Lithium supplement material, preparation method and application thereof

Abstract

The present disclosure belongs to the technical field of battery materials, and particularly relates to a lithium supplement material, a preparation method thereof, and an application thereof. The lithium supplement material has the chemical formula of Li 1+n Ni x Mn y O2, where n + x + y = 1, 0 < n < 0.2, 0.3 < x < 0.45, 0.5 < y < 0.65; the lithium supplement material is an aggregate of primary particles, the short-axis length of the primary particles is selected from 200 - 300 nm, and the long-axis length of the primary particles is selected from 420 - 650 nm; the D50 particle size of the aggregate is selected from 2.25 - 3.50 μm. The rate performance and cycle performance of a lithium-ion battery containing the lithium supplement material provided by the present disclosure can be significantly improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of battery materials, and in particular to a lithium supplement material, a preparation method thereof, and an application thereof. Background Art

[0002] Lithium-ion battery is a widely used secondary battery. At present, the commonly used negative electrode material for lithium-ion batteries is graphite, but due to the limited theoretical capacity of graphite negative electrodes, the development of lithium-ion batteries towards high energy density is restricted. Therefore, negative electrode materials with higher capacity such as silicon-based negative electrodes, tin-based negative electrodes, and hard carbon negative electrodes are gradually being applied to lithium-ion batteries. However, negative electrode materials with higher capacity such as silicon-based negative electrodes, tin-based negative electrodes, and hard carbon negative electrodes generally have the disadvantage of low initial charge and discharge efficiency, which seriously affects the full battery capacity and the improvement of actual energy density.

[0003] The disadvantage of low initial charge and discharge efficiency of the above-mentioned negative electrode materials can be solved by replenishing lithium in the negative electrode sheet. The current lithium replenishment methods mainly include: (1) replenishing lithium by mechanically pressing metal lithium foil and negative electrode sheet; (2) sprinkling lithium powder on the surface of the negative electrode sheet to replenish lithium; (3) preparing lithium powder into slurry and then coating it on the surface of the negative electrode sheet to replenish lithium; (4) depositing lithium on the surface of the negative electrode sheet by vacuum thermal evaporation; (5) inserting lithium into the negative electrode sheet by electroplating or electrodeposition; (6) mixing the negative electrode material with metal lithium powder and ball milling, or heating and melting the metal lithium and mixing it with the negative electrode material to directly replenish the negative electrode material with lithium; (7) first preparing lithium silicide powder Li x Si, and then mix the lithium silicide powder with the negative electrode material to supplement lithium.

[0004] However, the operation of replenishing lithium to the negative electrode is usually complicated and has serious safety hazards. Therefore, some technicians are studying the replenishment of lithium to the positive electrode, for example, Li2NiO2, Li5FeO4, Li3N, Li2O2, Li2S, etc. Taking Li3N as an example, Li3N has the advantages of high lithium replenishment capacity and a relatively safe lithium replenishment process. However, Li3N has poor chemical stability in the air and is easily converted into lithium carbonate in the air and releases ammonia, which affects the lithium replenishment effect of Li3N. Therefore, it is urgent to develop a lithium replenishment material with better lithium replenishment effect. Summary of the invention

[0005] The present invention provides a lithium supplement material, a preparation method and application thereof, to solve the deficiencies in the related art.

[0006] According to a first aspect of an embodiment of the present disclosure, a lithium supplement material is provided, wherein the lithium supplement material has Li 1+ n Ni x Mn yThe chemical formula of O2, wherein n+x+y=1, 0<n<0.2, 0.5<y<0.65, 0.3<x<0.45; and the lithium supplement material is an aggregate of primary particles, the minor axis length of the primary particles is selected from 200-300nm, and the major axis length of the primary particles is selected from 420-650nm; the D50 particle size of the aggregate is selected from 2.25-3.50μm.

[0007] In one aspect of the disclosed embodiments, the D90 particle size of the aggregates is selected from 3.82-5.70 μm.

[0008] In one aspect of the disclosed embodiments, the D10 particle size of the aggregates is selected from 1.52-2.28 μm.

[0009] According to a second aspect of an embodiment of the present disclosure, a method for preparing a lithium supplement material is provided, the method comprising the following steps:

[0010] Step 1: dissolving manganese salt and nickel salt in water, adding an aqueous solution of a complexing agent and a coprecipitant under stirring, then heating to 65°C-75°C, continuing stirring for 2-5 hours, and obtaining a precursor after aging;

[0011] Step 2: Mechanically mixing the precursor and the lithium salt to obtain a mixture;

[0012] Step 3: calcining the mixture at 450°C-600°C for 3-5h to obtain the lithium supplement material.

[0013] In one aspect of the embodiments of the present disclosure, step 1 comprises: dissolving manganese salt and nickel salt in water, adding 25%-50% of the total mass of the complexing agent at room temperature under stirring, then stirring for 15-30 minutes, then heating to 50°C-55°C, adding an aqueous solution of the coprecipitant and the remaining complexing agent, then stirring for 15-45 minutes, further heating to 65°C-75°C, continuing stirring for 2-5 hours, and obtaining a precursor after aging.

[0014] Preferably, step 1 comprises: dissolving manganese salt and nickel salt in water, adding 35%-45% of the total mass of the complexing agent at room temperature under stirring, stirring for 15-30 minutes, heating to 50°C-55°C, adding an aqueous solution of the coprecipitant and the remaining complexing agent, stirring for 25-40 minutes, further heating to 65°C-75°C, continuing stirring for 2-5 hours, and obtaining a precursor after aging.

[0015] In one aspect of the embodiments of the present disclosure, the manganese salt is selected from manganese sulfate.

[0016] In one aspect of the embodiments of the present disclosure, the nickel salt is selected from nickel sulfate.

[0017] In one aspect of the embodiments of the present disclosure, the complexing agent is selected from ammonia water.

[0018] In one aspect of the embodiments of the present disclosure, the coprecipitant is selected from at least one of sodium hydroxide, ammonium bicarbonate, sodium bicarbonate, ammonium oxalate and sodium oxalate.

[0019] In one aspect of the embodiments of the present disclosure, the coprecipitant is selected from ammonium oxalate.

[0020] In one aspect of the embodiments of the present disclosure, the lithium salt is selected from lithium carbonate.

[0021] In one aspect of the embodiments of the present disclosure, when the lithium salt is selected from lithium carbonate and the manganese salt is selected from manganese sulfate, the mass ratio of manganese sulfate to lithium carbonate is selected from (1.65-1.95):1.

[0022] In one aspect of the disclosed embodiment, in step 1, the stirring rate is selected from 3000-3800 r / min.

[0023] In one aspect of the embodiments of the present disclosure, when the manganese salt is selected from manganese sulfate and the nickel salt is selected from nickel sulfate, the mass ratio of manganese sulfate to nickel sulfate is selected from (1.35-1.65):1.

[0024] In one aspect of the embodiments of the present disclosure, when the manganese salt is selected from manganese sulfate and the complexing agent is selected from ammonia water, the mass ratio of ammonia water to manganese sulfate is selected from (0.75-1.0):1.

[0025] In one aspect of the embodiments of the present disclosure, when the manganese salt is selected from manganese sulfate and the coprecipitant is selected from ammonium oxalate, the mass ratio of ammonium oxalate to manganese sulfate is selected from (0.20-0.35):1.

[0026] In one aspect of the embodiments of the present disclosure, when the coprecipitant is selected from ammonium oxalate, the concentration of the aqueous solution of ammonium oxalate is selected from 15-50 g / L.

[0027] In one aspect of an embodiment of the present disclosure, the lithium supplement material provided by the present disclosure is an ellipsoidal particle or a spherical particle having a hollow structure or a hollow structure with a microcore, the wall thickness of the ellipsoidal particle or the spherical particle is 0.45-0.65 μm, and the diameter of the inner wall of the ellipsoidal particle or the spherical particle is 0.65-1.15 μm.

[0028] In one aspect of the embodiments of the present disclosure, the lithium supplement material has a thickness greater than or equal to 1.10 m 2 / g specific surface area.

[0029] In one aspect of the embodiments of the present disclosure, the lithium supplement material has a mass greater than or equal to 1.40 g / m3 The tap density.

[0030] According to a third aspect of an embodiment of the present disclosure, a positive electrode plate is provided, comprising a positive electrode current collector, a positive electrode active material, a conductive agent, a binder, and the aforementioned lithium supplement material or the lithium supplement material prepared by the aforementioned method.

[0031] In one aspect of the embodiments of the present disclosure, the positive electrode plate comprises a positive current collector, a positive electrode material layer and a lithium replenishing material layer, the positive electrode material layer comprises a positive electrode active material, a conductive agent and a binder, and the lithium replenishing material layer comprises a lithium replenishing material, a conductive agent and a binder; the positive current collector is arranged on one side of the positive electrode material layer, and the lithium replenishing material layer is arranged on a side of the positive electrode material layer away from the positive current collector.

[0032] In one aspect of an embodiment of the present disclosure, the positive electrode active material includes at least one of lithium cobalt oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium oxyphosphate, lithium vanadate, lithium manganate, lithium nickel oxide, lithium nickel cobalt manganese oxide, lithium-rich manganese-based material or lithium nickel cobalt aluminum oxide.

[0033] Preferably, the positive electrode active material is selected from lithium iron phosphate.

[0034] In one aspect of the embodiments of the present disclosure, the mass ratio of the lithium supplement material to the positive electrode active material is selected from (1.5-3.5):100.

[0035] According to a fifth aspect of the embodiments of the present disclosure, a lithium-ion battery is provided, wherein the lithium-ion battery comprises the aforementioned positive electrode plate.

[0036] According to a fifth aspect of an embodiment of the present disclosure, there is provided an electrochemical device, comprising the aforementioned positive electrode plate.

[0037] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects:

[0038] It can be seen from the above embodiments that the rate performance and cycle performance of a lithium-ion battery containing the lithium supplement material provided by the present disclosure in the positive electrode plate can be significantly improved.

[0039] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0041] Figure 1 This is a TEM image of the lithium supplement material prepared in Example 1.

[0042] Figure 2 This is the TEM image of the lithium supplement material prepared in Comparative Example 1. DETAILED DESCRIPTION

[0043] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0044] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The relevant embodiments described herein are illustrative and are used to provide a basic understanding of the present application. The embodiments of the present application should not be interpreted as limiting the present application.

[0045] For simplicity, only some numerical ranges are specifically disclosed herein. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and any upper limit can be combined with any other upper limit to form an unspecified range. In addition, each separately disclosed point or single value can itself be combined as a lower limit or upper limit with any other point or single value or with other lower limits or upper limits to form an unspecified range.

[0046] In this article, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

[0047] In the description herein, unless otherwise specified, “above” and “below” include the number.

[0048] Unless otherwise specified, the terms used in this disclosure have the commonly known meanings generally understood by those skilled in the art. Unless otherwise specified, the numerical values ​​of the various parameters mentioned in this disclosure can be measured using various measurement methods commonly used in the art (for example, they can be tested according to the methods given in the embodiments of this disclosure).

[0049] The term "about" is used to describe and illustrate small changes. When used in conjunction with an event or situation, the term may refer to an example in which the event or situation occurs precisely and an example in which the event or situation occurs very approximately. For example, when used in conjunction with a numerical value, the term may refer to a range of variation less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. In addition, amounts, ratios, and other numerical values ​​are sometimes presented in this article in a range format. It should be understood that such a range format is for convenience and simplicity, and should be flexibly understood to include not only numerical values ​​explicitly designated as range limits, but also all individual numerical values ​​or subranges encompassed within the range, as if each numerical value and subrange were explicitly designated.

[0050] A list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may contain a single component or multiple components. Item B may contain a single component or multiple components. Item C may contain a single component or multiple components.

[0051] In the present disclosure, the ammonia water used in the present disclosure is ammonia water with a concentration of 25%.

[0052] Positive electrode:

[0053] In some embodiments of the present disclosure, the positive electrode plate involved in the present disclosure includes a positive electrode current collector, a positive electrode material layer and a lithium replenishing material layer, the positive electrode material layer includes a positive electrode active material, a conductive agent and a binder, and the lithium replenishing material layer includes a lithium replenishing material, a conductive agent and a binder; a positive electrode plate is arranged on one side of the positive electrode material layer, and the lithium replenishing material layer is arranged on the side of the positive electrode material layer away from the positive electrode current collector.

[0054] In some embodiments of the present disclosure, the positive electrode active material includes a compound that reversibly intercalates and deintercalates lithium ions. The positive electrode active material may include a composite oxide containing lithium and at least one element selected from cobalt, manganese and nickel. The specific types of positive electrode active materials are not subject to specific restrictions and can be selected according to needs. The positive electrode active material is selected from at least one of lithium cobalt oxide LiCoO2 (LCO), lithium nickel manganese cobalt ternary material (NCM), lithium iron phosphate, and lithium manganese oxide. They can be used alone or in any combination of two or more.

[0055] In other embodiments of the present disclosure, the positive electrode active material includes at least one of lithium cobalt oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium phosphate, lithium vanadate, lithium manganate, lithium nickel oxide, lithium nickel cobalt manganese oxide, lithium-rich manganese-based materials or lithium nickel cobalt aluminum oxide.

[0056] In some embodiments of the present disclosure, the lithium supplement material is prepared by the following steps:

[0057] Step 1: dissolving manganese salt and nickel salt in water, adding an aqueous solution of a complexing agent and a coprecipitant under stirring, then heating to 55°C-60°C, continuing stirring for 2-5 hours, and obtaining a precursor after aging;

[0058] Step 2: Mechanically mixing the precursor and the lithium salt to obtain a mixture;

[0059] Step 3: calcining the mixture at 450° C.-600° C. to obtain a lithium supplement material.

[0060] In some embodiments of the present disclosure, based on the total mass of the positive electrode sheet, the mass percentage of the positive electrode material is 85%-95%.

[0061] In some embodiments of the present disclosure, the positive electrode material layer and the lithium supplement material layer further include a binder, and the mass percentage of the binder is 0.3%-5% based on the total mass of the positive electrode material layer. In some embodiments of the present disclosure, non-limiting examples of binders include polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic (ester) styrene-butadiene rubber, epoxy resin, nylon, etc., but are not limited thereto.

[0062] In some embodiments of the present disclosure, the positive electrode material layer and the lithium supplement material layer also include a conductive agent, and the mass percentage of the conductive agent is 0.3%-3% based on the total mass of the positive electrode material layer. In some embodiments of the present disclosure, the conductive material may include any conductive material as long as it does not cause chemical changes. Non-limiting examples of conductive agents include carbon-based materials (e.g., natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, etc.), metal-based materials (e.g., metal powder, metal fiber, etc., including, for example, copper, nickel, aluminum, silver, etc.), conductive polymers (e.g., polyphenylene derivatives) and mixtures thereof, but are not limited thereto.

[0063] In some embodiments of the present disclosure, the positive electrode current collector may be aluminum (Al), but is not limited thereto.

[0064] Negative electrode:

[0065] In some embodiments of the present disclosure, the lithium-ion battery provided by the present disclosure further includes a negative electrode plate, and the negative electrode plate includes a current collector and a negative electrode material layer disposed on the current collector. The specific types of negative electrode materials are not subject to specific restrictions and can be selected according to needs. Specifically, the negative electrode material includes natural graphite, artificial graphite, mesophase microcarbon beads (abbreviated as MCMB), hard carbon, soft carbon, silicon, silicon-carbon composites, Li-Sn alloys, Li-Sn-O alloys, Sn, SnO, SnO2, spinel structured lithiated TiO2-Li4Ti5O 12 , Li-Al alloy. Non-limiting examples of carbon materials include crystalline carbon, amorphous carbon and mixtures thereof. Crystalline carbon can be amorphous or flake-shaped, platelet-shaped, spherical or fibrous natural graphite or artificial graphite. Amorphous carbon can be soft carbon, hard carbon, mesophase pitch carbide, calcined coke, etc.

[0066] In some embodiments of the present disclosure, the negative electrode material layer may include a binder and optionally a conductive material. The binder improves the bonding between the negative electrode material particles and the bonding between the negative electrode material and the current collector.

[0067] In some embodiments of the present disclosure, non-limiting examples of binders include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, and the like.

[0068] In some embodiments of the present disclosure, the negative electrode material layer includes a conductive agent so that the electrode has conductivity. The conductive agent may include any conductive material as long as it does not cause chemical changes. Non-limiting examples of conductive materials include carbon-based materials (e.g., natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, etc.), metal-based materials (e.g., metal powder, metal fiber, etc., such as copper, nickel, aluminum, silver, etc.), conductive polymers (e.g., polyphenylene derivatives) and mixtures thereof.

[0069] In some embodiments of the present disclosure, the negative electrode sheet of the present disclosure includes a negative electrode material, a binder and a conductive agent.

[0070] In some embodiments of the present disclosure, the negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof.

[0071] Diaphragm:

[0072] In some embodiments of the present disclosure, the electrochemical device of the present disclosure is provided with a separator between the positive electrode plate and the negative electrode plate to prevent short circuit. The material and shape of the separator used in the electrochemical device of the present disclosure are not particularly limited, and it can be any technology disclosed in the prior art.

[0073] In some embodiments of the present disclosure, the separator includes a polymer or an inorganic substance formed of a material that is stable to the electrolyte of the present disclosure.

[0074] In some embodiments of the present disclosure, the separator may include a substrate layer and a surface treatment layer. The substrate layer is a non-woven fabric, a film or a composite film with a porous structure, and the material of the substrate layer includes at least one of polyethylene, polypropylene, polyethylene terephthalate and polyimide.

[0075] Specifically, a polypropylene porous film, a polyethylene porous film, a polypropylene non-woven fabric, a polyethylene non-woven fabric or a polypropylene-polyethylene-polypropylene porous composite film may be used.

[0076] A surface treatment layer is disposed on at least one surface of the substrate layer. The surface treatment layer may be a polymer layer or an inorganic layer, or a layer formed by mixing a polymer and an inorganic layer.

[0077] The inorganic layer comprises inorganic particles and a binder, wherein the inorganic particles are selected from one or a combination of aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, cerium dioxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide and barium sulfate. The binder is selected from one or a combination of polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinyl pyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene and polyhexafluoropropylene.

[0078] The polymer layer contains polymers, and the material of the polymer is selected from at least one of polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylic acid salt, polyvinyl pyrrolidone, polyvinyl ether, polyvinylidene fluoride, and poly(vinylidene fluoride-hexafluoropropylene).

[0079] Electrolyte:

[0080] The lithium-ion batteries and electrochemical devices of the present disclosure also include an electrolyte.

[0081] In some embodiments of the present disclosure, the electrolyte includes a lithium salt and a solvent.

[0082] In some embodiments of the present disclosure, the lithium salt includes at least one of an organic lithium salt or an inorganic lithium salt. In some embodiments, the lithium salt includes, but is not limited to: lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium difluorophosphate (LiPO2F2), lithium bis(trifluoromethanesulfonyl)imide LiN(CF3SO2)2 (LiTFSI), lithium bis(fluorosulfonyl)imide Li(N(SO2F)2) (LiFSI), lithium bis(oxalatoborate) LiB(C2O4)2 (LiBOB), or lithium di(oxalatoborate) LiBF2(C2O4) (LiDFOB).

[0083] In some embodiments of the present disclosure, the solvent may be selected from one or more of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), ethyl methyl sulfone (EMS) and diethyl sulfone (ESE).

[0084] In some embodiments of the present disclosure, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high temperature performance, additives that improve battery low temperature performance, etc.

[0085] Lithium-ion battery:

[0086] In some embodiments of the present disclosure, the lithium-ion battery involved in the present disclosure includes the above-mentioned positive electrode plate, negative electrode plate, separator, electrolyte, etc., but is not limited thereto.

[0087] In some embodiments of the present disclosure, the lithium-ion battery involved in the present disclosure may include an outer package, which may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer package of the lithium-ion battery may also be a soft package, such as a bag-type soft package. The material of the soft package may be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), etc.

[0088] In some embodiments of the present disclosure, the present disclosure further provides a battery module. The battery module includes the above-mentioned lithium-ion battery. The battery module of the present disclosure uses the above-mentioned lithium-ion battery, and therefore has at least the same advantages as the lithium-ion battery. The number of lithium-ion batteries contained in the battery module of the present disclosure can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module.

[0089] In some embodiments of the present disclosure, the present disclosure further provides a battery pack, which includes the above-mentioned battery module. The number of battery modules included in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0090] Electrochemical device:

[0091] In some embodiments of the present disclosure, the electrochemical device includes, but is not limited to: electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, power storage systems, etc. In order to meet the high power and high energy density requirements of the device for lithium-ion batteries, a battery pack or battery module may be used.

[0092] In other embodiments of the present disclosure, the electrochemical device may be a mobile phone, a tablet computer, a laptop computer, etc. The device is usually required to be light and thin, and a lithium-ion battery may be used as a power source.

[0093] The present application is further described below in conjunction with the examples. It should be understood that these examples are only used to illustrate the present application and are not used to limit the scope of the present application.

[0094] Embodiment and comparative example:

[0095] Embodiment 1:

[0096] Embodiment 1 comprises the following steps:

[0097] (1) Preparation of lithium supplement materials:

[0098] Dissolve 85g of manganese sulfate and 50g of nickel sulfate in 800mL of water, add 32mL of ammonia water under stirring (3650 r / min), stir at room temperature for 20min, then heat to 57°C, add 48mL of ammonia water and 700mL of 35 g / L ammonium oxalate, continue stirring for 35min, then further heat to 70°C, continue stirring for 4h, and obtain the precursor after aging.

[0099] The entire precursor was mixed with 45 g of lithium carbonate, ball-milled at 500 rpm for 4-8 h to obtain a mixture, and then dried;

[0100] The mixture was taken out and calcined at 550°C for 4 hours to obtain the lithium supplement material Li 1.12 Ni 0.32 Mn 0.56 O2. The TEM image of the lithium supplement material prepared in Example 1 is as follows Figure 1 As shown; wherein the lithium supplement material is an aggregate of primary particles, the short axis length of the primary particles is 200-300nm, and the long axis length of the primary particles is 420-650nm.

[0101] (2) Preparation of positive electrode sheet:

[0102] LiFePO4, conductive carbon black (Super-P), and binder polyvinylidene fluoride (PVDF) were mixed in a weight ratio of 92:4:4 in an N-methylpyrrolidone (NMP) solvent system and then coated on aluminum foil to control the coating surface density to 11 mg / cm 2 Up to 18 mg / cm 2 , dried at 105℃ for 4h before use;

[0103] The lithium supplement material prepared above was weighed according to 20% of the weight of LiFePO4, and then the lithium supplement material, conductive carbon black (Super-P), and binder polyvinylidene fluoride (PVDF) were weighed according to a weight ratio of 6:1:1, and then added to the N-methylpyrrolidone (NMP) solvent system and stirred and mixed to form a lithium supplement slurry, and then 1 / 10 volume of the lithium supplement slurry was evenly scraped onto the surface of the aforementioned LiFePO4 layer (that is, the lithium supplement material is 2wt% of the positive electrode active material), and then dried at 120°C for 3h, and then cold pressed, punched and welded to the pole ears to obtain the positive electrode sheet.

[0104] (3) Preparation of negative electrode sheet:

[0105] Artificial graphite, conductive agent SP (conductive carbon black), thickener sodium carboxymethyl cellulose (CMC), and adhesive styrene butadiene rubber (SBR) are fully stirred and mixed in a proper amount of deionized water solvent at a weight ratio of 95:2:2:1 to form a uniform negative electrode slurry. The slurry is coated on the negative electrode current collector copper foil, dried and cold pressed to obtain a negative electrode material layer, and then cut, slit, and weld the pole ears to obtain a negative electrode sheet.

[0106] (4) Preparation of lithium-ion batteries:

[0107] The positive electrode sheet, the isolation film, and the negative electrode sheet are stacked in order, so that the isolation film is placed between the positive electrode sheet and the negative electrode sheet to play an isolating role, and then wound to obtain a bare battery cell; the bare battery cell is placed in an outer packaging foil aluminum-plastic film, and the above-prepared electrolyte is injected into the dried bare battery cell. After vacuum packaging, standing, formation, shaping, capacity testing and other processes, the preparation of the lithium battery of Example 1 is completed.

[0108] Embodiment 2:

[0109] Embodiment 2 comprises the following steps:

[0110] (1) Preparation of lithium supplement materials:

[0111] Dissolve 85g of manganese sulfate and 50g of nickel sulfate in 800mL of water, add 15mL of ammonia water under stirring (3650 r / min), stir at room temperature for 20min, then heat to 57°C, add 65mL of ammonia water and 700mL of 35 g / L ammonium oxalate, continue stirring for 35min, then further heat to 70°C, continue stirring for 4h, and obtain the precursor after aging.

[0112] The obtained precursor was mixed with 45 g of lithium carbonate, ball-milled at 500 rpm for 4-8 h to obtain a mixture, and then dried;

[0113] The mixture was taken out and calcined at 550°C for 4 hours to obtain a lithium supplement material.

[0114] (2) Preparation of positive electrode sheet:

[0115] LiFePO4, conductive carbon black (Super-P), and binder polyvinylidene fluoride (PVDF) were mixed in a weight ratio of 92:4:4 in an N-methylpyrrolidone (NMP) solvent system and then coated on aluminum foil to control the coating surface density to 11 mg / cm 2 Up to 18 mg / cm 2 , dried at 105℃ for 4h before use;

[0116] The lithium supplement material prepared above was weighed according to 20% of the weight of LiFePO4, and then the lithium supplement material, conductive carbon black (Super-P), and binder polyvinylidene fluoride (PVDF) were weighed according to a weight ratio of 6:1:1, and then added to the N-methylpyrrolidone (NMP) solvent system and stirred and mixed to form a lithium supplement slurry, and then 1 / 10 volume of the lithium supplement slurry was evenly scraped onto the surface of the aforementioned LiFePO4 layer, and then dried at 120°C for 3h, and then cold pressed, punched and welded to the pole ears to obtain the positive electrode sheet.

[0117] (3) Preparation of negative electrode sheet:

[0118] Artificial graphite, conductive agent SP (conductive carbon black), thickener sodium carboxymethyl cellulose (CMC), and adhesive styrene butadiene rubber (SBR) are fully stirred and mixed in a proper amount of deionized water solvent at a weight ratio of 95:2:2:1 to form a uniform negative electrode slurry. The slurry is coated on the negative electrode current collector copper foil, dried and cold pressed to obtain a negative electrode material layer, and then cut, slit, and weld the pole ears to obtain a negative electrode sheet.

[0119] (4) Preparation of lithium-ion batteries:

[0120] The positive electrode sheet, the isolation film, and the negative electrode sheet are stacked in order, so that the isolation film is placed between the positive electrode sheet and the negative electrode sheet to play an isolating role, and then wound to obtain a bare battery cell; the bare battery cell is placed in an outer packaging foil aluminum-plastic film, and the above-prepared electrolyte is injected into the dried bare battery cell. After vacuum packaging, standing, formation, shaping, capacity testing and other processes, the preparation of the lithium battery of Example 2 is completed.

[0121] Embodiment 3:

[0122] Embodiment 3 comprises the following steps:

[0123] (1) Preparation of lithium supplement materials:

[0124] Dissolve 85g of manganese sulfate and 50g of nickel sulfate in 800mL of water, add 65mL of aqueous ammonia under stirring (3650 r / min), stir at room temperature for 20min, then heat to 57°C, add 15mL of aqueous ammonia and 700mL of 35 g / L ammonium oxalate, continue stirring for 35min, then further heat to 70°C, continue stirring for 4h, and obtain the precursor after aging.

[0125] The obtained precursor was mixed with 45 g of lithium carbonate, ball-milled at 500 rpm for 4-8 h to obtain a mixture, and then dried;

[0126] The mixture was taken out and calcined at 550°C for 4 hours to obtain a lithium supplement material.

[0127] (2) Preparation of positive electrode sheet:

[0128] LiFePO4, conductive carbon black (Super-P), and binder polyvinylidene fluoride (PVDF) were mixed in a weight ratio of 92:4:4 in an N-methylpyrrolidone (NMP) solvent system and then coated on aluminum foil to control the coating surface density to 11 mg / cm 2 Up to 18 mg / cm 2 , dried at 105℃ for 4h before use;

[0129] The lithium supplement material prepared above was weighed according to 20% of the weight of LiFePO4, and then the lithium supplement material, conductive carbon black (Super-P), and binder polyvinylidene fluoride (PVDF) were weighed according to a weight ratio of 6:1:1, and then added to the N-methylpyrrolidone (NMP) solvent system and stirred and mixed to form a lithium supplement slurry, and then 1 / 10 volume of the lithium supplement slurry was evenly scraped onto the surface of the aforementioned LiFePO4 layer, and then dried at 120°C for 3h, and then cold pressed, punched and welded to the pole ears to obtain the positive electrode sheet.

[0130] (3) Preparation of negative electrode sheet:

[0131] Artificial graphite, conductive agent SP (conductive carbon black), thickener sodium carboxymethyl cellulose (CMC), and adhesive styrene butadiene rubber (SBR) are fully stirred and mixed in a proper amount of deionized water solvent at a weight ratio of 95:2:2:1 to form a uniform negative electrode slurry. The slurry is coated on the negative electrode current collector copper foil, dried and cold pressed to obtain a negative electrode material layer, and then cut, slit, and weld the pole ears to obtain a negative electrode sheet.

[0132] (4) Preparation of lithium-ion batteries:

[0133] The positive electrode sheet, the isolation film, and the negative electrode sheet are stacked in order, so that the isolation film is placed between the positive electrode sheet and the negative electrode sheet to play an isolating role, and then wound to obtain a bare battery cell; the bare battery cell is placed in an outer packaging foil aluminum-plastic film, and the above-prepared electrolyte is injected into the dried bare battery cell. After vacuum packaging, standing, formation, shaping, capacity testing and other processes, the preparation of the lithium battery of Example 3 is completed.

[0134] Embodiment 4:

[0135] The steps of Example 4 are basically the same as those of Example 1, except that when preparing the lithium supplement material precursor, the following steps are included: 85g of manganese sulfate and 50g of nickel sulfate are dissolved in 800mL of water, 42mL of ammonia water is added under stirring (3650 r / min), stirred at room temperature for 20min, then heated to 57°C, 38mL of ammonia water and 700mL of prepared 35 g / L ammonium oxalate are added, stirring is continued for 35min, then, the temperature is further raised to 70°C, stirring is continued for 4h, and the precursor is obtained after aging.

[0136] Embodiment 5:

[0137] The steps of Example 5 are basically the same as those of Example 1, except that when preparing the lithium supplement material precursor, the following steps are included: 85g of manganese sulfate and 50g of nickel sulfate are dissolved in 800mL of water, 32mL of ammonia water is added under stirring (3650 r / min), stirred at room temperature for 20min, then heated to 57°C, 48mL of ammonia water and 450mL of prepared 0.5mol / L sodium hydroxide are added, stirring is continued for 35min, then, the temperature is further raised to 70°C, stirring is continued for 4h, and the precursor is obtained after aging.

[0138] Embodiment 6:

[0139] The steps of Example 6 are basically the same as those of Example 1, except that when preparing the lithium supplement material precursor, the following steps are included: 85g of manganese sulfate and 50g of nickel sulfate are dissolved in 800mL of water, 32mL of ammonia water is added under stirring (3650 r / min), stirred at room temperature for 20min, then heated to 57°C, 48mL of ammonia water and 500mL of 60 g / L ammonium bicarbonate are added, stirring is continued for 35min, then, the temperature is further raised to 70°C, stirring is continued for 4h, and the precursor is obtained after aging.

[0140] Embodiment 7:

[0141] The steps of Example 7 are basically the same as those of Example 1, except that the steps of preparing the positive electrode sheet include:

[0142] LiFePO4, conductive carbon black (Super-P), and binder polyvinylidene fluoride (PVDF) were mixed in a weight ratio of 92:4:4 in an N-methylpyrrolidone (NMP) solvent system and then coated on aluminum foil to control the coating surface density to 11 mg / cm 2 Up to 18 mg / cm 2 , dried at 105℃ for 4h before use;

[0143] The lithium supplement material prepared above was weighed according to 40% of the weight of LiFePO4, and then the lithium supplement material, conductive carbon black (Super-P), and binder polyvinylidene fluoride (PVDF) were weighed according to a weight ratio of 6:1:1, and then added to the N-methylpyrrolidone (NMP) solvent system and stirred and mixed to form a lithium supplement slurry, and then 1 / 10 volume of the lithium supplement slurry (that is, the lithium supplement material is 4wt% of the positive electrode active material) was evenly scraped onto the surface of the aforementioned LiFePO4 layer, and then dried at 120°C for 3h, and then cold pressed, punched and welded to the pole ear to obtain the positive electrode sheet of Example 7.

[0144] Embodiment 8:

[0145] The steps of Example 8 are basically the same as those of Example 1, except that the steps of preparing the positive electrode sheet include:

[0146] LiFePO4, conductive carbon black (Super-P), and binder polyvinylidene fluoride (PVDF) were mixed in a weight ratio of 92:4:4 in an N-methylpyrrolidone (NMP) solvent system and then coated on aluminum foil to control the coating surface density to 11 mg / cm 2 Up to 18 mg / cm 2 , dried at 105℃ for 4h before use;

[0147] The lithium supplement material prepared above was weighed according to 10% of the weight of LiFePO4, and then the lithium supplement material, conductive carbon black (Super-P), and binder polyvinylidene fluoride (PVDF) were weighed according to a weight ratio of 6:1:1, and then added to the N-methylpyrrolidone (NMP) solvent system and stirred and mixed to form a lithium supplement slurry, and then 1 / 10 volume of the lithium supplement slurry (that is, the lithium supplement material is 1wt% of the positive electrode active material) was evenly scraped onto the surface of the aforementioned LiFePO4 layer, and then dried at 120°C for 3h, and then cold pressed, punched and welded to the pole ear to obtain the positive electrode sheet of Example 8.

[0148] Comparative Example 1:

[0149] Comparative Example 1 comprises the following steps:

[0150] (1) Preparation of lithium supplement materials:

[0151] Dissolve 85g of manganese sulfate and 50g of nickel sulfate in 800mL of water, add 80mL of ammonia water and 700mL of 35 g / L ammonium oxalate under stirring (3650 r / min), stir for 55min, then heat to 70℃, continue stirring for 4h, and obtain the precursor after aging.

[0152] The obtained precursor was mixed with 45 g of lithium carbonate, ball-milled at 500 rpm for 4-8 h to obtain a mixture, and then dried;

[0153] The mixture was taken out and calcined at 550°C for 4 hours to obtain a lithium supplement material. Figure 2 As shown, it can be seen that the lithium supplement material prepared in Comparative Example 1 does not have a hollow structure. In Example 1, part of the complexing agent first forms coordination with the metal ions, and then under the action of the coprecipitant and the remaining complexing agent, the first formed complex is used as the core to form the aggregate of primary particles with a hollow structure shown in Example 1; while Comparative Example 1 directly forms microparticles without a hollow structure.

[0154] (2) Preparation of positive electrode sheet:

[0155] LiFePO4, conductive carbon black (Super-P), and binder polyvinylidene fluoride (PVDF) were mixed in a weight ratio of 92:4:4 in an N-methylpyrrolidone (NMP) solvent system and then coated on aluminum foil to control the coating surface density to 11 mg / cm 2 Up to 18 mg / cm 2 , dried at 105℃ for 4h before use;

[0156] The lithium supplement material prepared above was weighed according to 20% of the weight of LiFePO4, and then the lithium supplement material, conductive carbon black (Super-P), and binder polyvinylidene fluoride (PVDF) were weighed according to a weight ratio of 6:1:1, and then added to the N-methylpyrrolidone (NMP) solvent system and stirred and mixed to form a lithium supplement slurry, and then 1 / 10 volume of the lithium supplement slurry was evenly scraped onto the surface of the aforementioned LiFePO4 layer, and then dried at 120°C for 3h, and then cold pressed, punched and welded to the pole ears to obtain the positive electrode sheet.

[0157] (3) Preparation of negative electrode sheet:

[0158] Artificial graphite, conductive agent SP (conductive carbon black), thickener sodium carboxymethyl cellulose (CMC), and adhesive styrene butadiene rubber (SBR) are fully stirred and mixed in a proper amount of deionized water solvent at a weight ratio of 95:2:2:1 to form a uniform negative electrode slurry. The slurry is coated on the negative electrode current collector copper foil, dried and cold pressed to obtain a negative electrode material layer, and then cut, slit, and weld the pole ears to obtain a negative electrode sheet.

[0159] (4) Preparation of lithium-ion batteries:

[0160] The positive electrode sheet, the isolation film, and the negative electrode sheet are stacked in order, so that the isolation film is placed between the positive electrode sheet and the negative electrode sheet to play an isolating role, and then wound to obtain a bare battery cell; the bare battery cell is placed in an outer packaging foil aluminum-plastic film, and the prepared electrolyte is injected into the dried bare battery cell. After vacuum packaging, standing, formation, shaping, capacity testing and other processes, the preparation of the lithium battery of Comparative Example 1 is completed.

[0161] Comparative Example 2:

[0162] The steps of Comparative Example 2 are basically the same as those of Example 1, except that the preparation of the lithium supplement material precursor includes the following steps: dissolving 50 g of manganese sulfate and 85 g of nickel sulfate in 800 mL of water, adding 32 mL of ammonia water under stirring (3650 r / min), stirring at room temperature for 20 min, then heating to 57°C, adding 48 mL of ammonia water and 700 mL of prepared 35 g / L ammonium oxalate, continuing to stir for 35 min, then further heating to 70°C, continuing to stir for 4 h, and obtaining a precursor after aging.

[0163] Comparative Example 3:

[0164] The steps of Comparative Example 3 are basically the same as those of Example 1, except that the preparation of the lithium supplement material precursor includes the following steps: dissolving 50 g of manganese sulfate and 85 g of nickel sulfate in 800 mL of water, adding 32 mL of ammonia water under stirring (3650 r / min), stirring at room temperature for 20 min, then heating to 57°C, adding 48 mL of ammonia water and 450 mL of 0.5 mol / L sodium hydroxide, continuing to stir for 35 min, then further heating to 70°C, continuing to stir for 4 h, and obtaining a precursor after aging.

[0165] Comparative Example 4:

[0166] The steps of Comparative Example 4 are substantially the same as those of Example 1, except that the steps of preparing the positive electrode sheet include:

[0167] LiFePO4, conductive carbon black (Super-P), binder polyvinylidene fluoride (PVDF), and the lithium supplement material prepared above were fully stirred and mixed in an N-methylpyrrolidone (NMP) solvent system at a weight ratio of 92:4:4:1.84, and then coated on aluminum foil to control the coating surface density to 10 mg / cm 2 Up to 20 mg / cm 2 After drying at 105°C for 4 hours, cold pressing, punching and welding of the pole ears, the positive electrode sheet of Comparative Example 4 was obtained.

[0168] Electrochemical testing:

[0169] Rate performance test: After standing, the lithium-ion batteries of Examples 1-9 and Comparative Examples 1-3 were charged at a constant current rate of 0.1C to a voltage of 4.4V, then charged at a constant voltage to a current of 0.025C, and then discharged to 3V at rates of 0.1C, 0.5C and 1C, respectively, and the discharge gram capacity at different discharge rates was recorded.

[0170] Cycle performance test: After standing, the lithium-ion batteries of Examples 1-9 and Comparative Examples 1-3 were charged at a constant current rate of 0.1C to a voltage of 4.4V, then charged at a constant voltage to a current of 0.025C, and then discharged at a rate of 0.1C to, and the above charge / discharge steps were repeated for 2 cycles to complete the formation of the electrochemical device to be tested. Subsequently, 100 cycles were performed at a charge / discharge rate of 0.5C in the range of 3V-4.4V, and the capacity retention rate was calculated by the discharge gram capacity before and after the cycle. The results of the electrochemical test are shown in Table 1 below:

[0171] Table 1

[0172]

[0173] Comparing Comparative Example 1 with Examples 1, 7 and 8, it can be seen that the lithium supplement material cannot form a hollow structure in Comparative Example 1. Compared with Examples 1-8 in which the lithium supplement material has a hollow structure, a short axis length of 200-300 nm, and a long axis length of 420-650 nm, the specific capacity and the capacity retention rate at 0.5 C of Comparative Example 1 are significantly different from those of Examples 1-8; Comparing Comparative Examples 2-3 with Examples 1, 7 and 8, it can be seen that when the mass ratio of manganese sulfate to lithium carbonate is not within the range of (1.65-1.95):1, the formed Li 1+n Ni x Mn y The specific capacity of the O2 lithium-supplementing material and the capacity retention rate at 0.5C are somewhat different from those of Examples 1-8. Compared with the lithium-supplementing materials prepared in Examples 1, 7 and 8, the lithium-supplementing materials prepared in Comparative Examples 2-3 have higher delithiation potentials and smaller specific capacities, and therefore have poorer performance.

[0174] Comparing Comparative Example 4 with Examples 1, 7 and 8, it can be seen that the specific capacity and capacity retention rate of Comparative Example 4 are significantly deteriorated, which shows that the lithium supplement material prepared in the present disclosure cannot be mixed with the positive electrode active material and then coated on the positive electrode current collector.

[0175] By comparing Examples 1, 7 and 8 with Examples 2-6, it can be seen that the selection of the coprecipitant and the method of adding the complexing agent have an impact on the microscopic morphology of the prepared lithium supplement material. By using a suitable coprecipitant and complexing agent feeding method, the resulting hollow structure can not only not affect the migration of lithium ions, but also not embed too much lithium to cause a decrease in cycle performance. It can also maintain the structure and morphology after multiple cycles and can improve the capacity.

[0176] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the disclosure disclosed herein. The present disclosure is intended to cover any variations, uses or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary technical means in the art that are not disclosed in the present disclosure.

Claims

1. A method for preparing a lithium supplement material, characterized in that: The method comprises the following steps: Step 1: dissolving manganese salt and nickel salt in water, adding 25%-50% of the total mass of the complexing agent at room temperature under stirring, stirring for 15-30 minutes, heating to 50°C-55°C, adding the aqueous solution of the coprecipitant and the remaining complexing agent, stirring for 15-45 minutes, further heating to 65°C-75°C, stirring for 2-5 hours, and obtaining a precursor after aging; the complexing agent is selected from ammonia water; the coprecipitant is selected from ammonium oxalate; the manganese salt is selected from manganese sulfate; the mass ratio of ammonium oxalate to manganese sulfate is (0.20-0.35):1; the concentration of the ammonium oxalate aqueous solution is 15-50 g / L; the mass ratio of ammonia water to manganese sulfate is (0.75-1.0):1; Step 2: Mechanically mixing the precursor and the lithium salt to obtain a mixture; Step 3: calcining the mixture at 450° C.-600° C. for 3-5 hours to obtain the lithium supplement material; The lithium supplement material has Li 1+n Ni x Mn y The chemical formula of O2, wherein n+x+y=1, 0<n<0.2, 0.3<x<0.45, 0.5<y<0.65; and the lithium supplement material is an aggregate of primary particles, the minor axis length of the primary particles is selected from 200-300nm, and the major axis length of the primary particles is selected from 420-650nm; the D50 particle size of the aggregate is selected from 2.25-3.50μm.

2. The method according to claim 1, characterized in that Steps 1 to 3 meet at least one of the following conditions: (1) The nickel salt is selected from nickel sulfate; (2) The lithium salt is selected from lithium carbonate; (3) In step 1, the stirring rate is selected from 3000-3800 r / min.

3. The method according to claim 1, characterized in that The D90 particle size of the aggregates is selected from 3.82-5.70 μm.

4. The method according to claim 1, characterized in that: The D10 particle size of the aggregates is selected from 1.52-2.28 μm.

5. A positive electrode sheet, characterized in that: The positive electrode sheet comprises a positive electrode current collector, a positive electrode active material, a conductive agent, a binder, and a lithium supplement material prepared by the method according to any one of claims 1 to 4.

6. The positive electrode sheet according to claim 5, characterized in that: The positive electrode active material includes at least one of lithium cobalt oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium phosphate, lithium vanadate, lithium manganate, lithium nickel oxide, lithium nickel cobalt manganese oxide, lithium-rich manganese-based materials or lithium nickel cobalt aluminum oxide.

7. An electrochemical device, characterized in that: The electrochemical device comprises the positive electrode sheet according to claim 5 or 6.

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