Polymeric Ionic Liquid Research Articles

Single‐ion conducting polymer as lithium salt additive in polymerized ionic liquid block copolymer electrolyte

AbstractHerein, we describe the use of single‐ion conducting block copolymer (SIC) as an additional lithium salt additive to a ternary solid polymer electrolyte (SPE), consisting of a poly(styrene‐b‐1‐((2‐acryloyloxy)ethyl)‐3‐butylimidazolium bis(trifluoromethanesulfo‐nyl)imide) (S‐ImTFSI64‐16) block copolymer, a N‐propyl‐N‐methylpyrrolidinium bis(fluorosulfonyl)imide (C3mpyrFSI) ionic liquid (IL) and a lithium bis(fluorosulfonyl) imide (LiFSI) salt. For this purpose, the S‐ImTFSI64‐16 was substituted by a SIC, based on poly(styrene‐b‐((4‐styrenesulfonyl)(trifluoromethanesulfonyl)imide lithium salt)) (S‐STFSILi64‐16), at various molar ratios. The impact of the SIC concentration on the phase behavior and transport properties of the SPEs was investigated by means of differential scanning calorimetry, electrochemical impedance spectroscopy, and diffusion NMR. In addition, the electrochemical performance of the SPEs was assessed in lithium symmetrical cell at 50 and 80°C. Finally, the cycling performance of a selected SPE was also assessed at 80°C in a Li│NMC111 cell with capacity loading of 1.3 mAh.cm−2 at a C‐rate of 0.1 C. The Li│NMC111 full cell was able to deliver a stable capacity of 0.94 mAh.cm−2 after 20 cycles, corresponding to a capacity of 117 mAh.g−1. These results demonstrates that PIL block copolymer—IL—salt composites represent a promising choice of electrolyte for the next generation of solid‐state high energy density lithium metal batteries.

Ultrasensitive Ionic Liquid Polymer Composites with a Convex and Wrinkled Microstructure and Their Application as Wearable Pressure Sensors.

The development of pressure sensors with high sensitivity and effectiveness that exhibit linearity over a wide pressure range is crucial for wearable devices. In this study, we fabricated a novel ionic liquid (IL)/polymer composite with a convex and randomly wrinkled microstructure in a cost-effective and facile manner using an opaque glass and stretched polydimethylsiloxane template. The fabricated IL/polymer composite was used as the dielectric layer in a capacitive pressure sensor. The sensor exhibited a high linear sensitivity of 56.91 kPa-1 owing to the high interfacial capacitance formed by the electrical double layer of the IL/polymer composite over a relatively wide range (0-80 kPa). We also demonstrated the sensor performance for various applications such as a glove-attached sensor, sensor array, respiration monitoring mask, human pulse, blood pressure measurement, human motion detection, and a wide range of pressure sensing. It would be expected that the proposed pressure sensor has sufficient potential for use in wearable devices.

Highly ion-conductive anion exchange membranes with superior mechanical properties based on polymeric ionic liquid filled functionalized bacterial cellulose for alkaline fuel cells

How to simultaneously improve the ionic conductivity and mechanical properties is a key problem facing currently used anion-exchange membranes (AEMs). Here, biomass-based bacterial cellulose (BC) was used as a porous template to make TiO2 localized mineralization around the surface of BC nanofibers, and constructed a TiO2-coated BC porous substrate (TiO2@BC) with hierarchical structure. Then, the coated TiO2 nanoparticles was densely grafted by quaternary ammonium groups to obtain high ionic conduction ability. After filling with a polymeric ionic liquid (PIL) with high ion exchange capacity through in situ polymerization and crosslinking, the obtained novel PIL-filled AEM possessed ultrahigh ionic conductivity of 100.5 mS cm−1 at 80 °C, which was 72.1% higher than that of the PIL-filled pure BC membrane (only 58.4 mS cm−1). Moreover, by the aid of the synergistic reinforcement effect of TiO2@BC, the membrane exhibited extremely high dry strength of 95.3 MPa and satisfactory wet strength and flexibility. When at fully hydrate state, the membrane with the size of 1 × 4 cm (width × length) can hang a bottle containing 1000 g of water. The single cell equipped with this membrane output the peak power density of 40.2 mW cm−2, showing its great potential as a high-performance biomass-based AEM.

Magnetically-separable quasi-homogeneous catalyst: Brush-type ionic liquid polymer coated magnetic polymer microspheres for tandem reactions to produce 4H-pyrans/biodiesel

Employing magnetic polystyrene microspheres as the core and brush-type alkaline imidazolium ionic liquid polymers as the covalent bonds, a robust magnetically-separable quasi-homogeneous magnetic brush-type ionic liquid polymers ([Im][OH]/MP-B) was synthesized. Due to the features of brush-type ionic liquid polymer (BILPs), [Im][OH]/MP-B demonstrated high catalytic activity. With a broad variety of substrates, [Im][OH]/MP-B was applied in Knoevenagel-Michael tandem reactions for the synthesis of 4 H-pyrans (achieving 99.99% conversion and 93.6% yield) and transesterification tandem reactions for sustainable biodiesel production (achieving 99.9% conversion and 95.2% yield). Furthermore, the catalytic performance of [Im][OH]/MP-B was superior to that of [Im][OH]/MP-CL and [Im][OH]/MP-L and comparable with that of homogeneous catalysts. The reasonable and feasible reaction mechanism of magnetic ionic liquid polymers catalyzing tandem reactions was explored in-depth based on the catalytic performance and kinetics, which clearly demonstrated the catalytic activity and stability of [Im][OH]/MP-B. Notably, [Im][OH]/MP-B was effortlessly recovered by magnetic separation and reutilized numerous times with no evident change in catalytic performance, composition, or microstructure, indicating promising possibilities for ecologically friendly procedures. This work provides a potential strategy for the synthesis of magnetic BILPs for tandem reactions, which could serve as a platform for ecologically friendly and sustainable chemistry.

Biomass-Based Anion Exchange Membranes Using Poly (Ionic Liquid) Filled Bacterial Cellulose with Superior Ionic Conductivity and Significantly Improved Strength

ABSTRACT How to simultaneously improve the ionic conductivity and mechanical properties is a key problem facing currently used anion-exchange membranes (AEMs). Here, novel AEMs were prepared using quaternized bacterial cellulose (QBC) as a dual-functional substrate and then filled with a polymeric ionic liquid (poly(vinylbenzyl) trimethylammonium chloride, PVD) with high ion-exchange capacity through in situ polymerization and crosslinking. The dense quaternary ammonium groups grafted on the surface of BC nanofibers greatly increased the ionic conductivity, while the special three-dimensional network structure of BC significantly enhanced the tensile strength and chemical stability of the obtained PVD filled quaternized BC (QBC/PVD) membranes. The ionic conductivity of QBC/PVD membrane reached as high as 111 mS cm−1 at 80°C, which was 109% higher than that of the pure BC/PVD membrane (only 53 mS cm−1). Moreover, the QBC/PVD membrane exhibited extremely high dry strength of 72.3 MPa and satisfactory wet strength and flexibility, this membrane can hang a container containing 500 g of water when at fully hydrated state. The alkaline direct methanol fuel cell equipped with QBC/PVD output a peak power density of 64 mW cm−2, showing its great application potential as an AEM.

Low Vanadium Permeability Membranes Based on Flexible Hydrophilic Side Chain Grafted Polybenzimidazole/Polymeric Ionic Liquid for VRFBs

Based on amino polybenzimidazoles with flexible hydrophilic side chains (AmPBI-MOE) and polymeric ionic liquid (PIL), a series of composite membranes (AmPBI-MOE-PIL-X) were fabricated for vanadium redox flow battery applications. Here, 1-Bromo-2-(2-methoxyethoxy)ethane was grafted onto amino polybenzimidazole (AmPBI) by the method of halogenated hydrocarbons, and PIL was synthesized from ionic liquids by in situ radical polymerization to build a hydrogen-bonded cross-linked network within the film. The hydrophilic side chain improves the proton conductivity. With the increase in ionic liquids, the vanadium transmittance and the proton conductivity increase. The AmPBI-MOE-PIL-5 membrane not only exhibits a vanadium ions permeability of 0.88 × 10−9 cm2 min−1, which is much lower than Nafion117 (6.07 × 10−8 cm2 min−1), but also shows a very excellent blocking ability for vanadium ion. The AmPBI-MOE-PIL-5 membrane shows excellent performances at 60 mA cm−2, with VE of 87.93% and EE of 82.87%, both higher than that of Nafion117 membrane in VRFB.

A Highly Ion‐Conductive Solid Polymer Electrolyte with Good Thermal Stability and Nonflammability for All‐Solid‐State Li Metal Batteries

Lithium metal batteries (LMBs) have been recognized as one of the most promising energy storage devices due to their high energy density. The leakage, corrosion to Li metal anode, and flammability of organic liquid electrolytes bring great security problems for LMBs. Polymeric ionic liquid (PIL)‐based solid polymer electrolytes (SPE), possessing nonflammability, excellent thermal, chemical, electrochemical stability, are a kind of promising SPE for highly safe all‐solid‐state LMBs. Nevertheless, the low ambient conductivity of pristine PIL‐based SPE restricts their application in solid‐state LMBs. Herein, an ionic liquid monomer (denoted as GIM) is designed and synthesized and copolymerized with vinyl ethylene carbonate (VEC) monomer by UV‐light curing to prepare P(GIM‐VEC) SPE. The prepared P(GIM‐VEC) SPE is thermally stable and intrinsically nonflammable, possesses high ambient ionic conductivity, and can suppress lithium dendrite growth and stabilize the solid electrolyte interface. Thus, the resultant all‐solid‐state LiFePO4 (LFP)|P(GIM‐VEC)|Li battery exhibits a high initial discharge capacity of 152.7 mAh g−1 at 0.1 C along with a good stability and rate capability at room temperature. Herein, new guidance is provided for developing ambient workable SPEs with high ionic conductivity, nonflammability, and excellent thermal stability for all‐solid‐state Li metal batteries.

PANF supported polymeric ionic liquids: Amphiphilic microenvironment for efficient preparation of biodiesel

Efficient and green production is extremely essential to the development of society and environment, and supported polymeric ionic liquids as heterogeneous catalysts are the current research hotspot for chemists. In this study, imidazolium ionic liquids were supported on modified polyacrylonitrile fiber (PANF) by reversible addition fragmentation chain transfer (RAFT) polymerization, and a series of fiber-supported basic catalysts (PANF@VIm-nX) were obtained by ion exchange with different anions. The modified fibers were characterized by FT-IR, XRD, TGA, SEM, 13C CP-MAS NMR and ICP-MS. The results show that the modified fibers are successful and the catalysts have sufficient active sites and mechanical strength to meet the application requirements. Several supported poly(ionic liquid)s catalysts were used to promote the transesterification of methanol and soybean oil to produce biodiesel. The effects ofionicliquidswith different structures on the reaction yield were sufficiently investigated. The anions of ionic liquids and the length of hydrophobic alkyl chains have synergistic effects on the catalytic performance of the catalyst. The fiber catalyst (PANF@VIm-8OMe) with 8 carbon alkyl chains and OMe anion showed the optimal catalytic efficiency. The yield of biodiesel was as high as 95.4 % within 6 h with a catalyst dosage of 4 wt% and a methanol to oil ratio of 30:1 at 60 ℃. In addition, the fiber catalyst had excellent stability and durability, which could be recycled more than 6 times. Finally, the fiber could be twined on the stirring impeller of the reactor, indicating its potential industrial application prospect.

Sulphonic Acid‐Functionalized Polymeric Ionic Liquids Catalyzed Conversion of Carbohydrates into Levulinic Acid in One‐Pot Reaction

AbstractSulphonic acid‐functionalized polymeric ionic liquids (PILs) were synthesized and applied into catalytic conversion of cellulose into levulinic acid (LA). The structure, thermal stability, and Hammett acidity function (H0) of PILs were characterized and all were more thermostable than those of small‐molecular ionic liquids (IL). At the optimum reaction conditions, the LA yield was maximized to 79.4 % by catalyst [Pim]CH3SO3. More importantly, catalyst [Pim]CH3SO3 performed well in other biomass conversion, such as cellobiose, starch and rice husk. The product LA can be easily extracted by methyl isobutyl ketone from the reaction mixture. The PILs with high catalytic activity were easily recycled with an LA yield up to 68.9 % even after five cycles. These sufficient PILs will offer new approaches for transforming biomass to platform chemicals.

Environmental impact analysis of surface printing and 3D inkjet printing applications using an imine based covalent organic framework: A life cycle assessment study

Covalent organic frameworks (COFs) are emerging materials with structural modularity that allows their application in many fields. The aim of this work is to determine the environmental impact of using an imine based covalent organic framework (RT-COF-1) for both surface printing (Case A) and 3D inkjet printing (Case B) by applying Life Cycle Assessment (LCA) methodology. Experimental data on RT-COF-1 synthesis as well as results obtained by simulation of their precursors production, 1,3,5-tris-(4-aminophenyl) benzene (TAPB) and 1,3,5-benzenetricarbaldehyde (BTCA), are used. LCA results show that monomer synthesis is the most important contributor to environmental impacts in both case studies. On the other hand, the contribution of solvents used in Case A is also remarkable. The comparison between both case studies indicates that the environmental impacts of Case B is lower than that of Case A (reduction within 5%–65%). Finally, LCA results of Case B are compared to other materials used for 3D-printing, such as polymerizable ionic liquids (PILs). The results show that RT–COF–1 compares favourably with PILs in five of nine impact categories, being especially relevant the reductions achieved in the abiotic depletion and acidification potential (>90%), in the primary energy consumption (⁓35%) and carbon footprint (⁓50%), suggesting the potential of RT–COF–1 as 3D-printing material from an environmental perspective. This work is a first step for further research to highlight the main environmental burdens of using COF-based materials in this application.

Synthesis of High-Molecular-Weight Biobased Aliphatic Polyesters by Acyclic Diene Metathesis Polymerization in Ionic Liquids.

Acyclic diene metathesis (ADMET) polymerization of an α,ω-diene monomer of bis(undec-10-enoate) with isosorbide (M1) using a RuCl2(IMesH2)(CH-2-O i Pr-C6H4) (HG2, IMesH2 = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene) catalyst and conducted at 50 °C (in vacuo) in ionic liquids (ILs) afforded higher-molecular-weight polymers (P1, M n = 32 200-39 200) than those reported previously (M n = 5600-14700). 1-n-Butyl-3-methyl imidazolium hexafluorophosphate ([Bmim]PF6) and 1-n-hexyl-3-methyl imidazolium bis(trifluoromethanesulfonyl)imide ([Hmim]TFSI) were suitable as effective solvents among a series of imidazolium salts and the pyridinium salts. The polymerization of α,ω-diene monomers of bis(undec-10-enoate) with isomannide (M2), 1,4-cyclohexanedimethanol (M3), and 1,4-butanediol (M4) in [Bmim]PF6 and [Hmim]TFSI also afforded the higher-molecular-weight polymers. The M n values in the resultant polymers did not decrease even under the scale-up conditions (300 mg to 1.0 g scale, M1, M2, and M4) in the polymerizations in [Hmim]TFSI; the subsequent reaction of P1 with ethylene (0.8 MPa, 50 °C, and 5 h) gave oligomers (proceeded via depolymerization). Tandem hydrogenation of the resultant unsaturated polymers (P1) in a [Bmim]PF6-toluene biphasic system upon the addition of Al2O3 (1.0 MPa H2 at 50 °C) gave the corresponding saturated polymers (HP1), which waswere isolated by a phase separation in the toluene layer. The [Bmim]PF6 layer containing the ruthenium catalyst could be recycled without a decrease in the activity/selectivity of the olefin hydrogenation at least eight times.

Liquid polymerized ionic liquids for energy storage applications

Supported liquid membranes (SLM) offer promise of improved molecular and ionic transport in polyelectrolyte membranes (PEM), key components in batteries and fuel cells. Incorporation of ionic liquids (IL) into PEM has demonstrated increased molecular and ionic transport, and it is probable that liquid polymerized ionic liquids (LPIL) also will benefit such PEM properties. Herein we demonstrate preparation of LPIL copolymers that have suitable functionality for tethering such LPIL to SLM. We uncover a design principle for producing LPIL, wherein liquid homopolymers that are precursors for PIL are partially modified and converted into LPIL. We show that the homopolymer poly(bromoundecyl acrylate), poly(AcOC11H22Br), is such a liquid precursor. We explore conversion of this homopolymer into LPIL by using it to alkylate 1-methyl imidazole.

Unraveling energy storage behavior of independent ions in carbon electrode for supercapacitors by polymeric ionic liquids and electrochemical quartz crystal microbalance

A fundamental understanding of the charge storage mechanism of electrochemical double-layer capacitors (EDLCs) requires an in-depth storage behavior investigation of independent ions (individual cations or anions) on the electrode surface. The direct in-situ observation for energy storage behavior of individual ions under realistic conditions remains challenge. Herein, in-situ monitoring the energy storage behavior of independent ions is realized with assistance of polymeric ionic liquids skillfully. Triangle cyclic voltammogram (CV) curves indicate that polymeric imidazole cations PVBIm+ with huge size cannot enter the active carbon pores upon charging, whereas only free anions can. The CV and electrochemical quartz crystal microbalance (EQCM) simultaneously detect ion adsorption/desorption during charging. It’s proposed that ion adsorption/desorption is governed by electrostatic attraction and repulsion of charged particles. PVBIm+ are adsorbed on the electrode surface due to ion adsorption mechanism during the negative polarization and have a small capacity contribution. Free anions contribute capacitance, their number entering the pore is determined by the interaction between polycaions and anions. Moreover, PVBIm(0.1)+ with higher polymerization degree may promote desorption of polycations and prevent further adsorption of anions at higher potential in positive polarization. This work not only observes the charging behavior of independent ions, but also reveals the relevant charging mechanism through EQCM, paving the way for panorama of EDLC.

Chloride Ion‐Containing Polymeric Ionic Liquids for Application as Electrolytes in Solid‐State Batteries

Macromol. Chem. Phys. 2023, 224, 2200317 DOI: https://doi.org/10.1002/macp.202200317 In the original publication of this article, a funding source is missing in the Acknowledgements. The missing funding statement is as follows: “U.L.M. acknowledges the funding from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 898878 (USOME).”

Thermoresponsive homo-polymeric ionic liquid as molecular transporters via tailoring interchain π-π interactions and its unique temp-resistance behavior during ions pairing

In this study, a polymeric ionic liquid (PIL) called Poly[ECH-BIM]Cl was polymerized by ring-opening and quaternization reaction of benzimidazole and epichlorohydrin without additional ion-exchange reaction. Both 1H NMR and fourier transform infrared (FTIR) confirmed the chemical structure of Poly[ECH-BIM]Cl. Poly[ECH-BIM]Cl in water was thermoresponsive and its UCST transition was studied by UV–vis spectrometry, dynamic light scattering (DLS) and scanning electron microscopy (SEM) at variable temperature. Moreover, the first introduced Temp-resistance behavior during ions pairing found Poly[ECH-BIM]Cl had properties similar to those of the precipitation of inorganic salts from their saturated solutions. The variable-temperature 1H NMR analysis demonstrated that the tailored interchain π-π interactions promoted the aggregation of macromolecular chains and particles formed from Poly[ECH-BIM]Cl aqueous solution. The results showed that increasing the interaction between cations of PIL can endow its thermosensibility and the possibility of being a programmable shuttle.

Conjugate acid-base bi-functional polymeric ionic liquids (CAB-PILs) as efficient catalysts for CO2 capture and subsequent glycidol cycloaddition reaction

Conjugate acid-base bi-functional PILs (CAB-PILs) with carboxylate and carboxyl branches were synthesized and used as catalysts for the cycloaddition reaction of glycidol with CO2. Two functional ionic monomers, 3-(carboxymethyl)-1-vinyl-1H-imidazol-3-ium chloride (CEImCl) and 2-(1-vinyl-1H-imidazol-3-ium-3-yl) acetate (CCIm), were introduced into the CAB-PILs skeleton. In this case, we proved the excellent characteristics of the catalyst containing both Lewis base and Bronsted acid sites for converting CO2 to cyclic carbonate under mild conditions. The catalyst showed good reusability and remained excellent activity after five reaction cycles. Combined with XPS, FTIR and DFT calculations, it is proved that the CCIm ionic monomer not only play the role of CO2 absorption center, but also has synergistic effect with CEImCl in CAB-PILs to promote cycloaddition reaction.

Unraveling the Influence of Li+‐cation and TFSI−‐anion in Poly(ionic liquid) Binders for Lithium‐Metal Batteries

AbstractIon transport in composite electrodes plays a key role in the electrochemical performance of lithium‐metal batteries (LMBs), particularly at high current densities, and hence, some works have suggested the use of ionic conducting polymers as binders. Herein, in order to assess the importance of the type of ion conduction in binders, two poly(ionic liquid) polymers were analyzed as binders in LiFePO4 (LFP) cathodes: poly(lithium 1‐[3‐(methacryloyloxy)propylsulfonyl]‐1‐(trifluoromethane sulfonyl) imide) (PMTFSI−Li), and poly(diallyldimethylammonium bis(trifluoromethane sulfonyl)imide) (PDADMA−TFSI). Their functionalities allow modulating the individual transport of their counter‐ions, Li+ and TFSI−, respectively; in comparison with conventional PVDF binder. Thus, LFP−C‐Binder cathodes, namely C−PVDF, C−PDADMA−TFSI and C−PMTFSI−Li, were evaluated in LMBs. C−PMTFSI−Li exhibited the best performance reaching the theoretical specific capacity (170.3±0.8 mAh g−1) at C/10, an outstanding capacity at 10 C (100.6±0.5 mAh g−1), and long lifespan (>500 cycles at 1 C). C−PDADMA−TFSI showed good long‐term cycling and high performance at high C‐rate, while C−PVDF ended up fading before reaching 500 cycles. Surprisingly, it was observed that the presence of ionic binders into the cathode formulation influenced on Li0 metal deposition morphology, leading to a more homogeneous plating (specially PMTFSI−Li) in comparison with PVDF; and therefore, exhibiting a mitigation of mossy lithium growth.

A cationic polymeric interface enabling dendrite-free and highly stable aqueous Zn-metal batteries

Recently, aqueous rechargeable zinc-ion batteries (AZIBs) have attracted much attention owing to their low cost and intrinsic safety. However, the reversibility of AZIBs is limited by dendrite growth on the Zn anode, which leads to low Coulombic efficiency and potential short circuit during cycling. Herein, we develop a new strategy using electrostatic shielding to enable a highly reversible Zn anode. Specifically, a cationic polymeric ionic liquid (PIL) coating layer with a strong positive charge evens out the charge distribution on the surface of the Zn electrode, enabling uniform stripping and deposition of Zn. As a result, a symmetric Zn–Zn cell can sustain stripping-plating for over 2000 h at 1 mA cm−2 with a capacity limit of 1 mAh cm−2, far exceeding the performance of bare Zn electrode. A highly reversible Zn stripping-plating on Cu substrate is also achieved with an average coulombic efficiency of 99.5% over 1100 cycles. PILZ layer can even allow a uniform Zn deposition of up to 30 μm thick, allowing large utilization of the Zn foil. Moreover, the coating layer enables the stable cycling of a MnO2–Zn full cell with a high areal capacity of 1 mAh cm−2.

Polymer dispersed ionic liquid electrolytes with high ionic conductivity for ultrastable solid‐state lithium batteries

AbstractSolid polymer electrolytes (SPEs) have emerged as one of the most promising candidates for building solid‐state lithium batteries due to their excellent flexibility, scalability, and interfacial compatibility with electrodes. However, the low ionic conductivity and poor cyclic stability of SPEs do not meet the requirements for practical applications of lithium batteries. Here, a novel polymer dispersed ionic liquid‐based solid polymer electrolyte (PDIL‐SPE) is fabricated using the in situ polymerization‐induced phase separation (PIPS) method. The as‐prepared PDIL‐SPE possesses both outstanding ionic conductivity (0.74 mS cm−1 at 25°C) and a wide electrochemical window (up to 4.86 V), and the formed unique three‐dimensional (3D) co‐continuous structure of polymer matrix and ionic liquid in PDIL‐SPE can promote the transport of lithium ions. Also, the 3D co‐continuous structure of PDIL‐SPE effectively accommodates the severe volume expansion for prolonged lithium plating and stripping processes over 1000 h at 0.5 mA cm−2 under 25°C. Moreover, the LiFePO4//Li coin cell can work stably over 150 cycles at a 1 C rate under room temperature with a capacity retention of 90.6% from 111.1 to 100.7 mAh g−1. The PDIL‐SPE composite is a promising material system for enabling the ultrastable operation of solid‐state lithium‐metal batteries.

High-Performance Integrated rGO-[Polymeric Ionic Liquid] [Heteropolyanions] for Catalytic Degradation of Azo Dyes

Polymeric ionic liquid (such as poly[ViEtIm]Br)-modified reduced graphene oxide (rGO), rGO-poly[ViEtIm]Br, was nominated as an open carrier to construct a degradation platform. The large specific surface of rGO together with the anion-exchange property of poly[ViEtIm]Br terminals led to the wide growth of heteropolyanions (like [PW12O40]3-, [PMo12O40]3-, and [SiW12O40]4-), thus assembling the integrated catalyst rGO-poly[ViEtIm][heteropolyanions]. The grafted poly[ViEtIm]Br provided an anchor point to interlink the polar heteropolyanions and the nonpolar rGO substrate, endowing this graphene-based catalyst with excellent dispersibility. The adequate exposure of heteropolyanions further promoted the decolorization capability during the degradation procedure. Morphology, structure, and properties of materials were confirmed and monitored via transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-vis) spectroscopy, etc. rGO-poly[ViEtIm][PW12O40] was selected as the optimal catalyst with degradation efficiency toward methyl orange reaching 98.7% in 3 h. In addition, the excellent structural stability of the catalyst improved the decolorization efficiency, which reached 95% after recycling five times.