Recycled and upgraded regenerated battery negative electrode material

Abstract

One or more aspects of the present disclosure provide methods for recovering and upgrading a secondary battery anode material. The method includes: producing a raw anode material by processing a spent battery material containing a first anode material; purifying the original negative electrode material; and generating a second anode material using the purified raw anode material. In some embodiments, the first anode material includes graphite. And the second negative electrode material comprises a graphite-silicon composite material and / or a graphite-silicon oxide composite material. The second negative electrode material may be a battery-grade negative electrode material that can be directly used for a new battery electrode.

Description

Cross Reference to Related Applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 386,242, filed December 6, 2022, entitled “Recycling and Upcycling Spent Battery Anode Materials,” the entire contents of which are incorporated herein by reference. Government Support Statement

[0002] This invention was made with government support under DE-SC0020868 awarded by the Department of Energy. The government has certain rights in the invention. TECHNICAL FIELD

[0003] The present application relates generally to the field of battery recycling, and more specifically, to the recycling and upcycling of spent battery graphite anode materials. BACKGROUND

[0004] Lithium-ion batteries (LIBs) are widely used in many electronic devices, vehicles, and the like. Spent LIBs can cause environmental problems and resource waste. Spent LIBs can become an important secondary source of various materials used to produce new batteries. Therefore, reducing the cost of recycling and increasing the recovery rate can significantly reduce the life cycle cost of LIBs, avoid material shortages, reduce the environmental impact of new material production, and provide low-cost active materials for manufacturing new batteries. With the projected increase in battery production over the next decade, primary waste generated during production is another key source of global recycling efforts.

[0005] Most studies focus on the recovery of positive electrode metal materials. There are few reports on the recycling of negative electrode graphite materials in spent LIBs. With the shortage of resources in modern society and the increase in production costs, graphite, as a common raw material in the production field, has wide application value. The recycling and regeneration of negative electrode graphite in spent batteries cannot be ignored.

[0006] However, aged materials are typically 5 to 10 years older than current materials. Due to the improvement of electrode material performance and the continuous development of new chemical systems, regenerated anode materials can not meet the new market demand.

[0007] Developing an efficient recycling and upcycling process to recycle anode materials in a high-value form and resell to manufacturers is key to driving LIB recycling. An efficient anode recycling and upcycling system can reduce the cost of new batteries and increase the use of recycled battery materials.

[0008] Silicon-carbon composites have received significant attention as potential replacements for graphite in commercial lithium-ion batteries. However, these materials face challenges in addressing the volume expansion problem of silicon, which can impact the performance and lifespan of the battery. Spent graphite emerges as a promising candidate material for producing high-performance silicon-carbon composites at low cost. If the porous structure of spent graphite is refined to achieve an ideal uniformity and density of pores and a good combination with silicon, it can effectively alleviate the volume expansion problem of silicon. SUMMARY

[0009] The following is a simplified summary of the disclosure to present certain aspects of the disclosure in a simplified form, in order to provide a basic understanding of the disclosure. This summary is not an extensive overview of the disclosure. It is neither intended to identify key or critical elements of the disclosure nor to delineate any scope of any specific embodiments of the disclosure or any scope of the claims. Its sole purpose is to present some concepts of the disclosure in a simplified form as a prelude to the more detailed description that is to follow.

[0010] According to some embodiments of the disclosure, a method for battery recycling is provided. The method includes purifying a raw negative electrode material including a first negative electrode material, and synthesizing a second negative electrode material using the first negative electrode material and one or more silicon-containing precursors using the purified raw negative electrode material to generate the second negative electrode material. The raw negative electrode material is produced from spent batteries or other graphite sources. The first negative electrode material includes graphite. The second negative electrode material includes a graphite-silicon composite and / or a graphite-silicon oxide composite.

[0011] In some embodiments, the method further includes producing the raw negative electrode material by separating a plurality of components of a spent battery material, wherein the plurality of components of the spent battery material includes the raw negative electrode material and a raw positive electrode material.

[0012] In some embodiments, purifying the raw negative electrode material includes removing one or more impurities from the raw negative electrode material, the one or more impurities including at least one of a metal, a metal oxide, an inorganic impurity, or an organic impurity.

[0013] In some embodiments, purifying the raw negative electrode material includes performing a plasma purification process to remove the inorganic impurity or the organic impurity from the raw negative electrode material.

[0014] In some embodiments, generating the second negative electrode material using the first negative electrode material and the one or more silicon-containing precursors includes at least one of coating the one or more silicon-containing precursors on the first negative electrode material or embedding the one or more silicon-containing precursors in the first negative electrode material.

[0015] In some embodiments, the one or more silicon-containing precursors include silicon (Si) particles having a diameter of 1 nanometer to 1000 nanometers.

[0016] In some embodiments, the one or more silicon-containing precursors include at least one of trimethylsilanol, hexamethyldisiloxane, hexamethylcyclotrisiloxane, tetramethyldisiloxane, triethylsilanol, octamethyltrisiloxane, decamethyltetrasiloxane, silane, dichlorosilane, trichlorosilane, or silicon tetrachloride.

[0017] In some embodiments, the method further includes processing the second anode material through a heat treatment process under a controllable atmosphere.

[0018] In some embodiments, the controllable atmosphere includes at least one of nitrogen (N2) or argon (Ar).

[0019] In some embodiments, generating the second anode material using the purified original anode material further includes performing a surface activation process on the purified original anode material prior to synthesizing the second anode material using the first anode material and the one or more silicon-containing precursors.

[0020] In some embodiments, performing the surface activation process on the purified original anode material includes adding a functional group on the first anode material.

[0021] In some embodiments, performing the surface activation process on the purified original anode material further includes producing a porous graphite anode material using the purified original anode material.

[0022] In some embodiments, synthesizing the second anode material using the first anode material and the one or more silicon-containing precursors includes generating the second anode material by processing the surface-activated anode material using the one or more silicon-containing precursors in a heat treatment process.

[0023] In some embodiments, a heat treatment temperature of the heat treatment process is between approximately 700 degrees Celsius to approximately 2000 degrees Celsius. In some embodiments, an atmosphere gas in the heat treatment process includes at least one of nitrogen (N2) or argon (Ar).

[0024] In some embodiments, the method further includes regenerating the first anode material contained in the original anode material by processing the purified original anode material in a heat treatment process.

[0025] In some embodiments, the heat treatment process has a heat treatment temperature between about 700 degrees Celsius and about 2000 degrees Celsius, and the atmosphere gas in the heat treatment process includes at least one of hydrogen (H2), nitrogen (N2), or argon (Ar). In some embodiments, the atmosphere gas further includes one or more of methane (CH4), acetylene (C2H2), ethylene (C2H4), propylene (C3H6), and propane (C3H8).

[0026] According to one or more aspects of the disclosure, a battery recycling system is provided. The system includes a purification module for purifying raw negative electrode material including a first negative electrode material, wherein the raw negative electrode material is produced from a spent battery, and the first negative electrode material includes graphite; and a negative electrode material generator for generating a second negative electrode material using the purified raw negative electrode material, wherein the negative electrode material generator synthesizes the second negative electrode material using the first negative electrode material and one or more silicon-containing precursors, and the second negative electrode material comprises a graphite-silicon composite material.

[0027] In some embodiments, the second negative electrode material comprises at least one of a graphite-silicon composite material or a graphite-silicon oxide composite material.

[0028] In some embodiments, the negative electrode material generator further surface activates the purified raw negative electrode material before synthesizing the second negative electrode material using the first negative electrode material and one or more silicon-containing precursors. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a block diagram of a system for negative electrode recycling and upcycling according to some embodiments of the disclosure;

[0030] Figure 2 is a block diagram of an example purification module according to some embodiments of the disclosure;

[0031] Figure 3 is a block diagram of an example negative electrode upcycling module according to some embodiments of the disclosure;

[0032] Figure 4A 、 4B and 4C respectively show Scanning Electron Microscope (SEM) images of an example raw negative electrode material, a purified raw negative electrode material, and a regenerated first negative electrode material according to some embodiments of the disclosure;

[0033] Figure 5A and 5B are energy dispersive X-ray (EDX) spectra of an example graphite negative electrode material before and after purification according to some embodiments of the disclosure;

[0034] Figures 6A to 6C Electrochemical performance comparison between commercial graphite and upcycled graphite is shown;

[0035] Figure 7A Electron microscope (SEM) images of an example upcycled graphite-silicon composite material according to some embodiments of the present disclosure are shown;

[0036] Figure 7B Energy dispersive X-ray (EDX) spectra of an example upcycled graphite-silicon composite material according to some embodiments of the present disclosure are shown;

[0037] Figure 8 Charge-discharge curves of an example upcycled graphite-silicon composite anode material are shown;

[0038] Figure 9 A method flow diagram for anode recycling and upcycling according to some embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0039] Aspects of the present disclosure provide mechanisms (e.g., systems, apparatuses, methods, etc.) for spent battery anode material recycling and upcycling. As referred to in the present disclosure, a battery can be any electrical storage device. In some embodiments, the battery can be a lithium-ion battery (LIB). The mechanisms described in the present disclosure can process aged batteries and produce repaired and / or upcycled anode materials that can be used for new battery anodes.

[0040] Recycling lithium-ion batteries can include discharging spent lithium-ion batteries and separating spent graphite using physical methods such as disassembly, comminution, sieving, and other mechanical processes. The separated raw graphite anode material can be processed to produce recycled anode materials (e.g., by direct regeneration of the graphite) and / or upcycled anode materials (e.g., by upcycling the graphite anode material into a graphite-based material with additional functionalities required for energy and environmental applications).

[0041] The raw graphite material obtained by separating the raw graphite material from other components of the spent battery can not meet the standards of the battery industry due to impurities and structural defects present in the graphite material. Existing techniques for recycling graphite anode materials from spent batteries typically involve processing the raw graphite material using hydrometallurgical and / or pyrometallurgical processes. However, both pyrometallurgical and hydrometallurgical processes are high energy-consuming processes that can generate environmental pollutants (e.g., furans, dioxins, and highly acidic wastewater).

[0042] The present disclosure provides an end-to-end process for direct recycling and upcycling of aged anode material from anode to anode. The end-to-end process can involve pre-processing of spent lithium-ion batteries, component separation and purification of pristine anode material, and direct regeneration and upcycling of anode material. The end-to-end process can also involve a purification and regeneration process to directly recycle aged graphite anode material. The end-to-end process can also include a surface activation process to facilitate bonding between surface-activated graphite and a silicon precursor for direct upcycling to produce graphite-silicon (Gr-Si) composite anode material.

[0043] According to one or more aspects of the present disclosure, a system for direct recycling and upcycling of battery graphite anode material is provided. The system can process spent batteries and can produce regenerated and / or upcycled anode material that can be used for new battery electrodes. For example, the system can separate pristine anode material from spent battery material. The pristine anode material can include one or more first anode materials (e.g., graphite), impurities, etc. contained in the spent battery material. The pristine anode material can then be purified by removing the impurities. The purified pristine anode material can be processed to generate anode material (battery-grade anode material) that can be directly used for new battery electrodes. For example, the first anode material contained in the purified pristine anode material can be regenerated (e.g., recycled) as battery-grade anode material. As another example, one or more second anode materials can be generated using the first anode material. In some embodiments, the second anode material can include one or more graphite-silicon (Gr-Si) composites and / or graphite-silicon oxide (Gr-SiOx) composites made using the first anode material and a silicon-containing precursor.

[0044] Graphite-silicon (Gr-Si) and graphite-silicon oxide (Gr-SiOx) composites are promising anode materials for commercial lithium-ion batteries. However, existing solutions for producing graphite-silicon anode materials fail to provide a solution to reduce the volume expansion of silicon. Spent graphite material can be used to produce high-performance graphite-silicon composites at low cost. The mechanisms described in the present disclosure can use aged graphite anode material to produce high-energy graphite-silicon composite anode material, thereby enabling direct upcycling from anode to anode.

[0045] Direct recycling / upcycling of graphite anode materials using the disclosed methods will improve the commercial viability of lithium-ion batteries and reduce battery costs, thereby accelerating the electrification of transportation and large-scale energy storage for renewable energy. The upcycled graphite-silicon (Gr-Si) and / or graphite-silicon oxide (Gr-SiOx) based composites can then be subjected to targeted surface optimization treatments to promote electronic contact, improve rate capability, and improve cycle stability. Thus, the mechanisms described in the present disclosure can enable an upcycled, “value-added” anode that selectively leverages the engineered value of scrap graphite while reducing downstream remanufacturing requirements.

[0046] Figure 1 is a schematic diagram illustrating an example 100 of a battery recycling system. As shown, the system 100 can include a pre-processing module 110, an assembly separator 120, and an anode material generator 130. Without loss of generality, the system 100 can include more or fewer modules. For example, two modules can be combined into one module, or one module can be divided into two or more modules.

[0047] The pre-processing module 110 can process the spent battery materials to produce pre-processed spent battery materials for further processing. For example, the pre-processing module 110 can include a battery disassembly system that can disassemble the spent batteries to remove the packaging materials of the spent batteries. The packaging materials (e.g., plastics, metals, etc.) can be recycled. The cells of the spent batteries can be disassembled into small pieces using a crusher and / or a shredder. For example, the cells can be shredded in a nitrogen (N2) environment. In one implementation, the spent batteries can be discharged before being processed by the pre-processing module. In some embodiments, pre-processing the spent battery materials can include removing electrolytes from the spent battery materials, collecting packaging plastics and separators, performing powder separation to collect black powder, etc.

[0048] The component separator 120 can process the pre-treated waste battery material produced by the pre-treatment module 110 to separate the various components of the waste battery material. The separated components may include original positive electrode material, original negative electrode material, current collector metal, separator plastic, electrolyte, etc. The positive electrode material may include lithium-based layered metal oxides (such as LiCoO2, LiNiO2, LiMnO2, LiNiCoMnO2, LiNiCoAlO2, etc.). The original negative electrode material may include one or more first negative electrode materials contained in the waste battery material, impurities (such as metal oxides, metals, inorganic impurities, organic impurities, etc.). The first negative electrode material may be and / or include graphite. The component separator 120 may include one or more magnetic separators that can separate metals from the waste battery material, a vibrating screen capable of separating positive electrode material powder particles and negative electrode material powder particles from bulk materials, etc. In some embodiments, the component separator 120 may include one or more reactors for processing the pre-treated waste battery material and generating original positive electrode material, original negative electrode material, etc.

[0049] Raw negative electrode material separated from other components of spent batteries can be fed to a negative electrode material generator 130 for processing. The negative electrode material generator 130 can generate one or more negative electrode materials (also referred to as "battery-grade negative electrode materials") that can be used as electrodes for new batteries. For example, the negative electrode material generator 130 can regenerate a first negative electrode material contained in the raw negative electrode material. As another example, the negative electrode material generator 130 can utilize the first negative electrode material contained in the raw negative electrode material to generate one or more second negative electrode materials. In some embodiments, the second negative electrode material may include one or more composite negative electrode materials, such as Gr-Si composite materials, Gr-SiOx composite materials, etc.

[0050] like Figure 1 As shown, the negative electrode material generator 130 may include a purification module 131, a negative electrode material recycling module 133, and a negative electrode material upgrading and remanufacturing module 135. The purification module 131 can remove one or more impurities from the raw negative electrode material and produce purified negative electrode material (e.g., graphite particles). Examples of impurities may include metallic impurities (such as lithium (Li), cobalt (Co), manganese (Mn), nickel (Ni), aluminum (Al), copper (Cu), zinc (Zn), and iron (Fe)), metal oxides (such as aluminum oxide (Al2O3), copper oxide (CuO)), fluorine (F) and / or phosphorus (P) impurities (such as lithium fluoride (LiF), lithium phosphate (Li3PO4)), etc. In some embodiments, impurities include positive electrode material from spent battery materials. The purification module 131 may also perform a plasma purification process to remove inorganic or organic impurities from the raw negative electrode material. In some embodiments, the purification module 131 may include a combination of... Figure 2One or more components of the purification module 200 are described. In some embodiments, the plasma purification process can be implemented using the techniques described in PCT / US2021 / 060502 entitled “Systems and methods for lithium-ion battery cathode material recovery, regeneration, and upgrading” filed on November 23, 2021, the entire contents of which are incorporated herein by reference.

[0051] The purified anode material can then be processed by the recovery module 133 and / or the upcycling module 135 to produce anode material that can be used for new battery electrodes (battery-grade anode material). The anode material recovery module 133 can regenerate the first anode material contained in the spent battery material. The regenerated first anode material can be battery-grade anode material that can be used for new battery electrodes. For example, the anode material recovery module 133 can process the graphite anode material through a thermal treatment process under a controlled atmosphere to produce battery-grade anode material for manufacturing new batteries. In some embodiments, the thermal treatment temperature can be between approximately 700 degrees Celsius to approximately 2000 degrees Celsius. In some aspects, the controlled atmosphere gas can include hydrogen (H2), nitrogen (N2), argon (Ar), and the like, and combinations thereof. In some embodiments, the atmosphere gas does not contain oxygen. To enhance the bonding strength between the introduced silicon compounds and the porous graphite matrix, carbon-containing compounds such as alkanes, alkenes, and alkynes can be introduced into the gas atmosphere as additional carbon sources. Examples of suitable gases include methane (CH4), acetylene (C2H2), ethylene (C2H4), propylene (C3H6), and propane (C3H8). These gases can be introduced at a volume concentration in the range of 0.1% to 20%.

[0052] The anode material upcycling module 135 can produce one or more second anode materials using the first anode material. For example, the anode material upcycling module 135 can generate one or more Gr-Si composite materials and / or Gr-SiOx composite materials using the purified graphite material and / or suitable silicon-containing precursors. In some embodiments, the anode upcycling module 135 can include a combination of a thermal treatment process, a plasma treatment process, and / or a chemical vapor deposition process. Figure 3 One or more components of the anode upcycling module 300 are described.

[0053] Figure 2 A block diagram of an example 200 of a purification module in accordance with some embodiments of the present disclosure is shown. As shown, the purification module 200 can include a pre-purification unit 210, a plasma purification unit 220, and / or any other suitable components for purifying raw anode material separated from spent batteries for further recovery and / or upcycling processing as described in the present disclosure. The purification module 200 can purify raw anode material (e.g., graphite material) separated from spent batteries to produce purified anode material (e.g., battery-grade anode material) that can be used for new battery electrodes. In some embodiments, the purification module 200 can include a pre-purification unit 210, a plasma purification unit 220, and / or any other suitable components for purifying raw anode material separated from spent batteries for further recovery and / or upcycling processing as described in the present disclosure. The purification module 200 can purify raw anode material (e.g., graphite material) separated from spent batteries to produce purified anode material (e.g., battery-grade anode material) that can be used for new battery electrodes. Figure 1The purified negative electrode material can be produced from the raw negative electrode material produced by the middle assembly separator 120 and can be produced for further recycling and / or upcycling. The raw negative electrode material can include one or more first negative electrode materials, such as a graphite material. The purified negative electrode material can include a purified graphite material (e.g., graphite particles).

[0054] The pre-purification unit 210 can remove one or more impurities from the raw negative electrode material. For example, the pre-purification unit 210 can include one or more magnetic separators capable of removing one or more metal impurities from the separated raw negative electrode material. For another example, the pre-purification unit 210 can use an acid or a base solution to remove one or more metal and oxide impurities. The acid can include, for example, hydrochloric acid (HC1), sulfuric acid (H2SO4), nitric acid (HNO3), phosphoric acid (H3PO4), etc. The base can include, for example, lithium hydroxide (LiOH), sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH4OH), etc. Still further, the pre-purification unit 210 can include an air classification or cyclone separation system that can separate particles of metal impurities and metal oxides by air classification or cyclone separation under reduced pressure. The air classification or cyclone separation can be performed using a carrier gas including oxygen (O2), air, nitrogen (N2), argon (Ar), etc. Examples of metal impurities include iron (Fe), aluminum (Al), copper (Cu), etc. Examples of metal oxide impurities include aluminum oxide (Al2O3), copper oxide (CuO), zirconium oxide (ZrO2), lithium cobalt oxide (LiCoO2), lithium nickel cobalt manganese oxide (LiNiCoMnO2), lithium nickel cobalt aluminum oxide (LiNiCoAlO2), etc. In some embodiments, one or more impurities can be removed by reacting the solid material with a concentrated base in a pressure vessel, followed by filtration. In some embodiments, one or more impurities can be removed by reacting the solid material with a concentrated acid, followed by filtration.

[0055] In some embodiments, the impurities on the negative electrode material can also include positive electrode materials. The pre-purification unit 210 can separate the positive electrode materials from the raw negative electrode material. For example, the negative electrode graphite and the positive electrode oxides can be separated by treating the first solid material in a heavy solvent or a salt solution. The density of the solution / solvent can be between the density of graphite (2.3 g / cm3) and the density of the positive electrode oxides (5.5-7 g / cm3). The high-density solution can be recycled for the next batch. Examples of the high-density solution and the solvent include zinc bromide (ZnBr2), sodium polytungstate, or a mixture of the chemicals in a solution.

[0056] The plasma purification unit 220 can further purify the pre-purified negative material produced by the pre-purification unit 210. For example, the plasma purification unit 220 can remove organic impurities (e.g., fluorine (F) and / or phosphorus (P) containing impurities) from the pre-purified graphite negative material. In some embodiments, the plasma purification unit 220 can include a plasma reactor. In some embodiments, the plasma purification unit 220 includes one or more plasma reactors as described in PCT / US2021 / 060502 entitled “Systems and Methods for Lithium Ion Battery Cathode Material Recovery, Regeneration, and Upcycling” filed on November 23, 2021, the entire contents of which are incorporated by reference herein. The plasma purification unit 220 can flow the pre-purified negative material into a non-equilibrium plasma through a plasma region for a predetermined plasma exposure time at a predetermined plasma power density. The flow rate, the predetermined solid-to-gas volume ratio, the predetermined plasma power density, and the predetermined plasma exposure time are collectively tuned to reduce or eliminate physisorbed and / or covalently bound surface impurities on the pre-purified negative material.

[0057] In some embodiments, the predetermined flow rate is between 2 meters per second to 20 meters per second. In some embodiments, the predetermined solid-to-gas volume ratio is between 0.001 to 0.1. In some embodiments, the predetermined plasma power density is 0.3 kilowatts to 30 kilowatts per kilogram of pre-purified aged graphite negative material. In some embodiments, the predetermined plasma exposure time is between 0.05 seconds to 30 seconds. In some embodiments, the carrier gas can include oxygen (O2), air, nitrogen (N2), argon (Ar), and the like, and combinations thereof.

[0058] Figure 3is a block diagram of an example 300 of a negative electrode upcycling module according to some embodiments of the present disclosure. As shown, the negative electrode upcycling module 300 can include a surface activation unit 310, a precursor generator 320, a precursor encapsulation unit 330, a heat treatment unit 340, and / or any other suitable components for generating one or more second negative electrode materials from one or more first negative electrode materials (e.g., purified negative electrode materials generated by the purification module 131 and / or the purification module 200). The surface activation unit 310 can be a process reactor (e.g., a plasma reactor) for adding functional groups on the surface through surface treatment. The precursor generator 320 is a precursor feeder (e.g., a tank) containing a solid, liquid, or gaseous silicon-containing precursor. The precursor encapsulation unit 330 is a reaction section (e.g., a furnace) for the interaction between graphite and the silicon precursor. The heat treatment unit 340 can be a tube furnace for performing heat treatment to produce the final Gr-Si or Gr-SiOx composite material. The second negative electrode materials produced by the negative electrode upcycling module 300 can include one or more battery-grade negative electrode materials of Gr-Si composite materials and / or Gr-SiOx composite materials suitable for new battery manufacturing. Without loss of generality, the disclosed negative electrode upcycling module 300 can include more or fewer units. For example, two units can be combined into one unit, or one unit can be divided into two or more units.

[0059] The surface activation unit 310 can utilize one or more surface activation methods to treat the purified raw anode material. As previously described, the purified raw anode material includes one or more first anode materials contained in the spent battery material. The surface activation process can increase the reactivity of the first anode material with the silicon-containing precursor. For example, the surface activation unit 310 can add functional groups (e.g., -OH, -COOH, C=0, etc.) to the surface of the purified first anode material (e.g., purified graphite anode material) to accelerate the reaction and bonding between the first anode material and other materials (e.g., precursors and / or silicon-containing materials) used to generate the second anode material. As a more specific example, the surface activation unit 310 can perform one or more acid treatment processes to introduce -OH groups to the surface of the purified first anode material. The acid can include, for example, HC1, H2S04, HN03, H3P04, etc. As another example, the surface activation unit 310 can generate free radicals at the surface of the first anode material by performing a plasma treatment to increase its activity. In some embodiments, the surface activation involves using 5 kilograms of raw anode with a mixed acid consisting of a 2 molar per liter sulfuric acid solution (2M H2S04) and a 1 molar per liter hydrochloric acid solution (1M HC1) with a total volume of 10 liters. In some embodiments, the reaction can be performed at a temperature of 60 °C for about one hour. After the reaction is complete, the solid material is filtered, washed, and then dried. To further perform surface activation, these purified anodes can be treated in a basic solution. In this step, 5 kilograms of raw anode is treated with a sodium hydroxide (NaOH) solution with a concentration of 6 moles per liter (6M NaOH) with a total volume of 10 liters at the same temperature of 60 °C for 1 hour.

[0060] In some embodiments, the surface activation unit 310 can use a pore-forming agent to treat the purified raw anode material to generate a porous structure in the graphite material to produce a porous graphite material. The porous structure in the graphite material can provide additional surface area and / or reaction sites for the implantation of the silicon precursor and more space for volume expansion during the charge and discharge process. The porous structure can facilitate the penetration of electrolyte, which can result in a larger electrode-electrolyte interface. This can provide more active sites for electrochemical and electrocatalytic reactions.

[0061] In some embodiments, the generation of the porous graphite material can include catalytic gasification of the purified graphite material in a reducing gas atmosphere with various metal, salt, and metal oxide catalysts. In some embodiments, the reducing gas can include hydrogen, carbon monoxide, carbon dioxide, water vapor, etc., or combinations thereof. In some embodiments, the catalyst can include nickel (Ni), zinc (Zn), sodium (Na), potassium (K), iron chloride (FeCh), nickel nitrate (Ni(N03)2), iron nitrate (Fe(N03)3), etc., or combinations thereof. In some embodiments, an acid solution can be used to remove any residual catalyst from the porous graphite material. One example of this process includes mixing 1.5 kilograms of purified graphite with 5 liters of nickel nitrate solution containing 10 grams of Ni(N03)2-6H20 and stirring for 2 hours. After filtration and drying, the resulting powder is placed in a tube furnace and heated to 800 °C at a rate of 5 °C per minute under a nitrogen (N2) atmosphere. Once the temperature is stabilized at 800 °C, liquid water is pumped into the furnace at a flow rate of 0.20 milliliters per minute. The reaction is then allowed to continue for approximately 10 hours.

[0062] In some embodiments, the concentration of the catalyst precursor can be between approximately 0.1 wt.% and approximately 50 wt.%. In some embodiments, the concentration of the reducing gas can be between approximately 0.1% and approximately 20% by volume. In some embodiments, the carrier gas for the reducing gas can include nitrogen (N2), argon (Ar), etc., and combinations thereof. In some embodiments, the pore-creating reaction temperature is between approximately 40 degrees Celsius and approximately 1000 degrees Celsius.

[0063] In some embodiments, the surface activation can be achieved by plasma treatment. The plasma treatment can be performed using a dielectric barrier discharge (DBD) electrode located downstream of the particle and gas mixer, where the DBD electrode is adapted to provide a non-equilibrium plasma to introduce free radicals to the particle surface. In some embodiments, the plasma treatment can be performed by the plasma purification unit 220 in the system 200 described above. Figure 2 The gas composition for the plasma treatment can be a single gas, or a combination of argon (Ar), oxygen (02), water vapor (H20), hydrogen (H2), and small hydrocarbon molecules (e.g., methane (CH4), acetylene (C2H2), propane (C3H8), and propylene (C3H6)). One example of the plasma treatment conditions includes an initial negative feed rate of 6 kilograms per hour, a gas mixture of 1% oxygen in argon, a gas flow rate of 20 cubic meters per hour, a gas temperature of 300 degrees Celsius, a plasma discharge power of 6000 watts, and a residence time of 30 seconds.

[0064] The precursor generator 320 can generate and / or provide one or more suitable precursors for generating the second anode material. The precursors can include, for example, silicon-based precursors (e.g., solid precursors, liquid precursors, gaseous precursors, etc. that contain silicon), surface-activated graphite materials, binders containing suitable solvents, etc. In some embodiments, the silicon-based precursors can include one or more silicon nanoparticles (e.g., silicon particles having a diameter of 1 nm to 1000 nm), trimethylsilanol, hexamethyldisiloxane, hexamethylcyclotrisiloxane, tetramethyldisiloxane, triethylsilanol, octamethyltrisiloxane, decamethyltetrasiloxane, etc.

[0065] In some embodiments, the concentration of the silicon precursor (e.g., solid silicon precursor or liquid silicon precursor) can be between about 1 wt.% and about 50 wt.%. In some embodiments, the binder can include one or more of polyvinyl butyral (PVB), polyvinyl alcohol (PVA), polyethylene glycol (PEG), etc. The concentration of the binder can be between about 0.1 wt.% and about 20 wt.%. In some embodiments, the solvent can include water, ethanol, methanol, isopropyl alcohol, ethylene glycol, etc.

[0066] In some embodiments, the concentration of the gaseous silicon precursor can be between about 1 wt.% and about 100 wt.%. In some embodiments, the silicon-based gaseous precursor can include silane, dichlorosilane, trichlorosilane, silicon tetrachloride, etc., and combinations thereof. In some embodiments, the carrier gas of the reducing gas can include nitrogen (N2), argon (Ar), and combinations thereof. In some embodiments, the reaction temperature is between 40 degrees Celsius and 500 degrees Celsius.

[0067] The surface-activated first anode material produced by the surface activation unit 310 can be provided to a precursor encapsulation unit 330 for further processing. The precursor encapsulation unit 330 can utilize the surface-activated first anode material and the precursors provided by the precursor generator 320 to generate one or more second anode materials. The second anode materials can include one or more composite anode materials, such as Gr-Si composite materials, Gr-SiOxcomposite materials, etc. For example, the precursor encapsulation unit 330 can synthesize one or more Gr-Si composite materials by coating and / or embedding a silicon precursor on the first anode material. In some embodiments, the Gr-Si or Gr-SiOxcomposite materials can be synthesized by a spray pyrolysis coating process. By adjusting the operating parameters such as flow rate of the precursor, nozzle configuration, process temperature, and carrier gas, the coating process can be well controlled. In some embodiments, the Gr-Si composite materials can be synthesized using a sol-gel process, which involves a drying process to remove the remaining liquid phase (solvent), and the drying process is usually accompanied by a large amount of shrinkage and densification phenomena. By adjusting the ramping rate, temperature, and stirring speed, the uniformity of the composite materials produced by the sol-gel process can be well controlled. In some embodiments, the Gr-Si composite materials can be synthesized using a ball milling process. A ball mill is a grinding device used for grinding or mixing materials. In some embodiments, the Gr-Si composite materials can be synthesized by a dry coating process. For example, a mixing system is used to uniformly coat the silicon precursor on the graphite material. The mixing system can perform surface modification, prepare fine-particle composite materials, and perform precise mixing using a dry powder process. The raw materials are dispersed in a high-speed gas stream and processed by mechanical impact force.

[0068] The heat treatment unit 340 can process the second anode materials (e.g., composite anode materials) through a heat treatment process under a controllable atmosphere to produce battery-grade anode materials for manufacturing new batteries. In certain aspects, the heat treatment temperature can be between about 700 degrees Celsius and about 2000 degrees Celsius. In some embodiments, the controllable atmosphere gas can include nitrogen (N2), argon (Ar), etc.

[0069] Figure 4A 、 4B FIGS. 1, 2, 3, 4C, and 4D respectively show SEM images of an example raw anode material separated from an aged lithium-ion battery by the component separator 120, a purified raw anode material produced by the purification module 131, and a regenerated first anode material produced by the recycling module 133. As shown in FIG. 1, the raw anode material separated from the packaging, separator, electrolyte, and current collector of the spent lithium-ion battery contains impurities. After pre-purification and plasma deep cleaning processes, a purified anode material with a clean surface is obtained. The regenerated first anode material as shown in FIG. 4D has a clean surface and is free of impurities. Figure 4A FIG. 4D.Figure 4C As shown.

[0070] Figure 5A and 5B The impurity content of the example pristine anode material before and after purification by purification module 131 is shown. As shown in the figure, the impurity content of aluminum (Al) and titanium (Ti) is significantly reduced.

[0071] Half-cells were prepared using directly recycled graphite and commercial graphite as working electrodes, and electrochemical tests were performed at room temperature with lithium metal as the counter electrode in a voltage range of 0.01 V to 1.50 V. Figure 6A As shown, the initial discharge specific capacity of the recycled graphite and commercial graphite samples at a C / 10 rate reached 342 mAh / g and 330 mAh / g, respectively. For cycle performance and rate performance tests, as shown... Figure 6B and Figure 6C As shown, the capacity retention of the recycled graphite samples is comparable to or higher than that of commercial graphite samples, indicating that the structure of the recycled graphite material can be fully restored for use in new battery applications.

[0072] Figure 7A and Figure 7B The following are respectively shown by Figure 3 SEM images and EDX spectra of example upgraded and remanufactured Gr-Si composite anode materials produced by Upgrade and Remanufacture Module 135. Figure 7A SEM images of an upgraded and remanufactured Gr-Si composite material prepared from spent lithium-ion batteries, including graphite anode material, are shown. Figure 7B Showing Figure 7A EDX spectra of C and Si elements in the medium sample. Figure 7B As shown, the silicon precursor is well coated on the surface of the graphite material. As also shown, silicon is uniformly distributed throughout the graphite particles.

[0073] Half-cells were prepared using directly upgraded and remanufactured Gr-Si composite anode material as the working electrode, and electrochemical tests were conducted at room temperature with lithium metal as the counter electrode in a voltage range of 0.005 V to 3.0 V. Figure 8 As shown, the upgraded and remanufactured Gr-Si composite material achieved a first discharge specific capacity of 655 mAh / g at a C / 20 rate, far exceeding that of directly recycled graphite anodes (342 mAh / g). This upgraded and remanufactured Gr-Si composite material with significantly improved capacity can be widely used as anode material in high-energy batteries.

[0074] Figure 9 This is a flowchart illustrating an example method 900 for negative electrode recycling and upgrading, according to some embodiments of the present disclosure.

[0075] At 910, raw negative material can be produced by processing the spent battery material. For example, the pre-processing module 110 and / or the component separator 120 as shown in FIG. 1 can pre-process the spent battery material and separate the individual components (e.g., raw positive material, raw negative material, metal, plastic, lithium scrap, etc.) of the spent battery material as described above. The raw negative material can include one or more first negative materials (e.g., graphite negative material) and one or more impurities (e.g., metal, metal oxide, inorganic impurities, organic impurities, etc.). Figure 1

[0076] For example, the spent battery material (e.g., nickel cobalt manganese (NCM)-graphite battery) can be reduced in size. In some embodiments, the spent battery material can be pulverized into pieces between 1 centimeter and 5 centimeters in size using a pulverizer under a nitrogen (N2) atmosphere. The pulverized battery can be dried in a dryer at a suitable temperature for a suitable time to remove electrolyte. For example, approximately 10 kilograms of the pulverized battery can be dried in a dryer at 150 degrees Celsius for 2 hours to remove electrolyte. The separator and packaging material in the spent battery material can be removed using one or more density separators. The resulting mixture contains positive and negative electrode materials, specifically powders on the current collectors. Then, the positive and negative powders in the spent battery material can be dislodged at a suitable temperature (e.g., 500 degrees Celsius) in a furnace under a nitrogen stream for a suitable time (e.g., approximately one hour). In some embodiments, the flow rate of the nitrogen stream can be 1 cubic meter per hour. After cooling, the negative and positive powders can be sieved using a vibrating sieve separator. Then, the negative and positive materials can be separated using a density separator.

[0077] At 920, the raw negative material can be purified. For example, one or more impurities can be purified and / or removed from the raw negative material. The impurities can include, for example, metal, metal oxide, inorganic impurities, organic impurities, etc. The impurities can be removed by the purification module 131 as described above in FIG. 1 and / or the purification module 200 in FIG. 2. Figure 1 Figure 2 For a more specific example, to remove impurities and improve the quality of the graphite material, 3 kilograms of raw graphite is purified with 1M sulfuric acid (H2SO4) at a temperature of 60 degrees Celsius for 2 hours. After the reaction is complete, the solid material is filtered, washed, and dried to ensure its cleanliness and suitability for further processing.

[0078] ​​In some embodiments, purifying the raw anode material can further include performing a plasma purification process to remove inorganic or organic impurities from the raw anode material. For example, the purified raw graphite can be activated at a controlled rate of 100 grams per minute. An argon (Ar) gas stream with 1% oxygen (O2) by volume is used at a flow rate of 50 liters per minute. The plasma power is set to 6000 watts and the residence time is maintained at 30 seconds. This activation step changes the surface properties of the graphite, increasing its reactivity and making it more suitable for subsequent steps. In some embodiments, the plasma purification process can be implemented using the techniques described in PCT / US2021 / 060502 entitled “Systems and methods for lithium-ion battery cathode material recovery, regeneration, and improvement” filed on November 23, 2021, the entire contents of which are incorporated by reference herein.

[0079] In 930, a second anode material can be generated using the purified raw anode material. The second anode material can include a graphite-silicon (Gr-Si) composite, a graphite-silicon oxide (Gr-SiOx) composite, etc. For example, the purified raw anode material can be subjected to a surface activation process in 931. In some embodiments, the surface activation process can be performed in conjunction with the plasma purification process. Figure 3 The surface activation unit 310 in the system 300 can perform a surface activation process on the purified raw anode material (purified first anode material). Figure 3 The surface activation unit 310 in the system 300 can perform a surface activation process on the purified raw anode material (purified first anode material).

[0080] In 933, a second anode material can be synthesized using the first anode material and one or more silicon-containing precursors. In some embodiments in which the purified raw anode material (purified first anode material) is subjected to a surface activation process prior to synthesizing the second anode material, the second anode material can be synthesized using the surface-activated first anode material. For example, the silicon-containing precursors can be coated on and / or embedded in the surface-activated first anode material. The silicon-containing precursors can include silicon particles having a diameter of between about 1 nanometer and about 1000 nanometers. The precursors can include, for example, trimethylsilanol, hexamethyldisiloxane, hexamethylcyclotrisiloxane, tetramethyldisiloxane, triethylsilanol, octamethyltrisiloxane, decamethyltetrasiloxane, silane, dichlorosilane, trichlorosilane, silicon tetrachloride, etc. In conjunction with the surface activation unit 310 in the system 300, the precursor encapsulation unit 330 can synthesize the second anode material. Figure 3 In conjunction with the surface activation unit 310 in the system 300, the precursor encapsulation unit 330 can synthesize the second anode material. Figure 3 As a more specific example, 3 kilograms of activated graphite is mixed with 250 grams of a silicon precursor, such as trimethylsilanol, in a 10 liter aqueous solution to make a mixture. The mixture is vigorously stirred at a temperature of 50 degrees Celsius at a rate of 600 revolutions per minute for 2 hours.

[0081] At 935, the second anode material can be further processed by a thermal treatment process under a controllable atmosphere to produce a battery-grade anode material for manufacturing new batteries. The controllable atmosphere can include gases such as nitrogen (N2), argon (Ar), and combinations thereof. The thermal treatment process has a thermal treatment temperature between about 700 degrees Celsius and about 2000 degrees Celsius. The thermal treatment process can be performed by, for example, the thermal treatment unit 340 in combination with the above Figure 3 As a more specific example, the mixture described above is subjected to an annealing process at a temperature of 1500 degrees Celsius for 10 hours. A continuous flow of nitrogen is maintained during this step to maintain an inert atmosphere. The annealing process improves the structural stability and electrochemical performance of the silicon-graphite composite material.

[0082] In some embodiments, the first anode material contained in the raw anode material can be regenerated at 940 by processing the purified raw material. For example, the purified raw material can be processed by a thermal treatment process by the recycling module 133 in Figure 1

[0083] For ease of explanation, the methods of the present disclosure are described and presented as a series of steps. However, the steps according to the present disclosure can occur in various orders and / or simultaneously, and can also involve other steps not presented and described by the present disclosure. Moreover, not all of the illustrated steps can be necessary to practice the methods according to the present subject matter. Additionally, those skilled in the art will understand and appreciate the fact that the methods can also be presented using a state diagram or event diagram, as a series of interrelated states.

[0084] In some embodiments, the terms "about," "approximately," and "substantially" can mean within ±20% of a target size, in some embodiments, within ±10% of a target size, in some embodiments, within ±5% of a target size, and in some embodiments, within ±2%. The terms "about" and "approximately" can include the target size itself.

[0085] In the above description, numerous details are set forth. It is apparent, however, to one skilled in the art, that the present disclosure can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring the present disclosure.

[0086] The terms "first," "second," "third," "fourth," and the like used in the present disclosure as used herein are labels to distinguish between elements and are not necessarily intended to signify order of importance, sequence, or chronology.

[0087] ​The word "example" or "exemplary" is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "example" or "exemplary" is not necessarily to be construed as advantageous over other aspects or designs. Rather, use of the words "example" or "exemplary" is intended to present concepts in a concrete fashion. As used in this application, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless specified otherwise, or clear from context, "X includes A or B" is intended to mean any of the natural inclusive permutations. That is, if X includes A; X includes B; or X includes both A and B, then "X includes A or B" is satisfied under any of the foregoing instances. In addition, the articles "a" and "an" as used in this application and the appended claims should generally be construed to mean "one or more" unless specified otherwise or clear from context to be directed to a singular form. The use of the term "an embodiment" or "one embodiment" throughout is intended to present what is described as an example embodiment only. It is further intended that any "one embodiment" or "an embodiment" presented can not be to the exclusion of other

[0088] While numerous changes and modifications will no doubt come to mind to one skilled in the art, it is understood that it is intended to cover all such changes and modifications as fall within the scope of the disclosure. Accordingly, it is to be understood that the examples shown and described above are only illustrative of the many embodiments of the present disclosure. Therefore, the scope of the claims should not be limited to the details shown and described herein but should be given the broadest interpretation under the law.

Claims

1. A method for battery recycling and upcycling, comprising: purifying a raw anode material comprising a first anode material, wherein the raw anode material is produced from a spent battery material, and the first anode material comprises graphite; and producing a second anode material using the purified raw anode material, comprising: synthesizing the second anode material using the first anode material and one or more silicon-containing precursors.

2. The method of claim 1, wherein the second anode material comprises at least one of a graphite-silicon composite or a graphite-silicon oxide composite.

3. The method of claim 1, further comprising producing the pristine negative electrode material by separating a plurality of components in the spent battery material, wherein, a plurality of components of the spent battery material comprises a raw anode material and a raw cathode material.

4. The method of claim 1, wherein, purifying the raw anode material comprises removing one or more impurities from the raw anode material, the impurities comprising at least one of a metal, a metal oxide, an inorganic impurity, or an organic impurity.

5. The method of claim 4, wherein, purifying the raw anode material comprises performing a plasma purification to remove the inorganic impurities or the organic impurities from the raw anode material, and performing an activation treatment to generate more activated functional groups on a surface of the raw anode material.

6. The method of claim 1, wherein producing a second anode material using the first anode material and one or more silicon-containing precursors comprises at least one of: coating the one or more silicon-containing precursors on the first anode material, or embedding the one or more silicon-containing precursors in the first anode material.

7. The method of claim 6, wherein the one or more silicon-containing precursors comprise silicon (Si) or silicon oxide (SiOx) particles having a diameter of 1 nanometer to 1000 nanometers.

8. The method of claim 6, wherein the one or more silicon-containing precursors comprise at least one of trimethylsilanol, hexamethyldisiloxane, hexamethylcyclotrisiloxane, tetramethyldisiloxane, triethylsilanol, octamethyltrisiloxane, decamethyltetrasiloxane, silane, dichlorosilane, trichlorosilane, or silicon tetrachloride.

9. The method of claim 1, further comprising: treating the second anode material through a thermal treatment process under a controllable atmosphere.

10. The method of claim 9, wherein the controllable atmosphere comprises at least one of hydrogen (H2), nitrogen (N2), or argon (Ar).

11. The method of claim 1, wherein generating the second anode material using the purified raw anode material further comprises: performing a surface activation treatment on the purified raw anode material prior to synthesizing the second anode material using the first anode material and the one or more silicon-containing precursors.

12. The method of claim 11, wherein performing a surface activation treatment on the purified raw anode material comprises: adding functional groups on the first anode material.

13. The method of claim 11, wherein performing a surface activation treatment on the purified raw anode material further comprises producing a porous graphite anode material using the purified raw anode material.

14. The method of claim 13, wherein synthesizing a second anode material using the first anode material and the one or more silicon-containing precursors comprises: treating the surface-activated anode material through a thermal treatment process using the one or more silicon-containing precursors to generate the second anode material. treating the surface-activated anode material through a thermal treatment process using the one or more silicon-containing precursors to generate the second anode material.

15. The method of claim 14, wherein a heat treatment temperature of the heat treatment process is between about 700 degrees Celsius and about 2000 degrees Celsius, and wherein an atmosphere gas in the heat treatment process comprises at least one of hydrogen (H2), nitrogen (N2), or argon (Ar).

16. The method of claim 1, further comprising regenerating the first anode material included in the raw anode material by treating the purified raw material in a heat treatment process.

17. The method of claim 16, wherein a heat treatment temperature of the heat treatment process is between about 700 degrees Celsius and about 2000 degrees Celsius, and wherein an atmosphere gas in the heat treatment process comprises at least one of hydrogen (H2), nitrogen (N2), or argon (Ar).

18. A battery recycling system, comprising: a purification module configured to purify a raw anode material including a first anode material, wherein the raw anode material is produced from a spent battery material, and the first anode material includes graphite; and an anode material generator configured to generate a second anode material using the purified raw anode material, wherein the anode material generator synthesizes the second anode material using the first anode material and one or more silicon-containing precursors, wherein the second anode material includes a graphite-silicon composite material.

19. The system of claim 18, wherein, the second anode material includes at least one of a graphite-silicon (Gr-Si) composite material or a graphite-silicon oxide (Gr-SiOx) composite material.

20. The system of claim 19, wherein, the anode material generator further surface activates the purified raw anode material prior to synthesizing the second anode material using the first anode material and the one or more silicon-containing precursors.

Images