Hydrogen-Bonded Organic Framework Nanochannels for Salinity Gradient Energy Conversion

The salinity gradient at the seawater and river water interfaces is an abundant renewable energy source, which can be converted into electrical power through the selective nanofluidic nanochannel membranes. However, the practical applications of reported nanomaterials are limited by the poor ion selectivity and low ion flux. Herein, we demonstrate hydrogen-bonded organic framework (HOF) nanochannels for osmotic power generation. The porous structure formed by hydrogen bonds and π-π interactions and the internal unprotonated carboxyl groups endow the HOF nanochannels with great cation selectivity and high ion flux. By mixing seawater and river water, 44.4 wt % HOF nanochannel membranes exhibit a maximum output power density of 6.04 W/m2, which outperforms the commercial benchmark of 5 W/m2. This study lays the foundation for the applications of HOF to the harvest of salinity gradient energy.