Exalted epi-osmotic energy harvesting in activated carbon nanochannels

Nanofluidics technology has made considerable progress over the last decade. Using Van der Waals assembly, it is now possible to make atomically smooth, pristine carbon bidimensional capillaries with atomic scale precision. In this presentation we show an alternative route to fabricate bidimensional, 'activated' carbon nanochannels using electron beam irradiation and Van der Waals assembly. We discover that the 'activated' carbon conduits outperforms by orders of magnitude pristine carbon materials in terms of osmotic energy conversion, with power density values reaching a hundred of kW/m². We attribute the huge increase in osmotic currents across activated carbon nanochannels as compared to pristine channels to an optimal combination of high surface charge and low friction on the activated carbon, boosting interfacially driven, epi-osmotic transport. Our results pave the way to the development of efficient carbon-based membranes for osmotic power harvesting under salinity gradients.

T. Emmerich, K.S Vasu, A. Nigues, A. Keerthi, B. Radha, A. Siria and, L. Bocquet, submitted.