Conducting Polymer-Based Nanofluidic Membranes for Osmotic Energy Conversion

Osmotic energy conversion (blue energy), serving as a sustainable marine renewable energy source, converts Gibbs free energy originating from salt concentration differences into electric power by virtue of ion-selective nanofluidic membranes. Conventional commercial ion-exchange polymer membranes suffer from inherent limitations, including low transmembrane flux, insufficient ion permselectivity, severe interfacial concentration polarization, poor salt tolerance, and unsatisfactory long-term structural stability. These drawbacks greatly restrict the energy conversion efficiency and large-scale engineering application of reverse electrodialysis (RED). Conductive polymers (CPs), mainly including polypyrrole (PPy), polyaniline (PANI), polythiophene (PTh), and their derivatives, possess the distinctive merits of tunable surface charge density and polarity, outstanding electronic conductivity, facile nanochannel structural regulation, and reversible redox responsiveness, making them ideal building blocks for advanced nanofluidic membranes for high-efficiency osmotic energy conversion. This review summarizes recent progress in the fabrication of conductive polymer-based nanofluidic membranes, comprehensively compares the osmotic output performance of typical CP material systems, and discusses the core metrics of osmotic energy conversion output performance. By providing an overview of these developments, this review aims to offer insights into the future development of conductive polymer-based nanofluidic membranes for osmotic energy conversion.