Multiscale carbon - Based ion channel fiber membrane for efficient osmotic energy capture

Abstract

The green energy generated by salinity gradient at the river-sea junction can be captured by Reverse Electrodialysis (RED) technology. The ion migration in the energy conversion process occurs in the narrow ion channel inside the permeable membrane of the core component. In practical applications, membrane used for osmotic energy conversion needs to meet the necessary conditions such as effective nano-channels, sufficient surface charges, large-scale preparation and stable energy output. It is challenging to achieve all of these requirement at the same time and calls for an exquisite design of the permeable membrane. Herein, we demonstrate an ion channel membrane regulated by a carbon-based membrane with hierarchical channels for efficient osmotic energy conversion. Porous carbon (PC) nanosheets with high porosity and high modulus are filled into carbon nanofibers (CNFS)/graphene oxide (GO) composite membrane, increasing ion transport channels and providing additional space charge to improve ion selectivity. The power output from PC@GO/CNFs membranes modified with nano-porous carbon reaches 4.3 W·m−2. In addition, the ion-selective membrane obtained by this strategy has the advantages of simple process, adjustable area and good stability. This simple strategy is one of the feasible paths for infiltration to be collected effectively. Ion-selective membrane is the key component for osmotic energy conversion.