Metallic Two-Dimensional MoS₂ Composites as High-Performance Osmotic Energy Conversion Membranes

Abstract

Molybdenum disulfide (MoS 2 ) has shown large promise in harvesting osmotic energy. However, the current investigations generally focus on proof-of-concept nanoscale singlepore devices with a semiconductor phase structure. Exploration of the application viability of MoS 2 in a more robust macroscopicscale two-dimensional (2D) nanofluidic membrane and acquisition of fundamentals of how the phase structure influences the power generation process are highly demanded. Here, we demonstrate that robust and stable composite membranes made up of 2D metallic MoS 2 can act as high-performance osmotic power generators. Both experiment and simulation reveal that the higher electron density of metallic MoS 2 increases the affinity of cations to the surface, which renders the system excellent ion selectivity and high ionic flux and greatly promotes transmembrane ion diffusion. When natural river water and seawater are mixed, the power density can achieve about 6.7 W m −2 . This work shows the great potential of metallic MoS 2 in nanofluidic energy devices.

Interfacial Super‐Assembly of Ordered Mesoporous Carbon‐Silica/AAO Hybrid Membrane with Enhanced Permselectivity for Temperature‐ and pH‐Sensitive Smart Ion Transport

“…[3] Reverse electrodialysis (RED) is an emerging membrane-based technology that can directly capture electricity by driving the ions through an ion selective mem-brane. [4] Nanofluidic systems with nano-scale channels have attracted extensive interest owing to their superiority in better controlling the transport of ions and molecule in aqueous solutions. [5] Therefore,membrane-based RED nanofluidic systems have been widely constructed to harvest the salinity gradient energy in the past few years.F or example, silk fiber, [6] Mxenes materials [7] and aramid nanofiber (ANF) [8] were used as the nano-sized building blocks to construct the nanofluidic devices.However,the concentration polarization phenomenon at the interface of low concentration electrolyte and channel exit weakens the selectivity of such membranes,r esulting in low energy efficiency.…”

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

“… 61 Until now, 2D laminar nanoporous membranes have been created using various materials, such as carbides, nitrides, 166 carbonitrides of early transition metals (MXene), 167 graphene, 123,168,169 black-phosphorus (phosphorene), 170 boron nitride nanosheets, 124 and kaolinite, 171 among others. 172 …”

“…61 Until now, 2D laminar nanoporous membranes have been created using various materials, such as carbides, nitrides, 166 carbonitrides of early transition metals (MXene), 167 graphene, 123,168,169 blackphosphorus (phosphorene), 170 boron nitride nanosheets, 124 and kaolinite, 171 among others. 172 There are at least two common methods for the creation of 2D laminar membranes: (a) vacuum ltration and (b) layer-bylayer (LbL) assembly. Membranes based on MXene, graphene, black phosphorus, and reconstructed kaolinite are usually obtained by vacuum ltration of a stable colloidal dispersion of the material that produces the assembly of the membrane (Fig.…”

“…Up-scaled 2D membranes usually involve 2D-laminar membranes. Well-known examples of these materials for developing SGE devices are graphene, 123,168,233 hexagonal boron nitride, carbon nitride, 166 MXene, 167 molybdenum disulde, 172 among others. 116,171,234 In the case of 2D layered membranes the interstitial spaces among the nanosheets act as "lamellar channels" enabling ion transport.…”

“…227 More recently, Zhu et al introduced the rst up-scaled 2Dmembrane based on MoS 2 for energy conversion purposes. 172 The main difficulty in creating large areas of MoS 2 2Dmembranes comes from the low strength and stability of the stacked membrane. However, by combining MoS 2 nanosheets with cellulose nanobers (CNFs), the authors demonstrated a MoS 2 lamellar nanoporous membrane with high conductivity, high ion selectivity, good mechanical strength, and stability in aqueous media.…”