LiOH Concentration Research Articles

Properties of Li1.3Al0.7Ti1.3(PO4)3 Ceramic Solid Electrolyte Densified by Cold Sintering Process

Replacing a flammable organic liquid electrolyte with a non-flammable solid electrolyte is the most promising way to improve the safety of Li-ion batteries. Oxide-based solid electrolytes have the advantages of good chemical stability and ease of handling, but for many of them, the high temperature sintering is required for densification and reduction of grain-boundary resistance for Li-ion conduction. However, co-sintering with electrode active materials at high temperature for fabrication of solid state batteries may cause side reactions and increase the internal resistance.1 Cold sintering (CS) is an attractive process for lowering the densification temperature of various ceramic materials.2 - 7 In this study, we applied CS for the densification of Li-ion conductive Li1.3Al0.7Ti1.3(PO4)3 (LATP) ceramic electrolyte. LATP powder was mixed with proper amount of deionized water or LiOH solution with various concentration as a transient liquid phase (TLP) and densified by CS at 200-250 °C for 0.5 h under uni-axial pressure of 600 MPa. After CS, the relative density of LATP pellet was increased to 85-90 %, and LiOH addition to TLP is effective for increasing the density. Grain size of LATP in the pellet is 0.5-1 µm and nanoparticle precipitation was observed near the grain-boundary area. Similar microstructure is confirmed in previous works.2 - 7 XRD measurements reveal the formation of LiTiOPO4 phase after CS. The amount of LiTiOPO4 phase tends to increase with LiOH concentration. It is thought that this heterogeneous phase precipitate during CS process and plays a role in bonding between LATP particles.From impedance measurement, we obtained ionic conductivity of 4 × 10-5 S/cm at room temperature in LATP densified at 250 °C by CS with TLP with an optimum LiOH concentration, which is higher than LATP densified by CS with TLP without LiOH (1.7 × 10-5 S/cm) and pressed LATP powder without adding TLP (3.6 × 10-7 S/cm). However, the conductivity of LATP by CS is lower than LATP sintered at 1000 ºC (= 2.3 × 10-4 S/cm). To improve ionic conducting property further, controlling the amount of precipitation phases after CS is necessary.This work was supported by Grant-in-Aid for Scientific Research (JSPS KAKENHI) Grant Number 22K18793 from the Japan Society for the promotion of Science (JSPS), and Innovative Elemental Technology Research in Green Technologies for Excellence (GteX) Program Grant Number JPMJGX23S7 of the Japan Science and Technology Agency (JST).References P. Jiang et al., Energy Technol. 11, 2201288 (2023).J. Guo et al., Angew. Chem., Int. Ed. 55, 11457-11461 (2016).J-H. Seo et al., Ceram. Internat. 43, 15370-15374 (2017).J-H. Seo et al., Jpn. J. Appl. Phys. 60, 037001 (2021).N. Hamao et al., Materials 14, 4737 (2021).N. Hamao et al., Chem. Lett. 50, 1784-1786 (2021).A. Mormeneo-Segarra et al., Ceram. Internat. 49, 36497-36506 (2023).

Investigation of the corrosion behavior of 29NC alloy in LiCl-KCl melt at 500 oC depending on the content of Li2O and LiOH from 0 to 2 mol. %

Molten chloride salt electrolytes are promising for use as a working medium for the implementation of high-temperature technologies. Alkali metal chlorides are an aggressive environment in relation to structural materials. One of the possible methods of reducing the corrosion damage of a structural material is the method of oxygen passivation of the surface of a metal or alloy by introducing a certain amount of oxygen-containing additives into the melt. The article considers the effect of oxygen-containing impurities (lithium oxide and lithium hydroxide) on the corrosive behavior of a metal material — an alloy of the composition iron–cobalt–nickel. To assess the corrosion resistance of materials, gravimetric analysis, micro-X-ray spectral analysis (XRSA) of the surface and cross-section sections, and X-ray phase analysis (XRF) of the sample surface were used. The dependences of the corrosion rate of the material on the concentration of oxygen-containing additives Li2O and LiOH are presented. Based on the data set of gravimetric, MRSA and XRF data, it was found that 29NC alloy samples in the LiCl–KCl–nLi2O salt melt are not susceptible to corrosion, but in the LiCl–KCl–nLiOH melt, the speed of the 29NC alloy increases significantly due to the interaction of the LiOH additive with the most electronegative component of the alloy — iron.

In the LiCl-KCl melt at 500<sup>о</sup>С depending on the content of Li<sub>2</sub>О и LiOH

Molten alkali metal chlorides used in pyrotechnologies are aggressive corrosive agents. The high operating temperature of the process, the heterogeneity of the environment, and the significant corrosion activity of the molten salt necessitate both the search for stable structural materials and the development of methods for protecting the structural elements of high-temperature technological devices. Corrosion loss reduction techniques traditionally used in low temperature environments are not applicable at high temperatures. The article examines the influence of oxygen-containing impurities (lithium oxide and hydroxide) on the corrosion behavior of metallic nickel (grade NP1) – the main component of candidate structural alloys, a thermodynamically and structurally stable material in the melt for the process of electrolytic refining of spent nuclear fuel. A method for preparing the LiCl–KCl salt electrolyte and obtaining lithium oxide by thermal decomposition of anhydrous lithium hydroxide under vacuum is described, and the concentrations of impurities in the electrolyte and the synthesized lithium oxide are determined. An installation for conducting corrosion tests in an inert atmosphere of a glove box is presented. To assess the corrosion resistance of the material, the following were used: gravimetric analysis, X-ray diffraction analysis of the surface and cross-sectional sections, and X-ray diffraction analysis of the surface of the samples. The dependences of the corrosion rate of the material on the concentration of oxygen-containing additives Li2O and LiOH were obtained. Based on a combination of gravimetric, X-ray microspectral and X-ray phase analysis data, it was established that metallic nickel samples demonstrate high corrosion resistance in the studied melts with the introduction of Li2O and LiOH additives.

Bipolar Membrane Capacitive Deionization for the Selective Capture of Lithium Ions from Brines and Conversion to Lithium Hydroxide

Meeting the increasing demand for lithium in vehicle electrification and renewable energy storage requires innovations in lithium-ion (Li+) separations. Traditional solar evaporation methods for lithium recovery are slow and consume tremendous volumes of water and secondary chemicals (acids and bases). This study introduces a bipolar membrane capacitive deionization (BPM-CDI) unit for direct lithium extraction and LiOH production without the external addition of acids and bases. Utilizing de-lithiated lithium-iron-phosphate (LFP) coated carbon cloth electrodes, the BPM-CDI unit demonstrates selective Li+ capture over competing ions. Molecular dynamics simulations and H-cell experiments elucidate pH inversion mechanisms during Li+ release, yielding LiOH. The BPM-CDI platform efficiently removes Li+ from synthetic brines featuring 8x higher Mg2+ concentrations (200 ppm Mg2+) and 26x higher Na+ concentrations (682 ppm Na+), achieving a LiOH concentration of 124 ppm (36 ppm Li+) after 8 cycles of recirculation. Post-mortem analysis confirms electrode integrity and stability. BPM-CDI integrated with selective electrodes is a promising electrochemical separation-reactor platform for lithium recovery while producing LiOH.

Designing of low-temperature high performance semiconductor ionic fuel cells based on molten hydroxide percolation network

A low-temperature high performance semiconductor ionic membrane fuel cell (SIMFC) featuring a γ-Al2O3/NCAL symmetrical electrode and a ceria-based Li0.85Na0.15OH/Mg0.1Al0.2Ce0.7O2-δ (LNCMA) electrolyte has been designed. This device attains a maximum power density (MPD) of 1111 mW/cm2 and demonstrates stability for nearly 40 h at 550 ℃. Additionally, the system remains operational at 350 ℃, delivering an excellent MPD of 114 mW/cm2. The amazing research can be attributed to a molten network of hydroxide that serves as a highway for oxygen ion interface conduction, leading to an enhancement in the ionic conductivity and a reduction in ohmic impedance of the SIMFC. In the testing environment of this newly developed SIMFC device, the γ-Al2O3/NCAL electrode provides a protective effect on LiOH, enabling higher concentrations of molten LiOH to be retained and percolated into the electrolyte. Subsequently, the composite Li0.85Na0.15OH directly introduced into LNCMA melts and readily connects with LiOH from the anode, forming a molten network. As a result, the SIMFC, designed based on the concept of the molten hydroxide percolation network, achieves improved fuel cell performance and enables the operation of the SIMFC even at 350 ℃. This study showcases a convenient method for constructing a molten hydroxide percolation network, which provides the necessary low-temperature conductivity required for SIMFCs.

Formation and Detriments of Residual Alkaline Compounds on High-Nickel Layered Oxide Cathodes.

High-nickel layered oxides LiNixM1-xO2 (x≥0.9) have emerged as promising cathode materials for automotive batteries due to their high energy density and lower cost. However, the formation and accumulation of surface alkaline compounds during storage hinder their mass production and commercialization. Here, a validated chemical method is employed to deconvolute and quantify the evolution of each residual lithium compound in four representative cathodes during ambient-air storage, viz., LiNiO2 (LNO), LiNi0.95Co0.05O2 (NC), LiNi0.95Mn0.05O2 (NM), and LiNi0.95Al0.05O2 (NA). Furthermore, the activation energy of the reaction between water and the cathode is determined by measuring the leached LiOH concentration at various temperatures. While residual lithium and time-of-flight secondary-ion mass spectrometry measurements collectively reveal that the air stability overall follows the trend of NM>NA≈NC>LNO, the aged NM exhibits the highest charge-transfer resistance and the worst electrochemical performance among the cathodes. In situ, X-ray diffraction and scanning transmission electron microscopy unveil that the aged NM is plagued by a large area of resistive spinel-like M3-xLixO4 phases, leading to aggravated particle reaction heterogeneity. Finally, a one-step recalcination method is demonstrated effective in fully restoring the degraded cathodes. This work provides insights into overcoming air sensitivity issues of high-Ni cathodes.

Experimental, RSM modelling, and DFT simulation of CO2 adsorption on Modified activated carbon with LiOH

This research investigates the enhancement of CO2 adsorption capacity through the use of modified activated carbon (AC) with LiOH, focusing on operational conditions and adsorbent properties. Response Surface Methodology (RSM) is employed to optimize process parameters for maximizing CO2 adsorption capacity. The study considers temperature, pressure, LiOH concentration for modification, and adsorbent weight as independent variables across five levels. Analysis of Variance reveals that LiOH concentration, adsorbent quantity, pressure, and temperature significantly influence CO2 adsorption. Optimal values for temperature (30°C), pressure (9 bar), LiOH concentration (0.5 mol/L), and adsorbent weight (0.5 g) result in a maximal CO2 adsorption capacity of 154.90 mg/g. Equilibrium adsorption capacity is utilized for modeling, with the Freundlich model proving suitable for CO2 adsorption on LiOH-AC. Kinetic modeling indicates the second-order model's suitability for temperatures of 30 °C and 50 °C, while the Elovich model fits temperatures of 70 °C and 90 °C. Thermodynamic modeling at the optimized conditions (303 K and 6 bar) yields ∆H, ∆S, and ∆G values of adsorption as 12.258 kJ/mol, − 0.017 kJ/mol·K, and − 7.031 kJ/mol, respectively. Furthermore, structural considerations of AC are discussed alongside modeling and simulation, presenting the adsorption rate of CO2 and the binding energy index based on Density Functional Theory (DFT).

Corrosion and fretting-corrosion behavior of Zr-Nb alloy under aqueous LiOH solution

Zirconium alloys are the key materials for nuclear reactor’s core components due to low neutron cross-section and good mechanical and corrosion properties. During operation in nuclear reactor, some core components (exposed to the corrosive environment of coolant water having LiOH) may undergo corrosion and fretting-corrosion. This work presents a novel experimental approach for investigating the Zr-2.5 Nb alloy's corrosion and in-situ fretting-corrosion response. The corrosion analysis was performed using Electrochemical Impedance Spectroscopy (EIS) and potentiodynamic polarization, to study the effect of LiOH concentration in water and exposure duration. It is observed that the corrosion rate increases with increasing the concentration of LiOH in water and decreases with increasing the exposure duration. The fretting-corrosion tests were performed between SS-410 and Zr-2.5 Nb in aqueous LiOH solution. The results reveal that the contact resistance and coefficient of friction (COF) decrease with increasing concentration of LiOH in the solution. The present work highlights the scientific understanding of corrosion and fretting-corrosion phenomena in zirconium alloy and elucidates key mechanisms and factors governing the degradation behavior which can help in preventing the failure of the components.

Impact of Li-ions and CO2 on the electrochemical efficiency of Al and Al-4%Sn in KOH electrolyte for alkaline batteries application

This study investigates the electrochemical behavior of aluminum (Al) and aluminum‑tin (Al-Sn) alloy as anodes in aluminum-air (Al-air) batteries in a potassium hydroxide (KOH) electrolyte with varying concentrations of lithium hydroxide (LiOH), in both the presence and absence of carbon dioxide gas (CO2). Experimental techniques such as potentiodynamic polarization (Tafel behavior), galvanostatic charging-discharging processes, and electrochemical impedance spectroscopy (EIS) were employed. Characterization techniques including X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) were utilized to analyze the surface products of each electrode. The findings indicate a significant decrease in the corrosion current density (icorr.) for both two electrodes with increasing LiOH concentration, however, Al-Sn exhibits lower values than those of commercial Al. Moreover, the presence of Li-ions revealed an interesting phenomenon of Al, where icorr. gradually decreased with temperature rise. Also, in the presence of CO2, icorr. significantly decreased for both two electrodes, particularly Al-Sn, indicating complete repression of the corrosion process on the surface. The corrosion rate of the studied electrodes in basic solutions, with and without CO2, follows the order: KOH > KOH + LiOH > KOH + LiOH + CO2. Galvanostatic charge-discharge measurements demonstrated higher capacity, improved electrochemical performance, and excellent charge-discharge behavior in the presence of LiOH. The electrochemical findings align well with the results from XRD, SEM, and EDX analysis.

Non-stoichiometry and electrochemical properties of lithiated iron hydroxysulfides.

LiFeOHS is a material with Li2(OH)2 layers intercalated between Fe2S2 planes. Its hydrothermal synthesis in various concentrations of LiOH yields materials with a high non-stoichiometry of the Li/Fe ratio which can be explained by partial substitution of Li+ for Fe2+ in the Li2(OH)2 layers. Thermogravimetry, X-ray diffraction and Mössbauer studies indicate that the charge balance is obtained by substitution of hydroxyl ions OH- by oxide ions O2-. This material has been tested as an electrode for lithium-ion batteries against lithium metal. Specific capacities above 200 mA h g-1 at C/10 are achieved, involving 1 lithium per chemical formula when cycled between 1 V and 3 V vs. lithium. The first irreversible discharge leads to the insertion of one lithium atom and the evolution of hydrogen gas while iron remains in its +2-oxidation state. An original Li2OFeS oxysulfide is formed. The following reversible oxidation/reduction cycles involve the Fe3+/Fe2+ redox couple between the two limiting compositions: Li2OFeIIS and LiOFeIIIS.

Corrosion protection and failure mechanism of ZrO2 coating on zirconium alloy Zry-4 under varied LiOH concentrations in lithiated water at 360 °C/18.5 MPa

Maintaining a good corrosion resistance in primary coolant loop during normal operations is a prerequisite for ZrO2 as a protective coating on zirconium alloy cladding. Research on corrosion performance of ZrO2 coating in nuclear water chemistry is relatively deficient, and existing reports failed to provide an in-depth explanation for the failure causes of ZrO2 coating. Here, we proposed a detailed corrosion process of ZrO2 coating in lithiated water at 360 °C and 18.5 MPa based on experimental study and molecular dynamics simulation. The protective effect and failure mechanism of ZrO2 coating on Zry-4 under varied LiOH concentrations was further revealed. ZrO2 coating provided a favorable corrosion protection with the occurrence of localized corrosion at low LiOH concentrations. Factors influencing the corrosion resistance include pitting corrosion extension, enhanced Li+ permeation, short-circuit diffusion of O2– and ZrO2 phase transformation. In highly-concentrated LiOH solutions, intergranular corrosion, internal oxidation and perforation result in coating failure. Zr ions were released to the coating surface to form flocculent ZrO2 and ZrO2 clusters due to the strong diffusion and dissolution tendency of α-Zr in the Zry-4 substrate. This work can give some references to understand the service behavior of nuclear coatings under variable water chemistry conditions and promoting in-pile application of ZrO2 coating.

Synthesis of Single Crystal Li2NpO4 and Li4NpO5 from Aqueous Lithium Hydroxide Solutions under Mild Hydrothermal Conditions.

The ternary oxides, Li2NpO4 and Li4NpO5, were synthesized under mild hydrothermal conditions using concentrated LiOH solutions containing NpO2(NO3)2. The reactions resulted in the formation of single crystals of both compounds, enabling the determination of their single crystal structures for the first time. Exploration of the synthetic phase space demonstrates that the resulting neptunate phases are dependent on the concentration of LiOH, transitioning from Li2NpO4, containing a typical octahedral neptunyl geometry with two shorter Np≡O bonds, at lower LiOH concentrations to Li4NpO5 with two long and four short Np-O bonds under saturated solution conditions. Reactions exploring the same synthetic conditions are also reported for uranyl(VI) for comparison. Raman spectra of the compounds were collected and analyzed to evaluate the Np-O bonding in these compounds.

Effect of Electrolyte Concentration on the Electrochemical Performance of Spray Deposited LiFePO4.

LiFePO4 is a common electrode cathode material that still needs some improvements regarding its electronic conductivity and the synthesis process in order to be easily scalable. In this work, a simple, multiple-pass deposition technique was utilized in which the spray-gun was moved across the substrate creating a "wet film", in which-after thermal annealing at very mild temperatures (i.e., 65 °C)-a LiFePO4 cathode was formed on graphite. The growth of the LiFePO4 layer was confirmed via X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. The layer was thick, consisting of agglomerated non-uniform flake-like particles with an average diameter of 1.5 to 3 μm. The cathode was tested in different LiOH concentrations of 0.5 M, 1 M, and 2 M, indicating an quasi-rectangular and nearly symmetric shape ascribed to non-faradaic charging processes, with the highest ion transfer for 2 M LiOH (i.e., 6.2 × 10-9 cm2/cm). Nevertheless, the 1 M aqueous LiOH electrolyte presented both satisfactory ion storage and stability. In particular, the diffusion coefficient was estimated to be 5.46 × 10-9 cm2/s, with 12 mAh/g and a 99% capacity retention rate after 100 cycles.

Separation of lithium chloride from ammonium chloride by an electrodialysis-based integrated process

Li+ and NH4+ have the same charge, valence, and similar ionic hydration radii. Hence, it is challenging to separate them through individual electrodialysis. Herein, an electrodialysis (ED)-based integrated process is proposed to separate Li+ from the mixed solution of LiCl and NH4Cl and simultaneously generate a concentrated LiOH solution. First, bipolar membrane electrodialysis (BMED) converts the mixed solution into the alkali solution of LiOH and NH3·H2O. The BMED performance was investigated by varying the operating parameters. The results show that the BMED membrane stack with the BP-A-C configuration performs better than the one with the BP-C configuration. A solution of 2.16 mmol/L LiOH and 0.05 mol/L NH3·H2O, selected as the initial alkali solution for the alkali tank, can reduce the energy consumption from 88.51 to 83.45 kW·h/kg, and improve the current efficiency from 53.45% to 56.69% slightly. Reducing the initial volume ratio of the alkali solution to the feed can concentrate the generated alkali solution and increase the LiOH conversion ratio simultaneously. Furthermore, reducing the initial feed concentration can efficiently improve the BMED performance. A maximum LiOH conversion ratio of 97.10% can be achieved in the BMED process. Second, ammonia removal with direct air stripping (AR-DAS) process is performed on the mixed alkali solution of LiOH and NH3·H2O to remove the ammonia and obtain the pure LiOH solution. The results show an ammonia removal ratio of more than 99%. Third, conventional electrodialysis (CED) concentrates the LiOH solution. Effects of the applied voltages and initial LiOH solution concentrations on the CED performance were investigated. The results show that a higher applied voltage increases energy consumption, while a higher initial LiOH solution concentration improves the LiOH concentration ratio. A maximum LiOH concentration ratio of 2.19 can be achieved in the CED process. Moreover, through analysis, the final solid products, generated by evaporation and crystallization, are LiOH·H2O crystals with the purity of 94.3 ± 3.56%. This work suggests that the ED-based integrated process is a highly effective approach to separating the mixed salt solutions of Li+ and NH4+.

Synthesis, characterization, and effect of electrolyte concentration on the electrochemical performance of Li2Cu(WO4)2 as a high-performance positive electrode for hybrid supercapacitors

In the present work, a polycationic dilithium copper bis(tungstate) oxide was prepared. The electrochemical performances of the synthesized material were evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), galvanostatic charge-discharge (GCD), and cyclic stability studies. First, the electrochemical performance of the Li2Cu(WO4)2 electrode was studied in lithium hydroxide electrolyte with different concentrations 1, 2, 3, 4, and 5 M. A mechanism of electrochemical OH-ions intercalation in different concentrations of LiOH into the Li2Cu(WO4)2 electrode material was studied. This study showed that the Li2Cu(WO4)2 electrode has a specific capacity that varies with the concentration of the electrolyte. The 4 M LiOH electrolyte showed a maximum capacity value of 505C/g at a current density of 5 A/g, indicating that the electrolyte concentration effects on the electrochemical performance of the electrode. The results showed that the Li2Cu(WO4)2 electrode had a specific capacity of 722C/g at 1 A/g in the 4 M LiOH electrolyte. The electrode shows excellent retention of 80.7 % of its initial specific capacity after 10,000 galvanostatic charge-discharge cycles at 20 A/g. In addition, the hybrid supercapacitor device is further fabricated with activated carbon as cathode materials and a Li2Cu(WO4)2 electrode as the anode and improved a high energy density of 69.6 Wh/kg at a power density of 900 W/kg as well as an excellent retention capacity (84.8 %) after 10,000 cycles at 10 A/g.

Electrodialysis of Lithium Sulphate Solution: Model Development and Validation

A comprehensive mathematical model is proposed to study the transport phenomena in an Electrodialysis (ED) process employed to recover lithium hydroxide and sulfuric acid from the lithium sulphate solution derived from a recycling process of spent lithium-ion battery material. The model is developed based on the conservation equations of mass and ions, and considers electrolyte solutions consisting of mono- and multivalence ions. The concentration polarization at ion exchanged membranes (IEMs) and their adjacent diffusion boundary layers as a function of the applied current, inlet concentrations and flow rate are computed. Experimental data from a three-compartment ED cell are used for validation. A parametric study is performed to evaluate the impact of parameters on transmembrane fluxes of ion and water. It is revealed that increasing current leads to the enhancement of the transmembrane water and concentration polarization across IEMs. Feeding solutions consisting of smaller ions result in lower water transfer through IEMs. Raising the lithium concentration at the dilute channel increases the LiOH concentration due to reduced transmembrane water transfer. Using the uncertainty propagation method, it is found that current and counter-ion radius are the most influential parameters affecting the outlet concentration of concentrate channel and transmembrane water transfer.

In situ growth of Li4Ti5O12 nanoparticles on Ti3C2Tx MXene for efficient electron transfer as high-rate anode of Li ion battery

How to prepare monodispersed Li4Ti5O12 (LTO) nanoparticles and build effective interface with conductive matrix are significant for its high-rate performance, but still big challenges to be fulfilled well now. Herein, we successfully prepared monodispersed LTO nanoparticles on Ti3C2Tx MXene (M-LTO) in situ through a natural oxidation and hydrothermal lithiation process. The mild oxidation and proper LiOH concentration are proved critical to control the states of final products. Oriented growth was found between LTO and Ti3C2Tx MXene, i.e., LTO [110]//Ti3C2Tx [001], indicating the presence of in-situ interface. It is very effective to facilitates the electron transfer between collector/LTO interface, which exhibited low electron polarization resistance, and helped M-LTO samples achieve higher capacity retention than LTO-Ti3C2Tx mixture and pure LTO. Typically, M-LTO-8 sample delivered a reversible capacity of 137 mAh g−1 at 10 C and over 125 mAh g−1 at a high rate of 50 C, with a capacity retention of 87.5% after 1000 cycles at 10 C. This work highlighted the in-situ oriented growth of LTO from Ti3C2Tx MXene, revealed its advantage for high-rate performance, and provided new insights for high-rate electrode design.

Effect of process conditions on generation of hydrochloric acid and lithium hydroxide from simulated lithium chloride solution using bipolar membrane electrodialysis

A feasibility study was carried out on generation of hydrochloric acid and lithium hydroxide from the simulated lithium chloride solution using EX3B model bipolar membrane electrodialysis (BMED). The influence of a series of process parameters, such as feed concentration, initial acid and base concentration in device component, feed solution volume, and current density were investigated. In addition, the maximum achievable concentrations of HCl and LiOH, the average current efficiency, and specific energy consumption were also studied and compared in this paper to the existing literature. Higher LiCl concentrations in the feed solution were found to be beneficial in increasing the final concentrations of HCl and LiOH, as well as improving current efficiency while decreasing specific energy consumption. However, when its concentration was less than 4 g/L, the membrane stack voltage curve of BMED increased rapidly, attributed to the higher solution resistance. Also low initial concentration of acid and base employed in device component can improve the current efficiency. Increasing of the initial concentration of acid and base solution lowered energy consumption. Moreover, a high current density could rapidly increase HCl and LiOH concentration and enhance water movements of BMED process, but reduced the current efficiency. The maximum achievable concentration of HCl and LiOH generated from 130 g/L LiCl solution were close to 3.24 mol/L and 3.57 mol/L, respectively. In summary, the present study confirmed the feasible application for the generation of HCl and LiOH from simulated lithium chloride solution with BMED.

Application and Analysis of Bipolar Membrane Electrodialysis for LiOH Production at High Electrolyte Concentrations: Current Scope and Challenges.

The objective of this work was to evaluate obtaining LiOH directly from brines with high LiCl concentrations using bipolar membrane electrodialysis by the analysis of Li+ ion transport phenomena. For this purpose, Neosepta BP and Fumasep FBM bipolar membranes were characterized by linear sweep voltammetry, and the Li+ transport number in cation-exchange membranes was determined. In addition, a laboratory-scale reactor was designed, constructed, and tested to develop experimental LiOH production tests. The selected LiCl concentration range, based on productive process concentrations for Salar de Atacama (Chile), was between 14 and 34 wt%. Concentration and current density effects on LiOH production, current efficiency, and specific electricity consumption were evaluated. The highest current efficiency obtained was 0.77 at initial concentrations of LiOH 0.5 wt% and LiCl 14 wt%. On the other hand, a concentrated LiOH solution (between 3.34 wt% and 4.35 wt%, with a solution purity between 96.0% and 95.4%, respectively) was obtained. The results of this work show the feasibility of LiOH production from concentrated brines by means of bipolar membrane electrodialysis, bringing the implementation of this technology closer to LiOH production on a larger scale. Moreover, being an electrochemical process, this could be driven by Solar PV, taking advantage of the high solar radiation conditions in the Atacama Desert in Chile.

Effect of Li+ on the composition and morphology of C-A-S-H

In this paper, C-A-S-H with different Li contents have been synthesized by hydrothermal method at 95℃. Incorporation of Li decreases mean interlayer distance, increases crystallinity and polymerization degree of C-A-S-H. The specific surface area of C-(Li)-A-S-H decreases sharply with the addition of LiOH. What’s more, katoite forms on the surface of C-(Li)-A-S-H and results in the change of pore structure at high LiOH concentrations. The results show that Ca/Li ratio is the key parameter for Li incorporation into C-A-S-H.