CO2 In Ionic Liquids Research Articles

Experimental Investigation on Solubility Characteristics of CO2–Ionic Liquids as New Working Pairs for Absorption Refrigeration Systems

Experimental Investigation on Solubility Characteristics of CO2–Ionic Liquids as New Working Pairs for Absorption Refrigeration Systems

Electrochemical reduction of CO2 in ionic liquid: Mechanistic study of Li–CO2 batteries via in situ ambient pressure X-ray photoelectron spectroscopy

In-depth mechanistic understanding of CO 2 reduction reaction (CRR) and CO 2 evolution reaction (CER) is the prerequisite to develop stable and efficient Li–CO 2 batteries. In this study, we investigate the redox reaction of CO 2 on the porous carbon surface in ionic liquid electrolyte via synchrotron-based in situ ambient pressure X-ray photoelectron spectroscopy (APXPS) technique. We used ionic liquid to facilitate CO 2 capture and stabilize CRR intermediate anions owing to its strong solvation for Li + . We demonstrate that pure CO 2 reduction is not electrochemically active at room temperature on porous carbon electrode and its kinetics can be remarkably improved by H 2 O, which could be responsible for the discrepancy on CRR kinetics in the literature. However, in the presence of H 2 O, the formed LiOH gradually converted to Li 2 CO 3 leading to severe electrolyte degradation in charging reaction. With the assistance of O 2 in the ionic liquid -based electrolyte, we show, for the first time, CRR yields a low-valence amorphous carbon and Li 2 O 2 /Li 2 O in the Li–CO 2 batteries. The formed amorphous carbon, Li 2 O 2 and Li 2 O exhibit higher rechargeability and faster kinetics compared with Li 2 CO 3 -oxidation. These new findings provide direct evidence of CRR mechanism and insights in resolving the discrepancy on CRR kinetics in Li–CO 2 batteries. • Synchrotron-based in-situ APXPS is developed to probe the Li–CO 2 reaction chemistry in ionic liquid electrolyte. • Pure CO 2 reduction is not electrochemically active at room temperature and its kinetics can be significantly improved by H 2 O. • CO 2 reduction in ionic liquid yields amorphous carbon and Li 2 O 2 /Li 2 O which are more reversible than Li 2 CO 3 .

Phase Equilibrium Characteristics of CO2 and Ionic Liquids with [FAP]− Anion Used for Absorption-Compression Refrigeration Working Pairs

The study of the phase equilibrium characteristics of CO2-ionic liquids (ILs) as new absorption-compression type refrigeration working pairs is of great importance. Three kinds of ILs, i.e., [emim][FAP], [bmim][FAP] and [hmim][FAP], were chosen as potential absorbents. The solubility of CO2 in these ILs was measured experimentally within 0 to 5.0 MPa at temperatures of 293.15 K to 333.15 K, and the effects of temperature, pressure, IL anion and cation structure and stirring action on CO2 solubility were also discussed and analyzed. The results showed that the longer alkyl chains in an identical IL family, the alkyl fluoride group in IL anions and the stirring action by a magnetic stirrer had positive effects on the solubility of CO2. In the three ILs, [hmim][FAP] possessed the best performance for CO2 absorption; the solubility of CO2 reached 0.7641 at a pressure of 5 MPa and temperature of 293.15 K, the maximum solubility measured in this work. The CO2-[hmim][FAP] binary mixture is recommended as a potentially applicable working pair for CO2 absorption-compression refrigeration systems.

Prediction of the Solubility of CO2 in Imidazolium Ionic Liquids Based on Selective Ensemble Modeling Method

Solubility data is one of the essential basic data for CO2 capture by ionic liquids. A selective ensemble modeling method, proposed to overcome the shortcomings of current methods, was developed and applied to the prediction of the solubility of CO2 in imidazolium ionic liquids. Firstly, multiple different sub–models were established based on the diversities of data, structural, and parameter design philosophy. Secondly, the fuzzy C–means algorithm was used to cluster the sub–models, and the collinearity detection method was adopted to eliminate the sub–models with high collinearity. Finally, the information entropy method integrated the sub–models into the selective ensemble model. The validation of the CO2 solubility predictions against experimental data showed that the proposed ensemble model had better performance than its previous alternative, because more effective information was extracted from different angles, and the diversity and accuracy among the sub–models were fully integrated. This work not only provided an effective modeling method for the prediction of the solubility of CO2 in ionic liquids, but also provided an effective method for the discrimination of ionic liquids for CO2 capture.

Experiments on vapour-liquid equilibrium of CO2-ionic liquid under flow conditions and influence on its refrigeration cycle

CO2 is a potential alternative refrigerant because of its excellent thermodynamic properties and environmental friendliness, but its high operating pressure in the refrigeration cycle limits its wide application. To reduce the operational high pressure of the conventional CO2 compression refrigeration system, a novel CO2 compression-absorption refrigeration system with ionic liquid (IL) as absorbent was proposed. The IL [emim][Tf2N] was selected and combined with CO2 as a working pair. Experimental investigations on the dynamic vapour-liquid equilibrium of CO2-[emim][Tf2N] under flow conditions and the influence on its refrigeration cycle were conducted. The effects of solution pump frequency, CO2 inlet temperature and pressure, and system pressure ratio on the key parameters such as depressurization amplitude, absorption completion and desorber temperature were investigated. Within the working conditions of this study, the system operational high pressure could be reduced by 29% at most, and the absorption completion of CO2-IL mixture at the absorber outlet could reach about 70%. It was found that both CO2 inlet pressure and temperature had important effects on the key parameters, and a larger pressure ratio could obtain larger depressurization amplitude and absorption completion and lower desorption temperature. These provide a reference for further optimizing system design and improving system performance.

Estimation of CO2 solubility in ionic liquids using connectionist tools based on thermodynamic and structural characteristics

Ionic Liquids (ILs) are a promising alternative to conventional amine-based solvents in CO2 absorption processes. Relatively high cost and viscous nature of ILs tempt researchers to find appropriate combination of cations and anions for targeting a competitive absorbent close to amines in terms of CO2 absorption capacity. Conducting extensive experimental studies appears to be time-consuming and expensive for a large number of common CO2/IL systems. One of the fast and reliable approaches to predict the solubility of CO2 in ILs is Machine Learning (ML)-based models or smart tools where the thermodynamic-based and structure-based property relationships can be explored. Four ML methods including Least Squares Support Vector Machine (LSSVM), Decision Tree (DT), Random Forest (RF), and Multilinear Regression (MLR) are employed in this study to obtain CO2 solubility in a structurally diverse set of ILs based on thermodynamic properties and Quantitative Structure–Activity Relationship (QSPR) model. In this paper, two datasets of CO2 solubility (taken from the literature) at various operating conditions are used; one model (or dataset) considers critical properties, molecular weight, and acentric factor of pure ILs as the input information, and the second one includes structural descriptors of cations and anions as the input parameters. Among different types of descriptors, the most important input variables (e.g., Homo-Lumo fraction and Disps (cation)) are selected using Genetic Algorithm (GA)-MLR method. The predictive ability of the introduced models is also analyzed using a four-fold external cross-validation procedure. A great match between the predicted values and experimental measurements is attained while using RF and DT techniques developed based on descriptors and thermodynamics properties. The structural descriptors-based models are more accurate and robust than those built on the critical properties. The feature selection approach is also applied to identify the most effective cation and anion descriptors. For both thermodynamic and QSPR modeling approaches, pressure has the maximum relative importance in the estimation of CO2 solubility in ILs. In the absence of temperature and pressure impacts, the critical pressure and Homo-Lumo fraction have the highest contribution to the thermodynamic – based and structural-based tools, respectively.

New insights into bulk and interface properties of [Bmim][Ac]/[Bmim][BF4] ionic liquid/CO2 systems — Molecular dynamics simulation approach

Ionic liquids (ILs) show great potentials for CO2 capture. In this research, we perform molecular dynamics (MD) simulations to explore bulk and interfacial behaviors of [Bmim][Ac] and [Bmim][BF4] ILs with and without CO2, in terms of transport phenomena and thermodynamics aspects. Physiochemical properties of pure ILs are calculated; structural properties such as radial distribution function (RDF) and self-diffusivity of the cations and anions are determined at various conditions. Great agreement is achieved between the experimental and calculated properties. Diffusion coefficients obtained for the cations and anions of the ILs are in the range of 3 × 10−12 to 34 × 10−12 m2/s. The cations have a higher diffusivity than the anions. It is found that the anion has an important effect on CO2 absorption, based on the coordination/structuring of CO2 around the cations and anions in the bulk systems of IL-CO2, as well as the comparison of volume expansion of the bulk system with that of pure ILs. With the addition of CO2 to ILs, the volume expansion is relatively smaller, compared to other organic solvents. The diffusion coefficient of CO2 in ILs varies from 1 × 10−10 to 3 × 10−10 m2/s, depending on temperature, CO2 concentration, and mixture viscosity. At the interface, association density between the cation and anion molecules increases. Upon CO2 diffusion, a dense interfacial layer is created that interrupts the association of the cation and anion, leading to a reduction in the interfacial tension. MD simulations also show that the diffusion of CO2 in the bulk occurs slowly. This study benefits designing appropriate ILs for various energy and environment applications under different process and thermodynamic conditions.

Electrochemical Synthesis of C-N Organic Compound Via Direct Reduction of CO2 in Ionic Liquid

The development of more efficient and sustainable methods for synthesizing C–N organic compound has always been a major focus of synthetic organic chemistry due to its critical roles natural environment and industries. Herein, we report a facile electrochemical approach to form C-N bonds form amines and CO2 in ionic liquid (IL) at room temperature under the metal-free condition. This reaction was carried out with very low potential under mild condition without adding any additives or tedious work-up. A broad range of amines could be catalyzed by active intermedia generated in a high efficient way, yielding the C-N bonds production selectively depended on the structure of amine and ionic liquid. This new strategy shows that a metal-free and friendly system could provide a platform not only to synthesize N-containing organic compounds with low-cost but also by efficient CO2 storage and utilization in an environmental friendly manner.

Supercritical carbon dioxide solubility in hydrophobic ionic liquid mixtures: Experimental determination and thermodynamic modeling

The solubility of supercritical carbon dioxide (scCO2) in the pure ionic liquids (ILs): 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate, [hmim][eFAP], and trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide [P6,6,6,14][Tf2N], and mixtures formed by mixing these ILs with trihexyltetradecylphosphonium tetraphenylborate ([P6,6,6,14][BPh4]), was experimentally measured by means of an equilibrium cell that was designed and assembled to allow obtaining the solubility using small amounts of ILs. This equilibrium cell was first tested using previously published experimental data where long times were necessary to reach equilibrium. However, good agreement with literature data was found. Thus, for pure [hmim][eFAP], the experimental data showed high solubility, which means molalities between 5.96 and 9.12, approximately (mole fractions between 0.78 and 0.85). However, mixing these ILs with 1% w/w [P6,6,6,14][BPh4], decreased or increased CO2 solubility depending on interactions between the ILs. The obtained experimental data was modeled using the vapor-liquid equilibrium relations by means of the Peng-Robinson equation of state and a two-parameter Van der Waals mixing rule, showing excellent agreement. Finally, the information obtained in this work could enable the study of the liquid-liquid phase microextraction with ionic liquids where the dissolution of CO2 in ILs could create an enhanced phase for the microextraction.

Searching for Solvents with an Increased Carbon Dioxide Solubility Using Multivariate Statistics.

Ionic liquids (ILs) are used in various fields of chemistry. One of them is CO2 capture, a process that is quite well described. The solubility of CO2 in ILs can be used as a model to investigate gas absorption processes. The aim is to find the relationships between the solubility of CO2 and other variables—physicochemical properties and parameters related to greenness. In this study, 12 variables are used to describe a dataset consisting of 26 ILs and 16 molecular solvents. We used a cluster analysis, a principal component analysis, and a K-means hierarchical clustering to find the patterns in the dataset and the discriminators between the clusters of compounds. The results showed that ILs and molecular solvents form two well-separated groups, and the variables were well separated into greenness-related and physicochemical properties. Such patterns suggest that the modeling of greenness properties and of the solubility of CO2 on physicochemical properties can be difficult.

Effective modeling methods to accurately predict the miscibility of CO2 in ionic liquids

CO2 solubility in ionic liquids (ILs) over wide temperature and pressure ranges of (283.15–373.35 K) and (99.8–85800.0 kPa), respectively, has been predicted using three models; a group method of data handling correlation (model I), a radial basis function network (model II), and an empirical relation (model III). The Nelder–Mead simplex and Levenberg–Marquardt algorithms were used to find the constants of the suggested functionality relations for models I and III, respectively. Model I with R2, RMSE and AARD% of 0.9650, 4.2727 and 8.46, respectively; model II with R2, RMSE and AARD% of 0.9942, 1.7172, and 4.23, respectively and model III with R2, RMSE and AARD% of 0.9886, 2.4248 and 4.25, respectively, were highly accurate in the prediction of experimental values. All the models proposed are vigorous and possess satisfactory error trends based on a comprehensive statistical assessment. To confirm the validity of the database, the dataset was subjected to a statistical outlier diagnostic test.

Mathematical modeling of CO2 absorption with ionic liquids in a membrane contactor, study of absorption kinetics and influence of temperature

AbstractBACKGROUNDThis work presents a comprehensive study of carbon dioxide (CO2) capture from CO2/N2 mixtures in a hollow fiber membrane contactor (HFMC). The absorbents considered were three different ionic liquids (ILs): 1‐ethyl‐3‐methylimidazolium acetate ([emim][OAc]), 1‐ethyl‐3‐methylimidazolium ethylsulfate ([emim][EtSO4]) and 1‐ethyl‐3‐methylimidazolium methyl sulfate ([emim][MeSO4]). A comprehensive two‐dimensional (2D) mathematical model for the transport of CO2 was developed and solved for steady‐state and pseudo steady‐state modes. For pseudo steady‐state mode, the 2D model was linked with a dynamic model applied on a tank from which the IL was recirculated into the shell side of the HFMC.RESULTSThe model showed excellent agreement between the simulations and experimental data within the range of 2 to 5% standard deviation. Initially, overall mass transfer coefficients of 7.6 × 10−6 (m s−1), 1.6 × 10−6 (m s−1) and 3.7 × 10−6 (m s−1) were obtained for [emim][OAc], [emim][EtSO4] and [emim][MeSO4], respectively. Solubility, diffusivity and absorption efficiency of CO2 in ILs showed strong dependence on the temperature. Furthermore, concentration drop in the wetted portion of the membrane, effect of porosity, tortuosity, gas and absorbent flow rates were systematically studied.CONCLUSIONFindings of both experimental and modeling work suggests that in spite of the difference of extraction efficiency, these ILs are potential absorbents for CO2 in membrane contactors. Moreover, the modeling approach was found very effective to predict the absorption behavior of CO2 in ILs and to study the wetting phenomena and parametric effects. © 2019 Society of Chemical Industry

Prediction carbon dioxide solubility in ionic liquids based on deep learning

Ionic liquids have a great potential in capture and separation of carbon dioxide (CO2), and the solubility of CO2 in ionic liquids is one of key data for engineering applications. In this paper, the critical properties of ionic liquids are combined with deep learning models (CP-DNN, CP-CNN, CP-RNN) to establish theoretical prediction models of CO2 solubility in ionic liquids. The predictive performance of these framworks is able to meet or exceed the predicted effects of the method based on thermodynamic models (PR,SRK) and machine learning method (XGBoost). For CP-RNN, the coefficient of determination (R 2) between experimental and predicted values is 0.988, CP-CNN is 0.999, and CP-DNN is 0.984. This research can avoid complex computational characterisation, it is to provide a theoretical method to further enrich and improve the data information analysis of the solubility of CO2 in ionic liquids.

Prediction of CO2 Solubility in Ionic Liquids Based on Multi-Model Fusion Method

Reducing the emissions of greenhouse gas is a worldwide problem that needs to be solved urgently for sustainable development in the future. The solubility of CO2 in ionic liquids is one of the important basic data for capturing CO2. Considering the disadvantages of experimental measurements, e.g., time-consuming and expensive, the complex parameters of mechanism modeling and the poor stability of single data-driven modeling, a multi-model fusion modeling method is proposed in order to predict the solubility of CO2 in ionic liquids. The multiple sub-models are built by the training set. The sub-models with better performance are selected through the validation set. Then, linear fusion models are established by minimizing the sum of squares of the error and information entropy method respectively. Finally, the performance of the fusion model is verified by the test set. The results showed that the prediction effect of the linear fusion models is better than that of the other three optimal sub-models. The prediction effect of the linear fusion model based on information entropy method is better than that of the least square error method. Through the research work, an effective and feasible modeling method is provided for accurately predicting the solubility of CO2 in ionic liquids. It can provide important basic conditions for evaluating and screening higher selective ionic liquids.

Modeling Carbon Dioxide Vibrational Frequencies in Ionic Liquids: IV. Temperature Dependence.

In previous papers in the series, the vibrational spectroscopy of CO2 in ionic liquids (ILs) was investigated at ambient conditions. Here, we extend these studies to understand the temperature dependence of the structure, dynamics, and thermodynamics of CO2 in the 1-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF6], IL. Using spectroscopic mapping techniques, the infrared absorption spectrum of the CO2 asymmetric stretch mode is simulated at a number of temperatures, and the results are found to be consistent with similar experimental studies. Structural correlation functions are used to reveal the thermodynamics of complete CO2 solvent cage breakdown. The enthalpy and entropy of activation for solvent cage reorganization are found to be 6.9 and 7.6 (kcal/mol)/K, respectively, and these values are similar to the those for spectral, orientational, and translational diffusion. Caging times for CO2 are calculated, and it is shown that the short time dynamics of CO2 are unaffected by temperature, even though the long-time dynamics are highly sensitive to temperature.

A molecular dynamics study of the solvation of carbon dioxide and other compounds in the ionic liquids [emim][B(CN)4] and [emim][NTf2

In this paper, we calculate solvation free energies of several compounds in ionic liquids. These free energies are used to compute properties such as Henry's law constants and activity coefficients, generally required in the design of environmentally sustainable processes. It is known, for instance, that carbon dioxide from combustion is one of the main sources of anthropogenic greenhouse gases. Recently, the propensity of the ionic liquid 1-ethyl-3-methylimidazolium tetracyanoborate ([emim][B(CN)4]) for the physisorption of CO2 has been reported, which makes it a potential solvent for carbon capture. In the present work, molecular dynamics simulations of the solvation of CO2 in ionic liquids [emim][B(CN)4] and 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide ([emim][NTf2]) are carried out both at infinite dilution and at high concentrations. A systematic study is performed by comparing several force fields and assessing the efficacy of simplifications in the simulations by using rigid-body dynamics and pairwise electrostatics. Our results confirm recent experimental observations that, for a given volume of solvent, lower pressure is required to absorb a certain amount of CO2 in [emim][B(CN)4] than in other ionic liquids.

Assessment of carbon dioxide solubility in ionic liquid/toluene/water systems by extended PR and PC-SAFT EOSs: Carbon capture implication

Recently, there has been a growing interest in CO2 capture using ionic liquids (ILs). To determine the CO2 absorption potential of ILs and their selectivity in the presence of other gaseous components in the mixture, the solubility of ILs at various operating conditions and the influence of impurities/additives such as water and toluene should be evaluated. Carbon capture capacity of the ILs can be examined using various methods such as experiments, thermodynamic approaches including Equations of State (EOSs), and molecular-based modeling. In this research work, the extended Peng–Robinson (PR) and Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) EOSs are utilized to assess the solubility and selectivity of CO2 in ILs through comparing the modeling results with experimental data. PC-SAFT and PR parameters are determined by employing the experimental density data. Modeling results reveal that the solubility values estimated by the PC-SAFT due to considering the association effects have a lower deviation (or a better performance) than PR EOS based on the magnitudes of Absolute Average Deviation (AAD %). The AAD (%) for [bmim][BF4], [bmim][PF6], [bmim][Tf2N], [hmim][Tf2N], [hmim][FAP], and [hmim][FAP] are calculated using PR EOS and PC-SAFT EOS, which are 2–5.7% and 3–7.5%, respectively. Furthermore, ternary systems of CO2 + ILs + water and CO2 + ILs + toluene are modeled to determine the effect of water and toluene on the gas solubility in ILs and viscosity of ILs with PC-SAFT EOS. Based on the results, low concentrations of water (0.1 wt%) have a negligible influence on the CO2 solubility in ILs. However, with increasing the water concentration, the solubility of water reduces significantly. On the other hand, the viscosity of ILs is reduced with increasing the water concentration. Viscosity reduction in the hydrophilic ILs is significant. It seems promising to add water up to 10 wt% to hydrophilic ILs, since a decrease in the viscosity to an amount close to the viscosity of water and a decrease in solubility by 9% are experienced. Finally, the selectivity of [hmim][Tf2N] in separation of CO2 from mixtures containing H2S, SO2, CH4, and H2 are reported. Based on the results, [hmim][Tf2N] is not appropriate for separation of CO2 from streams with a high concentration of H2S and SO2 gases.

A novel experimental apparatus for the study of low temperature regeneration CO2 capture solvents using hollow fibre membrane contactors

The design, capability and construction of a novel, experimental apparatus for the study of low temperature regeneration CO2 capture agents is presented. The decisions and challenges in developing a new experimental capability are discussed, as well as how it addresses the experimental intermediate between bench scale experiments and large, application specific projects. To demonstrate the utility and capability of the apparatus, a low temperature regenerating CO2 capture protic ionic liquid (PIL) solution – dimethylpropylenediamine acetate + 50% H2O – was used to remove CO2 from an incoming gas stream consisting of 10% (v/v) CO2 in air. SuperPhobic® 2.5 × 8 hollow fibre membrane contactors were used for both the absorption and regeneration processes. The loading-only experiment achieved pseudo steady state in approximately 12 min, achieving a pseudo steady-state mass transfer rate (Koverall) of (3.66 ± 0.2) × 10−5 m s−1, and a CO2 removal rate of 5.15 × 10−3 g m−2 s−1. This value is comparable to other ionic liquid CO2 capture agents such as 1-ethyl-3-methylimidazolium ethylsulfate that have also been measured under pseudo-steady state conditions. In continuous operation, where CO2 is absorbed and stripped in series, steady-state was achieved in approximately 15 h. Due to the higher concentration of CO2 in the liquid under steady-state conditions, the value of Koverall decreased to (1.80 ± 0.1) × 10−5 m s−1, with a CO2 removal rate of 2.89 × 10−3 g m−2 s-1. The effects of several parameters on the steady-state CO2 capture rate, namely vacuum pressure of regeneration and liquid flow through the contactor were studied. Several factors were found to affect the stability of the overall CO2 removal rate, including H2O loss from the aqueous solution. With the utility and flexibility of the designed system, we have demonstrated that PILs are certainly worthy of further investigation as CO2 capture agents for a range of applications.

Modified UNIFAC-Lei Model for Ionic Liquid–CH4 Systems

The modified UNIFAC-Lei model (Mod. UNIFAC-Lei) is proposed for the first time for ionic liquid (IL)–methane (CH4) systems over a wide temperature and pressure range. The group binary interaction parameters were obtained by correlating the experimental solubility data of CH4, both from the literature and that measured in this work. The CH4 solubility in common pure ILs and mixed ILs at temperatures down to 243.15 K was measured to determine unknown solubility data at low temperatures. The Mod. UNIFAC-Lei model can be used to predict CH4 solubility in both pure and mixed ILs, at either high or low temperatures. Moreover, it is interesting to find that cations and anions in complementary IL pairs ([C1][A1] + [C2][A2] or [C2][A1] + [C1][A2]) with equimolar amounts can be freely exchanged. A low temperature is favorable for increasing both the solubility of CH4 and the selectivity of CH4 to CO2 in ILs.

Electrical Response of a New Lipophilic Ionic Liquid and the Effect of CO2 on Its Conductivity Mechanism

Ionic liquids (ILs) have drawn sustained attention in the last twenty years due to their unique combination of intrinsic conductivity, very low vapour pressure and their ability to be tailored to an application via facile chemical modification [1]. As a consequence, the development of new ILs with improved properties and an in-depth understanding of the interplay existing between structures and properties are particularly active research fields. In this report preparation and study of a new lipophilic tetraoctyl-formamidinium bis(trifluoromethanesulfonyl) imide (TOFATFSI) ionic liquid [2], will be discussed. Tetraoctyl-formamidinium (TOFA) TFSI proved to be a water-insoluble IL that is completely miscible with the lower alkanes and the solutions are ionic conductors. Therefore, we were intrigued if conductivity could be induced in an even more demanding medium, i.e. supercritical carbon dioxide (scCO2) [3,4]. Following this, the conductivity and relaxation phenomena of this new IL are revealed through the analysis of the broadband electric spectra with a particular emphasis on the effect of temperature and CO2 pressure on the IL conductivity. It is found that temperature boosts the conductivity via an increase in the charge carrier mobility. Also, CO2 absorption affects both the conductivity and the permittivity of the material due to the presence of CO2–IL interactions that modulate the nanostructure and the size of the TOFATFSI aggregates, which increases both the mobility and the density of the charge carriers. Acknowledgements The authors wish to thank the Strategic Project of the University of Padova “Materials for Membrane-Electrode Assemblies to Electric Energy Conversion and Storage Devices (MAESTRA)” for funding. V.D.N. thanks the University Carlo III of Madrid for granting him the “Catedra de Excelentia” (Chair of Excellence).