Decoupling Diffusion- and Field-Driven Ion Transport in Graphene Oxide/Tungsten Disulfide Heterolaminar Composites

Abstract

Laminar graphene oxide (GO) films provide a model platform for studying ion transport in nanometer-scale two-dimensional (2D) nanochannels. We investigate how incorporation of tungsten disulfide (WS2) nanoflakes redistributes ionic transport in GO laminates between diffusion- and field-driven regimes. GO/WS2 composites show a pronounced decrease in transmembrane resistance and the emergence of non-ideal electrochemical response in cyclic voltammetry and impedance spectroscopy, while passive ion permeation is simultaneously suppressed. Cross-sectional scanning electron microscopy, Raman spectroscopy, and X-ray diffraction indicate that WS2 disrupts the ordered restacking of GO flakes, consistent with a transition from predominantly aligned GO flakes to a more heterogeneous internal microstructure. We propose that this structural disruption attenuates continuous low-friction GO nanochannel transport under concentration gradients while enabling alternative electrically responsive transport pathways under an applied field. These results show that heterolaminar 2D composites can decouple passive and field-driven ion transport through changes in stacking order and electrochemical interfacial response.