Process for recovering an alkalizing solvent

Abstract

The invention relates to a method for removing captured by-product halogen gases from anhydrous organic solvents (e.g. gamma-butyrolactone), wherein the captured substances preferably form alkali metal complexes (e.g. alkali metal perhalogenides), comprising the addition of lithium oxide or ammonia.

Description

[0001] Related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 539,160, filed September 19, 2023, and U.S. Provisional Application No. 63 / 554,290, filed September 19, 2023. The entire contents of these applications are incorporated herein by reference. Background of the Invention

[0004] Pre-lithiation methods for materials involve introducing lithium ions into the material's interior and / or surface, such as an anode. One such method includes patent number US9,598,789 by Grant et al., the entire contents of which are incorporated herein by reference. In one embodiment of this method, lithium chloride is dissolved in an anhydrous organic solvent, such as γ-butyrolactone (GBL). At the time of filing patent '798', it was believed that halide ions would form gaseous byproducts (e.g., Cl2). However, the identification of contaminants and byproducts generated during alkalization remains elusive. Ideally, the anhydrous organic solvent should be recyclable. In patent application number WO2023 / 147039, a novel method for removing contaminants using ion exchange resins was developed. While this process shows promise, the degradation of the resin over time remains a concern. Therefore, measures are needed to remove contaminants from organic solvents, particularly anhydrous organic solvents. Summary of the Invention

[0005] This invention is partly based on the discovery that during alkalization, halide ions (e.g., released in gaseous form, such as Cl2) released into an anhydrous organic solvent (e.g., GBL) can form complexes with alkali metal ions, thereby becoming trapped in the solvent, such as hyperhalide alkali metal complexes (e.g., lithium hyperhalides). This invention relates to methods for removing these trapped substances from organic solvents. In one embodiment, this invention relates to a method of contacting an organic solvent containing hyperhalide alkali metal complexes (e.g., a stream of alkali metal salts from an alkalization process) with lithium oxide (e.g., a lithium oxide suspension in a solvent). In another embodiment, this invention relates to a method of contacting an organic solvent containing hyperhalide alkali metal complexes with ammonia, for example, by injecting ammonia gas into the solvent or mixing the solvent with an ammonia-containing solvent. This invention includes a method for alkalizing materials in an anhydrous organic solvent, comprising the following steps:

[0006] (a) Providing materials;

[0007] (b) A bath comprising at least one dissolved alkali metal halide salt in an anhydrous organic solvent, wherein the bath is in contact with a material, preferably in a continuous process;

[0008] (c) Provide an electrolytic field plate, wherein the field plate establishes a field between the material and the field plate;

[0009] (d) A reduction current is applied to the material and an oxidation current is applied to the field plate, wherein alkali metal ions in the bath are alkalized into the material, thereby generating alkalized material and waste liquid;

[0010] (e) Contacting the waste liquid with ammonia to generate precipitate and regenerated organic solution; and

[0011] (f) Remove the precipitate.

[0012] The present invention also provides a method for lithiation of a material in anhydrous γ-butyrolactone, comprising the following steps:

[0013] (a) Providing materials;

[0014] (b) A bath comprising anhydrous γ-butyrolactone of lithium chloride, wherein the bath is in contact with a material, preferably in a continuous process;

[0015] (c) Provide an electrolytic field plate, wherein the field plate establishes a field between the material and the field plate;

[0016] (d) A reduction current is applied to the material and an oxidation current is applied to the field plate, wherein lithium ions in the bath are lithiated into the material, thereby generating lithiated material and waste liquid containing lithium superchloride;

[0017] (e) Contacting the waste liquid with ammonia to generate precipitate and regenerated organic solvent; and

[0018] (f) Remove the precipitate.

[0019] The present invention provides a method for reforming an organic solvent containing lithium superhalide, comprising: (a) contacting the organic solvent with ammonia to form a precipitate and reform the organic solvent; and (b) removing the precipitate. Attached Figure Description

[0020] The foregoing and other objects, features, and advantages of the present invention will become apparent from the following more detailed description of preferred embodiments of the invention, as illustrated in the accompanying drawings, wherein the same reference numerals refer to the same parts in different views. The following drawings are not drawn to scale and are intended to illustrate the principles of the invention.

[0021] Figure 1a Raman spectroscopy revealed the presence of chlorine gas (Cl2) generated during the pre-lithiation process. Raman spectroscopy was used to analyze four different process fluid samples, in which the Cl2 concentration gradually increased (calculated based on the pre-lithiation current). - The concentrations were 0 mM, 6 mM, 12 mM and 18 mM, respectively. Figure 1bFour samples were compared at a Raman shift of 275 cm. -1 The scattering intensity at that location.

[0022] Figure 2a UV-Vis spectroscopy demonstrates effective removal of Cl2 trapped in process fluids. Anhydrous GBL solution containing ammonia (NH3) is added in portions to a solution containing GBL, LiCl, and 12.5 mM Cl2. - The effects of adding 0 mL, 5 mL, 10 mL, 15 mL, and 20 mL of ammonia-containing GBL solution to the process fluid were observed. Untreated fluid without Cl2 was measured as a control. As the amount of NH3-containing GBL increased to 10 mL, the peak Cl2 concentration decreased. When NH3-containing GBL was added to the contaminated process fluid, the inventors observed the formation of a white particulate precipitate after filtration. Figure 2b The change in pH of the process fluid after adding a GBL solution containing NH3 is shown.

[0023] Figure 3 Raman spectroscopy confirmed the formation of NH4Cl. Detailed Implementation

[0024] This invention is partly based on the discovery that during alkali metal salt alkaliization, halide ions released into anhydrous organic solvents (e.g., GBL) can form complexes (e.g., hyperhalide alkali metal complexes). Therefore, in one embodiment, the invention comprises a composition including an organic solvent and a complex, such as a hyperhalide alkali metal complex.

[0025] The term "alkali metal halide" refers to a salt composed of an alkali metal ion and a halide ion in a 1:1 ratio, denoted as MX, where M is an alkali metal ion, such as lithium, sodium, potassium, rubidium, and cesium, preferably lithium, and X is a halide ion, such as F. - Cl - ,Br - 、 or I - Cl is preferred - The preferred alkali metal halide is lithium chloride. "Lithium halide" refers to the preferred alkali metal halide each time the term is used, as if it were explicitly listed each time, rather than being selected from a list.

[0026] The term "hyperhalide alkali metal complex" (or "alkali metal hyperhalide") is defined as the reaction product of one or more halide atoms or ions with a lithium halide dissolved in an organic solvent (such as γ-butyrolactone). Lithium hyperhalide complexes have been theoretically described, for example (Milovanovic J. Comput. Chem. 2021; 1-10, which are incorporated herein by reference). Hyperhalide alkali metal complexes are characterized by their molecular formula M...n X m Where M is an alkali metal ion (e.g., lithium, sodium, potassium, rubidium, and cesium, preferably lithium), and X is a halide ion, such as F. - Cl - ,Br - 、 or I - Cl is preferred - Both m and n are integers (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or greater), where m > n and / or m + n = 3 or greater. Lithium superhalide complexes include, but are not limited to:

[0027] .

[0028] The compositions of the present invention may include one or more different superhalogenated alkali metal complexes (e.g., lithium superhalogenated complexes) and optionally alkali metal halides (e.g., lithium chloride). For example, the compositions may include two or more of complexes and ionized species such as LiCl2, LiCl3, Li2Cl3, and Li2Cl4, as well as complexes of LiCl. Typically, with superhalogenated M... n X m The alkali metal in the complex is the same as the alkali metal in the alkali metal halide MX (e.g., in each superhalide alkali metal complex and alkali metal, M is lithium). Similarly, the superhalide M n X m Each halogen X in is the same as the halogen X in the alkali metal halide MX (e.g., chloride).

[0029] The composition further comprises an organic solvent or a non-aqueous solvent. Preferred organic solvents include conductive solvents, i.e., electrolyte solvents. More preferably, the solvent is selected from γ-butyrolactone (GBL), butanediol carbonate, propylene carbonate, ethylene carbonate (EC), vinylene carbonate (VC), ethylene vinyl carbonate (VEC), dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate, acetonitrile, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dimethyl sulfoxide, dioxolane, sulfolane, room-temperature ionic liquids, and mixtures thereof. In a more preferred embodiment, the non-aqueous solvent is γ-butyrolactone (GBL). Whenever the term "solvent" is used, GBL should be considered as the preferred solvent, as if explicitly listed each time it is used, rather than selected from a list. Anhydrous organic solvents are preferred.

[0030] Since the composition is preferably produced via an alkalization (e.g., lithiation) process and is intended for recycling in an alkalization (e.g., lithiation) electrode, the non-aqueous solvent may contain additives that promote the formation of a high-quality SEI layer. For example, VC, EC, VEC, CO2, and mixtures thereof may be added to the non-aqueous solvent.

[0031] A preferred composition comprises primarily an organic solvent (e.g., γ-butyrolactone), one or more superhalogenated alkali metal complexes (e.g., lithium superchloride complexes), dissolved chlorine (Cl2), and optionally a corresponding alkali metal (e.g., lithium chloride). The phrase "primarily composed of..." is intended to describe compositions produced by an alkalization process (e.g., the process described herein) without introducing any additional components or additives detrimental to the alkalization process. For example, "primarily composed of" GBL, Li... n Cl m The composition consisting of LiCl refers to a composition preferably recovered directly from the lithiation process, in which LiCl is dissolved in GBL to lithiate the electrode. Preferred alkali / lithiation processes include those described in Nanoscale Components, Inc.’s patents US9598789, US 10128491, US 9748599, US 10128487, US 11005088, and US 11380879, all of which are incorporated herein by reference.

[0032] Unbound by theory, it was assumed that during lithiation, chloride ions dissolved in γ-butyrolactone react with dissolved lithium chloride to form a lithium chloride complex. Experiments showed that under certain lithiation conditions, chloride ions might not react with GBL, nor be released as chloride gas into the reactor headspace. Instead, the inventors of this invention discovered that the released chloride ions complex with lithium chloride to form a complex. Due to the lithiation process, chloride ions released from LiCl are converted into chlorine gas (Cl2). Because the solvent contains lithium chloride, the generated chlorine gas cannot escape but forms a complex in the solvent. The inventors also found that this complex can be rapidly converted into lithium chloride, for example, by adding lithium oxide, thereby significantly improving the recycling of the alkali / lithiation bath. The inventors also found that by adding ammonia, halide ions (e.g., excess chloride ions) can be removed from organic solvents and alkali metal superhalides.

[0033] Therefore, in one embodiment, the present invention includes a method for converting an alkali metal superhalide into lithium chloride in an organic or non-aqueous solvent (e.g., GBL). In this method, a composition comprising an alkali metal superhalide (e.g., lithium superchloride) and an organic solvent (e.g., GBL) is mixed with an alkali metal oxide (e.g., lithium oxide (Li₂O)) to form an organic or non-aqueous solvent composition comprising an alkali metal halide (e.g., lithium chloride). In a second process, a composition comprising a halide and / or an alkali metal superhalide (e.g., lithium superchloride) and an organic solvent (e.g., GBL) is mixed with ammonia (e.g., gaseous ammonia in the same or different miscible organic solvents) to form a precipitate, which can then be selectively recovered or removed, for example, by filtration. In a preferred embodiment, an alkalization (e.g., lithiation) bath obtained through an alkalization process is used. The feedstocks added to the alkalization / lithiation bath include non-aqueous or organic solvents (e.g., solvents containing GBL) and alkali metal chlorides (MX, e.g., LiCl). When an alkali metal halide (e.g., lithium chloride) dissolves, lithium ions and chloride ions decompose into the electrolyte. During alkalization, halide ions are thought to form superchloride alkali metal complexes. Therefore, a lithiation bath is a composition comprising or primarily consisting of: preferably GBL, lithium superhalides, and residual unreacted lithium halides and / or their ions. For example, it is preferable to recover this composition directly from the lithiation process in which lithium chloride is dissolved in GBL to lithiate the electrode. Preferred alkalization / lithiation processes and lithiation compositions or lithiation baths are described in Nanoscale Components Ltd.'s patent applications US9598789, US10128491, US9748599, US10128487, US11005088, and US11380879, each of which is incorporated herein by reference.

[0034] In one embodiment, the invention includes a process for converting a complex (e.g., lithium perchlorate) into a halide precipitate in an organic or non-aqueous solvent (e.g., GBL), thereby removing trapped Cl2. A composition comprising a halide (e.g., LiCl), trapped Cl2 (in the form of a lithium complex, e.g., lithium perchlorate), and an organic solvent (e.g., GBL) is mixed with ammonia (e.g., gaseous ammonia in the same organic solvent as GBL) to form a precipitate, which is then removed by a suitable manner, e.g., filtration.

[0035] In one embodiment, the invention includes a method for removing trapped halogen gases (e.g., Cl2) from a lithiation bath. The method involves contacting the bath solution with ammonia to form a precipitate, which is then removed by means of filtration or the like. In some cases, the ammonia is gaseous ammonia contained in the same or a different miscible organic solvent as the bath solution, preferably the same solvent as the bath solution (e.g., GBL). In some cases, ammonia solution is injected directly into the bath. In a preferred embodiment, the ammonia is injected into a tank different from the lithiation reaction tank.

[0036] In one embodiment, the present invention includes the method for purifying a waste liquid stream as described herein. The waste liquid stream is contacted with ammonia to form a precipitate, which is then removed by means of filtration or the like to obtain a purified solvent. The purified solvent mainly consists of an organic solvent and an alkali metal halide. Preferably, the purified solvent mainly consists of GBL and an alkali metal halide. More preferably, the purified solvent mainly consists of GBL and LiCl. In some cases, the purified solvent can be used for lithiation reactions. In some cases, the purified solvent is returned to the lithiation bath.

[0037] In some embodiments, the terms "pre-lithiation" and "lithiation" are used interchangeably. Lithiation is preferably performed using lithium chloride dissolved in γ-butyrolactone (GBL). γ-Butyrolactone (GBL) has a good electrochemical window, including a lithium potential close to -3 volts relative to the standard hydrogen electrode (SHE). GBL is a high dielectric constant, low freezing point organic solvent capable of dissolving and ionizing LiCl solutions to concentrations up to approximately 0.5 M. This concentration can be achieved with only a small amount of heating. In one embodiment, the temperature required to dissolve and ionize 1 M LiCl is approximately 25°C to 65°C. In a more preferred embodiment, the heating temperature is approximately 30°C to 55°C. In a most preferred embodiment, the heating temperature is approximately 40°C. The dissolved gas, such as CO2 or SO2, can facilitate the lithiation process. It increases the solubility of the salt, the ionic conductivity of the non-aqueous solvent, and improves the lithiation efficiency. CO2 is chosen as the preferred dissolved gas due to its low cost, ease of drying, chemical safety, and potential compositional gas for a high-quality SEI layer. During lithiation, CO2 preferentially reacts with trace amounts of H2O and Li. + The reaction forms a stable, insoluble SEI material (Li₂O, Li₂CO₃, etc.). Residual CO₂ and its byproducts may be present in the resulting lithiation bath and should be included in the composition consisting mainly of GBL, lithium superhalides, and lithium halides.

[0038] Alkali metal halide salts (e.g., LiCl) can be added to a non-aqueous solvent using a salt addition device. An excess of solid lithium salt can be maintained within the metering unit to keep the lithium salt concentration in the bath at the desired level (i.e., a saturated solution of approximately 0.5 M) for an extended period. The metering unit can be configured to prevent solid salt from entering the bath. In a preferred embodiment, the lithium halide salt within the salt metering unit is lithium chloride (LiCl). The lithiation process can be continuous, semi-continuous, or intermittent. The lithiation electrode (e.g., the anode) can be removed from the lithiation bath and rinsed. GBL is a preferred solvent for rinsing the electrode. The rinsing solution can be directly introduced into the circulating fluid stream for purification.

[0039] The lithium bath can be removed from the lithium-ion container, thus forming a recovery stream. The recovery stream can be selectively filtered to remove any unwanted solids and / or dry matter (e.g., by distillation to remove any moisture).

[0040] The recycled stream can then be fed to a recycling unit where the lithiation composition, such as the composition of this invention, can be processed, comprising an organic solvent, an alkali metal hyperhalide, and optionally an alkali metal halide. The method involves adding Li₂O to the recycled stream taken from the lithiation bath, or to a composition comprising an organic solvent and an alkali metal hyperhalide complex. Li₂O can be added in solid, dispersion, or solution form, preferably in solid or dispersion form. Suspending Li₂O in the same solvent used in the lithiation bath or the composition is particularly advantageous. Li₂O is readily suspended in GBL. In one embodiment, a composition comprising GBL, lithium hyperhalide, and lithium chloride (e.g., the recycled stream) can be mixed with a GBL / Li₂O suspension. This reaction occurs rapidly at room temperature and even faster at higher temperatures. The resulting liquid or solution containing the organic solvent (e.g., GBL) and alkali metal halide (LiCl) can then be removed and optionally returned to the alkali / lithiation process. In one embodiment, after the recovered stream is mixed with solid or suspended Li₂O, the pressure generated by the fluid flow forms a porous Li₂O cake, thereby promoting close contact between Li₂O and dissolved lithium superhalide and improving reaction completeness. In one embodiment, the fluid flows upstream in a pipe with a filter at the top. The advantage of this design is that when the pressure in the recovery unit is released, the porous Li₂O cake is released and falls back into the pipe by gravity. The byproducts of Li₂O and lithium superhalide are oxygen and lithium chloride (LiCl), which remains in the GBL solution.

[0041] The resulting GBL-LiCl solution can be easily recovered into the lithium bath.

[0042] As described above, the present invention relates to the removal of trapped halogens (e.g., chlorine), such as halide ions present in the organic solvent as complexes, such as alkali metal superhalides, from an electrolyte comprising an organic solvent. The organic solvent preferably comprises GBL. The organic solvent is preferably anhydrous. As used herein, “waste liquid or waste stream” refers to a solution contaminated compared to the composition of the lithiation bath before the lithiation reaction, including, in addition to the initial solvent (e.g., GBL / LiCl), lithiation byproducts (e.g., halogens Cl2, complexes such as alkali metal superhalides). Therefore, in some embodiments, the waste stream is also referred to as “contaminated fluid,” “contaminated process fluid,” or “process fluid.” The waste stream includes the organic solvent used in the alkalization process. The waste stream, or an organic solvent comprising trapped gases forming complexes, is contacted with a reagent for removing the trapped substances. In one embodiment, the reagent is lithium oxide. In another embodiment, the reagent is ammonia, which can be added directly to the waste stream in gaseous form (e.g., bubbles passing through the waste stream) or dissolved in an organic solvent. Ammonia forms a precipitate that is easily filtered.

[0043] In some implementations, the waste stream is circulated via an ammonia injection device. In some cases, the ammonia injection assembly includes a flow controller for injecting ammonia into the waste stream. The ammonia is injected into the waste stream at a rate optimized based on the waste stream flow rate and the speed of the lithiation and circulation processes. The rate is optimized based on the generation rate of the captured gas (e.g., Cl2).

[0044] The reaction between ammonia and the captured substance can be illustrated by the reaction between ammonia and Cl2:

[0045] 2NH3 + 3Cl2 → N2 + 6HCl

[0046] 6NH3 + 6HCl  6NH4Cl

[0047] Therefore, in this case, the ammonia injection rate can be calculated based on the reaction molar ratio of ammonia to chlorine of 8:3 to remove chlorine from the waste stream.

[0048] In some implementations, ammonia is injected into the waste stream at a rate of approximately 1 mL / min to 1000 L / hr.

[0049] In some implementations, ammonia is injected into the waste stream at a rate such that the molar ratio of ammonia to the captured substance (such as Cl2) is greater than about 1. In some cases, ammonia is injected into the waste stream at a rate of about 1 to about 100, about 1 to about 10, or about 2, about 3, about 4, about 5, about 6, about 7, about 8, or about 9.

[0050] The ammonia injection assembly can be installed on a tank containing waste stream (preferably a recovery tank separate from the tank where the lithiation reaction occurs) to remove captured substances and convert the waste stream into a purified solvent that can be reused for lithiation. Preferably, the ammonia injection unit can be installed on a separate recovery tank. In some cases, multiple recovery tanks are used to repeat the reaction between ammonia and the captured substances.

[0051] The lithiation bath is circulated at a controlled rate to maintain a stable chlorine concentration. The stable chlorine concentration ranges from approximately 0.0001 to approximately 1 mol / L, or from approximately 0.0002 to approximately 0.5 mol / L, or from approximately 0.0005 to approximately 0.3 mol / L, or from approximately 0.001 to approximately 0.2 mol / L. In some cases, the stable chlorine concentration is approximately 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, or 0.01 mol / L. In some cases, stable chlorine concentrations are approximately 0.0011, 0.0012, 0.0013, 0.0014, 0.0015, 0.0016, 0.0017, 0.0018, 0.0019, 0.0020, 0.0021, 0.0022, 0.0023, 0.0024, or 0.0025 mol / L.

[0052] When ammonia is injected into the waste stream, precipitate particles (e.g., ammonium chloride) are formed. These precipitate particles are preferably removed by filtration to obtain a composition free of residues, as well as purified solvent (e.g., GBL and lithium chloride). The purified solvent is then returned to the lithium bath.

[0053] If the reagent is added by dissolving it in an organic solvent (for clarity, referred to as the "dissolving organic solvent"), this dissolving organic solvent is preferably miscible with the organic solvent in the waste stream. Preferably, the organic solvent used for dissolution is the same as the organic solvent in the waste liquid, and preferably comprises, is mainly composed of, or is composed of GBL. Dissolving the reagent in an organic solvent at room temperature to a concentration close to or at saturation can effectively improve the dissolution efficiency; this saturation concentration can be determined experimentally. However, smaller quantities are also possible.

[0054] This invention relates to a method for recovering or reforming an alkalization / lithiation bath comprising (or primarily consisting of) an organic non-aqueous solvent (e.g., GBL) and an alkali metal halide and any reaction products thereof (e.g., hyperhalide alkali metal complexes), the method comprising adding lithium oxide to the bath and removing unreacted lithium oxide.

[0055] This invention also relates to a method for recovering or reforming an alkalization / lithiation bath, the bath comprising (or primarily consisting of) an organic non-aqueous solvent (e.g., GBL) and an alkali metal halide and any reaction products thereof (e.g., hyperhalide alkali metal complexes), the method comprising adding ammonia to the bath to form a precipitate, and then removing the precipitate. The precipitate is ammonium chloride. Therefore, this invention also relates to a method for producing ammonium chloride.

[0056] A preferred embodiment of the present invention includes a method for alkalizing a material in an anhydrous organic solvent, the method comprising the following steps:

[0057] (a) Providing materials;

[0058] (b) A bath is provided comprising an anhydrous organic solvent having at least one dissolved alkali metal halide salt, wherein the bath is in contact with a material, preferably in a continuous manner, and wherein the bath is covered with a layer of dry gas.

[0059] (c) Provide an electrolytic field plate, wherein the field plate establishes a field between the material and the field plate;

[0060] (d) A reduction current is applied to the material and an oxidation current is applied to the field plate, wherein alkali metal ions in the bath are alkalized into the material;

[0061] (e) Contacting an anhydrous organic solvent with lithium oxide; and

[0062] (f) Optionally, remove unreacted lithium oxide.

[0063] The alkalizing material may include both the anode and cathode. Such materials may include graphite, coke, carbon, tin, tin oxide, silicon, silicon oxide, aluminum, lithium-active metals, alloy metals, and mixtures thereof. The material may also include metal oxides of nickel, aluminum, cobalt, manganese, and iron, and mixtures thereof. The material may also include sulfur and phosphorus, and mixtures thereof. The material may also include a metallic substrate (e.g., copper or nickel).

[0064] The processes and methods of the present invention are carried out in or using organic solvents. Typically, the organic solvents are anhydrous and are electrolytes. The same or different organic solvents may be used in the various steps of the method or process. For example, in cases involving the lithiation of materials (e.g., anodes) according to the present invention, γ-butyrolactone is a preferred solvent because it dissolves lithium halides (e.g., lithium chloride). γ-Butyrolactone has a good electrochemical window, including a lithium potential close to -3 volts relative to a standard hydrogen electrode (SHE). It is a high-performance solvent with a high dielectric constant and a low freezing point, capable of dissolving and ionizing a 0.5 M lithium chloride solution. Only a small amount of heat is required to achieve this concentration. In one embodiment, the temperature of the lithium chloride solution can be maintained between approximately 20°C and 65°C, for example, between 30°C and 65°C, such as between 38°C and 55°C. In a more preferred embodiment, the temperature is between approximately 25°C and 55°C. In a most preferred embodiment, the temperature is approximately 40°C.

[0065] The lithium bath can also have an internal circulation pump and distribution manifold to prevent localized insufficient salt concentration.

[0066] Dissolved gases (e.g., CO2) can facilitate the lithiation process. They increase the solubility of the salt, the ionic conductivity of the non-aqueous solvent, and improve lithiation efficiency. CO2 is chosen as the preferred dissolved gas due to its low cost, ease of drying, chemical safety, and its potential role as a component gas for high-quality SEI layers. During lithiation, CO2 preferentially reacts with trace amounts of H2O and Li+ to form stable, insoluble SEI materials (Li2O, Li2CO3, etc.). According to this process, the moisture content in the lithiation bath is reduced by consuming CO2 and H2O, with careful control of the moisture content between approximately 0 and 2000 ppm, preferably 5 to 200 ppm, and more preferably 5 to 100 ppm. This allows for the continuous production of anolyte lithiation layers with high-quality SEI materials.

[0067] For example, in γ-butyrolactone solvent, lithium-ion deposition (or general lithiation) of 0.25 to 0.5 M LiCl salts will occur at a voltage of approximately 4.1 volts measured between the anode and the reference electrode, with a reduction current density reaching 2 mA / cm². 2 Or more. The optimal current density varies depending on the properties of the electrode to be lithiated. To precisely control the current and associated voltage, it may be necessary to divide the field plate into several regions. Other metals, such as sodium, can also be alloyed, intercalated, or plated using this method. Initially, it was thought that the lithiation process would release chlorine gas. However, it was later discovered that chlorine gas still remained in the solution. Therefore, measures were needed to remove halides from the organic solvent.

[0068] After the anode is lithium-lithiated as described above, it can be assembled with the cathode material to form a battery or electrochemical cell. The anode, dried cathode, and separator are then assembled into a dried battery casing, such as a button cell casing, pouch cell, cylindrical cell, or prismatic cell. An electrolyte is added, preferably while the battery is sealed under vacuum. Preferred electrolytes include EC / DMC / DEC and 1M LiPF6 and 1% VC. The battery is then sealed (e.g., vacuum-sealed) and preferably stored at ambient temperature or a high temperature (between about 15 and 60°C) for 1 to 24 hours, preferably 3 to 18 hours, allowing the electrolyte to adsorb and expand, and further form an SEI. The battery is then ready for electrochemical cycling.

[0069] The present invention also includes a method for lithiation of a material in anhydrous γ-butyrolactone, the method comprising the following steps:

[0070] (a) Providing materials;

[0071] (b) A bath containing anhydrous γ-butyrolactone comprising lithium chloride is provided, wherein the bath is in contact with the material, preferably in a continuous manner;

[0072] (c) Provide an electrolytic field plate, wherein the field plate establishes a field between the material and the field plate;

[0073] (d) A reduction current is applied to the material and an oxidation current is applied to the field plate, wherein lithium ions in the bath are lithiated into the material, thereby generating lithiated material and waste liquid containing lithium superchloride;

[0074] (e) Contacting the waste liquid with ammonia to generate precipitates and regenerated organic solvents; and

[0075] (f) Remove precipitates.

[0076] In some embodiments, the present invention further includes a method for preparing ammonium chloride, the method comprising the following steps:

[0077] (a) Provides an anhydrous organic solvent comprising dissolved lithium chloride;

[0078] (b) Optionally, (i) an electrolytic field plate is provided, wherein the field plate establishes an electric field between the material immersed in the anhydrous organic solvent and the field plate, and (ii) a reduction current is applied to the material and an oxidation current is applied to the field plate, thereby producing lithium-ionized material and waste liquid;

[0079] (c) Contacting the waste liquid with ammonia to form a precipitate consisting of ammonium chloride and recycled organic solvent; and

[0080] (d) Remove precipitates.

[0081] In some cases, anhydrous organic solvents include γ-butyrolactone.

[0082] In some cases, step (c) involves blowing ammonia gas into the waste liquid.

[0083] In some cases, step (c) involves contacting the waste liquid with a miscible organic solvent containing ammonia.

[0084] In some cases, anhydrous organic solvents include γ-butyrolactone, and miscible organic solvents include γ-butyrolactone.

[0085] In some cases, miscible organic solvents include ammonia or ammonia-saturated solvents.

[0086] In some cases, the sediment is filtered out.

[0087] Example

[0088] A double-sided coated graphite composite electrode was used, coated on a 19 cm wide copper foil, and pre-lithiated using a roll-to-roll method. The coated electrode was 15 cm wide, with 2 cm of exposed copper on each side. The electrode consisted of 95-96% graphite, 0.5-1% conductive additives, 1.3-2.0% CMC, and 2.5% SBR. The weight of the graphite composite electrode without the foil was 16 mg / cm², and the coating density was 1.5 g / cm³.

[0089] Before entering the lithium bath, the graphite composite electrode passes through a heated convection air dryer set at 60°C with an airflow of 12 standard cubic feet per minute to remove residual moisture.

[0090] In the pre-lithiation device, graphite counter electrodes are used on both sides of the graphite composite electrode to expose a chlorine-electrode counter electrode with a width of 15 cm. A dielectric shielding layer is placed on the graphite counter electrode to prevent lithiation from occurring at the exposed copper foil edges.

[0091] The electrolyte used for pre-lithiation is kept at a constant temperature of 40 degrees Celsius and mainly consists of γ-butyrolactone solvent, 0.3 mol / L dissolved lithium chloride salt, and approximately 0.01 mol / L dissolved carbon dioxide gas. The total volume of the electrolyte is approximately 11 liters.

[0092] The target pre-lithiation dose was 0.42 mAh / cm² of lithium at a constant current density of 1.75 mA / cm². The wet mesh length of the roll-to-roll electrolyzer used for pre-lithiation was 42 cm. To meet the requirement of a 14-minute electrode dwell time in the bath to achieve the target lithiation dose, the electrode linear velocity was set to 3 cm / min.

[0093] In this test, constant current electrolysis at 2.2A resulted in a chlorine generation rate of 0.04 mol / h in 11 liters of electrolyte. The experiment confirmed that Cl2 can be bubbled out of the GBL solution in the absence of lithium chloride (LiCl), but cannot be bubbled out in the presence of lithium chloride. During pre-lithiation, a large amount of the generated Cl2 remains in the bath, generating byproducts (such as the previously mentioned lithium superchloride). Therefore, during lithiation, the electrolyte containing byproducts flows through an ammonia injection component to neutralize the generated chlorine and form suspended ammonium chloride particles in the electrolyte. Ammonia was introduced into the electrolyte stream at a rate of 40 standard mL / min using a mass flow controller. This ammonia rate was calculated based on a molar ratio of 8:3 between ammonia and chlorine, with the aim of removing chlorine from the fluid. The electrolyte was circulated at a rate of 360 mL / min to stabilize the chlorine concentration in the lithiation bath at 0.0019 mol / L.

[0094] Downstream of the ammonia injection process, ammonium chloride particles are generated in the liquid stream and are removed by filtration. Subsequently, the electrolyte is returned to the lithium bath.

[0095] The effect of Raman spectroscopy on the precipitation and retention of chlorine by ammonia was characterized and analyzed. The test results are as follows: Figure 1a As shown. The chloride ion concentration in the lithiation bath can be calculated using the following formula, which incorporates two parameters: lithiation current and lithiation time.

[0096]

[0097] Lithiation current in [A] Lithiation time in [s] Faraday constant in [C / mol] (ca. 96500 C / mol) Volume of solvent in the cell during lithiation in [L]

[0098] Although preferred embodiments of the present invention have been shown and described herein, those skilled in the art will understand that various changes and modifications can be made to them without departing from the actual scope of protection of the invention, and equivalent solutions can be used to replace various components. Therefore, the invention is not limited to the specific embodiments disclosed, but covers all embodiments falling within the scope of protection of the appended claims.

Claims

1. A method for alkalizing a material in an anhydrous organic solvent, comprising the following steps: (a) Providing materials; (b) A bath comprising at least one dissolved alkali metal halide salt in an anhydrous organic solvent, wherein the bath is in contact with a material, preferably in a continuous process; (c) Provide an electrolytic field plate, wherein the field plate establishes a field between the material and the field plate; (d) Apply a reducing current to the material and an oxidizing current to the field plate, wherein alkali metal ions in the bath alkalize the material, thereby generating alkalized material and waste liquid; (e) Contacting the waste liquid with ammonia to generate precipitates and regenerated organic solvents; and (f) Remove precipitates.

2. The method of claim 1, wherein the dissolved halide salt comprises lithium chloride.

3. The method according to claim 1 or 2, wherein the anhydrous organic solvent comprises γ-butyrolactone.

4. The method according to any of the preceding claims, wherein step (e) comprises blowing ammonia gas into the waste liquid.

5. The method according to any one of claims 1-3, wherein step (e) comprises contacting the waste liquid with an ammonia-containing miscible organic solvent.

6. The method of claim 5, wherein the anhydrous organic solvent comprises γ-butyrolactone, and the miscible organic solvent comprises γ-butyrolactone.

7. The method of claim 6, wherein the miscible organic solvent is saturated with ammonia.

8. The method according to any of the preceding claims, wherein, Filter the precipitate.

9. The method according to any of the preceding claims, wherein the purified organic solvent is added to the anhydrous organic solvent.

10. The method according to any of the preceding claims, wherein the precipitate is an ammonium salt.

11. The method according to claim 10, wherein the ammonium salt is ammonium chloride.

12. A method for purifying an organic solvent, said organic solvent comprising a complex formed from a halogen gas and an alkali metal halide (e.g., lithium superhalide), said method comprising: (a) Contacting an organic solvent with ammonia to form a precipitate and purified organic solvent; (b) Removal of precipitates.

13. The method of claim 12, wherein the organic solvent comprises γ-butyrolactone.

14. The method according to claim 12 or 13, wherein ammonia is bubbled into the organic solvent.

15. The method according to claim 12 or 13, wherein step (a) comprises contacting the organic solvent with a miscible organic solvent containing ammonia.

16. The method of claim 15, wherein the organic solvent comprises γ-butyrolactone, and the miscible organic solvent comprises γ-butyrolactone.

17. The method of claim 16, wherein the miscible organic solvent is saturated with ammonia.

18. The method according to any one of claims 12-17, wherein the precipitate is filtered.

19. A process comprising contacting an organic solvent comprising a superhalogenated alkali metal complex with ammonia to form a precipitate, wherein the ammonia may be ammonia gas or an ammonia-containing solvent.

20. The process according to claim 19, further comprising filtering the precipitate.

21. The process according to claim 19, wherein the organic solvent comprises γ-butyrolactone.

22. A composition comprising γ-butyrolactone, lithium superchloride, and lithium chloride.

23. A composition comprising γ-butyrolactone, lithium chloride, and trapped chlorine gas, wherein the trapped chlorine gas forms a complex with the lithium chloride in at least a portion thereof.

24. The composition of claim 23, wherein the complex comprises lithium superchloride.

25. The composition according to claim 23, further comprising ammonia.

26. The composition according to claim 25, further comprising ammonium chloride.

27. The composition of claim 26, wherein ammonium chloride is suspended in the composition in the form of particles.

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