Janus Metal–Organic Framework Membranes Boosting the Osmotic Energy Harvesting

Abstract

The unique ion-transport properties in nanoconfined pores enable nanofluidic devices with great potential in harvesting osmotic energy. The energy conversion performance could be significantly improved by the precise regulation of the “permeability–selectivity” trade-off and the ion concentration polarization effect. Here, we take the advantage of electrodeposition technique to fabricate a Janus metal–organic framework (J-MOF) membrane that possesses rapid ion-transport capability and impeccable ion selectivity. The asymmetric structure and asymmetric surface charge distribution of the J-MOF device can suppress the ion concentration polarization effect and enhance the ion charge separation, exhibiting an improved energy harvesting performance. An output power density of 3.44 W/m2 has been achieved with the J-MOF membrane at a 1000-fold concentration gradient. This work provides a new strategy for fabricating high-performance energy-harvesting devices.

Enhanced Osmotic Energy Conversion with Ultrahigh Ionic Conductivity in Sodium Polystyrenesulfonate/Cellulose Nanofiber Composite Membranes

“…Developing ISM technology promises to tap into osmotic energy from marine resources. ,, To maximize osmotic energy conversion efficiency, the ideal ISMs should boast higher ion selectivity and large ion flux, linked to higher surface charge density and lower resistance. , Achieving these properties often hinge on the chemical structure of ISMs. Recent efforts explored the use of two-dimensional materials, such as graphene, , molybdenum disulfide (MoS 2 ), MXene, − as well as porous materials like metal organic frameworks (MOFs), , and covalent organic frameworks (COFs), , to increase membrane porosity. Yet, insufficiencies in charged groups hinder ion selectivity, thereby hampering ISM advancement.…”

“…13,14 Achieving these properties often hinge on the chemical structure of ISMs. Recent efforts explored the use of two-dimensional materials, such as graphene, 15,16 molybdenum disulfide (MoS 2 ), 17 MXene, 18−20 as well as porous materials like metal organic frameworks (MOFs), 21,22 and covalent organic frameworks (COFs), 23,24 to increase membrane porosity. Yet, insufficiencies in charged groups hinder ion selectivity, thereby hampering ISM advancement.…”

Self-assembled two-dimensional metal–organic framework membranes as nanofluidic osmotic power generators

“…1–7 Most MOF membranes for osmotic energy harvesting in previous studies were polycrystalline membranes which were fabricated by growing MOF crystals onto or into porous substrates, such as porous anodic aluminum oxide (AAO), polyethylene terephthalate (PET), and alumina nanochannel membranes (ANMs). For example, polycrystalline UiO-66-NH 2 , 8 ZIF-8, 9 ZnTCPP, 6 HKUST-1, 10 PSS/HKUST-1, 7 UiO-66-(COOH) 2 , 11 MOF-303, 12 spiropyrans/MIL-53, 13 PSS/MOF-199, 14 and ZIF Hep 15 have achieved osmotic energy generation with power densities ranging 1.46 W m −2 to 45.6 W m −2 under various electrolyte solutions. Polycrystalline MIL-53-COOH single nanochannel membranes have shown an estimated power density of 3174.3 W m −2 with a concentration gradient of 1000 under HCl solutions.…”

Intriguing Two-Dimensional BeO-Based Tribo-Piezoelectric Nanogenerator

“…Energy harvesting technologies that can generate electricity from mechanical motion have received significant attention recently. − The piezoelectric effect is a widely used method to generate electrical energy from mechanical stress. ,,− The triboelectric effect, which involves the generation of charge separation due to friction between two materials, is another promising approach for energy harvesting. − In this context, nanogenerators based on tribo- and piezo-electric effects of materials have attracted increasing attention − due to their small size and scalability for various applications, such as self-powered sensors, wireless electronics, , and wearable devices. , However, tribo-piezoelectric nanogenerators (TPNGs) are still relatively inefficient compared to other energy harvesting techniques, such as solar cells or thermoelectric generators. Improving the efficiency of TPNGs is a major challenge and requires optimizing the materials and device design to maximize energy conversion.…”