Robust sulfonated poly (ether ether ketone) nanochannels for high-performance osmotic energy conversion

Abstract

The membrane-based reverse electrodialysis (RED) technique has a fundamental role in harvesting clean and sustainable osmotic energy existing in the salinity gradient. However, the current designs of membranes cannot cope with the high output power density and robustness. Here, we construct a sulfonated poly (ether ether ketone) (SPEEK) nanochannel membrane with numerous nanochannels for a membrane-based osmotic power generator. The parallel nanochannels with high space charges show excellent cation-selectivity, which could further be improved by adjusting the length and charge density of nanochannels. Based on numerical simulation, the system with space charge shows better conductivity and selectivity than those of a surface-charged nanochannel. The output power density of our proposed membrane-based device reaches up to 5.8 W/m2 by mixing artificial seawater and river water. Additionally, the SPEEK membranes exhibit good mechanical properties, endowing the possibility of creating a high-endurance scale-up membrane-based generator system. We believe that this work provides useful insights into material design and fluid transport for the power generator in osmotic energy conversion.

Nanofluidic osmotic power generators – advanced nanoporous membranes and nanochannels for blue energy harvesting

“…188,207 On the other hand, the creation of systems with a distribution of net charges within the entire volume of the nanochannel interior (space charge) rather than just on the nanochannel walls (surface charge) has demonstrated to be a simple way to improve the SGE performance. 65,118,208 In the last few years, asymmetric modications producing heterogeneous membranes composed of two different monolayer porous membranes have been used as an essential strategy to boost the power in NRED systems. 209,210 In 2019, Wei Guo and coworkers carried out a PNP-based study on the fundamental aspects of heterogeneous membranes as osmotic nanogenerators.…”

“…The employment of 3D materials has been proposed as a simple way to obtain membranes with low cost and easy scalability acting as efficient SGE devices. 65,135,184,244,245 The combination of interconnected 3D nanostructured networks together with the high surface and space charge leading to high conductance and selectivity has been identied as determining factors. 246 In the last year, several proofs-of-concept have been introduced in the synthesis, characterization, and energy conversion testing of these materials.…”

“… 188,207 On the other hand, the creation of systems with a distribution of net charges within the entire volume of the nanochannel interior (space charge) rather than just on the nanochannel walls (surface charge) has demonstrated to be a simple way to improve the SGE performance. 65,118,208 …”

Water treatment based on atomically engineered materials: Atomic layer deposition and beyond

“…The as-fabricated artificial nanochannels have application potential in ion-selective transport and osmotic energy harvesting. 38,133 Other applications Apart from the above cases, other advanced performance can be introduced by ALD/SIS engineering. One example of such novel functionality is the use of charged interfaces engineered for pollutant adsorption.…”

Bioinspired nanochannels based on polymeric membranes

“…By tuning the contents of the ionomers, the nanochannel membranes with different pore sizes and porosities can be obtained, which was applied for energy conversion, and achieved 2.66 W m −2 output power density. Zhao et al [122] synthesized a sulfonated poly(ether ether ketone) (SPEEK) nanochannel membrane involving numerous nanochannels by utilizing nonsolvent induced phase separation (NIPS) technique (Fig. 7b).…”