxide (GO) membrane via vacuum filtration is proposed, which endows the delaminated two-dimensional MXene-GO membrane (MGOm) with excellent electrical conductivity and chemical stability, achieving an excellent voltage-gated ion transport behavior. Owing to the presence of charges or dipoles within the membrane's channel, the movement of electrons or dipoles under the influence of membrane potential is possible. By varying the transmembrane potential, the transition between the closed and open states of the voltage-gated ion channel can be adjusted. When a negative potential is applied at osmotic pressure, the force between the charged MGOm sheet and the cation (K+) is enhanced, promoting ion permeation. Conversely, the application of positive potential attenuates electrostatic attraction, resulting in a decrease in ion permeability. In addition, the effects of MXene and GO with different modulation ratios on the voltage-gated ion transport have shown that when the modulation ratio of MXene : GO is 7 : 3, the optimal ion permeation rate is achieved. In conclusion, the conductive film with voltage-gated nanochannels is a promising alternative for ion transportation, opening up new avenues for the further exploration of MXene materials in energy storage devices.

Automated summary

This study proposes a strategy for preparing a layered MXene-graphene oxide (GO) membrane through vacuum filtration, which exhibits excellent electrical conductivity and chemical stability. The membrane shows a voltage-gated ion transport behavior, with the transition between closed and open states of the ion channel being adjustable by varying the transmembrane potential. The study also highlights the importance of the modulation ratio of MXene : GO, with a ratio of 7 : 3 achieving the optimal ion permeation rate.