Atomic snapshots show fast ion migration in ultra-thin clays

Research led by The University of Manchester has found that ions diffuse 10,000 times faster inside atomically thin clays than in bulk clay crystals. Clays are used in a wide variety of membrane applications, so this result offers the potential to achieve vastly improved desalination or fuel cell performance simply by switching to ultra-thin clays when producing the membranes. Clays, like graphite, consist of crystal layers stacked on top of each other and can be mechanically or chemically separated to produce ultra-thin materials. The layers themselves are just a few atoms thick, while the space between layers is molecularly narrow and contains ions. The interlayer ions can be altered in a controllable way by allowing different ion species to penetrate between the layers. This property, known as ion exchange, allows for control of the physical properties of these crystals in membrane applications. However, despite its relevance in these emerging technologies, the ion exchange process in atomically thin clays has remained largely unexplored.