2D laminar membranes for selective water and ion transport

Selective water and ion transport are essential in fields related to the environment, resources, energy, and more. Membranes, especially those constituted by 2D materials, are promising to control mass transport within nano- and sub-nanoscales. When stacked together, the ultrathin nanosheets of these materials can build up laminar membranes with an ordered layer-like structure. Numerous channels are thereby created among layers for fast and selective mass transport, which arouses huge research and application interests. This Review aims to present the latest theoretical and experimental advances of 2D laminar membranes for selective water and ion transport, covering three fundamental aspects. Starting with a concise introduction to the materials and assembly for laminar membranes, it then mainly focuses on systematically discussing the transport-controlling effects caused by intrinsic membrane structure and extrinsic influences. The relation between these effects and current membrane selective performance as well as future membrane designs is then elucidated. The most urgent challenges and corresponding opportunities that emerge around 2D laminar membranes are highlighted thereafter.