Negative electrode active material powder supplemented with metal M as well as preparation method, preparation device and application of negative electrode active material powder

Abstract

The invention belongs to the field of battery materials, and particularly relates to metal M-supplemented negative electrode active material powder and a preparation method, a preparation device and application thereof. The preparation device of the negative electrode active material powder supplemented with the metal M comprises a container, a diaphragm, an M-end current collector, a slurry stirring current collector, a slurry storage tank, a circulating pump and a metal M donor material, wherein the diaphragm is arranged in the container and divides the container into a metal reaction cavity and a slurry reaction cavity; the M-end current collector and the metal M donor material are arranged in the metal reaction cavity; and the slurry stirring current collector is arranged in the slurry reaction cavity. The metal M can be uniformly supplemented to the negative electrode active material, the process stability is improved, and the performance and the quality stability of the negative electrode prepared subsequently are improved.

Description

Technical Field

[0001] The present invention belongs to the field of battery materials, and specifically relates to the technical field of metal M (M=Li, Na and / or K) supplementation in negative electrode materials. Background Art

[0002] Metal M (lithium, sodium, potassium) ion batteries play a vital role in a variety of fields, including mobile electronics, new energy vehicles, and energy storage power stations. With the rapid development of these fields, the demand for battery energy density is increasing. However, during the battery's initial charge, factors such as the formation of the negative electrode SEI film can lead to irreversible loss of the metal M, which in turn affects its electrochemical performance, particularly its initial coulombic efficiency.

[0003] Taking lithium batteries as an example, pre-replenishing lithium in the battery's anode is an effective means of addressing the problem of irreversible lithium loss during the first cycle. This re-replenishment process not only improves the initial efficiency of the anode and forms a high-quality SEI interface, but also has the potential to pre-deposit a certain amount of metallic lithium in the lithium metal anode material, thereby fully realizing the potential of the anode material. Therefore, the development of technology for pre-replenishing metal M in battery anodes is particularly important.

[0004] Electrochemical pre-supplementation of metal M can precisely control the embedding and deposition amount of metal M, and can adjust SEI. However, the commonly used electrochemical metal M replenishment method is to first mix the active material, conductive agent, binder, etc., and then apply it on the current collector to prepare a negative electrode plate, and then perform non-in-situ electrochemical replenishment of metal M on the negative electrode plate through the charge and discharge process. For example, the Japanese patent document with publication number JP2020536348A discloses a negative electrode lithium replenishment method, which pre-prepare the negative electrode plate and then perform lithium insertion treatment on the plate. For another example, the patent document with publication number CN117832375A also discloses a similar device and method for pre-forming a negative electrode plate and then inserting lithium into the plate.

[0005] In summary, the process of pre-forming the electrode sheet and then filling the metal M has certain application prospects and can fill the negative electrode with metal M to a certain extent, but it still has certain limitations. For example, during the charge and discharge process, the electrode sheet bonding failure and conductive network destruction caused by reasons such as the expansion of the active material will make it difficult to control the uniformity of the metal M embedding and metal M deposition of the negative electrode sheet, and will also lead to uneven SEI film quality on the surface of the material. In addition, the metal M needs to be filled after the negative electrode sheet is prepared. Due to the polarization effect, the thickness of the electrode sheet also needs to be controlled, so the efficiency of metal M filling is also greatly reduced. The damage to the negative electrode sheet during the metal M filling process will also make it impossible to effectively exert the performance of the assembled battery. Most importantly, the electrochemical metal M filling process of the negative electrode sheet requires the addition of the electrode sheet assembly and disassembly process, which increases the complexity and uncontrollability of the production process.

[0006] Therefore, the industry needs a technology that can homogenize the negative electrode active material powder itself to supplement lithium, sodium or potassium. Summary of the Invention

[0007] In response to the problem of lack of technology for supplementing metal M with negative electrode active material powder, the first purpose of the present invention is to provide a device for preparing negative electrode active material powder supplemented with metal M, aiming to achieve uniform metal M supplementation of negative electrode active material powder based on the device.

[0008] The second object of the present invention is to provide a method for preparing negative electrode active material powder containing metal M using the preparation device.

[0009] The third object of the present invention is to provide an application of the negative electrode active material powder containing the metal M.

[0010] The mainstream method of metal M supplementation for negative electrodes in the industry is to pre-coat the negative electrode active material to form the electrode sheet, and then perform the metal M supplementation treatment on the electrode sheet. This process has many defects such as damage to the electrode sheet during the metal M supplementation stage, expansion and peeling of the negative electrode material. In response to the current situation in the industry, the present invention has previously attempted to propose a method for metal M supplementation for negative electrodes with powder. However, due to the lack of research on this type of method and the lack of equipment, it is difficult to solve problems such as the uniformity of the powder metal M supplementation. In response to the problems existing in the metal M supplementation with particles, the present invention has conducted in-depth research and provides the following improvement solutions:

[0011] A device for preparing a metal M-supplemented negative electrode active material powder includes a container, a separator, an M-terminal current collector (also called a first current collector), a slurry stirring current collector (also called a second current collector), a slurry storage tank, a circulation pump, and a metal M donor material; wherein the metal M is at least one of Li, Na, and K;

[0012] The diaphragm is arranged in the container and divides the container into a metal reaction chamber and a slurry reaction chamber;

[0013] The M-end current collector and the metal M donor material are arranged in the metal reaction chamber; the slurry stirring current collector is a current collector with a stirring function, which is arranged in the slurry reaction chamber;

[0014] A slurry inlet and a slurry outlet are also provided on the cavity wall of the slurry reaction chamber, wherein the slurry inlet and the slurry storage tank circulation outlet are connected through pipeline A, and the slurry outlet and the slurry storage tank circulation inlet are connected through pipeline B, wherein a circulation pump is provided on pipeline A and / or pipeline B.

[0015] In response to the problem of unsatisfactory uniformity of metal M supplementation in negative electrode powder, the present invention innovatively provides a reaction device, which combines the dual-chamber structure of the metal reaction chamber and the slurry reaction chamber, and further cooperates with the joint coordinated control of the slurry stirring collector with a stirring function, thereby achieving uniform metal M supplementation of the negative electrode active material, improving process stability, and improving the performance and quality stability of the subsequently prepared negative electrode.

[0016] In the present invention, the M-terminal current collector is a conductive metal, a conductive alloy, or a material with a conductive coating. Examples of the conductive metal include pure metals such as copper, aluminum, nickel, and platinum. Examples of the alloy include conductive copper alloys. Examples of the conductive coating include known organic-metal composite materials with conductive properties.

[0017] The metal M donor material is a material that can provide metal M; for example, it can be metal M or an alloy of metal M.

[0018] The metal M donor material is compounded on the M-terminal current collector, for example, by conventional physical, chemical or electrochemical methods.

[0019] In the present invention, the separator may be any separator material known in the industry, for example, it may be at least one of a polyolefin separator, a ceramic-coated separator, a non-woven separator, and a solid electrolyte.

[0020] The slurry stirring current collector is a conductive and stirring mechanism, which may include a stirring shaft and a stirring paddle (stirring mechanism) mounted on the stirring shaft. In the present invention, the use of a slurry stirring current collector with both simultaneous conductivity and stirring capabilities, combined with the dual-chamber electrolysis structure of the present invention, effectively improves the metal M replenishment performance of the particles and the process stability.

[0021] In the present invention, there are no special requirements for the structure of the stirring mechanism, as long as it can conduct electricity and can achieve slurry stirring. For example, as an optional solution, it can be a paddle-type, turbine-type, frame-type, or anchor-type blade; or a propeller-type, screw-type, or spiral-belt-type helical blade.

[0022] The stirring paddles may be multiple groups (eg, 1 to 5 groups) of stirring paddles arranged along the height direction of the stirring shaft.

[0023] In the present invention, the slurry stirring current collector is a 3D current collector, which is shaped like a multi-stage stirring mechanism with a stirring effect. It can be made of pure metals such as copper, aluminum, nickel, and platinum, alloys, or organic-metal composites. The slurry stirring current collector described in the present invention can enhance process synergy and improve the stability of the powdered metal M.

[0024] In the present invention, the slurry storage tank further comprises a feed bin and a discharge bin.

[0025] The present invention also provides a method for preparing metal M-supplemented negative electrode active material powder, which is prepared using the preparation device described in the present invention. During the preparation process, an electrolyte is pre-injected into a metal reaction chamber, and a slurry containing the negative electrode active material powder to be treated and the electrolyte is injected into a slurry reaction chamber. The circulation pump is turned on, and the slurry is stirred using a slurry stirring collector. The M-end collector and the slurry stirring collector are conductively connected to an external power supply to perform metal M supplementation treatment. Subsequently, the negative electrode active material powder and the liquid are separated to obtain the negative electrode active material powder after metal M supplementation.

[0026] In the present invention, the electrolyte is a mixed solution of a conductive salt containing metal M and a solvent, wherein the solvent includes at least one of a chain acid ester, a cyclic acid ester, a chain ether and a cyclic ether, and the concentration of metal M is 0.1~10M, further can be 0.5~2M; further can be 1~1.5M.

[0027] The negative electrode active material is at least one of a carbon negative electrode active material, an alloy negative electrode active material, a metal / carbon composite active material, and an oxide negative electrode active material;

[0028] Further, carbon negative electrode active materials may include graphite, soft carbon, hard carbon, etc.; alloy negative electrode active materials may include nano-silicon powder, silicon-carbon composite materials, SiOx materials, tin-based alloy materials, antimony-based alloy materials, etc.; metal-carbon composite active materials may include lithium-carbon composite materials, sodium-carbon composite materials, potassium-carbon composite materials, etc.; oxide negative electrode active materials may include lithium titanate, titanium dioxide, iron oxide, etc.

[0029] The slurry may further contain at least one of a conductive agent, a dispersant, and an additive.

[0030] Furthermore, the dispersant can be a conventional surfactant, such as, but not limited to, TX-100, with its content in the slurry being below 5 wt.%, further ranging from 0.5 to 4 wt.%, and even further ranging from 1 to 3 wt.%. In the present invention, the addition of the dispersant, combined with the structure and powder lithium replenishment concept described herein, helps further improve the uniformity and effectiveness of the powder lithium replenishment.

[0031] Furthermore, the conductive agent includes but is not limited to acetylene black, super-P, carbon nanotubes, etc., and its content in the slurry is less than 5 wt.%, further preferably 0.5-4 wt.%, and further preferably 1-3 wt.%. The conductive agent helps maintain a good electron path between the active material and the current collector, and helps improve the stability of the metal M.

[0032] Furthermore, the additives include, but are not limited to, boron-based additives (lithium bis(oxalatoborate), nitrogen-based additives (lithium nitrate), fluorine-based additives (fluoroethylene carbonate), silicon-based additives (diphenyldimethoxysilane), and phosphorus-based additives (triethyl phosphite). The amount of these additives can be adjusted as needed, for example, to comprise less than 10 wt.% of the electrolyte in the slurry, further ranging from 1 to 10 wt.%, and further ranging from 3 to 6 wt.%. Research in this invention demonstrates that the combination of these additives, the structure described in this invention, and the powder lithium replenishment strategy can further improve the uniformity and effectiveness of powder lithium replenishment, and contribute to improving the surface structure and electrochemical properties of the replenished material.

[0033] Furthermore, the metal M replenishing process includes a single metal M replenishing process or multiple metal M replenishing processes;

[0034] The multiple metal M replenishment process is a single metal M replenishment process repeated N times, wherein N is an integer from 2 to 20, preferably from 5 to 15. In the present invention, the combination of the aforementioned devices and the multiple metal M replenishment process can further enhance the lithium replenishment effect and stability of the process.

[0035] In the present invention, the process of single metal M replenishment is: the M-end current collector is conductively connected to the positive electrode of the external power supply, the slurry stirring current collector is conductively connected to the negative electrode of the external power supply, and power is applied at a fixed current density until the cut-off voltage is 0V. Then, the conductive connection mode of the external power supply (that is, the M-end current collector is conductively connected to the negative electrode of the external power supply, and the slurry stirring current collector is conductively connected to the positive electrode of the external power supply) is reversed, and power is applied at a fixed current density until the cut-off voltage is 3V. This is repeated a fixed number of times or until the coulombic efficiency is stable.

[0036] In the present invention, there is no special requirement for the current density during the lithium replenishment stage, and it can be, for example, 0.005 to 0.05 mA / cm 2 ; further can be 0.01~0.03 mA / cm 2 .

[0037] In the present invention, the voltage range during the lithium replenishment process can be 0-4V, and further can be 0-3V.

[0038] The present invention also provides a negative electrode active material powder for supplementing the metal M.

[0039] The present invention also provides an application of the metal M-supplemented negative electrode active material powder, which is used as a negative electrode active material, compounded with a conductive agent and a binder, coated on a current collector, and dried to obtain a negative electrode sheet.

[0040] Furthermore, the negative electrode plate and the positive electrode plate are assembled to form a battery.

[0041] Beneficial effects

[0042] The present invention innovatively provides a particle M-replenishing reaction device, which, through the dual-chamber combination of the metal reaction chamber and the slurry reaction chamber, further cooperates with the slurry stirring current collector to achieve uniform metal M replenishment of the negative electrode active material, improve process stability, and enhance the performance and quality stability of the subsequently prepared negative electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the structure of the electrochemical metal M replenishment device.

[0044] Figure 2 This is the cycle diagram of the material after lithium supplementation in Example 1. DETAILED DESCRIPTION

[0045] Exemplary embodiments of the present invention are described below with reference to the accompanying drawings.

[0046] See also Figure 1 The present invention provides an electrochemical metal M replenishment device (such as lithium replenishment, sodium replenishment or potassium replenishment), which includes: (1) a container, (2) an M-end current collector, (3) a metal reaction chamber, (4) a diaphragm, (5) a slurry stirring current collector, (6) a slurry reaction chamber, (7) a slurry storage tank, (8) a circulation pump, and (9) a metal M donor material.

[0047] The diaphragm (4) is arranged in the container (1) and divides the container (1) into a metal reaction chamber (3) and a slurry reaction chamber (6);

[0048] The M-end current collector (2) and the metal M donor material (9) are arranged in the metal reaction chamber (3) (the metal M donor material (9) can be composited on the M-end current collector (2)); the slurry stirring current collector (5) is arranged in the slurry reaction chamber (6);

[0049] A slurry inlet and a slurry outlet are also provided on the cavity wall of the slurry reaction chamber (6), wherein the slurry inlet and the circulation outlet of the slurry storage tank (7) are connected via a pipeline A, and the slurry outlet and the circulation inlet of the slurry storage tank (7) are connected via a pipeline B, wherein a circulation pump (8) is provided on pipeline A and / or pipeline B.

[0050] The slurry stirring current collector (5) comprises a stirring shaft and a stirring paddle arranged on the stirring shaft.

[0051] In the present invention, there is no special requirement for the structure of the stirring blade. For example, as an optional solution, the following case can be used as follows: Figure 1 Paddle type stirring blade shown.

[0052] The stirring shaft is vertically positioned within the slurry reaction chamber. One to four stirring paddles are arranged along the height of the stirring shaft. The slurry stirring current collector is made of a conductive material, such as a single conductive metal, a conductive alloy, or a material coated with a conductive coating.

[0053] In the present invention, the method for supplementing the metal M using the device is, for example:

[0054] S1. Slurrying the negative electrode active material to be treated and the electrolyte to form a slurry; selectively adding at least one of a dispersant, a conductive agent and an additive to the slurry;

[0055] S2, placing the M-end current collector containing metal M into the metal reaction chamber;

[0056] S3. Inject the electrolyte into the metal reaction chamber, inject the slurry into the slurry storage tank and the slurry positive electrode reaction chamber, turn on the circulation pump and start the stirring function of the slurry stirring current collector;

[0057] S4. Turn on the power supply. First, the M-end current collector and the slurry stirring current collector are conductively connected to the positive electrode and the negative electrode of the external power supply, respectively. Power is supplied at a fixed current density until the cut-off voltage is 0V. Then, the power supply is reversed (reverse connection, that is, the M-end current collector and the slurry stirring current collector are conductively connected to the negative electrode and the positive electrode of the external power supply, respectively). Power is supplied at a fixed current density until the cut-off voltage is 3V to supplement the active material with metal M. After the metal M supplementation is completed, an active slurry is obtained. The active slurry is washed with an organic solvent and separated and dried to obtain a pre-metal M supplemented active material.

[0058] Taking into account the need for lithium replenishment, the charge and discharge steps of S4 can be repeated to achieve continuous replenishment of metal M.

[0059] A negative electrode made of a pre-supplemented metal M active material prepared using the device and method is assembled into a battery that forms the corresponding metal M. For example, a negative electrode active material that supplements lithium is prepared to form a negative electrode, and this is assembled to form a lithium secondary battery. A negative electrode active material that supplements sodium is prepared to form a negative electrode, and this is assembled to form a sodium secondary battery. A negative electrode active material that supplements potassium is prepared to form a negative electrode, and this is assembled to form a potassium secondary battery.

[0060] In the present invention, the steps of preparing the negative electrode by pre-supplementing the metal M active material include, for example, slurrying the pre-supplemented metal M active material, a conductive agent, and a binder, coating the slurry on the negative electrode current collector, and then drying to prepare the negative electrode.

[0061] In the following cases, conventional commercial hard carbon is used as the negative electrode active material to be treated.

[0062] In the following case, the base electrolyte may be electrolyte A, which is an organic solution containing LiPF6, wherein the solvent comprises EC / DEC / DMC in a volume ratio of 1:1:1; wherein EC is ethylene carbonate, DEC is diethyl carbonate, and DMC is dimethyl carbonate.

[0063] In addition, the electrolyte B of the present invention may be an electrolyte obtained by adding fluoroethylene carbonate FEC to the electrolyte A, wherein the concentration of FEC in the electrolyte B is 5 wt.%.

[0064] Example 1

[0065] This embodiment uses Figure 1 The electrochemical metal M replenishment device, taking the hard carbon negative electrode material for lithium-ion batteries as an example, specifically adopts the following electrochemical lithium replenishment method:

[0066] S1. Active material (hard carbon), electrolyte A, dispersant (TX-100), and conductive agent (carbon nanotubes) are uniformly mixed in a mass ratio of 10:86:2:2 to form a slurry;

[0067] S2. Inserting a lithium plate / copper current collector (M-terminal current collector-M donor material composite material, which refers to a lithium foil composited on a copper current collector) into the metal reaction chamber;

[0068] S3. Inject electrolyte A into the metal reaction chamber, inject the slurry into the slurry storage tank and the slurry reaction chamber, turn on the stirring mechanism (slurry stirring current collector, having four sets of copper four-blade paddle stirring mechanisms arranged along the height direction) at a speed of 300 rpm, and turn on the circulation pump at a flow rate of 0.5 L / h;

[0069] S4, turn on the power supply to replenish lithium for the active material. The specific process is to charge and discharge the slurry once. First, the M-end current collector and the slurry stirring current collector are respectively connected to the positive and negative electrodes of the external power supply. 2 The current density is 0.01 mA / cm 2 The current density is applied until the cutoff voltage reaches 3V, and the lithium replenishment is completed to obtain an active slurry. The active slurry is washed with EC solvent and dried to obtain a pre-lithiated active material;

[0070] A slurry of pre-lithiated active material, conductive agent (acetylene black), and binder (PVDF) was prepared in NMP solvent at a mass ratio of 9:0.5:0.5, and then applied to a copper current collector to prepare a hard carbon negative electrode sheet. The hard carbon negative electrode sheet was then assembled with a LiCoO2 positive electrode sheet (the positive electrode material includes LiCoO2, PVDF, and acetylene black at a mass ratio of 9:0.5:0.5) to form a full battery. The electrolyte was electrolyte B. During the test, the battery was pre-activated at a current density of 0.1C for 3 cycles, and then cycled at 1C and 30°C for 350 cycles with a voltage range of 1.5~4.2V. The cycling results are shown in Figure 2 .

[0071] Example 2

[0072] The only difference from Example 1 is that the slurry further contains an additive, fluoroethylene carbonate FEC, and the content of FEC is 5 wt.% based on the weight of electrolyte A. Other operations and parameters are the same as those in Example 1.

[0073] Example 3

[0074] Compared with Example 1, the only difference is that the charge and discharge process of step S4 is repeated 10 times, that is, the slurry is charged and discharged continuously for 10 times.

[0075] Example 4

[0076] This embodiment uses Figure 1 The electrochemical metal M replenishment device, taking the hard carbon negative electrode material for sodium ion batteries as an example, specifically adopts the following electrochemical lithium replenishment method:

[0077] S1. Active material (hard carbon), electrolyte C (1 M NaPF6 organic solution, in which the solvent is EC / DEC with a volume ratio of 1:1), dispersant (TX-100), and conductive agent (carbon nanotubes) are uniformly mixed in a mass ratio of 10:86:2:2 to form a slurry;

[0078] S2, inserting the sodium plate / aluminum current collector into the metal reaction chamber;

[0079] S3. Inject electrolyte C into the metal reaction chamber, inject slurry into the slurry storage tank and slurry reaction chamber, and open the slurry uniformity device at a flow rate of 0.5 L / min;

[0080] S4. Turn on the power supply to replenish lithium for the active material. The specific process is to charge and discharge the slurry 10 times, with a cut-off voltage range of 0~3V and a current density of 0.01 mA / cm 2 After lithium replenishment is completed, an active slurry is obtained. The active slurry is washed with EC solvent and dried to obtain a pre-lithiated active material;

[0081] A slurry was prepared in NMP solvent using pre-sodiumized active material, conductive agent (acetylene black), and binder (PVDF) in a mass ratio of 9:0.5:0.5, which was then scraped onto a copper current collector to prepare a hard carbon negative electrode sheet. The slurry was then assembled with a sodium vanadium phosphate positive electrode sheet into a full battery. The electrolyte was 1 M NaPF6 solution, the solvent was DME, the current density was 20 mA / g, and the voltage range was 1.0-3.8 V.

[0082] Example 5

[0083] Compared with Example 1, the only difference is that no dispersant is added to the slurry, and other operations and parameters are the same as Example 1.

[0084] Example 6

[0085] Compared with Example 1, the only difference is that no conductive agent is added to the slurry, and other operations and parameters are the same as Example 1.

[0086] Comparative Example 1

[0087] Compared with Example 1, the only difference is that hard carbon that has not undergone a pre-lithiation process is used as the active material to prepare the negative electrode sheet, and the same full battery is assembled.

[0088] The test found that the first-cycle coulombic efficiency was 57.02%; the first-cycle discharge capacity was 95.52 mAh / g.

[0089] Comparative Example 2

[0090] Compared with Example 1, the only difference is that the slurry stirring current collector is not used. Instead, it is replaced by a non-conductive stirring device with a stirring function and a copper foil current collector. During the electrolysis process, the stirring device is turned on, and the current collectors in the metal reaction chamber and the slurry reaction chamber are conductively connected. Other operations and parameters are the same as in Example 1.

[0091] Other operations and parameters are the same as in Example 1.

[0092] Comparative Example 3

[0093] Compared with Comparative Example 2, the only difference is that no stirring device is added to the slurry reaction chamber, and other operations and parameters are the same as Comparative Example 2.

[0094] Comparative Example 4

[0095] A conventional method of forming a negative electrode first and then replenishing the negative electrode with lithium was adopted. The steps were as follows: hard carbon (same as in Example 1), a conductive agent (acetylene black), and a binder (PVDF) were prepared into a slurry in an NMP solvent at a mass ratio of 9:0.5:0.5, and then applied to a copper current collector by blade coating to prepare a hard carbon negative electrode. The hard carbon negative electrode and lithium foil were assembled into a half-cell. The specific process was to charge and discharge the electrode once, with a cut-off voltage range of 0-3V and a current density of 1 mA / cm 2 The lithium replenishment is completed and the lithium replenishment electrode is obtained. The lithium replenishment is assembled with the LiCoO2 positive electrode to form a full battery, and the electrolyte is electrolyte B.

[0096] The results of multiple batches of repeated experiments in each embodiment are shown in Table 1.

[0097]

[0098] In Table 1, Example 2, compared to Example 1, further adds an additive to the slurry, which, when used in conjunction with the lithium replenishment device of the present invention, further enhances the lithium replenishment effect and process stability. Furthermore, Example 3, along with Example 1, demonstrates that the lithium replenishment effect and process stability can be further improved by using the lithium replenishment device of the present invention in conjunction with a multi-stage lithium replenishment process.

[0099] It can be seen from Example 4 that sodium supplementation can also be achieved by adopting the process of the present invention.

[0100] It can be seen from Examples 1, 5 and 6 that further adding a dispersant and / or a conductive agent to the slurry in combination with the lithium replenishment device and process of the present invention can further enhance the lithium replenishment performance of the negative electrode powder and the process stability.

[0101] The results of repeated experiments of multiple batches for each comparative example are shown in Table 2.

[0102]

[0103] In Table 2, compared with Example 1, Comparative Example 2, and Comparative Example 3, the use of the current collector with conductive-stirring functions of the present invention in the lithium replenishment process can unexpectedly further enhance the lithium replenishment effect and the stability of the lithium replenishment process.

[0104] In addition, by comparing Example 1 with Comparative Example 4 (conventional electrode lithium replenishment), the lithium replenishment performance and process stability can be further enhanced by using the lithium replenishment device and process of the present invention.

[0105] In summary, the lithium replenishment device and method described in the present invention can achieve the particle lithium replenishment effect and improve the lithium replenishment performance and lithium replenishment process stability.

Claims

1. A device for preparing anode active material powder supplemented with metal M, characterized in that: Including container, diaphragm, M-end current collector, slurry stirring current collector, slurry storage tank, circulation pump, metal M donor material; Wherein, the metal M is at least one of Li, Na, and K; The diaphragm is arranged in the container and divides the container into a metal reaction chamber and a slurry reaction chamber; The M-end current collector and the metal M donor material are arranged in the metal reaction chamber; the slurry stirring current collector is a current collector with a stirring function, which is arranged in the slurry reaction chamber; A slurry inlet and a slurry outlet are also provided on the cavity wall of the slurry reaction chamber, wherein the slurry inlet and the slurry storage tank circulation outlet are connected through pipeline A, and the slurry outlet and the slurry storage tank circulation inlet are connected through pipeline B, wherein a circulation pump is provided on pipeline A and / or pipeline B.

2. The device for preparing the metal M-supplemented negative electrode active material powder according to claim 1, wherein: The M-terminal current collector is a conductive metal, a conductive alloy, or a material with a conductive coating; The metal M donor material is a material that can provide metal M; Wherein, the metal M donor material is compounded on the M-end current collector.

3. The device for preparing the metal M-supplemented negative electrode active material powder according to claim 1, wherein: The diaphragm includes at least one of a polyolefin diaphragm, a ceramic coated diaphragm, a non-woven fabric diaphragm, and a solid electrolyte; The slurry stirring current collector is a mechanism with electrical conductivity and stirring function, which includes a stirring shaft and a stirring paddle arranged on the stirring shaft; The stirring blade can be a paddle-type, turbine-type, frame-type, anchor-type blade; or a propeller-type, screw-type, or ribbon-type helical blade.

4. A method for preparing a metal M-supplemented negative electrode active material powder, characterized in that: The preparation is carried out using the preparation device described in any one of claims 1 to 3, and during the preparation process, an electrolyte is injected into the metal reaction chamber in advance, a slurry in which the negative electrode active material powder to be treated and the electrolyte are dispersed is injected into the slurry reaction chamber, the circulation pump is turned on, the slurry stirring collector is used for stirring, and the M-end collector and the slurry stirring collector are conductively connected to an external power supply to perform metal M supplementation treatment, and then the negative electrode active material powder and the electrolyte are separated to obtain the negative electrode active material powder after metal M supplementation.

5. The method for preparing the metal M-supplemented negative electrode active material powder according to claim 4, wherein: The electrolyte is a mixed solution of a conductive salt containing metal M and a solvent, wherein the solvent includes at least one of a chain acid ester, a cyclic acid ester, a chain ether and a cyclic ether, and the concentration of the metal M is 0.1~10M; The negative electrode active material is at least one of a carbon negative electrode active material, an alloy negative electrode active material, a metal / carbon negative electrode composite active material, and an oxide negative electrode active material; The slurry further comprises at least one of a conductive agent, a dispersant, and an additive.

6. The method for preparing the metal M-supplemented negative electrode active material powder according to claim 5, wherein: The slurry contains a conductive agent and a dispersant; Wherein, the content of the dispersant in the slurry is less than 5wt.%; the content of the conductive agent in the slurry is less than 5wt.%; The slurry may further selectively contain additives, wherein the additives include at least one of boron-based additives, nitrogen-based additives, fluorine-based additives, silicon-based additives, and phosphorus-based additives; The amount of the additive is less than 10 wt.% of the electrolyte in the slurry.

7. The method for preparing the metal M-supplemented negative electrode active material powder according to any one of claims 4 to 6, wherein: The metal M replenishing process includes a single metal M replenishing process or a multiple metal M replenishing process; The multiple metal M replenishment process is a single metal M replenishment process repeated N times, where N is an integer of 2 to 20.

8. A metal M-supplemented negative electrode active material powder prepared by the preparation method according to any one of claims 4 to 7.

9. A use of the metal M-supplemented negative electrode active material powder according to claim 8, characterized in that: It is used as the negative electrode active material and compounded with a conductive agent and a binder to prepare a negative electrode sheet.

10. The use of the metal M-supplemented negative electrode active material powder according to claim 9, characterized in that: The negative electrode sheet and the positive electrode sheet are assembled to form a battery.

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