Prediction of gas solubility in battery formulations

Kolář, Petr; Nakata, Hiroaki; Shen, Junwei; Tsuboi, Akito; Suzuki, Hikaru; Ue, Makoto

doi:10.1016/j.fluid.2004.10.019

Cited by 28 publications

(8 citation statements)

References 11 publications

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“…This means that the vast majority of CO 2 accumulates in the head space of our OEMS cell (≈98%) rather than in the electrolyte (≈2%), which is actually an important prerequisite for quantitative mass spectrometry (when sampling the gas phase representative for the entire gas amount evolved in the cell). Since the Henry's law constants of H 2 , C 2 H 4 , CO, and Ar are even higher, 67 this requirement is closely met for all gases in this study. Generally speaking, the accuracy of mass spectrometer experiments for battery applications depends on the V el /V gas ratio and thus on the individual cell design.…”

mentioning

confidence: 90%

The Effect of CO₂on Alkyl Carbonate Trans-Esterification during Formation of Graphite Electrodes in Li-Ion Batteries

Strehle

Solchenbach

Metzger

et al. 2017

J. Electrochem. Soc.

103

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Apart from the often-described formation of interphases between the electrodes and the electrolyte in Li-ion batteries, changes of the bulk electrolyte also occur during cycling. In this study, we use On-line Electrochemical Mass Spectrometry (OEMS) to measure the gas evolution associated with changes in the electrolyte during the initial cycles of graphite/lithium half-cells in an electrolyte composed of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and the conducting salt LiPF 6 . The reduction of the electrolyte at the graphite surface within the first cycle is accompanied by the release of lithium alkoxides (LiOR), which initiate the conversion of the co-solvent EMC into the linear carbonates dimethyl carbonate (DMC) and diethyl carbonate (DEC). This trans-esterification can be suppressed by the use of additives such as vinylene carbonate (VC) and vinyl ethylene carbonate (VEC). Upon reduction, VC generates CO 2 , while VEC generates 1,3-butadiene. The beneficial impact of the additives arises from these gases, which scavenge the highly reactive LiOR species by forming non-reactive products. Furthermore, our results demonstrate the positive effect of CO 2 on the cell chemistry and the importance of adjusting the electrolyte volume and additive concentration with respect to the active material mass in Li-ion batteries. Li-ion batteries (LIBs) have been successfully used in electronic devices during the past 25 years. Recently, the expanding market of hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs) powered by LIBs has pushed the requirements on this technology even further.1-4 However, the application of LIBs particularly in PHEVs and BEVs is still hampered by their limited safety, thermal stability, and cycle life. Although the applied electrolyte solutions are prone to thermal decomposition, mixtures of cyclic and linear organic carbonate solvents in combination with the conducting salt LiPF 6 are widely used for LIBs. They represent an optimum between low viscosity, low vapor pressure, good salt solubility, and high conductivity. The electrolyte composition plays an important role in terms of cycle life. During the initial cycles, the electrolyte is reduced at the anode and forms a passivating layer, the so-called solid electrolyte interphase (SEI). The SEI prevents the further reduction of the bulk electrolyte by blocking the electron transport while allowing Li-ions to pass through. Its stability is thus critical for attaining long LIB cycle and storage life, 5,6 whereby electrolyte additives have been shown to substantially alter the composition of the SEI and to improve its effectiveness. 7Besides the formation of electrode interphases, also changes of the bulk electrolyte can occur during the cycling of a cell. These processes can be induced either by thermal reactions or by the dissolution and/or further reaction of reduced or oxidized electrolyte species from the anode or cathode, respectively. For example, the thermal decomposi...

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mentioning

confidence: 90%

The Effect of CO₂on Alkyl Carbonate Trans-Esterification during Formation of Graphite Electrodes in Li-Ion Batteries

Strehle

Solchenbach

Metzger

et al. 2017

J. Electrochem. Soc.

103

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“…Such underestimations can also be seen in a recent COSMO-RS calculation of CO 2 solubility in organic carbonate solvents. [16] Herein, we attempt to overcome the above deficiency by expressing gas solubility in terms of the chemical potential of the solute molecule in its gas phase m ig (T), defined at a given (low) reference pressure, for example P 0 = 1 bar (1 bar = 10 5 Pa). The chemical potential of the gas phase at a general pressure P can then be written as: Equating the left-hand-side of Equation (1) and the righthand-side of Equation (4) yields the following (nonlinear) equation for PA C H T U N G T R E N N U N G (x, T):…”

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confidence: 99%

Theoretical Screening of Ionic Liquid Solvents for Carbon Capture

Maiti

2009

ChemSusChem

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[a] With global warming established as a critical problem, it is extremely important to cut down on emissions of CO 2 into the atmosphere. Prior to sequestration, it is necessary to separate the CO 2 from its emission source, for example, flue gas in a coal-fired power plant. The few coal plants with commercial CO 2 capture capability all use processes based on chemical absorption with a monoethanolamine (MEA) solvent. Unfortunately, MEA is a nonselective solvent prone to degradation and equipment corrosion, and mandates large equipment sizes, thereby increasing costs.Ionic liquids (ILs) [1] constitute an alternative solvent system and offer distinct advantages over traditional solvents such as MEA, some of which include: (1) high chemical stability; (2) low corrosion; (3) almost zero vapor pressure (i.e., "green"); (4) supportable on membranes; [2] and (5) a huge library of anion and cation choices, which can be potentially optimized for CO 2 solubility and selectivity.Over the last few years several ILs have been experimentally demonstrated to be efficient solvents for CO 2 . [3][4][5][6][7][8] This data provides useful trends that can be used to optimize the choice of ILs for CO 2 capture. However, each new experiment costs time and money and is often hindered because a specific IL may not be readily available. Thus, it is highly desirable to have a computational/theoretical tool that can quickly and accurately compute CO 2 solubility in any solvent (as a function of pressure and temperature). Atomic-level simulations, either molecular dynamics or binding-energy calculations, can provide useful insights into the interactions of CO 2 with the cation and the anion. [9][10][11] However, an accurate computation of solubility in such complex fluids faces many challenges, including accurate force-field development, clever Monte Carlo moves, and very long simulation times required for good statistical averaging.For a fast exploration, design, and screening of effective solvents it is highly desirable to adopt a general-purpose thermodynamic approach that computes the chemical potential of a solute (CO 2 in this case) in any solvent at an arbitrary dilution. A widely used method is the "conductor-like screening model for real solvents" (COSMO-RS), [12,13] which uses the statistical distribution (histogram) of the surface charge density of individual molecules, called the s profile, to derive an expression for the ensemble-averaged Gibbs free energy of an interacting system of molecules (solute + solvent at specified mole fractions) in the condensed (liquid) phase. From this a pseudochemical potential (m) of each species (i.e., the Gibbs free energy per molecule without the mixing entropy contribution) is obtained. If the pseudo-chemical potential of a solute molecule at a temperature T in a solution containing a mole-fraction x of the solute is m solution A C H T U N G T R E N N U N G (x, T), and that in the solute's own liquid environment is m self (T), then assuming ideal mixing law we have under equilibrium (k...

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“…One challenge for the present application is that the solute species (CO 2 ) is dissolving not from the solid or liquid, but from the gas phase. Although, there is a standard prescription of computing gas solubility with COSMO‐RS that involves the experimental vapor pressure, this can lead to a severe overestimation of CO 2 solubility at a given pressure and temperature as compared to experimental results . Instead, we have shown that the following equation works better with consistent accuracy:

P = \frac{P^{0}}{ϕ (P, T)} x \exp [{μ_{solution} * (x, T) - μ_{i g} * (T)} / k_{normalB} T]

where x is the molar solubility at pressure P and temperature T ,

ϕ (P, T)

is the fugacity coefficient of the dissolving gas, and μ ig * is the dilute‐limit pseudo‐chemical potential of the ideal dissolving gas defined at a low reference pressure of P 0 = 1 bar.…”

Section: Examples Of Molecular Modeling In Carbon Capturementioning

confidence: 94%

Atomistic modeling toward high-efficiency carbon capture: A brief survey with a few illustrative examples

Maiti

2013

Int. J. Quantum Chem.

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With the negative environmental implications of the anthropogenic emission of greenhouse gases like CO 2 having been scientifically established, emphasis is being placed on a concerted global effort to prevent such gases from reaching the atmosphere. Especially important are capture efforts at large point emission sources like fossil fuel power generation, natural gas processing, and various industrial plants. Given the importance and scale of such activities, it is a significant priority to optimize the capture process in terms of speed, energy requirements, and cost efficiency. For CO 2 capture, in particular, multiple systems are being pursued both with near-term retrofitting and medium-to long-term designs in mind, including: (1) liquid solvents like amines, carbonates, and ionic liquids (ILs); (2) microporous sorbents like zeolites, activated carbon, and metal-organic frameworks; (3) solid sorbents like metal-oxides and ionic clays; and (4) polymeric and inorganic membrane separators. Each system is unique in its molecularlevel guest-host interactions, chemistry, heats of adsorption/ desorption, and equilibrium thermodynamic and transport properties as a function of loading, temperature, and pressure. This opens up exciting opportunities for molecular modeling in the design and optimization of materials systems. Here, we offer a brief survey of molecular modeling applications in the field of carbon capture, with a few illustrative examples from our own work primarily involving amine solutions and ILs. Important molecular dynamics, Monte Carlo, and correlationsbased work in the literature relevant to CO 2 capture in other systems are also discussed.

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Prediction of gas solubility in battery formulations

Cited by 28 publications

References 11 publications

The Effect of CO₂on Alkyl Carbonate Trans-Esterification during Formation of Graphite Electrodes in Li-Ion Batteries

The Effect of CO₂on Alkyl Carbonate Trans-Esterification during Formation of Graphite Electrodes in Li-Ion Batteries

Theoretical Screening of Ionic Liquid Solvents for Carbon Capture

Atomistic modeling toward high-efficiency carbon capture: A brief survey with a few illustrative examples

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Prediction of gas solubility in battery formulations

Cited by 28 publications

References 11 publications

The Effect of CO2on Alkyl Carbonate Trans-Esterification during Formation of Graphite Electrodes in Li-Ion Batteries

The Effect of CO2on Alkyl Carbonate Trans-Esterification during Formation of Graphite Electrodes in Li-Ion Batteries

Theoretical Screening of Ionic Liquid Solvents for Carbon Capture

Atomistic modeling toward high-efficiency carbon capture: A brief survey with a few illustrative examples

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Product

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The Effect of CO₂on Alkyl Carbonate Trans-Esterification during Formation of Graphite Electrodes in Li-Ion Batteries

The Effect of CO₂on Alkyl Carbonate Trans-Esterification during Formation of Graphite Electrodes in Li-Ion Batteries