Ultrathin Self‐Standing Covalent Organic Frameworks toward Highly‐Efficient Nanofluidic Osmotic Energy Generator

Abstract

Nanofluidics is promising in the construction of highly-efficient osmotic energy generator, but it is still a challenge to develop large-scale and highperformance nanofluidic membranes. The emerging covalent organic frameworks (COFs) provide a desirable platform to create nanofluidic membranes with high ion selectivity and permeability towards effective osmotic energy conversion. Herein, an ultrathin self-standing COF nanofluidic membranes based on terephthalaldehyde-tetrakis(4-aminophenyl)methane is developed to construct high-efficiency nanofluidic osmotic energy generator. Benefiting from the nano-confined channels (1.4 nm) and negative surface charges, the COF based nanofluidic membrane demonstrates both excellent cation selectivity and high ion conductance. Moreover, an ultrathin thickness of ≈1.5 µm significantly reduces the membrane resistance. Consequently, the nanofluidic osmotic energy generator based on COF membrane can deliver a high output power of 5.31 W m −2 under a 50-fold salinity gradient simulating natural river/ sea junction, which is superior to most reported systems and reaches the industrial level. More importantly, such a COF nanofluidic membrane exhibits excellent stability in response to various environmental factors, including wide saline solution concentration, temperature and pH ranges. This work is anticipated to highlight the great potential of 1D COF nanofluidic membranes toward highly-efficient osmotic energy generators.

An Ionic Diode Covalent Organic Framework Membrane for Efficient Osmotic Energy Conversion

“…Covalent organic frameworks (COFs), a class of crystalline organic porous materials exhibiting permanent porosity and atomically ordered structures, have shown great potential for precise molecular/ion transport. − The highly crystalline two-dimensional (2D) COF membranes have attracted particular attention for energy storage , and conversion ,− owing to the presence of ordered nanofluidic channels. We recently reported a highly crystalline and oriented COF membrane that offered an increased ion flux and output power density. , Jiang et al reported a COF membrane containing the highest charge density among all the reported nanoporous membranes .…”

Recent trends in covalent organic frameworks (COFs) for carbon dioxide reduction

“…Recently, Wang et al constructed an ultrathin self-standing 1D COF nanofluidic membrane (denoted as BDA-TAM) having the ability to build an efficient nanofluidic osmotic energy generator. 29 As this, COF-based nanofluidic membrane, contains negative surface charges, it exhibits good selectivity towards cations and hence strong ionic conductance. Furthermore, the extraordinary stability of BDA-TAM extended across a wide range of saline solutions, temperatures, and pH values.…”

Surface Charge Modification on 2D Nanofluidic Membrane for Regulating Ion Transport

“…[1][2][3][4] Inspired by biological nanochannels, various biomimetic nanochannels have been constructed and used to regulate the transport behavior of ions in artificial systems. The design and application of materials based on biomimetic nanochannels have also been further developed, and promoted in the fields of gas separation, [5] water treatment, [6] osmotic energy harvesting, [7] and energy storage. [8] Membranes with nanochannel configures that modulate ion transport are known as nanofluidic membranes.…”