Pristine SPES Research Articles

Sulphonated poly(ethersulfone)/carbon nano-onions-based nanocomposite membranes with high ion-conducting channels for salt removal via electrodialysis.

Herein, we are reporting the carbon nano onions (CNO)-based sulphonated poly(ethersulfone) (SPES) composite membranes by varying CNO content in SPES matrix for water desalination applications. CNOs were cost-effectively synthesized using flaxseed oil as a carbon source in an energy efficient flame pyrolysis process. The physico- and electrochemical properties of nanocomposite membranes were evaluated and compared to pristine SPES. Moreover, the chemical characterisation of composite membranes and CNOs were illustrated using techniques such as nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FE-SEM), thermogravimetric analysis (TGA) and universal tensile machine (UTM). In the series of nanocomposite membranes, SPES-0.25 composite membrane displayed the highest water uptake (WU), ion exchange membrane (IEC) and ionic conductivity (IC) values that were enhanced by 9.25%, ~ 44.78% and ~ 6.10%, respectively, compared to pristine SPES membrane. The electrodialytic performance can be achieved maximum when membranes possess low power consumption (PC) and high energy efficiency (Ee). Therefore, the value of Ee and Pc for SPES-0.25 membrane has been determined to be 99.01 ± 0.97% and 0.92 ± 0.01 kWh kg-1, which are 1.12 and 1.11 times higher than the pristine SPES membrane. Hence, integrating CNO nanoparticles into the SPES matrix enhanced the ion-conducting channels.

Polydopamine-coated graphene oxide nanosheets embedded in sulfonated poly(ether sulfone) hybrid UF membranes with superior antifouling properties for water treatment

• Fouling-resistant UF membranes developed by blending PDA-coated GO with SPES. • Agglomeration of the nanofillers was avoided even at 10 wt% loading. • Hybrid membranes showed superior permeability, HA rejection and fouling resistance. • Pristine and 10 wt% PDGO loaded membranes yielded R ir of 32% and 6.9%, respectively. A novel high-performance hybrid ultrafiltration (UF) membrane was fabricated by blending polydopamine-coated graphene oxide (PDGO) nanosheets with sulfonated poly(ether sulfone) (SPES) via phase inversion method and tested for the removal of natural organic matter (humic acid; HA) from aqueous solution. The PDGO nanosheets were synthesized via self-polymerization of dopamine with GO nanosheets in alkaline tris-buffer solution at room temperature for 24 h and were fully characterized. Hybrid SPES membranes were prepared by incorporating 1–10 wt% of PDGO, which were further characterized by Raman spectroscopy, surface zeta potential, and field emission scanning electron microscopy to confirm membrane stability without any defects even by adding up to 10 wt%, of PDGO nanosheets. The membranes demonstrated a significant increase in hydrophilicity, water flux, and retention rate for HA (R HA ). For instance, water permeability with 5 wt% PDGO (M5) (680.7 L m −2 h −1 bar −1 ) was ca. 1.8-folds that of the pristine SPES membrane (380.8 L m −2 h −1 bar −1 ), while maintaining an HA rejection (R HA ) of 91.7% for a 50 ppm HA feed solution. This was accompanied by a distinct increase in surface hydrophilicity of M5, which showed a water contact angle of 27.8°, well below that of pristine SPES membrane (59.1°). The hybrid UF membranes also demonstrated a significant reduction in HA adhesion onto the membrane surface along with a superior antifouling performance for the membrane containing 10 wt% PDGO, giving irreversible fouling ratio (R ir ) of only 6.9% compared to 32.7% for the pristine membrane.

Modified MOF‐Based Composite All‐Solid‐State Polymer Electrolyte with Improved Comprehensive Performance for Dendrite‐Free Li‐Ion Batteries

AbstractSolid‐state polymer electrolytes (SPEs) used for Li‐ion batteries have consistently received widely−attention owing to its high safety, excellent flexibility, and good compatibility with electrodes. However, pristine SPEs are difficult to satisfy all necessary demands for the practical applications in high‐performance Li‐ion batteries. Herein, a polycaprolactone modified metal‐organic framework (MOF‐PCL) composite polymer electrolyte (CSPE) is fabricated through the facile UV‐light induced photopolymerization of boronic ester crosslinking monomer (BEM) and poly (ethylene glycol) diacrylate (PEGDA) in the presence of lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) and MOF‐PCL. The existence of MOF‐PCL in the electrolyte can not only obviously improve the ion conduction, but also enhance electrochemical stability simultaneously. Besides, the boron‐doped network structure can further promote the transport of Li‐ions. As a result, the obtained CSPE has a higher lithium‐ion transference number of 0.59 and a wide electrochemical window of 5.29 V. Moreover, the LiFePO4/Li cell based on this CSPE also exhibits excellent long‐cycling and rate performance. Undoubtedly, this study not only can provide a new designed method for SPEs with comprehensive performance, but also exhibits a good application potential of this modified MOF‐based CSPE with borate ester in the high‐performance Li‐ion batteries.

Sulfonated Poly(ether sulfone) based sulfonated molybdenum sulfide composite membranes and their applications in salt removal and alkali recovery

The adequate and potable water to meet present and future demand is much lower than the fresh water available. To fulfil the surplus demand of fresh drinking water, the management and treatment of waste water to be taken forward. In this view, electrodialysis (ED) has attracted immense attention nowadays to satisfy current water demands for drinking and industrial purpose. Ion exchange membranes are the cores of electrodialysis. Herein, composite cation exchange membranes are prepared for salt removal and water treatment using sulfonated poly(ether sulfone) (SPES) and sulfonated molybdenum sulfide (S–MoS2). Effect of S–MoS2 in membranes, water-related properties, ion transport, thermal and mechanical properties of synthesized composite membranes are evaluated. Incorporation of S–MoS2 in SPES enhance the performance of the membranes, and 5 wt % S–MoS2 composite membrane (DES-5) shows the 67% higher water sorption and 25% higher IEC compared to pristine SPES membrane. Their suitability is accessed in terms of salt removal via electrodialysis and alkali recovery via diffusion dialysis. The 5 wt % S–MoS2/SPES composite membrane exhibits 0.98 kWh/kg power consumption during salt removal that is 22% lower than 1.26 kWh/kg obtained for pristine SPES. Current efficiency towards salt removal and separation factor for alkali recovery for DES-5 membrane are 69.47% and 60.32, respectively, which are much higher than virgin SPES membrane.

SPES/PVDF Binary Membrane as an Alternative Proton Exchange Membrane in Vanadium Redox Flow Battery Application

SPES/PVDF blends were employed to prepare the ion exchange membranes for vanadium redox flow battery (VRB) application for the first time. The addition of the highly crystalline and hydrophobic PVDF effectively limited the swelling behavior of SPES. The vanadium ion permeability of SPES/PVDF membranes was one order of magnitude lower than that of Nafion117 membrane and pristine SPES membrane. Single cells with SPES/PVDF composite membranes showed significantly lower capacity loss, higher coulombic efficiency and higher energy efficiency than that with Nafion117 and pristine SPES membranes. The blend membrane with 40wt% of PVDF (denoted as S0.6P0.4) showed energy efficiency of 83.2% at 30 mA∙cm-2, which was superior to that of the Nafion117 and SPES membranes. In the self-discharge test, S0.6P0.4 membrane showed twice longer duration in open circuit decay than that with Nafion117 membrane. With all the good properties and low cost, the SPES/PVDF membranes are expected to have excellent commercial prospects as ion exchange membranes for VRB system.

Sulfonated poly (ether sulfone)/poly (vinyl alcohol) blend membranes customized with tungsten disulfide nanosheets for DMFC applications

Sulfonated poly (ether sulfone) (SPES) and poly (vinyl alcohol) (PVA) blend nanocomposite proton exchange membranes were fabricated and tailored with exfoliated tungsten disulfide (E-WS2) nanosheets with the aim of achieving better methanol resistant properties for direct methanol fuel cell (DMFC) applications. Reinforcement due to the existence of E-WS2 nanosheets on composite membrane imparted superior mechanical and thermal stability. Surface morphology of the composite membranes in terms of roughness is examined by AFM. Further, the results confirmed the intercalation of E-WS2 nanosheets onto the polymer matrix. The incorporation of E-WS2 nanosheets onto SPES/PVA system shows highest proton conductivity of 1.18 × 10−2 Scm−1 (at 25 °C) and mechanical stability of 143 MPa upon comparison with pristine SPES membrane. Furthermore, the methanol absorption by membrane matrix is found to be 3.42 × 10−8 cm2s−1. Overall results confirmed that SPES/PVA/E-WS2 nanocomposite proton exchange membranes are promising for applications in DMFCs.

Preparation and characterization of SPES/PVA (double-layer) membrane for vanadium redox flow battery

The double-layer membrane consisting of sulfonated poly(ether sulfone) (SPES) sub-layer and polyvinyl alcohol (PVA) sub-layer (denoted as SPES/PVA membrane) was prepared and employed as the separator for vanadium redox flow battery (VRB) system to evaluate the vanadium ions permeability and cell performance. The SPES/PVA membrane is a double-layer structure and exhibits dramatically lower vanadium ions permeability and better cell performance compared to the pristine SPES membrane, PVA membrane, and Nafion117 membrane. The vanadium ion permeability of SPES/PVA membrane is one order of magnitude lower than that of Nafion117 membrane. In further work, the single cell with SPES/PVA membrane showed significantly lower capacity loss, higher coulombic efficiency (>92.5%), and higher energy efficiency (>83.9%) than Nafion117 membrane. In the self-discharge test, SPES/PVA membrane showed 1.8 times longer duration in the open circuit decay than Nafion117 membrane. With all the good properties and low cost, this new kind of double-layer membrane is suggested to have excellent commercial prospects as an ion exchange membrane for VRB systems.

SPES/PVDF/TPA composite membrane as an alternative proton exchange membrane in vanadium redox flow battery application

A new kind of composite membrane consisting of sulfonated poly(ether sulfone) (SPES), poly(vinylidene fluoride) (PVDF), and phosphotungstic acid (TPA) has been prepared and employed as the ion-exchange membrane for vanadium redox flow battery (VRB) application. The addition of the highly crystalline and hydrophobic PVDF effectively confines the swelling behavior of SPES/PVDF/TPA. The composite membrane exhibits one order of magnitude lower vanadium ions permeability and much better single cell performance compared to pristine SPES and Nafion 115 membranes. The single cell with SPES/PVDF/TPA membrane shows much lower capacity loss, higher coulombic efficiency (>97%), and higher energy efficiency (>82%) than which with Nafion 115 membrane. In the self-discharge test, single cell with SPES/PVDF/TPA membrane shows much longer duration in the open-circuit voltage decay than which with Nafion 115 membrane. With all the good performances and low cost, the SPES/PVDF/TPA membrane is expected to have excellent commercial prospects as ion-exchange membrane for VRB system.

Quaternized graphene oxide modified ionic cross-linked sulfonated polymer electrolyte composite proton exchange membranes with enhanced properties

A series of novel ionic cross-linked sulfonated poly(ether sulfone) (SPES)-based proton exchange membranes (PEMs) were successfully constructed by using quaternized graphene oxide (QGO) as the inorganic fillers and cross-linking agents. The ionic cross-linking networks were implemented by the interactions between the sulfonic acid groups of SPES and the quaternary ammonium groups of QGO. The influences of different loading contents of QGO on the properties of the ionic cross-linked composite membranes were studied. The composite membranes showed the enhanced mechanical properties and improved oxidative stabilities. Meanwhile, the swelling ratio, water uptake and methanol permeability of the ionic cross-linked SPES/QGO composite membranes were much lower than that of the pristine SPES membrane. The swelling ratio and water uptake of SPES-10-QGO composite membrane had the minimum values among all the composite membranes. In addition, although the proton conductivity of ionic cross-linked SPES membranes by QGO decreased, SPES-10-QGO still exhibited high proton conductivity of about 0.08Scm−1 at 80°C. All the results indicated that the ionic cross-linked composite membranes with balanced properties were the potential candidate materials for PEMs.

Sulfonated poly(ether sulfone)/poly(vinylidene fluoride) hybrid membrane for vanadium redox flow battery

Sulfonated poly(ether sulfone)/poly(vinylidene fluoride) (SPES/PVDF) blends are prepared and employed as the separator for vanadium redox flow battery (VRB) to evaluate the vanadium ions permeability and cell performance. The SPES/PVDF membranes exhibit dramatically vanadium ions permeability and cell performance compared with pristine SPES and Nafion115 membrane. The vanadium ion permeability of SPES/PVDF membrane is 1 order of magnitude lower than that of Nafion115 membrane. The low-cost composite membrane exhibits a better performance than Nafion115 membrane at the same operating condition. VRB single cell with SPES/PVDF membrane shows significantly lower capacity loss, higher coulombic efficiency (>98%) and higher energy efficiency (>84%) than that with Nafion115 membrane. In the self-discharge test, S0.7P0.3 membrane shows twice longer duration in the open circuit decay than that with Nafion115 membrane. With all the good properties and low cost, the SPES/PVDF membrane is expected to have excellent commercial prospects as an ion exchange membrane for VRB systems.

Mesoporous ceria-silica/poly(arylene ether sulfone) composite membranes for durability of fuel cell electrolyte membrane

Sulfonated poly(arylene ether sulfone) (sPES)/mesoporous ceria-silica electrolyte composite membranes were prepared using a solvent casting method. The composite membranes with two components were prepared well on glass dish using dimethyl sulfoxide (DMSO) as well as N,N-dimethyl acetamide (DMAc) solvents, at various concentrations from 2.5 up to 30 wt% of the mesoporous ceria-silica powder. The degree of sulfonation was 50% for sPES and the mesoporous ceria-silica material had a 2D hexagonal (p6mm) mesostructure with the Ce/Si ratio of 0.5 and the sulfur atoms of 3.1 mmol/g in sulfonic acid groups. The oxidation stability against hydroxyl radicals (OH) was investigated both with Fenton's test and the hydrogen peroxide exposure. Hydrogen peroxide vapor exposure experiments was developed to screen the oxidation stability in a short time under high temperature and low relative humidity conditions, which is more similar to actual fuel cell system. The composite membranes exhibited higher oxidation stability than a pristine sPES membrane. However, the proton conductivity decreased with the incorporation of mesoprous ceria-silica, which should be resolved through further study using combination of the polymer matrix with different structure and the modification of mesoporous ceria-silica.

Hydrocarbon-based polymer electrolyte cerium composite membranes for improved proton exchange membrane fuel cell durability

Hydrocarbon-based cerium composite membranes were prepared for proton exchange membrane fuel cell applications to increase oxidative stability. Different amounts of cerium ions were impregnated in sulfonated poly(arylene ether sulfone) (SPES) membranes and their physicochemical properties were investigated according to the cerium content. Field-emission scanning electron microscopy and inductively coupled plasma analyses confirmed the presence of cerium ions in the composite membranes and 1H NMR indicated the successful coordination of sulfonic acid groups with the metal ions. Increasing amounts of cerium ions resulted in decreases in the proton conductivity and water uptake, but enhanced oxidative stability. The oxidative stability of the composite membranes was proven via a hydrogen peroxide exposure experiment which mimicked fuel cell operating conditions. In addition, more than 2200 h was achieved with the composite membrane under in situ accelerated open circuit voltage (OCV) durability testing (DOE protocol), whereas the corresponding pristine SPES membrane attained only 670 h.

Ion exchange membranes based upon crosslinked sulfonated polyethersulfone for electrochemical applications

Synthesis and characterization of new ion exchange membranes made from chlorosulfonated polyethersulfone (SO2Cl-PES) crosslinked by polyaminated crosslinking reagents have been performed. Two examples are described: one crosslinked by hexane diamine, the other by amino-polyethersulfone (NH2-PES). Sulfonated polyether sulfone (S-PES) and NH2-PES have similar chemical structures that allow compatibility. Surprisingly enough, better results were obtained using amino-polyethersulfone. The best results have been obtained using SO2Cl-PES with 1.3 SO2Cl group per monomer unit crosslinked by 0.2 equivalent of NH2-PES. The membranes, less brittle than pristine SPES and insoluble in solvents such as DMAc, were characterized by TGA, DMA, DSC, ionic conductivity, transport numbers, and water swelling. The results showed that these membranes presented very promising performances for use in Proton Exchange Membrane Fuel Cells.

Crosslinked SPES-SPPSU membranes for high temperature PEMFCs

Highly sulfonated polyethersulfone (SPES; Ione exchange capacity = 3.2 meq/g) and polyphenylsulfone (SPPSU; ion exchange capacity = 3.2 meq/g) were synthesized. To get high thermal and chemical stability, a blend membrane was prepared by the composite of SPES and SPPSU. The SPES-SPPSU blend membrane after the annealing treatment at 180 °C was stable in water and other organic solvents, and the thermal stability was also more increased than that of pristine SPES and SPPSU polymers due to the crosslinking formation among SPES and SPPSU. The maximum conductivity of 0.12 S/cm was obtained at the temperature of 140 °C and RH 90%.

Preparation of new proton exchange membranes using sulfonated poly(ether sulfone) modified by octylamine (SPESOS)

Sulfonated poly(arylene ether sulfone) (SPES) has received considerable attention in membrane preparation for proton exchange membrane fuel cell (PEMFC). But such membranes are brittle and difficult to handle in operation. We investigated new membranes using SPES grafted with various degrees of octylamine. Five new materials made from sulfonated polyethersulfone sulfonamide (SPESOS) were synthetized with different grades of grafting. They were made from SPES, with initially an ionic exchange capacity (IEC) of 2.4 meq g −1 (1.3 H + per monomer unit). Pristine SPES with that IEC is water swelling and becomes soluble at 80 °C, its proton conductivity is in the range of 0.1 S cm −1 at room temperature in aqueous H 2SO 4 1 M, similar to that of Nafion ®. After grafting with various amounts of octylamine, the material is water insoluble; membranes are less brittle and show sufficient ionic conductivity. Proton transport numbers were measured close to 1.