Tetraglyme Research Articles

Investigating Molecular Interactions through Computational Modeling, Thermodynamic Analysis, and Acoustic Measurements of LiOTf in Aqueous TEGDME and DME Solutions at Different Temperatures.

This study investigates solute-solvent interactions in ternary systems consisting of lithium trifluoromethanesulfonate (LiOTf) as the solute and tetraethylene glycol dimethyl ether (TEGDME) and 1,2-dimethoxyethane (DME) as solvents over a range of temperatures (293.15-313.15 K). A multidisciplinary approach involving computational modeling, thermodynamic analysis, and acoustic measurements was used to elucidate molecular-level dynamics. The positive V ϕ 0 values in the thermodynamic analysis revealed the prevalence of solute-solvent interactions in the investigated ternary (LiOTf + H2O + DME/TEGDME) solutions. Hepler's constant was determined to predict the structure maker/breaker behavior. Cyclic voltammetry analysis showed that TEGDME offers a higher electrochemical window (EW) of 1.36 V in 0.01 TEGDME and 1.40 V in 0.05 TEGDME compared with that of 1.25 V in 0.01 DME and 1.38 V in 0.05 DME, yielding favorable and comparable working EWs. DFT calculations using the B3LYP functional and 6-311++G(d,p) basis set provided insights into the electron-donating and -accepting properties of the molecules, showing higher reactivity for LiOTf. These findings present novel insights into ternary electrolyte systems, which hold the potential for applications in energy storage technologies.

In Situ Surface-Enhanced Infrared Absorption Spectroscopy to Explore the Stability of Electrolyte in Nonaqueous Lithium Oxygen Batteries

Tetraethylene glycol dimethyl ether (TEGDME) decomposition on the Au electrode surface is studied using in situ attenuated total reflectance surface enhanced infrared absorption spectroscopy (ATR-SEIRAS). Due to the weak solvation of TEGDME, the superoxide intermediate (LiO2/O2−) of the discharge process rapidly gains electrons on the electrode surface to generate Li2O2. Furthermore, alkyl radical, formed by LiO2/O2− extracting hydrogen from ether, undergoes oxidative decomposition reactions to form by-products. During the charge process, amorphous film-like Li2O2 obtained from surface-phase mechanism oxidizes in the low potential range of 3–3.4 V, while the oxidation potential of large-sized crystal Li2O2 particles obtained from solution-phase mechanism is above 3.4 V. Besides, TEGDME is intrinsically unstable and can decompose at 3.8 V even the solution is saturated with argon, indicating that the degradation of ether-based electrolyte is inevitable during the cycling process. This work confirms the feasibility of ATR-SEIRAS in probing the reaction mechanism and electrolyte stability of lithium oxygen batteries, and provides direct spectroscopic evidence for subsequent optimization of electrolyte components.

Effect of Nanoparticles As Additives on Lithium-Ion Transport in Composite Polymer Electrolytes

Advancing solid-state battery technology holds immense promise in the context of climate change, providing a sustainable path toward efficient energy storage and electric vehicles. Li metal batteries are an ideal candidate for this need due to the high theoretical specific capacity of Li metal (3860 mA h g-1). Composite polymer electrolytes (CPEs) are being explored for lithium-metal solid state batteries (SSBs) due to their potentially high ionic conductivity, ease of processing, and ideal mechanical properties. In this work, we looked at poly(ethylene oxide) and lithium bis(trifluoromethanesulfonyl)imide (PEO-LiTFSI) as a polymer matrix due to its superb mechanical properties, low material cost, and ideal interfacial contact with the Li anode. The addition of 20 wt % tetraethylene glycol dimethyl ether (TEGDME) plasticizer to the PEO-LiTFSI matrix had a significant increase in conductivity at room temperature compared to neat PEO-LiTFSI. Furthermore, the incorporation of TEGDME resulted in enhanced flexibility, strength, and workability. This clearly illustrates the positive impact of the plasticizer on both conductivity and mechanical properties. To further improve the CPE performance, we added 20 wt % of different 500 nm nanoparticles to the PEO-LiTFSI-20 wt % TEGDME matrix. In CPEs with added neat aluminum oxide (Al2O3) nanoparticles the conductivity, transference number, limiting current, and interfacial resistance were all unchanged compared to the plasticizer mixture. Since the addition of the Li-inactive, neat Al2O3 nanoparticles had no impact on cell performance, we then tested the addition of ionically conductive, silane-functionalized Li7La3Zr2O12 nanoparticles (s@LLZO) but observed no significant change in ionic conductivity. However, there was a large decrease in interfacial resistance and an increase in transference number. As a result, the limiting current with s@LLZO nanoparticles was tripled as compared to the addition of the same size neat Al2O3 nanoparticles. To see if the addition of the silane to LLZO interface was the main reason behind the improved cell performance, we also tested silanized aluminum oxide nanoparticles (s@ Al2O3) but observed no significant changes when compared to neat Al2O3. These results confirmed that the addition of the lithium containing s@LLZO nanoparticles is beneficial to the overall cell performance of CPE, and we are currently investigating the mechanism of the improved Li-transport. Further optimization of these systems holds the potential to significantly enhance the charging rates of SSBs using composite polymer electrolytes.

Utilizing Ionic Liquid Mixtures to Modify Lithium Solvation Chemistry and Electrolyte Properties

Ionic liquids are appealing as electrolytes because of their wide electrochemical windows, moderate conductivities, minimal flammability and ability to tune the structure-property relationships. Shortcomings with the use of ionic liquids in lithium-based batteries are due to poor lithium ion transport, lack of formation of a stable solid electrolyte interphase (SEI) and limited lower temperature operations. To overcome the shortcomings, ionic liquids can be mixed with co-solvents or additives. SEI formers, co-solvents for lowering melting points and increasing conductivities, and agents to modify the interactions with lithium can all be introduced to the ionic liquid electrolytes. In the work to be presented here, the strategy of mixing solvate ionic liquids (Li(G4)TFSI) with task-specific pyrrolidinum-based ionic liquids that have short polyether side chains will be presented. Li(G4)TFSI is a solvate ionic liquid with an equimolar ratio of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and tetraethylene glycol dimethyl ether (G4). Li(G4)TFSI with an oxygen-to-lithium ratio of 5 ([O]/[Li+]=5), has a high lithium concentration and improved low temperature liquid range compared to traditional ionic liquids. By adding the task-specific ionic liquids with solvate ionic liquid analogous side chains, the properties of the electrolyte can further be tuned while aiming to keep the anion from solvating the Li ion which hinders its transport. The length of the polyether groups on the ionic liquid were varied to have constant ratios of ionic liquid:LiTFSI:G4 or to maintain a constant [O]/[Li+] ratio. The influence of the anion utilized with the ionic liquid was also investigated. The physical and electrochemical characteristics of the ionic liquid mixtures were evaluated to better understand how key properties and solvating power affect reversible lithium deposition and stripping across a range of temperatures. Through the use of ionic liquid-based mixtures, many of the desirable properties of the ionic liquids can be retained while the undesired properties of the ionic liquids can be mitigated, making for more favorable electrolytes.

Revelation of Reaction and Capacity-Fading Mechanisms of Quasi-Solid-State Zn-Ion Batteries with δ-MnO2 As the Positive Active Material

Zinc-ion batteries (ZIBs) are widely researched and developed as favorable energy storage technologies thanks to their low cost, high safety, and availability towards mass production. When compared to typical liquid-based batteries, especially the water-based ones, quasi-solid-state batteries offer additional benefits including less corrosion, no gas evolution, no leakage and wider operating temperature range. The polymer electrolyte, combining poly(ethylene oxide) (PEO), Zn(OTf)2, and a minuscule quantity of Tetraethylene glycol dimethyl ether (TEGDME), is the key component of our quasi-solid-state batteries. The respective active materials of the positive and negative electrodes are δ-MnO2 and Zn. Note that cellulose nanofiber (CNF) is added as reinforcement in the polymer-electrolyte separator. We have assembled the batteries in a pouch cell and electrochemically tested by galvanostatic cycling at 10 mA·g-1. The first specific discharge capacity obtained is about 150 mAh·g-1. Then we have correlated the electrochemical reactions at δ-MnO2 involving Zn2+ and e- to its microstructural alteration by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and X-ray tomography. It was possible to observe that Mn in δ-MnO2 reduced its oxidation state from +4 to +3 after discharge and reversed to +4 after charge. Volume change of the δ-MnO2 particles during discharge and charge was also confirmed. Moreover, long-term cycling of the solid-state batteries, together with the microstructural analyses have been performed. After 100 cycles, the battery capacity remained less than 50 mAh·g-1. We have located the origin of such a capacity fading resulting from irreversible phase transformation of δ-MnO2 after interaction with Zn2+ and e-. This has opened our horizon to a new insight finding for comprehension of the mechanism within δ-MnO2 directly affecting the performances of solid-state ZIBs.

Hansen Solubility Parameter-Guided Solvent Selection for Solution-Phase Discharge in Li-CO2 Batteries.

Surface discharge mechanism-induced cathode passivation is a critical challenge that blocks the full liberation of the ultrahigh theoretical energy density of Li-CO2 batteries. Herein, we propose a novel concept based on Hansen solubility parameters (HSPs) to guide the selection of solvents for inducing the dissolution of discharge products, facilitating the detachment of in situ-formed metastable Li2C2O4 from the electrode surface and enabling a continuous Li2C2O4-dominated discharge process. Combining theoretical calculations with HSP predictions, we identified Pd-OCNTs as an ideal catalyst, with tetraethylene glycol dimethyl ether as the optimal solvent for Li2C2O4 production and stabilization. This combination facilitates the rapid diffusion of Li2C2O4 generated in situ near the catalyst surface out of the inner Helmholtz layer. Consequently, the system exhibits high energy efficiency of 96.7% and remarkable stability over 3200 h. This work provides critical insights into the solution-mediated dissolution process of Li2C2O4, informing strategies for multiphase interfacial reactions in Li-CO2 batteries.

Liquid-phase CO2 hydrogenation to methanol synthesis: Solvent screening, process design and techno-economic evaluation

This paper focuses on a liquid-phase CO2 hydrogenation process for methanol synthesis to enhance CO2 conversion. The feasibility of a liquid-phase CO2 hydrogenation process is comprehensively evaluated through a techno-economic analysis. The solvent tetraethylene glycol dimethyl ether is identified as one of the most favorable options following an analysis of the solubility data pertaining to various solvents and their influence on the reaction equilibrium of the substances within the system. The influence of process parameters, including temperature, pressure, solvent amount, and gas hourly space velocity (GHSV), on the conversion of CO2 and the selectivity for methanol is examined and optimized in a liquid-phase CO2 hydrogenation to methanol process without a gas recycle (Process 1), optimal reaction conditions are determined and a CO2 conversion of 95.19 % and a CH3OH yield of 94.77 % with a purity of 99.9 % are achieved. A liquid-phase process with a gas recycle (Process 2) is implemented to enhance the utilization of feed gas, achieving a CO2 conversion rate of 95.23 % and a methanol yield of 99.69 %. The liquid-phase process is further optimized by incorporating reactive distillation technology (Process 3), to enhance reaction efficiency and reduce energy consumption. Following the techno-economic evaluation, the energy efficiency of Process 3 is 7.79 % and 4.99 % higher than that of Process 1 and Process 2, respectively. The product cost of Process 3 is reduced by 8.75 % compared to Process 1 and by 4.25 % compared to Process 2. This research offers insights into the challenges associated with the development of the liquid-phase method.

Halogen-Bonding Nanoarchitectonics in Supramolecular Plasticizers for Breaking the Trade-Off between Ion Transport and Mechanical Strength of Polymer Electrolytes for High-Voltage Li-Metal Batteries.

The low ionic conductivity of poly(ethylene oxide) (PEO)-based polymer electrolytes at room temperature impedes their practical applications. The addition of a plasticizer into polymer electrolytes could significantly promote ion transport while inevitably decreasing their mechanical strength. Herein, we report a supramolecular plasticizer (SMP) to break the trade-off effect between ionic conductivity and mechanical properties in PEO-based polymer electrolytes. Accordingly, the SMP is constructed by tetraethylene glycol dimethyl ether (G4) and SbF3 through halogen bonds. The SMP-plasticized PEO electrolyte (PEO/SMP) presents a simultaneously enhanced ionic conductivity of 2.4 × 10-4 S cm-1 (25 °C) and a high mechanical strength of 8.1 MPa, compared to those of pristine PEO-based electrolytes. Benefiting from the halogen bonds between G4 and SbF3, the Li-O coordination in PEO/SMP is evidently weakened, and thus rapid Li+ transport is achieved. Furthermore, the PEO/SMP electrolyte possesses a wide electrochemical stability window of 4.5 V and, importantly, derives an inorganic-rich SEI with a low interfacial resistance on a lithium metal surface. By using PEO/SMP, the lithium-metal battery with the LiNi0.5Co0.2Mn0.3O2 cathode exhibits a good rate and long-term cycling performance with a capacity retention of 75.3% (500 cycles). This work offers a rational guideline for the design of polymer electrolytes suitable for high-performance lithium-metal batteries.

New insights into the oxidative and cytogenotoxic effects of Tetraglyme on human peripheral blood cells

The present study investigated the oxidative and cytogenotoxic potential of Tetraethylene glycol dimethyl ether (known as Tetraglyme) on healthy human peripheral blood lymphocytes, widely used as an in vitro model for assessing the human health risk posed by different chemical compounds. In a first step, Nuclear Magnetic Resonance (1H NMR) spectroscopy, and Ultra-High Performance Liquid Chromatography-Mass Spectrometry (UHPLC-MS) were employed to estimate Tetraglyme's stability under a wide range of pH values (4–12), and thus to identify potential by-products. Thereafter, isolated lymphocytes were treated with different concentrations of Tetraglyme (0.02–20 mg L−1) for assessing its oxidative (using the DCFH-DA staining), and cytogenotoxic potential (using the trypan blue exclusion test for estimating cell viability, Comet assay, as well as the cytokinesis-block micronucleus assay, with or without the addition of S9 metabolic activation system). According to the results, Tetraglyme remains stable at pH 4, but two additional derivatives (i.e. 1-[2-(2-ethoxyethoxy)ethoxy]-2-methoxyethane [C9H20O4] and 1-ethoxy-2-(2-ethoxyethoxy)ethane (Diethylene glycol diethyl ether) [C8H18O3]) were found in traces, under alkaline conditions (pH ≥7). Moreover, although Tetraglyme (and/or its derivatives) showed negligible alterations of cell viability (>92 %) in all cases, the pronounced ROS formation, DNA damage, cell proliferation arrest, and MN frequencies in challenged cells are indicative of its oxidative and cytogenotoxic potential. The significant alterations of Cytokinesis-Block Proliferation Index (CBPI) and Micronucleus (MN) frequencies in S9 challenged cells give further evidence for the potential involvement of Tetraglyme's metabolites in the observed cytogenotoxic mode of action. Although not conclusive, the present findings give rise to further research, utilizing different cell types and biological models, for elucidating Tetraglyme's toxic mode of action, as well as its environmental and human risk.

Lithium fluoride additive helps construct stable electrode-electrolyte interfaces to boost the performance of Mg-S batteries

Most magnesium electrolytes react with the Mg anode surface to form a non-favorable passive layer that inhibits shuttling of the Mg ions and results in the short cycle life of the Mg cells. In this work, we probe LiF as an effective electrolyte additive to address the challenges of electrolyte degradation, Mg anode passivation, and polysulfide shuttle. The key to our strategy lies in modifying the halogen-free electrolytes (HFE) electrolyte-based Mg(NO3)2·6H2O salt dissolved in acetonitrile (ACN) and tetra ethylene glycol dimethyl ether (G4) with LiF additives, which play a crucial role in engineering stable electrolyte interfaces. These additives alter the chemical composition of the solid electrolyte interface (SEI) layer on the surface of the Mg anode, enabling low overpotential of Mg2+ extraction/insertion, improving the Mg2+ transference, and enhancing the electrochemical performance of the electrolyte. The Mg-S cell with modified electrolyte delivers a high discharge capacity of over 400 mAh g−1 for >10 cycles, compared with the short cycle life in the case of using a blank electrolyte. This remarkable performance underscores the potential of our findings in advancing magnesium sulfur battery technology.

A multi-step discharge/charge model of Li[sbnd]O2 batteries coupled with electrolyte decomposition and carbon electrode corrosion reactions

Electrolyte decomposition and electrode corrosion stand as two primary side reactions in lithium‑oxygen (LiO2) batteries during their discharge/charge cycles. In this work, a comprehensive LiO2 battery model combining multi-step lithium peroxide (Li2O2) formation, electrolyte decomposition, and electrode corrosion is proposed. Based on this model, the deposition behaviors and cycling performance of the LiO2 battery under deep discharge/charge cycles are investigated. The stop of discharge is mainly ascribed to the loss of active surface area for the battery using tetraethylene glycol dimethyl ether (TEGDME) electrolyte, while both O2 transport limitation and active surface area loss lead to the discharge termination for battery using dimethyl sulfoxide (DMSO) electrolyte. The incomplete decomposition of Li2O2 and lithium carbonate (Li2CO3) clogs electrode pores, leading to a continuous decline in the discharge capacity of the LiO2 battery. For the TEGDME-based battery, the undecomposed Li2CO3 gradually dominates the deposition with cycles, wherein electrode corrosion becomes the primary source of the undecomposed Li2CO3 after 3 cycles. For the DMSO-based battery, undecomposed Li2O2 is always a dominant trigger for battery discharge capacity degradation, although electrode corrosion remains a key contributor to Li2CO3 generation. Despite the DMSO-based battery exhibiting lower rates of electrolyte decomposition and electrode corrosion, it demonstrates poorer cyclic performance than the TEGDME-based battery due to the generation of more toroidal Li2O2. Moreover, when the charging cut-off voltage is reduced to 4.2 V, discharge capacity diminishes more rapidly due to the increased accumulation of undecomposed Li2O2, despite suppressed Li2CO3 deposition. Finally, the results confirm that thick electrodes lead to deteriorating cycling performance, stemming from increased discharge/charge overpotential and extended discharge/charge times, thus intensifying the side reactions.

Unveiling Reaction Mechanisms of Non-Aqueous Zn-Ion Batteries – Zn/LiFePO4 System

Zinc-ion batteries (ZIBs) are among the most promising energy storage technologies because of their low cost, safety, and environmental friendliness. In this work, we focus on investigating the electrochemical reaction mechanisms of ZIBs with Lithium iron phosphate (LiFePO4) as an active material in the positive electrode, Zn(OTf)2+LiCl dissolving Tetraethylene glycol dimethyl ether (TEGDME) as the electrolyte, as well as metallic Zinc as the negative electrode. After testing the ZIB cells by galvanostatic cycling, the cells with TEGDME exhibit the best electrochemical performance in terms of long-term stability. The initial specific discharge capacity is 118.3 mAh g-1 and the capacity retention is 91.4% after 100 cycles at a current density of 10 mA g-1. We propose the reaction mechanisms during the charge-discharge processes involve extraction/insertion processes of Li+ into/out of the olivine structure of LiFePO4 as evidenced by X-ray near-edge spectroscopy (XANES). According to X-ray diffraction (XRD) analysis of the discharged and charged LiFePO4 electrodes, the crystal structure changes from LiFePO4 to FePO4 when charging and back into LiFePO4 again when discharging. Besides, XRD and scanning electron microscopy (SEM) confirm that the cycled Zn electrode is hardly present with passivation and/or corrosion. Therefore, this new combination of Zn/LiFePO4 and TEGDME has a potential for ZIB applications.

(Invited) Exciton Dynamics in Triplet Fusion of Diphenylanthracene in Fluid Solution and Crystalline Solid

Triplet fusion (TF) has recently attracted attention because of its great potential of various applications. Since high reaction efficiency of TF is demanded in any applications, it is necessary to clarify the mechanism of triplet exciton dynamics that is an important elementary process to enhance the TF efficiency. Therefore, in this paper, we study the triplet exciton dynamics of 9,10-diphenylanthracene (DPA), which shows the TF-based fluorescence, in a solvent of tetraethylene glycol dimethyl ether and in polycrystal of DPA, in combination with the triplet sensitization using platinum octaethylporphyrin. The observed emission kinetics and their magnetoluminescence effect indicate that the rotational and the multitrapping diffusions of the triplet exciton play an inherent role respectively in the fluid solution and in the polycrystalline solid.

Lithium-Ion Transport Properties in DMSO and TEGDME: Exploring the Influence of Solvation through Molecular Dynamics and Experiments.

This study explores the properties of aprotic electrolytes via the application of experimental methods, including nuclear magnetic resonance spectroscopy and electrochemical techniques, along with molecular dynamic modeling. The aim is to provide a quantitative description of the physico-chemical properties of two well-established electrolytes (case studies), each exhibiting significantly distinct dielectric properties: a LiTFSI (Lithium bis(trifluoromethanesulfonyl)imide) solution in dimethyl sulfoxide (DMSO, dielectric constant =46.68) and a LiTFSI solution in tetraethylene glycol dimethyl ether (TEGDME, =7.71). We obtained a comprehensive insight into the properties of the electrolytes at both the macroscopic-collective and molecular levels with particular emphasis on the interactions between the Li ions and solvent molecules. We discovered remarkable disparities in the structural arrangements, solvation behaviors, and bulk-related properties of these electrolyte systems, particularly in response to temperature changes.

A Dual Salt/Dual Solvent Electrolyte Enables Ultrahigh Utilization of Zinc Metal Anode for Aqueous Batteries.

Rechargeable aqueous zincbatteriesare promising in next-generation sustainable energy storage. However, the low zinc (Zn) metal anode reversibility and utilization in aqueous electrolytes due to Zn corrosion and poor Zn2+ deposition kinetics significantly hinder the development of Zn-ion batteries. Here, a dual salt/dual solvent electrolyte composed of Zn(BF4)2/Zn(Ac)2 in water/TEGDME (tetraethylene glycol dimethyl ether) solvents to achieve reversible Zn anode at an ultrahigh depth of discharge (DOD) is developed. An "inner co-salt and outer co-solvent" synergistic effect in this unique dual salt/dual solvent system is revealed. Experimental results and theoretical calculations provide evidence that the ether co-solvent inhibits water activity by forming hydrogen bonding with the water and coordination effects with the proton in the outer Zn2+ solvation structure. Meanwhile, the anion of zinc acetate co-salt enters the inner Zn2+ solvation structure, thereby accelerating the desolvation kinetics. Strikingly, based on the electrolyte design, the zinc anode shows high reversibility at an ultrahigh utilization of 60% DOD with 99.80% Coulombic efficiency and 9.39 mAh cm-2 high capacity. The results far exceed the performance reported in electrolyte design work recently. The work provides fundamental insights into inner co-salt and outer co-solvent synergistic regulation in multifunctional electrolytes for reversible aqueous metal-ion batteries.

Effect of introducing different molecular liquid solvents on electrochemical and physical properties of sodium ion conducting polymer gel electrolytes

The current investigation presents comparative studies on the effect of introducing three different molecular liquid solvents, namely ethylene carbonate: diethyl carbonate (EC:DEC), tetra ethylene glycol dimethyl ether (TEGDME), and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4) on the electrochemical and physical properties of sodium ion conducting polymer gel electrolytes (PGEs) containing sodium tetrafluoroborate (NaBF4) salt, and polyvinyllidene fluoride-co-hexafluoropropylene (PVdF-HFP) polymer. The PGE, which is optimized and contains the EC: DEC solvent, has an ionic conductivity of 8.9 × 10−4 S cm−1, electrochemical stability of 4.5 V and total ion transport number of 0.99 at 30 °C. Along with conductivity studies, the X-ray diffraction studies, show that the EC: DEC raises the entropy of the PGE to its maximum value. The thermogravimetric (TGA) and differential scanning calorimetry (DSC) investigations demonstrate that electrolyte with EC: DEC exhibits a weight loss of 13 % up to 200 °C and retain the gel phase up to 140 °C. The optimized electrolyte holds promise for forthcoming sodium based electrochemical devices.

Operando Raman Gradient Analysis for Temperature-Dependent Electrolyte Characterization.

Transport and thermodynamic properties are integral parameters to understand, model, and optimize state-of-the-art and next-generation battery electrolytes. The accurate measurement of these properties is experimentally challenging as well as time- and resource-intensive, and consequently, reports are scarce. Their dependence on temperature is explored even less and is commonly limited to a few temperature points. Recently, we introduced an operando Raman gradient analysis (ORGA) tool to extract transport and thermodynamic properties. Here, we expand the capabilities of ORGA by incorporating a temperature-sensitive external reference into the design. With this enhancement, we are able to visualize the local concentration of any Raman-active species in the electrolyte and detect lithium filament nucleation. We demonstrate and validate this new functionality of ORGA via an examination of lithium bis(fluorosulfonyl)imide (LiFSI) in tetraethylene glycol dimethyl ether (G4) as a function of temperature. All transport properties and activation energies are reported, and the effect of temperature is discussed.

Influence of glycol ether additive with low molecular weight on the interactions between CO2 and oil: Applications for enhanced shale oil recovery

The high-efficient development of shale oil is one of the urgent problems in the petroleum industry. The technology of CO2 enhanced oil recovery (EOR) has shown significant effects in developing shale oil. The effects of several glycol ether additives with low molecular weight on the interactions between CO2 and oil were investigated here. The solubility of glycol ether additive in CO2 was firstly characterized. Then, the effects of glycol ether additives on the interfacial tension (IFT) between CO2 and hexadecane and the volume expansion and extraction performance between CO2 and hexadecane under different pressures was investigated. The experimental results show that diethylene glycol dimethyl ether (DEG), triethylene glycol dimethyl ether (TEG), and tetraethylene glycol dimethyl ether (TTEG) all have low cloud point pressure and high affinity with CO2. Under the same mass fraction, DGE has the best effect to reduce the IFT between hexadecane and CO2 by more than 30.0%, while an overall reduction of 20.0%–30.0% for TEG and 10.0%–20.0% for TTEG. A new method to measure the extraction and expansion rates has been established and can calculate the swelling factor accurately. After adding 1.0% DEG, the expansion and extraction amounts of CO2 for hexadecane are respectively increased to 1.75 times and 2.25 times. The results show that glycol ether additives assisted CO2 have potential application for EOR. This study can provide theoretical guidance for the optimization of CO2 composite systems for oil displacement.

Ether-Water Co-Solvent Electrolytes Enhanced Vanadium Oxide Cathode Cyclic Behaviors for Zinc Batteries.

Vanadium-based compounds are fantastic cathodes for aqueous zinc metal batteries due to the high specific capacity and excellent rate capability. Nevertheless, the practical application has been hampered by the dissolution of vanadium in traditional aqueous electrolytes owing to the strong polarity of water molecules. Herein, we propose a hybrid electrolyte made of Zn(ClO4)2 salt in tetraethylene glycol dimethyl ether (G4) and H2O solvents to upgrade the cycle life of Zn//K0.486V2O5 battery. The G4 jointly solvates with Zn2+ ions and replaces a portion of the H2O molecules in the Zn2+ solvation sheath. It forms a strong bond with H2O, reducing its activity, and significantly inhibiting vanadium dissolution and water-induced parasitic reaction. Consequently, the optimized electrolyte with H2O and G4 volume ratio of 5 : 5 enhances the cycling stability of Zn//K0.486V2O5 battery, enabling it to reach up to 600 cycles. In addition, the battery demonstrates a satisfactory reversible capacity of 475.7 mAh g-1 and excellent rate performance attributed to the moderate ionic conductivity (28.8 mS cm-1) of the hybrid electrolyte. Last but not least, in the optimized electrolyte, the symmetric Zn//Zn cells deliver a long cycling performance of 400 h, while the asymmetric Zn//Cu cells shows a high average coulombic efficiency of 97.4 %.

Flexible High Lithium-Ion Conducting PEO-Based Solid Polymer Electrolyte with Liquid Plasticizers for High Performance Solid-State Lithium Batteries.

Lithium-ion secondary batteries (LIB) with high energy density have attracted much attention for electric vehicle (EV) applications. However, LIBs have a safety problem because these batteries contain a flammable organic electrolyte. As such, all-solid secondary batteries that are not flammable have been extensively reported recently. In this study, we have focused on polymer electrolytes, which is flexible and is expected to address the safety problem. However, the conventional polymer electrolytes have low electrial conductivity at room temperature. Various attempts have been made to solve this problem, such as the addition of inorganic fillers and ionic liquids; however, these composite polymer electrolytes have not yet reached a practical level of lithium-ion conductivity. In this study, high electrical conductivity and lithium dendrite formation-free PEO based composite electrolytes are developed with both a filler of Li6,4La3Zr1.4Ta0.6O12 and liquid plasticizers of tetraethylene glycol dimethyl ether and 1,2 dimethoxyethane. The proposed flexible polymer electrolyte shows a high electrical conduciviy of 6.01×10-4 S cm-1 at 25 °C.