title: Ion transport in complex layered graphene-based membranes with tuneable interlayer spacing.
abstract: Investigation of the transport properties of ions confined in nanoporous carbon is generally difficult because of the stochastic nature and distribution of multiscale complex and imperfect pore structures within the bulk material. We demonstrate a combined approach of experiment and simulation to describe the structure of complex layered graphene-based membranes, which allows their use as a unique porous platform to gain unprecedented insights into nanoconfined transport phenomena across the entire sub-10-nm scales. By correlation of experimental results with simulation of concentration-driven ion diffusion through the cascading layered graphene structure with sub-10-nm tuneable interlayer spacing, we are able to construct a robust, representative structural model that allows the establishment of a quantitative relationship among the nanoconfined ion transport properties in relation to the complex nanoporous structure of the layered membrane. This correlation reveals the remarkable effect of the structural imperfections of the membranes on ion transport and particularly the scaling behaviors of both diffusive and electrokinetic ion transport in graphene-based cascading nanochannels as a function of channel size from 10 nm down to subnanometer. Our analysis shows that the range of ion transport effects previously observed in simple one-dimensional nanofluidic systems will translate themselves into bulk, complex nanoslit porous systems in a very different manner, and the complex cascading porous circuities can enable new transport phenomena that are unattainable in simple fluidic systems.
authors.affiliation: Department of Materials Science and Engineering, Monash University, Melbourne, Victoria 3800, Australia.
authors.forename: Chi
authors.initials: C
authors.lastname: Cheng
authors.affiliation: Department of Materials Science and Engineering, Monash University, Melbourne, Victoria 3800, Australia.
authors.forename: Gengping
authors.initials: G
authors.lastname: Jiang
authors.affiliation: Australia Nuclear Science and Technology Organization, Sydney, New South Wales 2232, Australia.
authors.forename: Christopher J
authors.identifier: 0000-0001-6496-7008
authors.initials: CJ
authors.lastname: Garvey
authors.affiliation: Department of Materials Science and Engineering, Monash University, Melbourne, Victoria 3800, Australia.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Materials Science and Engineering, Monash University, Melbourne, Victoria 3800, Australia.; Monash Centre for Atomically Thin Materials, Monash University, Melbourne, Victoria 3800, Australia.
authors.forename: George P
authors.identifier: 0000-0001-8832-1164
authors.initials: GP
authors.lastname: Simon
authors.affiliation: Monash Centre for Atomically Thin Materials, Monash University, Melbourne, Victoria 3800, Australia.; Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Victoria 3800, Australia.
authors.forename: Jefferson Z
authors.initials: JZ
authors.lastname: Liu
authors.affiliation: Department of Materials Science and Engineering, Monash University, Melbourne, Victoria 3800, Australia.; Monash Centre for Atomically Thin Materials, Monash University, Melbourne, Victoria 3800, Australia.
authors.forename: Dan
authors.identifier: 0000-0003-3461-5751
authors.initials: D
authors.lastname: Li
keywords: Porous materials; graphene; nanoconfined ion transport; nanofluidics; nanoionics