Ionic Liquid-based Gel Polymer Electrolyte Research Articles

Gel polymer electrolyte-based dual screen-printed electrodes for the headspace quantification of 4-ethylphenol and ethanethiol simultaneously in wines

The identification and correction of negative factors, such as 4-ethylphenol and ethanethiol, is important to comply with food safety regulations and avoid economic losses to wineries. A simple amperometric measurement procedure that facilitates the simultaneous quantification of both compounds in the gas phase has been developed using fullerene and cobalt (II) phthalocyanine-modified dual screen-printed electrodes coated with a room temperature ionic liquid-based gel polymer electrolyte. The replacement of the typical aqueous supporting electrolyte by low-volatility ones improves both operational and storage lifetime. Under the optimum conditions of the experimental variables, Britton Robinson buffer pH 5 and applied potentials of + 0.86 V and + 0.40 V for each working electrode (vs. Ag ref. electrode), reproducibility values of 7.6% (n = 3) for 4-ethylphenol and 6.6% (n = 3) for ethanethiol were obtained, as well as capability of detection values of 23.8 μg/L and decision limits of 1.3 μg/L and 9.2 μg/L (α = β = 0.05), respectively. These dual electrochemical devices have successfully been applied to the headspace detection of both compounds in white and red wines, showing their potential to be routinely used for rapid analysis control in wineries.Graphical

Study of [EMIM] [EtSO4] ionic liquid-based gel polymer electrolyte mediated with hydroquinone redox additive for flexible supercapacitors

Gel Polymer Electrolytes (GPEs) are considered as suitable candidates in the design of energy storage devices like flexible supercapacitors due to their higher safety and flexibility. Incorporating small quantity of redox additives in GPE significantly improves their conductivity and is considered as an innovative method to enhance the capacitance of supercapacitors, because both electrolyte and electrode materials contribute to the capacitance. In this work, performance of Flexible Supercapacitor's (FSCs) using symmetrical Laser Induced Graphene (LIG) as electrodes and ionic liquid 1-Ethyl-3-Methylimidazolium Ethyl Sulfate [EMIM] [EtSO4] incorporated in Gel Polymer Electrolyte (GPE) with and without redox additive Hydroquinone (HQ) is presented. Upon electrochemical characterization using Galvanostatic Charge Discharge (GCD), it was found that the FSC with redox additive showed highest areal capacitance and energy density of 15.1 mFcm−2 and 1.54 μWhcm−2 respectively and FSC without redox additive showed an areal capacitance and energy density of 1.94 mFcm−2 and 0.14 μWhcm−2 respectively at 2 mAcm−2. The device with redox additive also showed 100 % columbic efficiency after 50 cycles and maintained 80 % capacitance for 5000 charge-discharge cycles. Additionally, the electrolyte with the redox additive showed superior conductivity of 10.8 mScm−1, demonstrating that modifying electrolyte by adding redox additive has been a simple yet effective method to enhance the overall performance of FSCs. Also, the synthesized LIG was characterized by X-ray Diffraction (XRD), Raman and Scanning Electron Microscopy techniques which confirmed the formation of bi-layer porous graphene.

A High-Performance Li-O2/Air Battery System with Dual Redox Mediators in the Hydrophobic Ionic Liquid-Based Gel Polymer Electrolyte

Lithium–oxygen (Li-O2) batteries have captured worldwide attention owing to their highest theoretical specific energy density. However, this promising system still suffers from huge discharge/charge overpotentials and poor cycling stability, which are related to the leakage/volatilization of organic liquid electrolytes and the inefficiency of solid catalysts. A mixing ionic liquid-based gel polymer electrolyte (IL-GPE)-based Li-O2 battery, consisting of a 20 mM 2,5-di-tert-butyl-1,4-benzoquinone (DBBQ) 40 mM N-methylphenothiazine (MPT)-containing IL-GPE and a single-walled carbon nanotube cathode, is designed for the first time here. This unique dual redox mediators-based GPE, which contains a polymer matrix immersed with mixed ionic liquid electrolyte, provides a proper ionic conductivity (0.48 mS cm−1) and effective protection for lithium anode. In addition, DBBQ, as the catalyst for an oxygen reduction reaction, can support the growth of discharge products through the solution–phase pathway. Simultaneously, MPT, as the catalyst for an oxygen evolution reaction, can decompose Li2O2 at low charge overpotentials. Hence, the DBBQ-MPT-IL-GPE-based Li-O2 battery can operate for 100 cycles with lower charge/discharge overpotentials. This investigation may offer a promising method to realize high-efficiency Li-O2/air batteries.

Study on ionic liquid-based gel polymer electrolytes for dual-graphite battery systems

Study on ionic liquid-based gel polymer electrolytes for dual-graphite battery systems

Phosphonate-Functionalized Ionic Liquid Gel Polymer Electrolyte with High Safety for Dendrite-Free Lithium Metal Batteries.

The conventional lithium-ion battery technology relies on the liquid carbonate-based electrolyte solution, which causes excessive side reactions, serious risk of electrolyte leakage, high flammability, and significant safety hazards. In this work, phosphonate-functionalized imidazolium ionic liquid (PFIL) is synthesized and used as a gel polymer electrolyte (GPE) to replace the organic carbonate-based electrolyte solution. The as-prepared ionic liquid-based gel polymer electrolyte (IL-GPE) shows low crystallinity, flame retardance, and excellent electrochemical performance. Thanks to the fast double channel transport of lithium ions in the IL-GPE electrolyte, a high ionic conductivity of 0.48 mS cm-1 and a lithium-ion transference number of 0.37 are exhibited. Symmetrical lithium cells with IL-GPE retain stable cycling even after 3000 h under 0.1 mA cm-2. IL-GPE exhibits good compatibility toward lithium metal, yielding excellent long-term electrochemical kinetic stability. IL-GPE induces the formation of a uniform and robust SEI layer, inhibiting the growth of lithium dendrites and improving the rate performance and cycle stability. Furthermore, Li/LiFePO4 cells exhibit a specific capacity of 63 mA h g-1 after 150 cycles at 5.0 C, with a capacity retention of 90.2%. It is foreseen that this GPE is a promising candidate to enhance the safety of high-performance lithium metal batteries.

Achieving Enhanced Mobility of Ions in Ionic Liquid-Based Gel Polymer Electrolytes By Incorporating Inorganic Nanofibers for Li-Ion Battery

Polymer electrolytes have received much attention in Li-ion battery research because of their unique properties, such as, high ionic conductivity, high mechanical strength including good electrode-electrolyte contact. A major research has been focused on improving the conductivity while retaining the mechanical stability of polymer electrolytes. In this context, ionic liquid-based gel polymer electrolytes are an excellent candidate. A detailed NMR investigation of PMMA-ILs gels electrolytes probing the structure and dynamics of ions was recently reported.[1] The presence of ILs in polymer matrix not only improves the conductivity but also enhances the self-healing capability. In another study, self-healing capability that reduces the dendrite formation at the interface has been discovered, for example, in PVDF-HFP-ILs electrolyte.[2] In this regard, this work reports the possible ways to enhance the ionic conductivity of such polymer electrolyte further by adding Al2O3 nanofibers. A series of PVDF-HFP-ILs with 1M LiTFSI in EMIMTFSI at different ratios of Al2O3nanofibers were prepared through solution cast technique. The dynamics of ions confined within polymer-Al2O3 matrix was explored through Impedence and PFG NMR spectroscopy. The amorphocity and the distribution of Al2O3 nanofibers are studied through XRD and SEM-EDX analyses. Lastly, the local structure of ions and their interaction with polymer and Al2O3 nanofibers were established through a detailed solid-state NMR analyses detecting 1H, 27Al, 13C, 19F, 7Li nuclei including 2D 13C{1H} HETCOR experiments. A reasonable enhancement in terms of ionic conductivity was observed with the addition of Al2O3 nanofibers, which improves the conducting pathways within the polymer network.[1] M. N. Garaga, N. Jayakody, C. C. Fraenza, B. Itin, and S. Greenbaum, Journal of Molecular Liquids 329, 115454 (2021).[2] T. Chen, W. Kong, Z. Zhang, L. Wang, Y. Hu, G. Zhu, R. Chen, L. Ma, W. Yan, Y. Wang, J. Liu, and Z. Jin, Nano Energy 54, 17 (2018).

High-Performance and Highly Safe Solvate Ionic Liquid-Based Gel Polymer Electrolyte by Rapid UV-Curing for Lithium-Ion Batteries.

Utilizing ionic liquids (ILs) with low flammability as the precursor component for a gel polymer electrolyte is a smart strategy out of safety concerns. Solvate ionic liquids (SILs) consist of equimolar lithium bis(trifluoromethylsulfonyl)imide and tetraglyme, alleviating the main problems of high viscosity and low Li+ conductivity of conventional ILs. In this study, within a very short time of 30 s, a SIL turns immobile using efficient and controllable UV-curing with an ethoxylated trimethylolpropane triacrylate (ETPTA) network, forming a homogeneous SIL-based gel polymer electrolyte (SGPE) with enhanced thermal stability (216 °C), robust mechanical strength (compression modulus: 1.701 MPa), and high ionic conductivity (0.63 mS cm-1 at room temperature). A Li|SGPE|LiFePO4 cell demonstrates high charge/discharge reversibility and cycling stability with a capacity retention rate of 99.7% after 750 cycles and an average Coulombic efficiency of 99.7%, owing to its excellent electrochemical compatibility with Li-metal. A close-contact electrode/electrolyte interface is formed by in situ curing of the electrolyte on the electrode surface, which enables the pouch full cell to work stably under the conditions of cutting/bending. In view of the excellent mechanical, thermal, and electrochemical performances of SGPE, it is believed to be a promising gel polymer electrolyte for constructing high-safety lithium-ion batteries (LIBs).

Flexible Aluminum-Air Battery Based on Ionic Liquid-Gel Polymer Electrolyte.

There is an urgent demand to develop high-performance flexible batteries for a wide range of contemporary emerging fields, including flexible electronics, wearable sensors, and implantable medical devices. However, the inherent safety and stability issues of traditional organic liquid-based electrolytes make their application in flexible batteries unsatisfactory. Therefore, exploring gel electrolytes with superior ionic conductivity and safety is considered to be the key to the development of flexible batteries. In this paper, two types of high-quality ionic liquid-based gel polymer electrolyte membranes (PVDF-ILs) are created by a conventional solution-casting method, which are further integrated into flexible aluminum-air batteries to guide the interface and process research, and the related discharge properties of two ionic liquid-based electrolyte membrane (PVDF-[C4mpyr]Cl, PVDF-[BMIM]Cl) in different bending states are discussed. The results show that PVDF-ILs have a rich pore structure and interwoven skeleton network, leading to relatively high ionic conductivity (2.97 × 10-3 S cm-1). Moreover, two types of batteries can meet the needs of flexibility, although there is a slight loss of power density under various bending conditions. In general, a PVDF-[C4mpyr]Cl-based flexible aluminum-air battery is suitable for the working conditions of high power and low bending angle, while the PVDF-[BMIM]Cl-based flexible aluminum-air battery is favored for microwatt low-power devices with high flexibility requirements.

Performance of ionic liquid–based quasi‐solid‐state hybrid battery supercapacitor fabricated with porous carbon capacitive cathode and proton battery anode

AbstractThe present paper reports preparation, characterization, and application of proton‐conducting ionic liquid–based gel polymer electrolyte (ILGPE) obtained by immobilizing liquid electrolyte solution (0.3M NH4Tf in EMIMTf) to the polymer PVdF‐HFP. These ILGPE offer excellent ionic conductivity ~1.30 × 10−2 S/cm at room temperature and used as separator membrane in the hybrid BatCap. DSC study confirms glass transitions and melting temperatures (Tg's and Tm's) of PVdF‐HFP/EMIMTF/NH4Tf decrease with increasing content of liquid electrolyte to the host polymer matrix PVdF‐HFP which, in turn, is responsible for increasing flexibility of membranes. Ionic transport number measurements (tion ~0.99, ~0.27) reveal that ions are the principal charge carriers in the present electrolyte system. The linear sweep voltammetry analysis shows the electrochemical stability window (ESW) of ILGPE film “PVdF‐HFP/EMIMTf/NH4Tf” is ~3.35 V. Two different hybrid BatCap cells are prepared with activated carbon and MWCNTs as a capacitive electrode (cathode) and ZnSO4·7H2O battery anode. The performance of the BatCaps is estimated using cyclic voltammetry and galvanostatic charge‐discharge techniques. The discharge capacity was observed ~2.4 and 17.2 mAh/g for Cell#1 and Cell#2, respectively, at the current load of 0.5 mA/cm2. After the initial fading (~20%), BatCap cells show stable performance up to 100 cycles.

The Stable 3D Zn Electrode for High-Power Density Zn Metal Batteries

A stable Zn metal electrode can develop rechargeable zinc metal batteries (RZMBs) which have the high theoretical capacity (820 mAh g−1), low redox potential, and intrinsic safety. However, the corrosion of Zn metal in aqueous electrolytes and Zn dendrite formation during the plating process lead to poor cycling and thus hinder the development of RZMBs. Here, we employed ionic liquid-based gel polymer (poly(vinylidene fluoride)-co-hexafluoropropylene, PVDF-HFP) and acetylene black (AB) to achieve a stable and flexible three-dimensional (3D) Zn/AB/PVDF-HFP film electrode with ionic and electronic conductive networks and high surface area, showing 26 times higher plating/stripping current than planar Zn plate. By developing a continuous structure between the ionic liquid-based gel polymer membrane and the flexible 3D Zn/AB/PVDF-HFP electrode, the low resistance, high rate capability and long cycle life (> 800 h) was obtained. Our work shows a flexible Zn film electrode and ionic liquid-based gel polymer electrolyte, could pave the path for rechargeable and high-cycle life thin-film RZMBs.

High energy density carbon supercapacitor with ionic liquid-based gel polymer electrolyte: Role of redox-additive potassium iodide

Carbon supercapacitors with quasi-solid and flexible gel polymer electrolytes (GPEs) are of current interest due to their potential applicability as commercial power sources. In the recent development, improvement in specific energy of such devices is the main focus of research. Enhancement in interfacial redox-activity by adding appropriate redox-agent in electrolyte is found an excellent method to improve specific energy. In this report, a free-standing, non-aqueous, redox-active GPE is presented comprising an ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide added with additive KI, entrapped in poly(vinylidene fluoride-co-hexafluoropropylene) for its application in quasi-solid-state-supercapacitors. The optimum composition of GPE shows flexible nature, excellent mechanical and thermal stabilities with high ionic conductivity (3.9 × 10−3 S cm-1 at room temperature) and wide electrochemical stability (∼5.05 V versus Ag). Carbon supercapacitor is fabricated with redox-active GPE and symmetrical electrodes of porous activated carbon (AC) derived from waste-biomass pollen-cone. The incorporation of KI in GPE instils fast redox-activity at the AC-electrode/GPE interfaces, hence, found responsible for substantial improvement in capacitance (from ∼115 to ∼250 F g−1) and energy (from ∼31 to ∼65 Wh kg−1) at maximum power of 34–36 kW kg−1. The supercapacitor with redox-active GPE demonstrates reasonable self-discharge behavior and cycling performance with only ∼11% initial fading. The capacitor offers retention rate of ∼70% in specific capacitance and energy after ∼10,000 charge-discharge cycles.

Preliminary study on the performance of a redox capacitor with the use of ionic liquid-based gel polymer electrolyte and polypyrrole electrodes

Redox capacitor, which is one type of supercapacitor, has been attracted tremendously as it shows a satisfactory specific capacitance, good cycle ability, and good stability. The present study reveals a redox capacitor fabricated with an ionic liquid (IL)-based gel polymer electrolyte (GPE). Electrodes of the redox capacitor were fabricated with the conducting polymer, polypyrrole (PPy). The composition of the GPE was polyvinylidenefluoride–co-hexafluoropropylene (PVdF–co-HFP): 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (1E3MITF): ZnTF. Characterization of redox capacitor was done by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) tests. The relaxation time constant (τ0) of the redox capacitor is about 31.57 s implying somewhat fast redox reactions. Initial single electrode specific capacitance (CSC) was 150.2 Fg−1, and at the 500th cycle, it was 40.03 Fg−1. The decrease of the CSC may be due to the formation of the passivation layer at the GPE/electrode interface, resulting in degradation upon cycling. The GCD test resulted 48.4 Fg−1 of initial single-electrode specific discharge capacitance (Csd) value. Upon 1000 cycles, it was reached 22.3 Fg−1. The decrease of Csd may be due to the degradation of the electrode and the IL-based GPE upon prolonged cycling.

Physical and electrochemical chattels of phosphonium ionic liquid-based solid and gel-polymer electrolyte for lithium secondary batteries

In this work, a methodical study on the influence of ionic conductivity on polymer electrolyte with different weight percentages of ionic liquid and plasticizers had been investigated in detail. Solution casting method has been employed for preparing polymer electrolyte (PE) blend having poly(vinylidenefluoride-co-hexafluoropropylene) P(VdF-co-HFP) as polymer, trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl) amide [P14,6,6,6][Tf2N] as ionic liquid and ethylene carbonate (EC) as well as propylene carbonate (PC) in 1: 1 ratio as plasticizers. The polymer electrolyte has been found out stable up to 450 °C, as measured from Thermal gravimetric analysis (TGA). Impedance spectral analysis reveals that the ionic conductivity of SPEs is 3.209 × 10–6 S/cm at 303 K with 25 wt% of ionic liquid. The addition of plasticizers (EC + PC (60 wt%)) results in two orders of magnitude of higher ionic conductivity (3.40 × 10–4 S/cm at 303 K), than that of SPEs. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) are performed to study the physico-chemical characteristics of polymer electrolytes. Electrochemical stability, potential window and discharge characteristics of the coin cell containing the electrolytes and LiFePO4 electrode were investigated using linear and cyclic voltammetry.

Structural and electrochemical studies of bromide derived ionic liquid-based gel polymer electrolyte for energy storage application

In the present studies, poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), ionic liquid {1-Ethyl-3-methylimidazolium bromide} (EMIM)(Br), and magnesium perchlorate Mg(ClO4)2 as salt were used to synthesize free standing electrolyte films by using solution cast technique. The prepared electrolyte films were investigated by using various structural and electrochemical techniques like scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) as well as ionic and temperature dependence studies. It has been observed that addition of ionic liquid significantly increases the properties like ionic conductivity, thermal stability, transparency etc. The maximum room temperature ionic conductivity for the optimized system was found to be of the order of 2.05 × 10−2 S cm−1 which is suitable for device fabrication point of view. The optimized electrolyte films are suitable for supercapacitor application.

Ionic liquid-based gel polymer electrolyte containing zwitterion for lithium-oxygen batteries

The key challenge of high energy density lithium-oxygen batteries is to develop a stable electrolyte system not only to suppress growth of lithium dendrite and solvent evaporation but also to resist the attack by superoxide anion radical formed at the cathode. Gel polymer electrolyte can effectively encapsulate organic solvent in the cell, suppress electrolyte decomposition and provide stable interfacial characteristics with lithium electrode. In this study, a three-dimensional cross-linked poly(methyl methacrylate)-based gel polymer electrolyte (GPE) containing non-volatile ionic liquid and zwitterion was synthesized and characterized for lithium-oxygen batteries. In this GPE, a zwitterion was proved to improve the transport properties of Li+ ions and enhance the interfacial stability towards the lithium electrode. As a result, the lithium-oxygen cell assembled with GPE containing ionic liquid and zwitterion exhibited a good cycling stability at a constant current density of 0.25 mA cm−2.

Enhanced structural and cycling stability of Li2CuO2-coated LiNi0.33Mn0.33Co0.33O2 cathode with flexible ionic liquid-based gel polymer electrolyte for lithium polymer batteries

Recently, ionic liquid-based gel polymer electrolytes (IL-GPEs) attracted increasing attention because of its use in developing safe and flexible rechargeable lithium-based batteries. The IL-GPE composed of microporous polymer PVdF-HFP incorporating different weight percentages of ionic liquid PYR13FSI with 20 wt.% lithium salt LiTFSI is prepared. These prepared films are investigated in detail by thermogravimetric analysis, impedance spectroscopy, cyclic voltammetry and linear sweep voltammetry measurements for battery application. The 70 wt.% IL containing GPE shows excellent thermal stability up to ∼240 °C and high lithium ion conductivity (1.6 × 10−3 S cm−1 at 30 °C) with wide electrochemical stability window (∼4.3 V vs. Li/Li+ at 30 °C). Furthermore, the Li+-ion conductive Li2CuO2 is coated on LiNi0.33Mn0.33Co0.33O2 (Li2CuO2@LNMC) cathode particle by using a wet chemical method. The structural and electrochemical properties of pristine and Li2CuO2@LNMC cathode are investigated using XRD, SEM, TEM and electrochemical analysis. The XRD pattern shows that no impurity phase is present in the Li2CuO2@LNMC cathode. Thin Li2CuO2 coating layer (20–25 nm) on the surface of LNMC particle is confirmed by TEM image. The optimized electrolyte is used to fabricate Li-cells (Li/LNMC and Li/Li2CuO2@LNMC). The charge-discharge results show that the initial specific discharge capacity of Li2CuO2@LNMC is ∼196 mAh g−1 at 0.1C (25 mA g−1), whereas, the pristine LNMC has ∼182 mAh g−1 under same condition. The Li2CuO2 coating layer improves electrochemical performance and cyclic stability of pristine cathode up to 100 cycles at 1 C-rate. The capacity retention is ∼69% for Li2CuO2@LNMC over 100 charge-discharge cycles at 1C, whereas, the capacity retention is only ∼30% for pristine LNMC. After cycling, the EIS results also indicate that the impedance of Li/LNMC cell reduces after Li2CuO2 modification.

High energy density and low self-discharge of a quasi-solid-state supercapacitor with carbon nanotubes incorporated redox-active ionic liquid-based gel polymer electrolyte

To achieve a quasi-solid-state supercapacitor (SC) with high energy density and low self-discharge, a redox-active poly(vinyl alcohol) (PVA)-based gel polymer electrolyte (GPE) is synthesized by the addition of 1-butyl-3-methylimidazolium bromide (BMIMBr) ionic liquid (IL) and carbon nanotubes (CNTs) into a PVA aqueous solution, followed by the addition of Li2SO4 and then the removal of excess water. The influences of BMIMBr-to-PVA and CNTs-to-PVA mass ratios on the ionic conductivity of GPE are discussed. The maximum ionic conductivity of GPE can reach 61.1 mS cm−1. A SC consisting of the optimized GPE and a pair of activated carbon (AC) electrodes exhibits a high energy density of 43.1 Wh kg−1, which can be assigned to the wide working voltage of 1.8 V as a result of the strong solvation effect of Li+ cations and SO42− anions, pseudocapacitance contribution from the redox reaction of Br−/Br3− at the electrolyte/electrode interface, and the three-dimensional (3D) conductive network of CNTs throughout the PVA matrix providing transport channel to facilitate ion transport. And the self-discharge is greatly suppressed due to the presence of 3D network of CNTs in the GPE. Additionally, the SC presents excellent cyclic stability.

Performance of a rechargeable cell using an ionic liquid gel polymer electrolyte and natural graphite electrode

With the concepts of green environment and the priority given on economical aspects, a great deal of research activities has been diverted towards clean and low-cost device fabrication. Central focus was on eliminating the use of toxic and expensive materials like Li and different solvents. Application of ionic liquid-based gel polymer electrolytes (GPEs) and non-Li electrodes can address many shortcomings associated with liquid, solid and GPEs. In the present study, characteristics of a rechargeable cell with 1-ethyl-3-methylimidazolium trifluoromethanesulphonate-based GPE having Zn and Sri Lankan natural graphite electrodes have been investigated. For characterization, electrochemical impedance spectroscopy, cyclic voltammetry and galvanostatic charge discharge test have been performed at room temperature. The open circuit voltage of the cell was about 1V. Specific charge and discharge capacities of the cell were 4.66 and $$2.99 \hbox { mA h g}^{-1}$$, respectively. Moreover, efficiency of the specific charge was 80.2% over 500 cycles, while efficiency of specific discharge was 92% over 1000 cycles. These results proved the suitability of the electrolyte and electrodes investigated in the present study to be used well in rechargeable cells.

Characterisation of an ionic liquid-based gel polymer electrolyte for potential applications

The Journal of the National Science Foundation of Sri Lanka publishes the results of research in all aspects of Science and Technology. The journal also has a website at http://www.nsf.gov.lk/. 2021 Impact Factor: 0.682The JNSF provides immediate open access to its content on the principle that making research freely available to the public supports a greater global exchange of knowledge.Cover :Leatherback (a), green (b - adult & f - hatchling), hawksbill (c) and olive ridley (d) turtles who nest in Sri Lankan beaches, green turtle crawl marks (e) and by-catch of sea turtles in fisheries (c & d)Photo credits: SJ Perera (a & c), WPN Perera (b & e), K Ekaratne (d & f)

Influence of ionic liquid structures on polyimide-based gel polymer electrolytes for high-safety lithium batteries

This study first investigates the effect of the choice of cation on three different ionic-liquid-based gel polymer electrolytes (ILPEs) with polyimide membranes. The preparation of three ILPEs based on electrospun membranes of PI and incorporating a room-temperature ionic liquid, 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide complexed with lithium bis(trifluoromethylsulfonyl)imide, is described. ILPE-EMImTFSI has an ionic conductivity as high as 5.3×10−3Scm−1 at 30°C. Furthermore, it shows higher thermal stability and electrochemical oxidation stability compared to the other two ILPEs because of its stronger bonds. These results indicate that polyimide-based ILPE-EMImTFSI is a good candidate for use in high-safety rechargeable lithium metal batteries.