Ultrathin H‐MXM as An “Ion Freeway” for High‐Performance Osmotic Energy Conversion

Nanofluidic membranes are currently being explored as potential candidates for osmotic energy harvesting. However, the development of high-performance nanofluidic membranes remains a challenge. In this study, the ultrathin MXene membrane (H-MXM) is prepared by ultrathin slicing and realize the ion horizontal transportation. The H-MXM membrane, with a thickness of only 3 µm and straight subnanometer channels, exhibits ultrafast ion transport capabilities resembling an "ion freeway". By mixing artificial seawater and river water, a power output of 93.6 W m^-2 is obtained. Just as cell membranes have an ultrathin thickness that allows for excellent penetration, this straight nanofluidic membrane also possesses an ultrathin structure. This unique feature helps to shorten the ion transport path, leading to an increased ion transport rate and improveS performance in osmotic energy conversion.