Heterogeneous Two-dimensional lamellar Ti3C2Tx membrane for osmotic power harvesting

Osmotic energy generated from salinity gradients has been recognized as a novel blue energy source. Membrane -based reverse electrodialysis (RED) is a promising strategy for harvesting electric power from salinity difference. However, practical RED process often suffers from the low energetic efficiency due to the inherent ion con-centration polarization phenomenon. Here, a heterogeneous two-dimensional lamellar Ti3C2Tx membrane with asymmetric geometry and charge properties was designed. The diode-like transport behavior with unidirectional ion conduction was observed, suggesting a preferential transport direction in the Ti3C2Tx hetero-nanochannel. When applied as the osmotic energy generators, the heterogeneous Ti3C2Tx membranes produced a maximum output power density of 16 W/m2 on mixing the natural brine and river water, higher than the commerciali-zation benchmark (5 W/m2). Theoretical calculations confirmed that the asymmetric membrane architecture achieved a balance between effectively weakening the concentration polarization and maintaining the high ion selectivity. This study is a significant step forward in the field of designing artificial nanofluidic membranes and highly efficient osmotic energy conversion systems.

Automated summary

This study presents the design of an asymmetric Ti3C2Tx membrane for efficient osmotic energy conversion. The experimental results show that the heterogeneous membrane can generate a higher power density than the commercial benchmark when mixed with natural brine and river water. Theoretical calculations further confirm the advantages of the membrane structure in reducing concentration polarization and maintaining high ion selectivity.