LiCl NaCl Research Articles

Thermodynamic Model of the H2O–LiCl–NaCl System for Study of Fluid Inclusions: Calculations Using the Pitzer Equations

Thermodynamic Model of the H2O–LiCl–NaCl System for Study of Fluid Inclusions: Calculations Using the Pitzer Equations

How cell design affects the performance of sodium-antimony-bismuth liquid metal batteries

Low-cost sodium-based liquid metal batteries are attractive candidates for grid-scale stationary energy storage. In this study, the performance of Na//SbBi9 test cells with molten salt electrolyte LiCl–NaCl–KCl (61-3-36 mol%) is evaluated for different cell designs. Cells with a metal foam hosting the negative electrode (5–6 Ah nominal capacity) and cells without foam are investigated. Additionally, the amount of electrolyte and the material used as positive current collector (PCC) are varied. The self-discharge current is only ∼0.35 mA/cm2 and depends reasonably on electrode distance and operating temperature. Contact resistances are 10 mΩ in total and thus smaller than the ohmic resistance of the electrolyte. The cell voltage is not affected by cell design, operating temperature, or cell age. Long-term cycling tests show a capacity decrease, which can be attributed to evaporation of Na. An additional capacity loss observed in cells with stainless steel PCC can be avoided by using Mo as PCC.

Electrodriven Chemical Looping Ammonia Synthesis Mediated by Lithium Imide

The chemical looping process for ammonia synthesis (CLAS) has advantages in avoiding competitive adsorptions of nitrogen and hydrogen and optimizing the thermodynamics and kinetics of a reaction step by step. Nitrogen carriers with favorable thermodynamic and kinetic properties are critical for such a process, especially under mild conditions. Recent studies have shown that alkali- and alkaline-earth-metal imides are attractive nitrogen carriers; however, the equilibrium concentration of NH3 in the hydrogenation of imides to ammonia and hydrides is low at atmospheric pressure. Moreover, the reaction rate of nitrogen fixation on the hydrides is slow. Here, we show that an electrodriven CLAS (ECLAS) mediated by a lithium imide is feasible in a LiCl–NaCl–KCl eutectic electrolytic cell with a nickel-foam electrode. We demonstrate that the reactions of lithium imide hydrogenation and lithium hydride nitridation are both promoted by the input of electric energy. The average ammonia production rate over such an electrodriven CLAS is ca. 8 times higher than that of a thermal-driven CLAS.

Design and development of novel LiCl–NaCl–KCl–ZnCl2 eutectic chlorides for thermal storage fluids in concentrating solar power (CSP) applications

Molten chloride mixtures are of great scientific and technical interest for sensible heat storage in solar power generation. In this work, the condensed phases in a LiCl–NaCl–KCl–ZnCl 2 multicomponent system were critically evaluated and predicted via literature review and simulations of LiCl–KCl and KCl–ZnCl 2 systems. Two innovative LiCl–NaCl–KCl–ZnCl 2 quaternary chloride systems with low melting points were proposed and developed on the basis of a thermodynamic design. The thermal–physical properties of these two eutectic compositions, including melting point, mixing enthalpy, specific heat capacity, density, thermal conductivity, and mass loss, were then experimentally determined. The experimental results were consistent with the theoretical predictions. The novel quaternary eutectic chlorides with excellent thermophysical properties developed herein are potential candidates for thermal energy storage and transfer materials in concentrating solar power plants. • Thermodynamic prediction of LiCl–NaCl–KCl–ZnCl 2 system was performed via CALPHAD. • Two novel quaternary eutectic chlorides were successfully designed for thermal energy storage and transfer. • Thermophysical properties of the system were determined by experiment and classical prediction method. • Thermodynamic performance of the novel chlorides was substantially improved compared with other potential materials. • The novel quaternary eutectic chlorides were proposed as potential candidate materials in CSP applications.

Stable phase equilibria in the quinary system LiCl–NaCl–KCl–SrCl2–H2O at 288 K

Sichuan Basin is rich in underground brines, which are important liquid mineral resources. In order to realize the exploitation and utilization of the brine resources, in this work, we used the isothermal dissolution equilibria method to study the phase equilibria of related subsystem for the underground brines. Consequently, the phase equilibria of the quinary system LiCl–NaCl–KCl–SrCl2–H2O at 288 K are studied in detail. The solubilities of salts in saturated liquid phase of the quinary system were measured by chemical analysis, and the equilibrium solid phases of the quinary system were identified by chemical analysis and X-ray powder diffraction. The phase diagrams of the quinary system LiCl–NaCl–KCl–SrCl2–H2O at 288 K were also given, and simplified dry base salt diagram, water content diagram and saturated salt content diagram of each salt saturation surface were presented respectively. The results show that the quinary system is a hydrate type. When LiCl, NaCl, KCl and SrCl2 are saturated respectively, the dry salt phase diagrams have different crystalline regions. When LiCl·2H2O is saturated, the crystalline regions are SrCl2·2H2O, NaCl and KCl; When NaCl is saturated, the crystalline regions are KCl, SrCl2·6H2O, SrCl2·2H2O and LiCl·2H2O; When KCl is saturated, the crystalline regions are NaCl, SrCl2·6H2O, SrCl2·2H2O and LiCl·2H2O; When SrCl2·6H2O is saturated, the crystalline regions are KCl, NaCl and SrCl2·2H2O.

Phase Equilibria in the Quaternary System LiCl–NaCl–SrCl2–H2O at 273 and 323 K

Phase Equilibria in the Quaternary System LiCl–NaCl–SrCl₂–H₂O at 273 and 323 K

Electrochemical properties of Ca–Pb electrode for calcium-based liquid metal batteries

The Ca–Pb electrode couple is considered to be one of the least expensive (∼36 $/(kW h)) among various optional materials for liquid–metal batteries (LMBs). The electrochemical properties of Ca–Pb alloy in a Ca∣LiCl–NaCl–CaCl2∣Pb cell were investigated in this paper. The electrode potential maintained a linear relationship in the current density range of 50–200 mA cm-2, which indicates that the alloying and dealloying processes of Ca with Pb attained rapid charge transfer and mass transport in the interface between the liquid electrode and electrolyte. The Ca–Pb electrode exhibited remarkable properties with a high discharge voltage of 0.6 V, a small self-discharge current density ( 98.84%). The postmortem analysis showed that intermetallics CaPb3 and CaPb were uniformly distributed in the electrode with different molar fractions of Ca, which indicates that the nucleation of solid intermetallics did not hinder the diffusion of Ca in the electrode. This investigation on Ca–Pb electrode sheds light on the further research and the design of electrodes for Ca-based LMBs.

Effect of Temperature on Electrodeposition of Ti in LiF – LiCl Eutectic Melt

1. Introduction Titanium metal has superior properties such as high specific strength, high corrosion resistance, biocompatibility, etc. In addition to these properties, crustal abundance of titanium is more than 40 times larger than those of commonly used copper and nickel. However, titanium is not used widely and commonly due to two problems: the high cost of present smelting method and the poor workability of itself. Therefore, both a new smelting method and a processing method are required. Plating titanium metal on an inexpensive substrate is one of the methods to resolve these problems. Electrodeposition of titanium is a promising plating method from the viewpoints of the cost and the flexibility in shape of substrate. Thus, electrodeposition of titanium metal has been investigated for a long time using high-temperature molten salts [1–4]. We have already reported that compact, smooth, and adherent titanium films are electrodeposited in molten KF–KCl and LiF–LiCl containing Ti(III) ions at 923 K [5–8]. However, crystal grains of titanium become large with the increase of a film thickness, which results in a rough surface. Concerning the crystal grain size, Wei et al. electrodeposited titanium in molten LiCl–NaCl–KCl–K2TiF6 (+ Ti metal) at 723–973 K and reported that the grain size became small as the temperature decreased [1]. This report suggests that titanium films are expected to have a smoother surface at a lower electrodeposition temperature. Therefore, in the present study, we investigated the effect of temperature on morphology and smoothness of electrodeposited titanium films in LiF–LiCl eutectic melt at 823–973 K. The effect of temperature on the electrochemical behavior of Ti(III) ions was also studied.2. Experimental The experiments were conducted in LiF–LiCl eutectic melt (LiF:LiCl = 30:70 mol%, m.p.: 774 K [9]) in an Ar glovebox. The experimental temperature was varied from 823 K to 973 K. Li2TiF6(2.00 mol%) and Ti sponge (1.33 mol%) were added to the bath and Ti(III) ions were prepared by comproportionation reaction. Ni plate, Mo flag, and Au flag electrodes were used as the working electrodes. The counter and reference electrodes were Ti rods. The potential of the reference electrode was calibrated by Li+/Li potential measured at a Mo flag electrode. Samples prepared by galvanostatic electrolysis of Ni plate substrates were analyzed by SEM/EDX after washing with distilled water to remove adhered salts.3. Results and Discussion Galvanostatic electrolysis was conducted at 823, 873, 923, and 973 K. Fig. 1 shows the optical and surface SEM images of the samples. The cathodic current density and electrolysis time were 100 mA cm−2 and 10 min, respectively. The surface roughness (Sa) was measured by SEM, which is also shown in Fig. 1. All the samples have a metallic luster. The sample at 823 K has the highest brightness with metallic luster. The surface SEM observations indicate that the crystal grain size increases as the temperature rises. This tendency is reasonably explained by a previous work on the temperature dependent grain growth of Ti [10]. The value of Sa also increases as the temperature increases. The smoothest Ti film with Sa = 2.05 ± 0.22 μm was obtained at 823 K. These results conclude that Ti film with smoother surface can be electrodeposited at a lower temperature by suppressing the grain growth of Ti. In the presentation, more detailed analysis results and the effect of temperature on the electrochemical behavior of Ti(III) ions will be discussed.Acknowledgement A part of this work was supported by JSPS Fellows grant number 19J15015. The present address of Kouji Yasuda is Graduate School of Engineering, Kyoto Univ.

Solid−liquid phase equilibria of the quinary system containing lithium, sodium, calcium, strontium and chloride ions at 273.15 K and 101.325 kPa

The solid–liquid phase equilibria of systems LiCl–NaCl–CaCl2–SrCl2–H2O and CaCl2–SrCl2–H2O at 273.15 K and 0.1 MPa were investigated with the isothermal equilibrium method. The solid–liquid equilibrium phase diagrams were constructed with the experimental solubilities. The phase diagram in the ternary system consists of one univariant solubility curve saturated with solid solution (Ca,Sr)Cl2·6H2O, and one crystallization field of the solid solution. There are three invariant points, seven isothermal univariant curves, and five crystallization regions saturated with NaCl corresponding to (Ca,Sr)Cl2·6H2O, SrCl2·2H2O, LiCl·2H2O, CaCl2·4H2O and LiCl·CaCl2·5H2O in the dry-salt diagram of the quinary system. The areas of crystallization zones decrease according to the above order. The J(NaCl), J(H2O), refractive index and density of the solution gradually change regularly with the increasing of J(CaCl2) in the solution. These results on phase diagrams of the quinary system can supply theoretical reference for lithium salts and strontium salts separation from calcium chloride type brine.

Phase Equilibria in the Ternary System NaCl–SrCl2–H2O (273 and 308 K) and Quaternary System LiCl–NaCl–SrCl2–H2O (308 K)

The phase equilibria of the ternary system NaCl–SrCl2–H2O at 273 and 308 K and quaternary system LiCl–NaCl–SrCl2–H2O at 308 K were measured by the isothermal dissolution equilibrium method. The pha...

Measurements and calculations of solid-liquid equilibria in two quaternary systems: LiCl–NaCl–SrCl2–H2O and LiCl–KCl–SrCl2–H2O at 298 K

Using the method of isothermal dissolution equilibrium, stable phase equilibria of unreported strontium-containing systems LiCl–NaCl–SrCl2–H2O and LiCl–KCl–SrCl2–H2O at 298 K have been studied in accordance with the compositions of the underground brine in western Sichuan Basin. The experimental results show that there are no solid solution and complex salt in two quaternary systems. The phase diagram of quaternary system LiCl–NaCl–SrCl2–H2O consists of two invariant points, five isothermal dissolution curves and four crystallization regions. The quaternary system LiCl–KCl–SrCl2–H2O belongs to a simple type and the phase diagram consists of two invariant points, five isothermal dissolution curves and four crystallization regions. The solubilities of salts in the above systems were accurately calculated with Pitzer electrolyte solution theory. It was found that the calculated phase diagrams coincided basically with the experimental phase diagrams by evaluated the accuracy through the experimental results. Meanwhile, the applicability of Pitzer parameters selected in this paper was validated.

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Using the method of isothermal dissolution equilibrium, stable phase equilibria of unreported strontium-containing systems LiCl–NaCl–SrCl2–H2O and LiCl–KCl–SrCl2–H2O at 298 K have been studied in accordance with the compositions of the underground brine in western Sichuan Basin. The experimental results show that there are no solid solution and complex salt in two quaternary systems. The phase diagram of quaternary system LiCl–NaCl–SrCl2–H2O consists of two invariant points, five isothermal dissolution curves and four crystallization regions. The quaternary system LiCl–KCl–SrCl2–H2O belongs to a simple type and the phase diagram consists of two invariant points, five isothermal dissolution curves and four crystallization regions. The solubilities of salts in the above systems were accurately calculated with Pitzer electrolyte solution theory. It was found that the calculated phase diagrams coincided basically with the experimental phase diagrams by evaluated the accuracy through the experimental results. Meanwhile, the applicability of Pitzer parameters selected in this paper was validated.

Stable Phase Equilibria in Quaternary LiCl–NaCl–MgCl<sub>2</sub>–H<sub>2</sub>O and NaCl–Na<sub>2</sub>B<sub>4</sub>O<sub>7</sub>–MgCl<sub>2</sub>–MgB<sub>4</sub>O<sub>7</sub>–H<sub>2</sub>O Systems at 273 K

Phase equilibria of quaternary LiCl–NaCl–MgCl2–H2O and NaCl–Na2B4O7–MgCl2–MgB4O7–H2O systems at 273 K were studied by isothermal dissolution. The isothermal solubility of each salt was measured. Based on the experimental data and the corresponding equilibrium solid phases, equilibrium phase diagrams and water content diagrams were drawn. The results show that the quaternary LiCl–NaCl–MgCl2–H2O system forms a double salt LiCl·MgCl2·7H2O at 273 K. The phase diagram contains two invariant points, five univariant curves and four crystalline regions. The crystalline regions are LiCl·2H2O, NaCl, MgCl2·6H2O and LiCl·MgCl2·7H2O, respectively. There are two invariant points, five univariant curves and four crystallizing fields in the quaternary NaCl–Na2B4O7–MgCl2–MgB4O7–H2O system at 273 K, and the corresponding crystallizing fields are NaCl, Na2B4O7·10H2O, MgCl2·6H2O and MgB4O7·9H2O.

Mineral solubilities of salts in the three quaternary systems: LiCl–NaCl–MgCl2–H2O, LiCl–KCl–MgCl2–H2O and Li2SO4–K2SO4–MgSO4–H2O at 288.15 K

In this paper, the stable phase equilibria of the quaternary systems LiCl–NaCl–MgCl2–H2O, LiCl–KCl–MgCl2–H2O and Li2SO4–K2SO4–MgSO4–H2O were studied at 288.15 K using an isothermal dissolution equilibrium method and the solubility of each system was measured. Based on experimental solubility data, the dry salt diagrams and the diagrams of water-content vs composition of three quaternary systems were plotted. In addition to the single salts, there is a double salt LiCl·MgCl2·7H2O formation at 288.15 K in quaternary system LiCl–NaCl–MgCl2–H2O. In quaternary system LiCl–KCl–MgCl2–H2O, there are two kinds of double salt LiCl·MgCl2·7H2O and KCl·MgCl2·6H2O. It has been found that LiCl has a strong salting-out effect on both NaCl and KCl, which result in NaCl and KCl having larger crystallization regions in each phase diagram. At 288.15 K, the phase diagram of quaternary system Li2SO4–K2SO4–MgSO4–H2O has phase fields of single salt Li2SO4·H2O, K2SO4 and MgSO4·7H2O, and that of double salts K2SO4·MgSO4·6H2O and Li2SO4·K2SO4. The solubilities of the three quaternary systems at 288.15 K were calculated by using the Pitzer electrolyte solution theory model. The parameters involved but not previously reported were obtained by using the solubility data of ternary subsystems and the method of multivariate linear regression. The results show that the calculated results are in good agreement with the experimental results.

Study of the Solubility, Supersolubility and Metastable Zone Width of Li2CO3 in the LiCl–NaCl–KCl–Na2SO4 System from 293.15 to 353.15K

Isothermal dissolution method and turbidity technology were employed to measure the solubility, the supersolubility, and the metastable zone width of Li2CO3 in mixed LiCl–NaCl–KCl–Na2SO4 solutions at temperatures ranging from 293.15 to 353.15 K. It was found that the solubility values of Li2CO3 increased as the Na2SO4 concentration increased and decreased as the NaCl and KCl concentrations increased. In addition, these two opposite effects both affected the solubility of Li2CO3 in mixed electrolyte solutions. NaCl and KCl impurities decreased Li2CO3 supersolubility, which could be overcome by adding a small amount of Na2SO4 salt. The influence of the impurities on the metastable zone width differed from their influence on the solubility. The metastable zone width in electrolyte solutions was mainly affected by Na2SO4 salt, where it increased with the increasing Na2SO4 concentration. Meanwhile, NaCl and KCl salts had little impact on the metastable zone width. Overall, this study provides the basic data fo...

Pitzer thermodynamic modeling study on solid–liquid equilibria of the quinary system LiCl–NaCl–CaCl2–SrCl2–H2O at 298.15 K

The Pitzer thermodynamic model for solid–liquid equilibria in the quinary system LiCl–NaCl–CaCl2–SrCl2–H2O at 298.15 K was constructed by combining the proper parameters and solubility product constants of the equilibrium solids.

Phase equilibria in system LiCl–NaCl–H2O at 308 and 348 K

The solubilities and densities of the solutions in the ternary system LiCl–NaCl–H2O at 308 and 348 K were determined by the method of isothermal dissolution equilibrium. There are one invariant point, two univariant isotherm dissolution curves, and two crystallization regions corresponding to monohydrate (LiCl · H2O) and NaCl, respectively. This system at both temperatures belongs to hydrate type I, and neither double salt nor solid solution was found. A comparison of the phase diagram for the ternary system at 273–348 K shows that the area of crystallization region of LiCl · H2O is decreased with the increasing of temperature, while that of NaCl is increased obviously. The solution density of the ternary system at two temperatures changes regularly with the increasing of LiCl concentration.

High-quality spinel LiCoTiO4single crystals with co-exposed {111} and {110} facets: flux growth, formation mechanism, magnetic behavior and their application in photocatalysis

Novel spinel LiCoTiO4 single crystals with co-exposed {111} and {110} facets were grown for the first time using a facile LiCl flux method. The obtained cubic-phase LiCoTiO4 crystals exhibit high crystallinity and regular octahedron-like geometric morphology. In this method, LiCl was used not only as an effective lithium source without any additives but also as the optimum molten medium compared with LiCl–NaCl and LiCl–KCl eutectic mixtures. The formation mechanism responsible for the flux-grown spinel LiCoTiO4 crystals with co-exposed {111} and {110} facets was also proposed. Moreover, the spinel LiCoTiO4 crystals showed a weak ferrimagnetic behavior with some antiferromagnetic effects. Photocatalytic tests revealed that the pure LiCoTiO4 sample had a relatively low photocatalytic activity although it had a relatively narrow band-gap energy (1.58 eV) corresponding well to the broad visible spectrum. However, the spinel LiCoTiO4 crystal could serve as an efficient visible-light sensitizer, and when coupled with graphitic carbon nitride (g-C3N4) nanosheets, the novel LiCoTiO4/g-C3N4 composites exhibited higher activity than pure g-C3N4 for the photocatalytic degradation of organic pollutants under simulated sunlight. A possible mechanism for the improved photocatalytic performance was also proposed. Overall, our present work opens a new approach to fabricating other lithiated transition-metal oxide spinel crystals for broad industrial applications.

Electrochemical deposition of carbon in LiCl–NaCl–Na2CO3 melts

Carbon deposition on a W cathode during the electrolysis was performed in molten LiCl–NaCl–Na2CO3 under CO2 atmosphere. The electrochemical process was investigated by cyclic voltammetry on the glass carbon electrode. The minimum energy consumption is 20.1 kWh for 1 kg of carbon. Constant voltage electrolysis combined with a real-time resolution mass spectrum demonstrated the absence of the formation of carbon monoxide even at 800 °C. The carbon products deposited at different electrolysis conditions were composed of amorphous carbon and mainly comprised of quasi-spherical carbon particles accompanied by small amounts of wire-like carbon.

Isothermal Evaporation Process Simulation Using the Pitzer Model for the Quinary System LiCl–NaCl–KCl–SrCl2–H2O at 298.15 K

In this study, the Pitzer thermodynamic model for solid-liquid equilibria in the quinary system LiCl–NaCl–KCl–SrCl2–H2O at 298.15 K was constructed by selecting the proper parameters for the subsystems in the literature. The solubility data of the systems NaCl–SrCl2–H2O, KCl–SrCl2–H2O, LiCl–SrCl2–H2O, and NaCl–KCl–SrCl2–H2O were used to evaluate the model. Good agreement between the experimental and calculated solubilities shows that the model is reliable. The Pitzer model for the quinary system at 298.15 K was then used to calculate the component solubilities and conduct computer simulation of isothermal evaporation of the mother liquor for the oilfield brine from Nanyishan district in the Qaidam Basin. The evaporation-crystallization path and sequence of salt precipitation, change in concentration and precipitation of lithium, sodium, potassium, and strontium, and water activities during the evaporation process were demonstrated. The salts precipitated from the brine in the order : KCl, NaCl, SrCl2∙6H2O, SrCl2∙2H2O, and LiCl∙H2O. The entire evaporation process may be divided into six stages. In each stage the variation trends for the relationships between ion concentrations or water activities and the evaporation ratio are different. This result of the simulation of brines can be used as a theoretical reference for comprehensive exploitation and utilization of this type ofmore » brine resources.« less