The development of ultra-thin membranes has always carried the promise of highly efficient, selective, and robust ion transport systems for filtration, sensing, and energy storage. Graphene stands out among scientific materials due to its strength, electrical properties, and absolute impermeability. Research from the University of Würzburg and Helmholtz Institute for RNA-based Infection Research (HIRI) demonstrates unexpected performance of graphene related to ion behavior.

New Findings on Graphene’s Ion Selectivity

Research contradicted the traditional understanding that graphene blocks every substance, including small ions, because it was found that monolayer graphene functions as an ion-selective filter but blocks other particles. Researchers found that the ion size and the size of its hydration shell determined its ability to penetrate through the graphene barrier.

They used suspended monolayer graphene over holes to measure ion flow, demonstrating that potassium (K⁺) and rubidium (Rb⁺) alkali metals passed through the structure, but ions with larger hydration shells became blocked. The data shows that membrane penetration depends on both the dimensions of the ions and the ease with which water is released by the ions during membrane transit.

This discovery reshapes our understanding of two-dimensional materials and their potential use in next-generation ion-selective membranes.

Experimental Design and Techniques Used

Analytical tests are performed with carefully engineered components, which helped the researchers verify their experimental conclusions. The researchers attached graphene sheets to substrates by depositing them into structures that had holes measuring one millionth of a meter. Through this process, the graphene sheets became suspended while remaining in contact with a single layer of graphene. Scientists used a precise method to measure how diverse ions interacted with the material through its ionic membranes.

The permeability was not random. Instead, it followed clear trends depending on the ionic radius and hydration energy. This points to a complex transport mechanism at the atomic scale, likely involving quantum and surface energy effects.

Scientific and Practical Significance

The implications of these findings stretch across multiple scientific fields:

• Nanofiltration and Desalination: Understanding ion selectivity at the monolayer level may lead to thinner, faster, and more selective membranes.

• Biosensing: Ion-permeable graphene can form the basis of next-gen sensors capable of detecting specific ions with high accuracy.

• Energy Storage and Conversion: Better control over ion flow supports the development of improved batteries, supercapacitors, and fuel cells.

This breakthrough also presents a more straightforward path to designing synthetic membranes that mimic biological ion channels—highly selective and incredibly efficient at the nanoscale.

How MSE Supplies Supports Graphene and Ion Transport Research

At MSE Supplies, we’re proud to offer a broad range of tools and materials for researchers working on graphene, membrane science, and ion transport.

• Graphene & Graphene Oxide and Nanoparticles & Nano Powder Materials: From monolayer graphene to advanced nanomaterials, we offer high-quality materials ideal for research and device development.

• Organic Chemicals: Essential for solution preparation, material modification, and supporting experimental conditions involving ions and electrolytes. From catalysts and ligands to polymers and ionic liquids, we offer a wide range of organic chemicals.

• Analytical Services: Get expert analysis through techniques like Raman spectroscopy, elemental composition testing, and electrochemical performance profiling.

These offerings make it easier for labs and research teams to explore the frontiers of material science with confidence.

This research opens new perspectives on the possible performance capabilities of extremely thin materials, such as graphene. Scientists have now demonstrated that graphene behaves like an active ion-regulating membrane, signaling the possibility of developing intelligent membrane systems and sophisticated ion management devices.

Looking to advance your work in ion transport or 2D materials? Visit MSE Supplies or contact our team to find the tools and support you need for your next breakthrough. Follow us on LinkedIn to get the latest news and updates!

References: 

1. Niyas, M. A., Shoyama, K., Grüne, M., & Würthner, F. (2025). Bilayer nanographene reveals halide permeation through a benzene hole. Nature. https://doi.org/10.1038/s41586-024-08299-8

2. Graphene made permeable for ions. (2023, December 8). https://www.uni-wuerzburg.de/en/news-and-events/news/detail/news/graphene-ion-permeable/