Direct regeneration of spent lithium electrodes via heat treatment

Abstract

Embodiments described herein relate to the regeneration of lithium-deficient electrodes (e.g., lithium iron phosphate, LFP). The process comprises several steps of heat treatment. A first step involves mixing the spent electrode material with lithium carbonate. The lithium carbonate and spent LFP are then subjected to a heating process in a total nitrogen environment. The first heat treatment brings the material to a maximum of approximately 550°C to remove excess water and oxygen. A second heat treatment brings the material to a maximum of approximately 1,000°C, where they are sintered together to form an electrode material similar to that of new.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the priority and benefit of U.S. Provisional Application No. 63 / 450,488, filed on March 7, 2023, titled "Direct Relithiation of Spent Lithium Electrodes via Heat Treatment", the entire disclosure of which is incorporated herein by reference.

[0002] The embodiments described herein generally relate to the repair of electrochemical cell electrodes, and more specifically, to methods and / or processes for regenerating depleted electrode materials.

Background Art

[0003] A battery typically consists of solid electrodes, a separator, an electrolyte, and auxiliary components related to, for example, packaging, thermal management, cell balancing, integration of current carriers to terminals, and / or other such components. Batteries can experience performance degradation over their lifespan due to unwanted chemical and / or physical processes that deplete the active materials contained within the battery's electrodes and / or cause disconnection / decomposition. Some known methods for recycling and / or refurbishing battery electrode materials involve high - temperature chemical (e.g., acid) - based dissolution of the electrode materials and / or immersion of the electrode coatings in a molten salt bath at very high temperatures (e.g., 450 °C or higher). Other approaches involve dissolution / leaching of the electrode materials in strong acids. The use of harsh chemical treatments is necessary due to the difficulty of mechanically separating the electrode constituents in conventional electrode coatings, as well as the presence of large amounts of binder materials and the hardness and density of the coatings after mechanical calendaring. Still other approaches involve electrolysis - based recovery of metals that result in large amounts of un - recovered electrode constituents while requiring high power consumption and significant investment in equipment.

[0004] Such methods have been found to cause damage / erosion of the underlying current collector, and the recovery of coating components (e.g., electrode active materials, conductive additives, and / or electrolyte salts) from the subsequent molten salt bath has been found to be uneconomical. Furthermore, the refurbishment and / or recycling of electrode active materials recovered from electrodes experiencing performance degradation can be difficult due to the loss of one or more components caused by undesirable, irreversible side effects that occur during the normal operation of the battery or electrochemical cell. Therefore, improved methods for repairing electrochemical cell electrodes are desirable both economically and environmentally. [Overview of the project]

[0005] Embodiments described herein relate to the repair of electrochemical cells via heat treatment. In some embodiments, a method for regenerating electroactive material contained in depleted electrode material may include: obtaining electroactive material; mixing additives with the electroactive material to produce replenished electroactive material; homogenizing the replenished electroactive material; and exposing the replenished electroactive material to a thermal process, which includes heating the replenished electroactive material to a first temperature and holding the replenished electroactive material at the first temperature for a first period of time while flowing a gas stream; heating the replenished electroactive material to a second temperature and holding the replenished electroactive material at the second temperature for a second period of time while flowing a gas stream; and cooling the replenished electroactive material from the second temperature to ambient temperature while flowing a gas stream.

[0006] In some embodiments, the method includes mixing one or more additives with an electrode active material to produce a supplemented electrode active material; heating the supplemented electrode active material to a first temperature while exposing it to a first gas; holding the supplemented electrode active material at the first temperature for a first period of time; heating the supplemented electrode active material to a second temperature while exposing it to a second gas; holding the supplemented electrode active material at the second temperature for a second period of time; and cooling the supplemented electrode active material from the second temperature to ambient temperature while exposing it to a second gas.

[0007] In some embodiments, a method for replenishing electrode active material contained in depleted electrode material includes: mixing an additive with electrode active material to produce a mixture; exposing the mixture to a gas stream for a first period at ambient temperature; heating the mixture to a replenishment temperature while being exposed to the gas stream; holding the mixture at the replenishment temperature for a second period while being exposed to the gas stream; and cooling the mixture to ambient temperature while being exposed to the gas stream to obtain replenished electrode active material. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a heat treatment process for relithiation of electrode materials according to one embodiment. [Figure 2] This is a flowchart of a process for relithiation of an electrode active material according to one embodiment. [Modes for carrying out the invention]

[0009] Rechargeable batteries, such as lithium-ion batteries, can exhibit capacity loss or “capacity degradation” over their service life. Capacity degradation manifests as a reduction in the battery’s ability to supply charge at rated voltage. Capacity degradation can result from the loss of recyclable lithium and / or electrical disconnection of the active material. In lithium-ion batteries, the cell’s complete lithium inventory is provided by the positive electrode (“cathode”) active material. Lithium can be lost through the formation of solid electrolyte interface (“SEI”) material or layers during the initial charging cycle, as well as consumption in irreversible side reactions within lithium-ion batteries, such as aging, storage, and / or the continued growth of SEI layers during cycling. Due to the fixed lithium budget of the cell, lithium loss resulting from any side reactions within the cell causes non-stoichiometry of the cathode active material. Conventional approaches to battery electrode recycling typically involve high-temperature chemical (e.g., acid) treatment of the electrode material to separate and / or isolate its main components, such as electrode active materials, conductive additives, and / or electrolyte salts. These powerful chemical recovery processes are necessary because it is difficult to mechanically separate other components of conventional electrode coatings, such as binders and / or adhesives. Many of these processes are time-consuming and labor-intensive, costly to implement, and yield low returns in terms of useful raw materials. Nevertheless, recycling remains a continuing goal for most battery manufacturers, given the diversity of valuable components in most battery compositions, as well as the economic and environmental costs associated with the wholesale disposal of electrochemical cells. Due to the challenges mentioned above, improved methods for electrode recycling are needed.

[0010] The embodiments described herein generally relate to methods and / or processes for the repair (also referred to as “recycling,” “reconstruction,” “regeneration,” “refurbishment,” “reuse,” or “remanufacturing”) of electrodes obtained from electrochemical cells. More specifically, the processes described herein relate to the replenishment and / or regeneration of lithium losses resulting from undesirable side reactions in electrochemical cells that lead to non-stoichiometry of the cathode active material. These processes, also referred herein as relithiation processes, can be implemented for the replenishment of lithium in electrode active materials contained in semi-solid electrodes. The relithiation processes described herein can also be implemented for the replenishment of lithium in electrode active materials from conventional battery solid electrodes.

[0011] In some embodiments, the electrodes described herein may include conventional solid electrodes, e.g., electrodes sintered or polymerized to have a solid shape factor. In some embodiments, the solid electrode may include a binder. In some embodiments, the electrodes described herein may include semi-solid electrodes. The semi-solid electrodes described herein can be manufactured with (i) greater thickness (e.g., greater than 100 μm, up to 2,000 μm or more) due to reduced flexibility and higher conductivity of the semi-solid electrode, (ii) with higher filling of the active material, and (iii) with a simplified manufacturing process utilizing fewer instruments. These relatively thick semi-solid electrodes reduce the volume, mass, and cost contribution of the inert component to the active component, thereby increasing the commercial appeal of batteries manufactured using semi-solid electrodes. In some embodiments, the semi-solid electrodes described herein are binderless and / or do not use a binder used in conventional battery manufacturing. Instead, the electrode volume typically occupied by the binder in conventional electrodes is occupied here by: The semi-solid electrodes described herein are: 1) an electrolyte that reduces the degree of curvature and increases the total amount of salt available for ion diffusion, thereby counteracting the salt depletion effect typical of thick conventional electrodes when used at high speeds; 2) an active material that increases the charging capacity of the battery; or 3) a conductive additive that increases the electronic conductivity of the electrode, thereby counteracting the high internal impedance of thick conventional electrodes. The reduction in curvature and increase in electronic conductivity of the semi-solid electrodes described herein result in excellent rate characteristics and charging capacity of electrochemical cells formed from semi-solid electrodes. Since the semi-solid electrodes described herein can be fabricated to be substantially thicker than conventional electrodes, the ratio of active material (i.e., semi-solid cathode and / or anode) to inert material (i.e., current collector and separator) can be made much higher in batteries formed from electrochemical cell stacks containing semi-solid electrodes compared to similar batteries formed from electrochemical cell stacks containing conventional electrodes. As a result, the overall charging capacity and energy density of batteries containing the semi-solid electrodes described herein are substantially increased.

[0012] In some embodiments, the electrode materials described herein may be fluid semi-solid or condensable liquid compositions. In some embodiments, the electrode materials described herein may be binderless or substantially binder-free. Fluid semi-solid electrodes may include a suspension of electrochemically active material (anode or cathode particles or microparticles) and, optionally, an electronically conductive material (e.g., carbon) in a non-aqueous liquid electrolyte. In other words, a semi-solid electrode is produced by co-suspending active electrode particles and conductive particles in an electrolyte. Examples of battery architectures utilizing semi-solid suspensions are described in International Patent Publication 2012 / 024499, titled "Stationary, Fluid Redox Electrode," and International Patent Publication 2012 / 088442, titled "Semi-Solid Filled Battery and Method of Manufacture," the entire disclosures of which are incorporated herein by reference.

[0013] In some embodiments, the relithiation process described herein may include obtaining an electrode active material from a depleted (i.e., used, stoichiometric, non-stoichiometric, or “spent”) electrode material; rinsing and / or washing the obtained electrode active material to remove one or more residues, such as electrolyte salts; mixing additives with the electrode active material to replenish lost lithium and produce and / or generate a replenished electrode active material; homogenizing the replenished electrode active material using a mechanical grinding process; and subjecting the replenished electrode active material to a heat treatment process to re-establish its electrochemical activity. The “depleted” electrode material described herein may include electrode material formed in electrodes, electrode material formed in electrochemical cells, electrode material used in electrochemical cells, and / or electrode material that has functioned in electrochemical reactions. In other words, electrode material that has come into existence as an electrode can be considered “depleted” electrode material because it is no longer the electrode material in its initial state. In some embodiments, the electrode material may include substantially depleted, semi-depleted, partially depleted, and nearly depleted electrode materials.

[0014] As used herein, the singular forms “a,” “an,” and “the” refer to multiple objects unless the context clearly indicates otherwise. For example, the term “component” is intended to mean a single component or combination of components, and “material” is intended to mean one or more materials or combinations thereof.

[0015] As used herein, the terms “about” and “approximately” generally mean plus or minus 10% of the stated value; for example, about 250 μm includes 225 μm to 275 μm, and about 1,000 μm includes 900 μm to 1,100 μm.

[0016] As used herein, the terms “set” and “multiple” may refer to multiple features or a single feature with multiple parts. For example, when referring to a set of electrodes, the set of electrodes may be considered as one electrode with multiple parts, or as multiple separate electrodes. Additionally, for example, when referring to multiple electrochemical cells, the multiple electrochemical cells may be considered as multiple separate electrochemical cells or a single electrochemical cell with multiple parts. Thus, a set of parts or multiple parts may include multiple parts that are continuous or discontinuous with respect to each other. Multiple particles or multiple materials may also be made from multiple articles that are produced separately and later joined together (e.g., by mixing, adhesive, or any preferred method).

[0017] As used herein, the terms “room temperature” and / or “ambient temperature” can refer to temperatures of about 15°C, about 16°C, about 17°C, about 18°C, about 19°C, about 20°C, about 21°C, about 22°C, about 23°C, about 24°C, or about 25°C. In some embodiments, room temperature is about 20°C to about 40°C (including both extreme values) (for example, about 20°C, 25°C, 30°C, 35°C, or 40°C (including both extreme values)).

[0018] Figure 1 shows a schematic diagram of a heat treatment process 100 for relithiation of electrode active materials (e.g., cathode electrode active material and / or anode active material) according to one embodiment. The heat treatment process 100 can be used to relithiate electrode active materials obtained from depleted electrode materials from electrochemical cells that have reached the “end of service” or exhibit capacity degradation. Depleted or used electrode active materials can be obtained from semi-solid electrodes (e.g., semi-solid cathodes or semi-solid anodes) or conventional solid electrodes (e.g., conventional solid cathodes or conventional solid anodes). The “depleted” nature of an electrode material refers to at least partial degradation, loss, or accumulation of the material such that the electrode active material is compositionally different from its state in the original assembly of the electrochemical device. For example, due to the loss of recyclable lithium in a lithium-ion battery, the stoichiometry of a cathode electrode active material may be measurably different from that of an “unused” cathode electrode active material (i.e., there has been a change in the relative amounts of its components). The heat treatment process 100 can be applied to the cathode electrode active material after the cathode electrode active material has been at least (1) mixed with additives to modify its composition, and (2) homogenized using any suitable grinding process as further described herein. The heat treatment process 100 is not limited to LiCoO2 (lithium cobalt oxide, "LCO"), Li(Ni,Mn,Co)O2 (lithium nickel manganese cobalt oxide, also referred to as "NMC" or "NCM"), LiNi 0.8 Co 0.15 Al 0.05 O2 (Lithium nickel cobalt aluminum oxide, "NCA"), LiMn2O4 (Lithium manganese oxide, "LMO"), LiCoPO4 (Lithium cobalt phosphate, "LCP"), LiNiPO4 (Lithium nickel phosphate, "LNP"), LiFePO4 (Lithium iron phosphate, "LFP"), LiMnPO4 (Lithium manganese phosphate, "LMP"), LiMn 0.85 Fe 0.15 PO4 (Lithium manganese iron phosphate, "LMFP"), and / or Li4Ti5O12 It can be applied to any suitable cathode-active material, including metal oxide cathodes such as lithium titanate ("LTO").

[0019] Figure 1 shows that the heat treatment process 100 includes exposing the electrode active material to an initial temperature over a period of time, and then heating the electrode active material according to a multi-stage temperature program while flowing a gas stream. The electrode active material may be mixed with additives before carrying out the heat treatment process, for example, to facilitate relithiation. In some embodiments, the additives may include, but are not limited to, lithium-containing additives, including lithium carbonate, lithium hydroxide, lithium nitrate, or lithium sulfate, or any preferred combination thereof. In some embodiments, the additives may include, but are not limited to, iron-containing additives, including Fe3(PO4)2·8H2O, Fe(CH3CO2)2, FeC2O4.2H2O, Fe3(NO3)3, FeCl3, Fe2O3, or any preferred combination thereof. In some embodiments, the additive may include, but is not limited to, nickel-containing additives comprising NiO, NiSO4.6H2O, NiCl2.6H2O, Ni(NO3)2.6H2O, Ni(CH3CO2)2.4H2O, Ni(OH)2, or any preferred combination thereof. In some embodiments, the additive may include, but is not limited to, manganese-containing additives comprising MnO2, MnSO4.H2O, MnCl2.4H2O, Mn(NO2)2.4H2O, Mn(CH3CO2)2, Mn(OH)2, or any preferred combination thereof. In some embodiments, the additive may include, but is not limited to, cobalt-containing additives comprising CoO, Co2O3, Co3O4, CoSO4.7H2O, CoCl2.6H2O, Co(NO3)2.6H2O, Co(CH3CO2)2.4H2O, Co(OH)2, or any preferred combination thereof.

[0020] During use, the electrode active material can be placed in an oven, furnace, and / or any suitable device capable of heating the electrode active material according to a multi-stage temperature program. In some embodiments, a gas stream may flow over the electrode active material during heating to provide a controlled atmosphere. In some embodiments, the gas stream is and / or may include air. In some embodiments, the gas stream is and / or may include an inert and / or non-reactive gas such as helium (He), argon (Ar), and / or nitrogen (N2). In such embodiments, the inert and / or non-reactive gas may be a high-purity gas. For example, in some embodiments, the gas stream is and / or may contain nitrogen gas having a concentration of nitrogen and / or nitrogen purity of about 99.0% (e.g., nitrogen gas classification N2.0), about 99.90% (e.g., nitrogen gas classification N3.0), about 99.990% (e.g., nitrogen gas classification N4.0), or about 99.999% (e.g., nitrogen gas classification N5.0, also referred to as ultra-high purity UHP). In some embodiments, the gas stream is and / or may contain oxygen (e.g., at least 99% pure oxygen). In some embodiments, the gas stream may be a gas mixture containing an inert and / or non-reactive gas and an oxygen-containing gas such as air (e.g., dry or anhydrous air) and / or pure oxygen. In such embodiments, the gas mixture may contain the oxygen-containing gas at a predetermined concentration. For example, the gas mixture may contain oxygen-containing gas at concentrations of at least about 0.5%, about 1.0%, about 1.5%, about 2.0%, about 3.0%, about 4.0%, about 5.0%, about 10%, about 15%, about 20.0%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, or about 95% (including all ranges in between). In some embodiments, the gas stream may be a gas mixture containing an inert and / or nonreactive gas and a reducing gas such as hydrogen (H2). In such embodiments, the gas mixture may contain hydrogen gas at a predetermined concentration.For example, the gas mixture can contain hydrogen gas at a concentration of at least about 0.5%, about 1.0%, about 1.5%, about 2.0%, about 3.0%, about 4.0%, about 5.0%, about 10%, about 15%, about 20.0%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, about 95%, or about 99% (including all ranges therebetween).

[0021] In some embodiments, the gas stream can be flowed at a flow rate of about 0 mL / min, at least about 10 mL / min, at least about 20 mL / min, at least about 50 mL / min, at least about 100 mL / min, at least about 150 mL / min, at least about 200 mL / min, at least about 250 mL / min, or at least about 300 mL / min (including all ranges therebetween). In some embodiments, the gas stream can be flowed at a flow rate of about 300 mL / min or less, about 270 mL / min or less, about 240 mL / min or less, about 210 mL / min or less, about 180 mL / min or less, about 150 mL / min or less, about 120 mL / min or less, about 90 mL / min or less, about 60 mL / min or less, about 30 mL / min or less, or about 10 mL / min or less (including all ranges therebetween).

[0022] FIG. 1 shows that the heat treatment process 100 includes exposing the electrode active material for a period Δt A while providing a gas flow (e.g., while flowing a gas stream) at room temperature and / or ambient temperature (T A ). In some embodiments, the period Δt A can be at least about 0.1 h, at least about 0.2 h, at least about 0.3 h, at least about 0.5 h, at least about 1 h, at least about 1.5 h, at least about 2 h, at least about 2.5 h, at least about 3 h, at least about 3.5 h, at least about 4 h, at least about 4.5 h, at least about 5 h, at least about 6 h, at least about 7 h, at least about 8 h, at least about 9 h, at least about 10 h, at least about 15 h, at least about 20 h, or at least about 24 h (including all ranges therebetween). In some embodiments, the period Δt AThe interval can be approximately 24 hours or less, approximately 20 hours or less, approximately 16 hours or less, approximately 12 hours or less, approximately 8 hours or less, approximately 4 hours or less, approximately 2 hours or less, approximately 1 hour or less, approximately 0.5 hours or less, approximately 0.1 hours or less (including all ranges in between). In some embodiments, the electrode active material comprises LFP and the gas flow comprises nitrogen (e.g., 99.999% nitrogen). In some embodiments, the electrode active material comprises NMC and the gas flow comprises oxygen and / or dry air.

[0023] Period Δt A During the period, ambient temperature T A Following exposure to the gas stream, the electrode-active material undergoes a period Δt A While using the same gas flow or gas stream that was used inside, at an ambient temperature T A The material can be heated from a temperature of 0 to a first temperature (T1) (e.g., an intermediate temperature) at a first heating rate R1. In some embodiments, the electrode active material can then be held at the first temperature T1 for a first period Δt1. In some embodiments, the first temperature T1 can be at least about 150°C, at least about 175°C, at least about 200°C, at least about 225°C, at least about 250°C, at least about 275°C, at least about 300°C, at least about 325°C, at least about 350°C, at least about 400°C, at least about 450°C, at least about 500°C, or at least about 550°C (including all ranges in between). In some embodiments, the first temperature T1 can be about 550°C or less, about 500°C or less, about 450°C or less, about 400°C or less, about 350°C or less, about 330°C or less, about 310°C or less, about 300°C or less, about 280°C or less, about 260°C or less, about 240°C or less, about 220°C or less, about 200°C or less, about 180°C or less, about 160°C or less, or about 140°C or less (including all ranges in between). Combinations of the ranges referenced above with respect to the first temperature T1 are also possible (e.g., at least about 150°C and less than about 5500°C, at least about 200°C and less than about 500°C, or in the range of about 150°C to about 550°C, etc. (including values ​​at both ends)). In some embodiments, the temperature is either about 250°C or about 450°C.

[0024] In some embodiments, the first period Δt1 can be at least about 0 hours ("h"), at least about 0.5 hours, at least about 1 hour, at least about 1.5 hours, at least about 2 hours, at least about 2.5 hours, at least about 3 hours, at least about 3.5 hours, at least about 4 hours, at least about 4.5 hours, at least about 5 hours, at least about 6 hours, at least about 7 hours, or at least about 8 hours (including all ranges in between). In some embodiments, the first period Δt1 can be about 8 hours or less, about 7 hours or less, about 6 hours or less, about 5 hours or less, about 4 hours or less, about 3 hours or less, about 2 hours or less, about 1 hour or less, or about 0.5 hours or less (including all ranges in between). In some embodiments, the first period Δt1 can be one of about 0 hours, about 3 hours, or about 5 hours. In some embodiments, the first period Δt1 is 0 hours. In such embodiments, instead of holding the electrode active material at a first temperature T1, the electrode active material can be continuously heated to a second temperature T2 (described in further detail herein) that is higher than the first temperature, without holding the electrode active material at the first temperature T1. In other words, in such embodiments, the operation of holding the electrode active material at the first temperature T1 can be skipped.

[0025] In some embodiments, the electrode active material is heated to ambient temperature T A The gas stream that flows while heating the electrode active material from the ambient temperature T1 and / or while maintaining the electrode active material at the ambient temperature T1 is A The gas stream that flows when maintained at this temperature can be substantially identical. In other embodiments, the electrode active material is set to ambient temperature T A The gas stream that flows while heating the electrode active material from the ambient temperature T1 and / or while maintaining the electrode active material at the ambient temperature T1 is A It can be different from the gas stream that flows when it is maintained.

[0026] During a first period Δt1, following exposure to a first temperature T1, the electrode active material can be heated from the first temperature T1 to a second temperature T2 at a second heating rate R2 while a gas stream is flowing. The cathode active material can then be held at the second temperature T2 for a second period Δt2. In some embodiments, the second temperature T2 can be at least about 500°C, at least about 550°C, at least about 600°C, at least about 650°C, at least about 700°C, at least about 750°C, at least about 800°C, at least about 850°C, at least about 900°C, at least about 950°C, or at least about 1,000°C (including all ranges in between). In some embodiments, the second temperature T2 can be about 1,000°C or less, about 950°C or less, about 900°C or less, 850°C, about 840°C or less, about 800°C or less, about 760°C or less, about 720°C or less, about 680°C or less, about 640°C or less, about 600°C or less, about 560°C or less, about 520°C or less, or about 500°C or less (including all ranges in between). Combinations of the ranges referenced above with respect to the second temperature T2 are also possible (e.g., at least about 650°C and less than about 750°C, at least about 680°C and less than about 720°C, or in the range of about 600°C to about 1,000°C).

[0027] In some embodiments, the second period Δt2 can be at least about 0.1h, at least about 0.2h, at least about 0.5h, at least about 0.7h, at least about 1.0h, at least about 1.5h, at least about 2.0h, at least about 2.5h, at least about 3.0h, at least about 4.0h, at least about 5.0h, at least about 6.0h, at least about 7.0h, at least about 8.0h, at least about 9.0h, at least about 10.0h, at least about 11.0h, at least about 12.0h, at least about 13.0h, at least about 14.0h, at least about 15.0h, or at least about 20.0h (including all ranges in between). In some embodiments, the second period Δt2 can be about 20 hours or less, about 15 hours or less, about 14 hours or less, about 13 hours or less, about 12 hours or less, about 11 hours or less, about 10 hours or less, about 9 hours or less, about 8 hours or less, about 7 hours or less, about 6 hours or less, about 5 hours or less, about 4 hours or less, about 3.0 hours or less, about 2.8 hours or less, about 2.6 hours or less, about 2.4 hours or less, about 2.2 hours or less, about 2.0 hours or less, about 1.8 hours or less, about 1.6 hours or less, about 1.4 hours or less, about 1.2 hours or less, about 1.0 hours or less, about 0.8 hours or less, about 0.6 hours or less, about 0.4 hours or less, or about 0.2 hours or less (including all ranges in between). With respect to the second period Δt2, combinations of the ranges referenced above are also possible (for example, at least about 0.5 hours and less than about 20 hours, at least about 1 hour and less than about 18 hours, or within the range of about 0.5 hours to about 20 hours).

[0028] In some embodiments, the gas stream flowing while the electrode-active material is being heated from a first temperature T1 to a second temperature T2, and / or while the electrode-active material is being maintained at the second temperature T2, is such that the electrode-active material is heated to ambient temperature T A The gas stream that flows when the electrode active material is maintained at a temperature T1 and / or when the electrode active material is maintained at a first temperature T1 can be substantially the same as the gas stream that flows when the electrode active material is heated from a first temperature T1 to a second temperature T2 and / or while the electrode active material is maintained at a second temperature T2. AThe gas stream that flows when (2) the electrode active material is maintained at a first temperature T1 may be different from the gas stream that flows when (2) the electrode active material is maintained at a first temperature T1.

[0029] During the second period Δt2, following exposure to the second temperature T2, the electrode active material undergoes gas flow from the second temperature T2 to the ambient temperature T2. A It can be cooled to a cooling rate R3. In some embodiments, the first heating rate R1, the second heating rate R2, and the cooling rate R3 can be at least about 0.5°C / min, at least about 1.0°C / min, at least about 1.5°C / min, at least about 2.0°C / min, at least about 2.5°C / min, at least about 3.0°C / min, at least about 3.5°C / min, at least about 4.0°C / min, at least about 4.5°C / min, at least about 5.0°C / min, at least about 5.5°C / min, at least about 6.0°C / min, at least about 6.5°C / min, at least about 7.0°C / min, at least about 7.5°C / min, at least about 8.0°C / min, at least about 8.5°C / min, at least about 9.0°C / min, at least about 9.5°C / min, or at least about 10°C / min (including all ranges in between). In some embodiments, the first heating rate R1, the second heating rate R2, and the cooling rate R3 can be 10°C / min or less, 9.0°C / min or less, 8.0°C / min or less, 7.0°C / min or less, 6.0°C / min or less, 5.0°C / min or less, 4.0°C / min or less, 3.0°C / min or less, 2.0°C / min or less, 1°C / min or less, or 0.5°C / min or less (including all ranges in between). Combinations of the ranges referenced above with respect to the first heating rate R1, the second heating rate R2, and the cooling rate R3 are also possible (e.g., at least about 1°C / min and less than about 3°C / min, or at least about 4.5°C / min and less than about 5.5°C / min).

[0030] In some embodiments, the first heating rate R1, the second heating rate R2, and the cooling rate R3 can be substantially the same. For example, in some embodiments, the first heating rate R1, the second heating rate R2, and the cooling rate R3 can be about 5°C / min. In other embodiments, the first heating rate R1 can be different from the second heating rate R2 and / or the cooling rate R3. In some embodiments, the first heating rate R1, the second heating rate R2, and the cooling rate R3 can each be different from one another. For example, in some embodiments, the first heating rate R1 can be about 0.5°C / min, the second heating rate R2 can be about 5°C / min, and the cooling rate R3 can be about 3.5°C / min.

[0031] In some embodiments, from a second temperature T2 to ambient temperature T A The gas stream flowing during the cooling of the cathode-active material is such that the cathode-active material reaches ambient temperature T A The gas stream flowing when the cathode active material is maintained at a first temperature T1 and / or a second temperature T2 can be substantially identical. In other embodiments, the cathode active material can be maintained from a second temperature T2 to ambient temperature T A The gas stream that flows during cooling to the cathode active material is at ambient temperature T A This can be different from the gas stream that flows when maintained at a first temperature T1 and / or a second temperature T2.

[0032] Figure 2 is a flowchart showing a process 200 for relithiation of electrode active material according to one embodiment. According to the relithiation process 200, the electrode active material is first obtained in step 201 from depleted electrode material contained in an electrochemical cell that has reached its “end of service” or exhibits capacity degradation. As described above, the “depleted” nature of the electrode material refers to at least partial degradation, loss, or accumulation of the material such that the electrode active material is compositionally different from its state in the original assembly of the electrochemical device. Step 201 may involve disassembling the electrochemical cell, as well as separating the depleted electrode material (e.g., cathode and anode) from other components of the electrochemical cell such as separators and / or current collectors. Separation of depleted electrode material from the electrochemical cell may include mechanical removal, such as scraping, brushing, or crushing the current collector such that the depleted electrode material is detached. In some embodiments, the separation of depleted electrode material from the electrochemical cell does not involve the use of chemicals (i.e., is simply mechanical). In some embodiments, the separation of depleted electrode material from an electrochemical cell involves the "clean" removal of the electrode material from its respective current collector (i.e., little to no damage to the current collector and / or substantially no current collector material in the separated electrode material). In particular, the mechanical separation of depleted semi-solid electrode material (i.e., from the current collector) may require only a low applied force to remove it, for example, due to its semi-solid physical state and / or lack of binder.

[0033] In some embodiments, the depleted electrode material can be, for example, a semi-solid fixed cathode or a semi-solid fluid cathode of the type used in a redox flow cell. The depleted cathode electrode material may include a cathode electrode active material such as a lithium-containing compound. In some embodiments, the electrode active material for the semi-solid cathode may include the general ordered rock salt compound LiMO2 group, which includes α-NaFeO2 (so-called “layered compounds”) or those having an orthorhombic-LiMnO2 structural type, or derivatives thereof that differ in crystal symmetry, atomic arrangement, or partial substitution of metals or oxygen. M includes, but is not limited to, at least one first transition metal, and may also include non-transition metals such as Al, Ca, Mg, or Zr. Examples of such compounds include LiCoO2, Mg-doped LiCoO2, LiNiO2, Li(Ni,Co,Al)O2 (known as “NCA”), and Li(Ni,Mn,Co)O2 (known as “NMC” or “NCM”). Other exemplary cathode electrode active materials include those with spinel structures, such as LiMn2O4 and its derivatives, so-called “layered spinel nanocomposites,” which have ordered rock salt and nanoscopic regions with spinel order, olivine LiMPO4 and its derivatives containing one or more of Mn, Fe, Co, or Ni, partially fluorinated compounds such as LiVPO4F, other “polyanion” compounds as described below, as well as V2O5 and V6O 11 vanadium oxide V x O y Includes.

[0034] In some embodiments, the semi-solid cathode electrode active material includes, for example, a transition metal polyanion compound as described in U.S. Patent No. 7,338,734, the entire disclosure of which is incorporated herein by reference. In some embodiments, the electrode active material includes an alkali metal transition metal oxide or phosphate, and, for example, the compound has composition A x (M' 1-a M″ a ) y (XD4) z , Ax (M' 1-a M″ a ) y (DXD4) z , or A x (M' 1-a M″ a ) y (X2D7) z It has such that the sum of x, the value obtained by multiplying y(1-a) by the formal valence or formal valence group of M′, and the value obtained by multiplying ya by the formal valence or formal valence group of M″, is equal to the value obtained by multiplying the formal valence of the XD4, X2D7, or DXD4 group by z, or composition (A 1-a M″ a ) x M′ y (XD4) z , (A 1-a M″ a ) x (M' y (DXD4)z(A 1-a M″ a ) x M′ y (X2D7) zThe compound contains such that the sum of (1-a)x multiplied by the formal valence or group of formal valencies of M'', and then multiplied by the formal valence or group of formal valencies of M′, is equal to the formal valence of the XD4, X2D7, or DXD4 group multiplied by z. In the compound, A is at least one of alkali metals and hydrogen, M′ is a first transition metal, X is at least one of phosphorus, sulfur, arsenic, molybdenum, and tungsten, M'' is any of the metals of Group IIA, Group IIIA, Group IVA, Group VA, Group VIA, Group VIA, Group VIIIA, Group IB, Group IIB, Group IIIB, Group IVB, Group VB, and Group VIB, and D is at least one of oxygen, nitrogen, carbon, or halogen. The cathode electrode active material can be an olivine structure compound LiMPO4, where M is one or more of V, Cr, Mn, Fe, Co, and Ni, and this compound is optionally doped at Li, M, and O sites. Li site deficiencies are compensated by the addition of metals or metalloids, and O site deficiencies are compensated by the addition of halogens. In some embodiments, the cathode electrode active material has an olivine structure and is of the formula (Li 1-x Z x The formula contains a thermally stable transition metal-doped lithium transition metal phosphate having MPO4, where M is one or more of V, Cr, Mn, Fe, Co, and Ni, Z is a non-alkali metal dopant such as one or more of Ti, Zr, Nb, Al, or Mg, and x is in the range of 0.005 to 0.05 (including both extreme values).

[0035] In other embodiments, the lithium transition metal phosphate material is Li 1-x-z M 1+zIt has the overall composition of PO4, where M includes at least one transition metal of the first column selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, and Ni. In the formula, x ranges from 0 to 1, and z can be positive or negative. M includes Fe, and z is from about 0.05 to 0.15 (including both end values). The material can exhibit a solid solution over the composition range of 0 < x < 0.15, or the material can exhibit a stable solid solution over the composition range of 0 to at least about 0.05, or the material can exhibit a stable solid solution over the composition range of 0 to at least about 0.07 at room temperature (22 - 25 °C). The material can also exhibit a solid solution in the lithium-deficient regime, for example, when x ≥ 0.8, or x ≥ 0.9, or x ≥ 0.95.

[0036] The depleted electrode material can also include a conductive additive, such as graphite, carbon powder, pyrolytic carbon, carbon black, carbon fiber, carbon microfiber, carbon nanotube (CNT), single-layer CNT, multi-layer CNT, fullerene carbon including "buckyballs", graphene sheets and / or an aggregate of graphene sheets, any other conductive material, alloy, or a combination thereof. The depleted cathode electrode material can also include a non-aqueous liquid electrolyte, as will be described in more detail below. In some embodiments, the depleted cathode electrode material can include a cathode electrode active material in particulate form suspended in a non-aqueous liquid electrolyte, and optionally, a conductive additive. In some embodiments, the conductive additive can have a shape including spherical, plate-like, or rod-like shapes to optimize the solid filling fraction, increase the net electronic conductivity of the semi-solid, and improve the rheological behavior of the semi-solid. In some embodiments, low aspect ratio or substantially equiaxial or spherical particles are used to improve the ability of the semi-solid electrode material to flow under stress.

[0037] In some embodiments, the particles have multiple sizes to increase the packing efficiency. In particular, the particle size distribution can be bimodal, where the average particle size of the larger particle mode is at least 5 times larger than the average particle size of the smaller particle mode. In some embodiments, a mixture of large and small particles improves the flow of material during cell packing and increases the solid volume fraction and packing density within the packed cell.

[0038] In some embodiments, the depleted electrode material (e.g., cathode and / or anode) may contain about 35% to about 75% by volume of active material. In some embodiments, the depleted electrode material may contain about 40% to about 75% by volume, 45% to about 75% by volume, about 50% to about 75% by volume, about 55% to about 75% by volume, about 60% to about 75% by volume, or about 65% to about 75% by volume of cathode active material (including all ranges in between). In some embodiments, the depleted cathode electrode material may contain about 0.5% to about 8% by volume of conductive additives. In some embodiments, the depleted electrode material may contain conductive additives in amounts of about 0.6% to about 7.5 vol%, about 0.7% to about 7.0 vol%, about 0.8% to about 6.5 vol%, about 0.9% to about 6 vol%, about 1.0 vol% to about 6 vol%, about 1.5 vol% to about 5.0 vol%, or about 2 vol% to about 4 vol% (including all ranges in between). In some embodiments, the depleted electrode material may contain about 25 vol% to about 70 vol% of electrolyte. In some embodiments, the electrode may contain about 30 vol% to about 50 vol%, or about 20 vol% to about 40 vol% of electrolyte (including all ranges in between).

[0039] In some embodiments, the depleted cathode (and / or anode) electrode may have a thickness of less than 100 μm (final single-sided coated thickness). In some embodiments, the cathode (e.g., semi-solid cathode) and / or anode (e.g., semi-solid anode) may have a thickness in the range of about 250 μm to about 2,000 μm. In some embodiments, the cathode and / or anode may have a thickness in the range of about 250 μm to about 600 μm, about 300 μm to about 600 μm, about 350 μm to about 600 μm, about 400 μm to about 600 μm, about 450 μm to about 600 μm, or about 500 μm to about 600 μm (including all ranges in between).

[0040] Optionally, in step 202, the relithiation process 200 includes rinsing the electrode active material to remove one or more residues, such as electrolyte salts, electrolyte solvents, or reaction products including, but not limited to, solid electrolyte interfaces (SEIs) formed during battery operation. The rinsing medium may be any polar organic solvent, such as dimethyl carbonate ("DMC"), or any solvent that is miscible with the electrolyte and in which the electrolyte salts are soluble. For example, solvents may include, but are not limited to, ethylene carbonate, propylene carbonate, butylene carbonate, and their chlorinated or fluorinated derivatives, as well as acyclic dialkyl carbonate esters such as dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, dibutyl carbonate, butyl methyl carbonate, butyl ethyl carbonate, and butyl propyl carbonate, γ-butyl lactone, dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methylsulfolane, acetonitrile, propionitrile, ethyl acetate, methyl propionate, ethyl propionate, dimethyl carbonate, and tetraglyceride. Rinsing can be carried out, for example, by immersing the depleted electrode material in the rinsing medium / solvent with or without stirring. Further details and / or examples of rinsing step 202 are described in U.S. Patent No. 10,411,310, titled "Methods for Electrochemical Cell Remediation," issued on September 10, 2019, the entire disclosure of which is incorporated herein by reference.

[0041] In step 203, the relithiation process 200 includes mixing and / or adding additives to the electrode active material to produce a replenished electrode active material. The addition of additives to the electrode active material can replenish the "deficient" lithium lost during the electrochemical cell cycle. In some embodiments, the additive(s) include a lithium source such as lithium carbonate, lithium hydroxide, lithium nitrate, lithium sulfate, or any lithium salt. In such embodiments, the lithium source can be mixed and / or added to replenish the amount of lithium loss on the electrode active material due to the electrochemical cell cycle. In some embodiments, the additive(s) may include, but are not limited to, iron-containing additives such as Fe3(PO4)2·8H2O, Fe(CH3CO2)2, FeC2O4.2H2O, Fe3(NO3)3, FeCl3, Fe2O3, or any preferred combination thereof. In some embodiments, the additive may include, but is not limited to, nickel-containing additives comprising NiO, NiSO4.6H2O, NiCl2.6H2O, Ni(NO3)2.6H2O, Ni(CH3CO2)2.4H2O, Ni(OH)2, or any preferred combination thereof. In some embodiments, the additive may include, but is not limited to, manganese-containing additives comprising MnO2, MnSO4.H2O, MnCl2.4H2O, Mn(NO2)2.4H2O, Mn(CH3CO2)2, Mn(OH)2, or any preferred combination thereof. In some embodiments, the additive may include, but is not limited to, cobalt-containing additives comprising CoO, Co2O3, Co3O4, CoSO4.7H2O, CoCl2.6H2O, Co(NO3)2.6H2O, Co(CH3CO2)2.4H2O, Co(OH)2, or any preferred combination thereof.

[0042] In step 203, the amount of lithium-containing additive(s) or any other additives desired to be mixed and / or added to the electrode active material can be determined from an analysis of the chemical composition of the electrode active material. For example, in some embodiments, the electrode active material can be characterized by inductively coupled plasma mass spectrometry (ICP-MS) to determine its elemental chemical composition. More specifically, the electrode active material can be analyzed via ICP-MS to determine the amount and / or extent of lithium present on the electrode active material. This amount and / or extent of lithium present on the electrode active material can be compared to the amount of lithium present in the initial state of the electrode active material (e.g., "unused" electrode active material not circulated on an electrochemical cell). For example, in some examples, the "unused" NCM111 electrode active material has a composition Li determined from ICP-MS analysis. 1.17 Ni 0.37 Co 0.38 Mn 0.38 It can have O2 and a lithium-transition metal ratio of about 1.04. The NCM electrode active material contained in the depleted electrode material (originally NCM111) is Li, as determined by ICP-MS analysis. 0.84 Ni 0.63 Co 0.25 Mn 0.38 The O2 composition may have a lithium-transition metal ratio of approximately 0.66 (i.e., a loss of approximately 36.5% lithium compared to unused NCM111). Therefore, the amount of lithium-containing additive that needs to be mixed and / or added to the electrode active material in step 204 can be determined as the mass or weight of the lithium-containing additive containing enough lithium to replenish the lost 36.5% lithium.

[0043] In some embodiments, the amount of additive mixed and / or added to the electrode active material may be the mass or weight of the additive, containing enough lithium to replenish about 1%, about 2%, about 3%, about 5%, about 8%, about 10%, about 12%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, or about 70% of the lost lithium (including all ranges in between). In some embodiments, the amount of additive mixed with or added to the electrode active material can be sufficient to replenish at least about 1%, at least about 2%, at least about 3%, at least about 4%, or at least about 5% of the active material (e.g., lithium, Mn, P, Fe, Co, Ni, etc.) that is lost from the electrode active material.

[0044] In step 204, the relithiation process 200 includes homogenizing the replenished electrode active material. In some embodiments, homogenization of the replenished electrode active material involves pulverizing or grinding the replenished electrode active material using a preferred mechanical grinding process. In some embodiments, the homogenization step 205 includes filling the replenished electrode material into a container having a ceramic grinding medium and mixing the replenished electrode material over a period of time in a batch process. In some embodiments, homogenization of the replenished electrode active material can be carried out in any one of, for example, a high-shear mixer, a planetary mixer, a centrifugal planetary mixture, a sigma mixture, a cam mixture, and / or a roller mixture. In some embodiments, the mixing of the electrode material can supply a specific mixing energy of at least about 90 J / g, at least about 100 J / g, about 90 J / g to about 150 J / g, or about 100 J / g to about 120 J / g (including all ranges in between). In some embodiments, process conditions (temperature, shear rate or rate schedule, component addition sequence, location, and rate, mixing or residence time) can be selected and / or modified to control the electrical, rheological, and / or compositional (e.g., uniformity) properties of the homogenized, supplemented electrode active material. In some embodiments, the velocity of the mixing element (e.g., the roller blade edge) can be about 0.5 cm / s to about 50 cm / s (including both values). In some embodiments, the minimum gap during the flow of fluid in the mixing event (e.g., the distance from the roller blade edge to the mixer enclosure wall) can be about 0.05 mm to about 5 mm (including both values). Accordingly, the shear rate (velocity scale divided by length scale) is about 1 rpm to about 10,000 rpm (including both values). In some embodiments, the shear rate can be less than 1 rpm, and in other embodiments, it is greater than 10,000 rpm.

[0045] In step 205, the relithiation process 200 includes exposing and / or subjecting the replenished electrode active material to a thermal process treatment. In some embodiments, the thermal treatment can be similar to and / or substantially identical to the thermal treatment process 100 described above with reference to Figure 1. For example, in step 206, the relithiation process 200 optionally provides a glass stream (e.g., a gas stream) while subjecting the replenished electrode active material to an ambient temperature T A The period Δt A This includes exposure over a period of Δt. A This can be at least about 0.1h, at least about 0.2h, at least about 0.3h, at least about 0.5h, at least about 1h, at least about 1.5h, at least about 2h, at least about 2.5h, at least about 3h, at least about 3.5h, at least about 4h, at least about 4.5h, at least about 5h, at least about 6h, at least about 7h, at least about 8h, at least about 9h, at least about 10h, at least about 15h, at least about 20h, or at least about 24h (including all ranges in between). In some embodiments, the period Δt A This can be approximately 24 hours or less, approximately 20 hours or less, approximately 16 hours or less, approximately 12 hours or less, approximately 8 hours or less, approximately 4 hours or less, approximately 2 hours or less, approximately 1 hour or less, approximately 0.5 hours or less, or approximately 0.1 hours or less (including all ranges in between).

[0046] In some embodiments, in step 206, the ambient temperature T of the replenished electrode active material A Exposure to can facilitate the removal of oxygen and moisture present in the replenished electrode active material. In some embodiments, in step 206, the ambient temperature T AThe gas stream flowing during exposure to the gas can be inert and / or may contain inert gases such as helium (He), argon (Ar), and / or nitrogen (N2), as well as / or non-reactive gases. In such embodiments, the inert and / or non-reactive gases can be high-purity gases. For example, in some embodiments, the gas stream can be, and / or may contain, nitrogen gas (e.g., nitrogen gas classification N5.0, also referred to as ultra-high purity UHP) having a nitrogen concentration and / or nitrogen purity of about 99.999%. In some embodiments, the gas can contain reactive gases, such as oxygen (e.g., 99.99% oxygen), and / or air (e.g., dry or anhydrous air). In other embodiments, the gas stream can be a gas mixture containing a first component and / or a second component. The first component can be an inert and / or non-reactive gas. The second component can be an oxygen-containing gas such as air or pure oxygen, or a reducing gas such as hydrogen. In such embodiments, the gas mixture may contain the second component at a predetermined concentration. For example, the gas mixture may contain a second component at concentrations of at least about 0.5%, about 1.0%, about 1.5%, about 2.0%, about 3.0%, about 4.0%, about 5.0%, about 10%, about 15%, about 20.0%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, or about 95% (including all ranges in between).

[0047] In some embodiments, the gas stream may flow during step 206 at a flow rate of 0 mL / min, at least about 10 mL / min, at least about 20 mL / min, at least about 50 mL / min, at least about 100 mL / min, at least about 150 mL / min, at least about 200 mL / min, at least about 250 mL / min, or at least about 300 mL / min (including all ranges in between). In some embodiments, the gas stream may flow at a flow rate of about 300 mL / min or less, about 270 mL / min or less, about 240 mL / min or less, about 210 mL / min or less, about 180 mL / min or less, about 150 mL / min or less, about 120 mL / min or less, about 90 mL / min or less, about 60 mL / min or less, about 30 mL / min or less, or about 10 mL / min or less (including all ranges in between).

[0048] In step 207, the relithiation process 200 (1) while flowing a gas stream, the replenished electrode active material is heated at a first heating rate R1 to ambient temperature (T A The steps include (1) heating the replenished electrode active material from (2) to a first temperature (T1), and (2) holding the replenished electrode active material at the first temperature T1 for a first period Δt1 while flowing a gas stream. The gas stream flowed in step 207 is selected to generate a controlled atmosphere similar to the atmosphere used in the original manufacture of the electrode material (i.e., before depletion or in its original manufacture). For example, in some embodiments, the replenished electrode active material is LiCoO2 (lithium cobalt oxide, "LCO"), Li(Ni,Mn,Co)O2 (also referred to as "NCM", lithium nickel manganese cobalt oxide, "NMC"), LiNi 0.8 Co 0.15 Al 0.05The gas stream may include metal oxide cathodes such as O2 (lithium nickel cobalt aluminum oxide, "NCA"), LiMn2O4 (lithium manganese oxide, "LMO"), LiCoPO4 (lithium cobalt phosphate, "LCP"), and / or LiNiPO4 (lithium nickel phosphate, "LNP"). In such embodiments, the gas stream flowed in step 207 may be an inert and / or oxidizing gas (e.g., one that generates an inert or oxidizing atmosphere). That is, the gas stream may be a gas mixture containing an inert gas and / or an oxygen-containing gas such as air or pure oxygen. Furthermore, the gas mixture may contain an oxygen-containing gas at a predetermined concentration. For example, a gas mixture may contain oxygen-containing gas at concentrations of at least about 0%, about 0.5%, about 1.0%, about 1.5%, about 2.0%, about 3.0%, about 4.0%, about 5.0%, about 10%, about 15%, about 20.0%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, about 95%, or about 100% (including all ranges in between).

[0049] In some embodiments, the supplemented electrode active material is LiFePO4 (lithium ion phosphate, "LFP"), LiMnPO4 (lithium manganese phosphate, "LMP"), LiMn 1-x Fe x PO4 (lithium manganese iron phosphate, "LMFP"), and Li4Ti5O 12This may include lithium titanate, "LTO". In such embodiments, the gas stream flowed in step 207 may be an inert gas or a reducing gas (e.g., generating an inert or reducing atmosphere). That is, the gas stream may be a gas mixture containing an inert gas and / or a reducing gas such as hydrogen. The gas mixture may contain hydrogen-containing gas at a predetermined concentration. For example, the gas mixture may contain hydrogen gas at concentrations of at least about 0%, about 0.5%, about 1.0%, about 1.5%, about 2.0%, about 3.0%, about 4.0%, about 5.0%, about 10%, about 15%, about 20.0%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, about 95%, or about 100% (including all ranges in between).

[0050] In some embodiments, the first period Δt1 can be at least about 0h, at least about 0.5h, at least about 1h, at least about 1.5h, at least about 2h, at least about 2.5h, at least about 3h, at least about 3.5h, at least about 4h, at least about 4.5h, at least about 5h, at least about 6h, at least about 7h, or at least about 8h (including all ranges in between). In some embodiments, the first period Δt1 can be about 8h or less, about 7h or less, about 6h or less, about 5h or less, about 4h or less, about 3h or less, about 2h or less, about 1h or less, or about 0.5h or less (including all ranges in between). In some embodiments, the first period Δt1 can be one of about 0h, about 3h, or about 5h. In some embodiments, the first period Δt1 is 0h. In such embodiments, instead of holding the electrode active material at a first temperature T1, the electrode active material can be continuously heated to a second temperature T2 (described in further detail herein) that is higher than the first temperature, without holding the electrode active material at the first temperature T1. In other words, in such embodiments, the operation of holding the electrode active material at the first temperature T1 can be skipped.

[0051] In some embodiments, the gas stream used in step 207 can flow at a flow rate similar to that disclosed above with respect to step 206 (for example, a flow rate in the range of 10 to 300 mL / min).

[0052] In some embodiments, the first temperature T1 can be at least about 150°C, at least about 175°C, at least about 200°C, at least about 225°C, at least about 250°C, at least about 275°C, at least about 300°C, at least about 325°C, at least about 350°C, at least about 400°C, at least about 450°C, at least about 500°C, or at least about 550°C (including all ranges in between). In some embodiments, the first temperature T1 can be about 550°C or less, about 500°C or less, about 450°C or less, about 400°C or less, about 350°C or less, about 330°C or less, about 310°C or less, about 300°C or less, about 280°C or less, about 260°C or less, about 240°C or less, about 220°C or less, about 200°C or less, about 180°C or less, about 160°C or less, or about 140°C or less (including all ranges in between). Combinations of the ranges referenced above are also possible with respect to the first temperature T1 (for example, at least about 150°C and less than about 260°C, or at least about 200°C and less than about 300°C, or within the range of about 150°C to about 550°C (including values ​​at both ends)). In some embodiments, the temperature is either about 250°C or about 450°C.

[0053] In step 208, the relithiation process 200 includes (1) heating the replenished electrode active material from a first temperature T1 to a second temperature (T2) at a second heating rate R2 while flowing a gas stream, and (2) holding the replenished electrode active material at the second temperature T2 for a second period Δt2 while flowing a gas stream. As disclosed above with reference to step 207, the gas stream flowed in step 208 is selected to generate a controlled atmosphere similar to the atmosphere used in the original manufacture of the electrode material (i.e., before depletion or in its original manufacture). For example, the replenished electrode active material may be LiCoO2 (lithium cobalt oxide, "LCO"), Li(Ni,Mn,Co)O2 (also referred to as "NCM", lithium nickel manganese cobalt oxide, "NMC"), LiNi 0.8 Co 0.15 Al 0.05 In embodiments including metal oxide cathodes such as O2 (lithium nickel cobalt aluminum oxide, "NCA"), LiMn2O4 (lithium manganese oxide, "LMO"), LiCoPO4 (lithium cobalt phosphate, "LCP"), and / or LiNiPO4 (lithium nickel phosphate, "LNP"), the gas stream can be an inert gas and / or an oxidizing gas. That is, the gas stream can be a gas mixture including an inert gas and / or an oxygen-containing gas such as air or pure oxygen. The concentration of the oxygen-containing gas can be similar to the concentration disclosed above with reference to step 207. Alternatively, the supplemented electrode active material may be LiFePO4 (lithium iron phosphate, "LFP"), LiMnPO4 (lithium manganese phosphate, "LMP"), LiMn 1-x Fe x PO4 (lithium manganese iron phosphate, "LMFP"), and Li4Ti5O 12In other embodiments, including lithium titanate ("LTO"), the gas stream can be inert and / or reducing. That is, the gas stream can be a gas mixture containing an inert gas and / or a reducing gas such as hydrogen. The concentration of the hydrogen gas can be similar to the concentration disclosed above with reference to step 207.

[0054] In some embodiments, the second period Δt2 can be at least about 0.1h, at least about 0.2h, at least about 0.5h, at least about 0.7h, at least about 1.0h, at least about 1.5h, at least about 2.0h, at least about 2.5h, at least about 3.0h, at least about 4.0h, at least about 5.0h, at least about 6.0h, at least about 7.0h, at least about 8.0h, at least about 9.0h, at least about 10.0h, at least about 11.0h, at least about 12.0h, at least about 13.0h, at least about 14.0h, at least about 15.0h, or at least about 20.0h (including all ranges in between). In some embodiments, the second period Δt2 can be about 20 hours or less, about 15 hours or less, about 14 hours or less, about 13 hours or less, about 12 hours or less, about 11 hours or less, about 10 hours or less, about 9 hours or less, about 8 hours or less, about 7 hours or less, about 6 hours or less, about 5 hours or less, about 4 hours or less, about 3.0 hours or less, about 2.8 hours or less, about 2.6 hours or less, about 2.4 hours or less, about 2.2 hours or less, about 2.0 hours or less, about 1.8 hours or less, about 1.6 hours or less, about 1.4 hours or less, about 1.2 hours or less, about 1.0 hours or less, about 0.8 hours or less, about 0.6 hours or less, about 0.4 hours or less, or about 0.2 hours or less (including all ranges in between).

[0055] In some embodiments, the gas stream used in step 208 can flow at a flow rate similar to that disclosed above with respect to steps 206 and 207 (for example, a flow rate in the range of 10 to 300 mL / min).

[0056] In some embodiments, the second temperature T2 can be at least about 500 °C, at least about 550 °C, at least about 600 °C, at least about 650 °C, at least about 700 °C, at least about 750 °C, at least about 800 °C, at least about 850 °C, at least about 900 °C, at least about 950 °C, or at least about 1,000 °C (including all ranges therebetween). In some embodiments, the second temperature T2 can be about 1,000 °C or less, about 950 °C or less, about 900 °C or less, about 850 °C or less, about 840 °C or less, about 800 °C or less, about 760 °C or less, about 720 °C or less, about 680 °C or less, about 640 °C or less, about 600 °C or less, about 560 °C or less, about 520 °C or less, or about 500 °C or less (including all ranges therebetween). Combinations of the ranges referenced above with respect to the second temperature T2 are also possible (e.g., at least about 650 °C and less than about 750 °C, at least about 680 °C and less than about 720 °C, or within the range of about 600 °C to about 1,000 °C (including the end values)).

[0057] In step 209, the re-lithiation process 200 includes cooling the replenished electrode active material from the second temperature T2 to ambient temperature T A at a cooling rate R3 while flowing a gas stream. In some embodiments, the gas stream flowing while cooling the replenished electrode active material from the second temperature T2 to ambient temperature T A can be substantially the same as the gas stream that flows when the replenished electrode active material is maintained at ambient temperature T A , the first temperature T1, and / or the second temperature T2. In other embodiments, the gas stream flowing while cooling the replenished electrode active material from the second temperature T2 to ambient temperature T A can be different from the gas stream that flows when the replenished electrode active material is maintained at ambient temperature T A , the first temperature T1, and / or the second temperature T2.

[0058] In some embodiments, the first heating rate R1, the second heating rate R2, and the cooling rate R3 can be at least about 0.5°C / min, at least about 1.0°C / min, at least about 1.5°C / min, at least about 2.0°C / min, at least about 2.5°C / min, at least about 3.0°C / min, at least about 3.5°C / min, at least about 4.0°C / min, at least about 4.5°C / min, at least about 5.0°C / min, at least about 5.5°C / min, at least about 6.0°C / min, at least about 6.5°C / min, at least about 7.0°C / min, at least about 7.5°C / min, at least about 8.0°C / min, at least about 8.5°C / min, at least about 9.0°C / min, at least about 9.5°C / min, or at least about 10°C / min (including all ranges in between). In some embodiments, the first heating rate R1, the second heating rate R2, and the cooling rate R3 can be 10°C / min or less, 9.0°C / min or less, 8.0°C / min or less, 7.0°C / min or less, 6.0°C / min or less, 5.0°C / min or less, 4.0°C / min or less, 3.0°C / min or less, 2.0°C / min or less, 1°C / min or less, or 0.5°C / min or less (including all ranges in between). Combinations of the ranges referenced above with respect to the first heating rate R1, the second heating rate R2, and the cooling rate R3 are also possible (e.g., at least about 1°C / min and less than about 3°C / min, or at least about 4.5°C / min and less than about 5.5°C / min).

[0059] The methods described herein can also be applied to any electrode material (i.e., non-depleted, stoichiometric, or substantially stoichiometric), such as scrap electrode material from an electrode manufacturing process. Such scrap material does not have to be “depleted,” but nevertheless can be subjected to one or more of rinsing, separation, reconstitution / repair, and heat treatment so that it can be incorporated into an unused electrochemical cell.

[0060] While various embodiments of systems, methods, and devices have been described above, it should be understood that they are presented only as examples and not as limitations. Where the methods and steps described above represent certain events occurring in a particular order, a person skilled in the art who benefits from this disclosure will recognize that the order of certain steps may be changed, and such changes constitute a variation of the invention. In addition, certain steps may be performed not only sequentially as described above, but also concurrently in parallel processing, if possible. Furthermore, one or more steps may be repeated within a given process. While embodiments have been illustrated and described in detail, it should be understood that various variations in form and detail are possible.

Claims

1. A method for regenerating electrode active materials contained in depleted electrode materials, wherein the method is To obtain electrode active materials, The additive is mixed with the electrode active material to produce a replenished electrode active material, Homogenizing the replenished electrode active material, Exposing the replenished electrode active material to a thermal process, The replenished electrode active material is heated to a first temperature while a gas stream is flowing, and the replenished electrode active material is maintained at the first temperature for a first period of time. While the gas stream is flowing, the replenished electrode active material is heated to a second temperature, and the replenished electrode active material is maintained at the second temperature for a second period of time, and A method comprising exposure, which includes cooling the replenished electrode active material from the second temperature to ambient temperature while flowing the gas stream.

2. The method according to claim 1, wherein the depleted electrode material is a semi-solid cathode or a conventional solid electrode.

3. The electrode active material is LiCoO ２ ("LCO"), Li(Ni, Mn, Co)O ２ ("NMC"), LiNi ０．８ Co ０．１５ Al ０．０５ O ２ ("NCA"), LiMnO ２ O ４ ("LMO"), LiCoPO ４ ("LCP"), or LiNiPO ４ ("LNP"), and the method according to claim 1 or 2 includes at least one of them.

4. The electrode active material is LiFePO ４ (“LFP”), LiMnPO ４ (“LMP”), LiMn １－ｘ Fe ｘ PO ４ ("LMFP"), or Li ４ Ti ５ O １２ The method according to any one of the prior claims, comprising at least one of the ("LTOs").

5. The method according to any one of the prior claims, wherein the additive is a lithium-containing additive.

6. The aforementioned additives include lithium carbonate, lithium hydroxide, lithium nitrate, lithium sulfate, and Fe ３ (PO ４ ) ２ 8H ２ O, Fe(CH ３ CO ２ ) ２ FeC ２ O ４ 2H ２ O, Fe ３ (NO ３ ) ３ FeCl ３ Fe ２ O ３ NiO, NiSO ４ 6H ２ O, NiCl ２ 6H ２ O, Ni (NO ３ ) ２ 6H ２ O, Ni(CH ３ CO ２ ) ２ 4H ２ O, Ni (OH) ２ MnO ２ , MnSO ４ . H ２ O, MnCl ２ 4H ２ O, Mn (NO ２ ) ２ 4H ２ O, Mn(CH ３ CO ２ ) ２ Mn(OH) ２ CoO, Co ２ O ３ Co ３ O ４ CoSO ４ 7H ２ O, CoCl ２ 6H ２ O, Co (NO ３ ) ２ 6H ２ O, Co(CH ３ CO ２ ) ２ 4H ２ O, or Co(OH) ２ The method according to claim 5, comprising at least one of the following.

7. The method according to claim 5 or 6, wherein the additive is mixed in an amount sufficient to replenish at least about 5% of the lithium lost from the electrode active material.

8. The method according to any one of the prior claims, wherein the first temperature is approximately 150°C to approximately 550°C.

9. The method according to claim 8, wherein the first temperature is one of about 250°C or about 450°C.

10. The method according to claim 8, wherein the first period is approximately 0 hours to approximately 7 hours.

11. The method according to claim 8, wherein the first period is one of approximately 0 hours, approximately 3 hours, or approximately 5 hours.

12. The method according to any one of the prior claims, wherein the heating to the first temperature is performed at a first heating rate, the first heating rate being about 5°C / min.

13. The method according to any one of the prior claims, wherein the second temperature is approximately 600°C to approximately 1,000°C.

14. The method according to claim 13, wherein the second temperature is approximately 700°C.

15. The method according to claim 13, wherein the second temperature is in the range of about 750°C to about 850°C.

16. The method according to claim 13, wherein the second period is approximately 0.5 hours to approximately 20 hours.

17. The method according to claim 13, wherein the second period is one of approximately one hour or approximately fifteen hours.

18. The method according to any one of the prior claims, wherein the heating to the second temperature is performed at a second heating rate, the second heating rate being about 5°C / min.

19. The method according to any one of the prior claims, wherein the cooling of the replenished electrode active material is performed at a cooling rate of about 5°C / min.

20. The method according to any one of the prior claims, wherein the gas stream is flowed at a flow rate in the range of about 0 ml / min to about 100 ml / min and contains 99.999% nitrogen.

21. The method according to any one of the prior claims, wherein the flow of the gas stream includes flowing at least one of oxygen or dry air.

22. It is a method, Mixing one or more additives with the used electrode active material to produce a replenished electrode active material, Heating the replenished electrode active material to a first temperature while exposing it to a first gas, The replenished electrode active material is maintained at the first temperature for a first period of time, The replenished electrode active material is heated to a second temperature while being exposed to a second gas, The replenished electrode active material is maintained at the second temperature for a second period of time, A method comprising cooling the replenished electrode active material from the second temperature to the ambient temperature while exposing it to the second gas.

23. The method according to claim 22, wherein the first gas and the second gas include the same gas.

24. The method according to claim 22 or 23, wherein the first gas and the second gas include at least one of nitrogen, oxygen, or dry air.

25. The method according to any one of the prior claims, wherein the electroactive material used is obtained from a depleted semi-solid electrode or a conventional solid electrode.

26. The electrode active material used is LiCoO ２ (“LCO”), Li(Ni,Mn,Co)O ２ (“NMC”), LiNi ０．８ Co ０．１５ Al ０．０５ O ２ (“NCA”), LiMn ２ O ４ (“LMO”), LiCoPO ４ ("LCP"), or LiNiPO ４ The method according to any one of the prior claims, comprising at least one of the ("LNP").

27. where the electrode active material used is LiFePO ４ ("LFP"), LiMnPO ４ ("LMP"), LiMn １－ｘ Fe ｘ PO ４ ("LMFP"), or Li ４ Ti ５ O １２ ("LTO"), the method according to any one of the preceding claims.

28. The method according to any one of the prior claims, wherein the additive is a lithium-containing additive.

29. The additive is lithium carbonate, lithium hydroxide, lithium nitrate, lithium sulfate, Fe ３ (PO ４ ) ２ ·8H ２ O, Fe(CH ３ CO ２ ) ２ , FeC ２ O ４ .2H ２ O, Fe ３ (NO ３ ) ３ , FeCl ３ [[ID=2,8]]Fe ２ O ３ , NiO, NiSO ４ .6H ２ O, NiCl ２ .6H<00001,12>O, Ni(NO ３ ) ２ .6H ２ O, Ni(CH7] ３ CO ２ )<, ２ [[ID=S2]].4H ２ O, Ni(OH) ２ , MnO ２ , MnSO ４ .H ２ O, MnCl ２ .4H ２ O, Mn(NO ２ ) ２ .4H ２ O, Mn(CH ３ CO ２ ) ２ , Mn(OH) ２ , CoO, Co ２ O ３ , Co ３ O ４ , CoSO ４ .7H ２ O, CoCl ２ .6H ２ O, Co(NO ３ )[[ID=S9]] ２ .6H ２ O, Co(CH ３ CO ２ ) ２ .4H ２ O, or Co(OH) ２ A method according to any one of the prior claims, comprising at least one of the above.

30. The method according to any one of the prior claims, wherein the first temperature is approximately 150°C to approximately 550°C.

31. The method according to claim 30, wherein the first period is approximately 0 hours to approximately 7 hours.

32. The method according to any one of the prior claims, wherein the heating to the first temperature is performed at a first heating rate, the first heating rate being about 5°C / min.

33. The method according to any one of the prior claims, wherein the second temperature is approximately 600°C to approximately 1,000°C.

34. The method according to claim 33, wherein the second period is approximately 0.5 hours to approximately 20 hours.

35. The method according to any one of the prior claims, wherein the heating to the second temperature is performed at a second heating rate, the second heating rate being about 5°C / min.

36. The method according to any one of the prior claims, wherein the cooling of the replenished electrode active material is performed at a cooling rate of about 5°C / min.

37. A method for replenishing electrode active material contained in depleted electrode material, wherein the method is Mixing the additive with the electrode active material to produce a mixture, The mixture is exposed to a gas stream for a first period of time at ambient temperature. The mixture is heated to the replenishment temperature while being exposed to the gas flow. The mixture is kept at the replenishment temperature for a second period while being exposed to the gas flow. A method comprising cooling the mixture to the ambient temperature while exposing it to the gas flow to obtain a replenished electrode active material.

38. The method according to claim 37, wherein the replenishment temperature is in the range of about 600°C to about 1,000°C.

39. The method according to claim 38, wherein the gas flow includes a flow of at least one of oxygen or dry air.

40. Before heating the mixture to the replenishment temperature, the mixture is heated to an intermediate temperature while exposed to the gas flow, wherein the intermediate temperature is less than the replenishment temperature. The method according to any one of the prior claims, further comprising: holding the mixture at the intermediate temperature for a third period of time while exposing it to the gas flow.

41. The method according to claim 40, wherein the replenishment temperature is approximately 150°C to approximately 550°C.

42. The method according to claim 41, wherein the gas flow includes a flow of at least one of nitrogen, oxygen, or dry air.

43. The method according to any one of the prior claims, wherein the electroactive material is obtained from a depleted semi-solid electrode or a conventional solid electrode.

44. The electrode active material is LiCoO ２ (“LCO”), Li(Ni,Mn,Co)O ２ (“NMC”), LiNi ０．８ Co ０．１５ Al ０．０５ O ２ (“NCA”), LiMn ２ O ４ (“LMO”), LiCoPO ４ ("LCP"), or LiNiPO ４ The method according to any one of the prior claims, comprising at least one of the ("LNP").

45. The electrode active material is LiFePO ４ (“LFP”), LiMnPO ４ (“LMP”), LiMn １－ｘ Fe ｘ PO ４ ("LMFP"), or Li ４ Ti ５ O １２ The method according to any one of the prior claims, comprising at least one of the ("LTOs").

46. The aforementioned additives include lithium carbonate, lithium hydroxide, lithium nitrate, lithium sulfate, and Fe ３ (PO ４ ) ２ 8H ２ O, Fe(CH ３ CO ２ ) ２ FeC ２ O ４ 2H ２ O, Fe ３ (NO ３ ) ３ FeCl ３ Fe ２ O ３ NiO, NiSO ４ 6H ２ O, NiCl ２ 6H ２ O, Ni (NO ３ ) ２ 6H ２ O, Ni(CH ３ CO ２ ) ２ 4H ２ O, Ni (OH) ２ MnO ２ , MnSO ４ . H ２ O, MnCl ２ 4H ２ O, Mn (NO ２ ) ２ 4H ２ O, Mn(CH ３ CO ２ ) ２ , Mn(OH) ２ CoO, Co ２ O ３ Co ３ O ４ CoSO ４ 7H ２ O, CoCl ２ 6H ２ O, Co (NO ３ ) ２ 6H ２ O, Co(CH ３ CO ２ ) ２ 4H ２ O, or Co(OH) ２ A method according to any one of the prior claims, comprising at least one of the above.

Images