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New membrane and electrode assembly concept to improve salinity energy harvesting, Youcef Brahmi and Annie Colin, Soft Matter, (2022)
https://www.sciencedirect.com/science/article/pii/S0196890422000930
Résumé :
The recovery of energy generated from the mixing of fresh and salt water is a new form of renewable energy. However, current processes for energy harvesting from salt gradients remain inefficient mainly because commercial selective membranes have low performances. Hopes for non-selective membranes with nanofluidic channels which have been designed to lower the internal resistance of the cell seem to be in vain. We present a new combination of reverse electrodialysis and capacitive double layer expansion for salinity gradient energy harvesting. Our originality consists in the use of a single selective membrane and two capacitive layers that adsorb ions. The assembly of these elements allows us to double the potential of the open circuit of the cell and thus to multiply by 4 the potentially recoverable power. We present a complete study of a device of a few square centimeters. Contrary to what is generally done, we directly measure the energy and power recovered from the salt gradients in a load resistor. We measure a net power of 2 W.m−2 which is twice the best results presented in the literature to date. Our device makes the principle of energy recovery from salt gradients economically viable.
