Multilevel geometric optimization in nanochannel membranes for osmotic energy conversion

Abstract

The application of biomimetic nanofluidic nanochannels for the harvest of osmotic energy has attracted considerable interest in recent years. However, there exists a lack in the comprehensive understanding of how geometric parameters similar to the complex configurations of biological counterparts affect the conversion of osmotic energy. In this paper, theoretical models are developed based upon Poisson-Nernst-Planck equations to simulate the performance of nanochannel membranes in generating osmotic power. The results reveal that employing asymmetric nanochannels results in enhanced cation selectively with the transference number increasing from 0.71 to 0.82. Furthermore, shortening the length of nanochannels can improve power generation performance. Various nanochannel configurations are designed to investigate the influence on output characteristics, in which the maximum power increases from 0.84 to 1.41 fW. The model predictions are further verified by experimental data based on nanofluidic devices. These findings provide valuable insights for the development of efficient osmotic energy harvesting devices.