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Heterogeneous Two-Dimensional Composite Membranes with Gradient Architecture and Hopping-Assisted Ion-Transport
Liwen Xie1,2, Ziqi Ren1,2, Gao Liu1,2
1State Key Laboratory of Bioinspired Interfacial Materials Science, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, China.
Journal of the American Chemical Society
|June 25, 2026
Summary
Researchers developed an asymmetric 2D nanocomposite membrane using graphene oxide (GO) and sodium alginate (SA) for efficient osmotic energy conversion. This design enhances ion selectivity and flux, achieving a high power density for sustainable energy generation.
Area of Science:
- Materials Science
- Nanotechnology
- Energy Conversion
Background:
- Two-dimensional (2D) nanocomposite membranes offer designability and strength but face challenges balancing ion selectivity and flux due to large interlayer spacing.
- Bioinspired asymmetry and enhanced ion transport dynamics are key strategies for advancing 2D nanocomposite membrane performance.
- Osmotic energy conversion is a promising renewable energy source requiring efficient membrane technologies.
Purpose of the Study:
- To design and investigate an asymmetric heterogeneous 2D composite membrane for efficient osmotic energy conversion.
- To improve the balance between ion selectivity and ion flux in 2D nanocomposite membranes.
- To explore the role of a gradient architecture and sodium alginate (SA) in facilitating ion transport.
Main Methods:
- Fabrication of a dual-layer asymmetric membrane using sulfonated graphene oxide (GO) nanosheets, bacterial cellulose (BC), and sodium alginate (SA).
- Characterization of the membrane's structure and ion transport properties.
- Performance evaluation using osmotic energy conversion experiments with a river water/seawater mixture and computational simulations (continuum and molecular dynamics).
Main Results:
- The asymmetric heterogeneous membrane achieved a power density of approximately 11 W m-2, outperforming conventional GO-based membranes.
- The dual-layer structure with a gradient architecture and SA-enabled microenvironment promoted hopping-assisted Na+ transport.
- Simulations confirmed reduced transport barriers and concentration polarization losses due to the asymmetric design and SA incorporation.
Conclusions:
- The developed asymmetric heterogeneous 2D composite membrane effectively balances ion selectivity and flux for efficient osmotic energy conversion.
- The bioinspired asymmetric design strategy, integrating gradient architecture and SA, significantly enhances membrane performance.
- This work provides a pathway for developing advanced membranes for sustainable osmotic power generation.
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