Two-dimensional lamellar membranes assembled from nanosheets are attractive for molecular and ionic transport, but simultaneously improving their mechanical robustness, aqueous stability, and transport performance remains challenging. Here, poly(vinyl alcohol) (PVA) was incorporated into few-layer graphene (FLG) membranes through co-dispersion, vacuum filtration, and hot pressing to tailor membrane structure and performance. Structural characterization revealed composition-dependent changes with increasing PVA loading. Moderate PVA incorporation improved membrane structural integrity, whereas higher PVA-to-FLG mass ratios promoted polymer-rich domains and increased structural heterogeneity. These structural changes were accompanied by distinct performance responses. The tensile strength increased from 28.6 MPa for pristine FLG membranes to 35.4 MPa at a PVA-to-FLG mass ratio of 0.10, while the Young’s modulus reached 5625 MPa at a ratio of 0.20. Meanwhile, the membrane prepared at a PVA-to-FLG mass ratio of 0.05 retained more than 97% of its initial mass after 100 days of electrolyte immersion and exhibited the highest apparent KCl/K₃[Fe(CN)₆] permeation-rate ratio of approximately 41. The mechanical improvements were accompanied by a decrease in in-plane electrical conductivity, highlighting the property-dependent effects of PVA incorporation. Overall, controlling the PVA-to-FLG mass ratio provides a simple strategy for tuning the structural organization, mechanical properties, aqueous stability, and salt-dependent transport behavior of FLG lamellar membranes.
