CN115425203A - Negative electrode material, preparation method thereof, negative electrode plate and secondary battery - Google Patents

Negative electrode material, preparation method thereof, negative electrode plate and secondary battery Download PDF

Info

Publication number
CN115425203A
CN115425203A CN202211148518.0A CN202211148518A CN115425203A CN 115425203 A CN115425203 A CN 115425203A CN 202211148518 A CN202211148518 A CN 202211148518A CN 115425203 A CN115425203 A CN 115425203A
Authority
CN
China
Prior art keywords
negative electrode
graphite
manganese
manganese pyrophosphate
material layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202211148518.0A
Other languages
Chinese (zh)
Inventor
李载波
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huizhou Liwinon Energy Technology Co Ltd
Original Assignee
Huizhou Liwinon Energy Technology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huizhou Liwinon Energy Technology Co Ltd filed Critical Huizhou Liwinon Energy Technology Co Ltd
Priority to CN202211148518.0A priority Critical patent/CN115425203A/en
Publication of CN115425203A publication Critical patent/CN115425203A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention belongs to the technical field of secondary batteries, and particularly relates to a negative electrode material, graphite and a manganese pyrophosphate material layer coated on the surface of the graphite. According to the negative electrode material, the surface of graphite is coated with the manganese pyrophosphate material layer, the manganese pyrophosphate has a multi-dimensional lithium ion diffusion channel, so that the graphite can be rapidly charged and discharged, and the manganese pyrophosphate has a stable lattice structure, so that the graphite can be subjected to multiple charge and discharge cycles under the rapid charge and discharge conditions.

Description

Negative electrode material, preparation method thereof, negative electrode plate and secondary battery
Technical Field
The invention belongs to the technical field of secondary batteries, and particularly relates to a negative electrode material, a preparation method of the negative electrode material, a negative electrode plate and a secondary battery.
Background
The length of the charge and discharge time is a main evaluation index for evaluating the dynamic performance of the lithium ion secondary battery, and in all main materials of the lithium ion secondary battery, a negative electrode material and an electrolyte are main factors influencing the dynamic performance of the lithium ion secondary battery, wherein the correlation of the negative electrode material is the largest. The lithium ion secondary battery cathode material which is most widely and successfully commercialized at present is graphite, and the graphite has the advantages of high capacity, low cost, small Swelling (Swelling) and the like, is greatly pursued by various manufacturers, is widely applied to the field of 3C consumer electronics, and along with the rapid development of hybrid and electric vehicles, lithium ion system batteries are widely used in the fields of power and energy storage, and higher requirements are put forward for various performances of the graphite cathode material.
The bottleneck encountered in the development of the current power battery or soft package battery is limited by the working voltage of the anode material and the charging capacity of the graphite cathode material; if the charging speed is too high, the impedance of lithium ions is increased when the lithium ions are inserted between graphite layers, so that the lithium insertion is difficult, the polarization of the negative electrode is increased, the lithium ions and electrons are subjected to reduction reaction on the surface of graphite, the lithium precipitation phenomenon is caused, and potential safety hazards are brought to the battery cell, so that the development of a graphite negative electrode material with strong charging capability under the condition of ensuring the energy density of the graphite negative electrode material is urgent.
In view of these problems, corresponding research is being conducted at home and abroad, and therefore a technical proposal for solving the above problems is urgently needed.
Disclosure of Invention
One of the objects of the present invention is: aiming at the defects of the prior art, the cathode material is provided, the surface of graphite is coated with a manganese pyrophosphate material layer, the manganese pyrophosphate has a multidimensional lithium ion diffusion channel, the graphite can realize rapid charge and discharge, and the manganese pyrophosphate has a stable lattice structure, so that the graphite can perform multiple charge and discharge cycles under the condition of rapid charge and discharge.
In order to achieve the purpose, the invention adopts the following technical scheme:
the negative electrode material comprises graphite and a manganese pyrophosphate material layer coated on the surface of the graphite.
Preferably, the coating rate of the manganese pyrophosphate material layer is 60-90%.
Preferably, the thickness of the manganese pyrophosphate material layer is 10-120 nm.
The second purpose of the invention is: aiming at the defects of the prior art, the method for preparing the cathode material is provided, and the manganese pyrophosphate layer is formed by mixing liquid phases, heating and sintering and generating manganese pyrophosphate on the surface of graphite in situ, so that the manganese pyrophosphate layer can be uniformly dispersed on the surface of the graphite, and the performance is more stable.
In order to achieve the above object, the present invention adopts the following technical documents:
a preparation method of the anode material comprises the following steps:
step S1, adding a manganese source and a phosphorus source into a solvent, mixing and stirring to obtain a mixed solution;
s2, adding graphite into the mixed solution, stirring and dispersing, vacuum filtering, heating, and vacuum drying to obtain a pre-product;
and S3, heating and sintering the pre-product in an inert atmosphere, cooling, and breaking to obtain the cathode material.
Preferably, the weight part ratio of the manganese source to the phosphorus source in the step S1 is 1-3.
Preferably, the temperature of the vacuum drying is 70-80 ℃, and the vacuum drying time is 5-15 h.
Preferably, the heating process in the step S3 is to heat the mixture to 150-300 ℃ at a heating rate of 5-10 ℃/min, then to 900-1000 ℃ at a heating rate of 2-5 ℃/min, and to keep the temperature for 4-12 h.
Preferably, the particle size after the crushing in the step S3 is 100 to 250 mesh.
The third purpose of the invention is that: aiming at the defects of the prior art, the negative pole piece is provided, and has good multiplying power performance and cycle performance.
In order to achieve the above object, the present invention adopts the following technical documents:
a negative pole piece comprises the negative pole material.
The fourth purpose of the invention is that: aiming at the defects of the prior art, the secondary battery is provided, and has good rate capability and cycle performance.
In order to achieve the above object, the present invention adopts the following technical documents:
a secondary battery comprises the negative pole piece.
Compared with the prior art, the invention has the beneficial effects that: according to the negative electrode material, the surface of graphite is coated with the manganese pyrophosphate material layer, the manganese pyrophosphate has a multi-dimensional lithium ion diffusion channel, so that the graphite can be rapidly charged and discharged, and the manganese pyrophosphate has a stable lattice structure, so that the graphite can be subjected to multiple charge and discharge cycles under the rapid charge and discharge conditions.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.
The negative electrode material comprises graphite and a manganese pyrophosphate material layer coated on the surface of the graphite. According to the negative electrode material, the surface of graphite is coated with the manganese pyrophosphate material layer, the manganese pyrophosphate has a multi-dimensional lithium ion diffusion channel, so that the graphite can be rapidly charged and discharged, and the manganese pyrophosphate has a stable lattice structure, so that the graphite can be subjected to multiple charge and discharge cycles under the rapid charge and discharge conditions.
The invention adopts in-situ manganese pyrophosphate liquid phase to coat a graphite cathode material, namely manganese pyrophosphate (Mn) 2 P 2 O 7 ) The polyanion inorganic salt material has an excellent lattice structure and a multidimensional lithium ion diffusion channel, can inhibit the reduction reaction of electrolyte, and reduces the degree of cell capacity loss caused by first effect reduction due to SEI film generation. In addition, because the manganese source participating in the reaction is an organic matter and contains a-C-H bond, the manganese source and the C-H bond on the surface of the graphite undergo dehydrogenation condensation reaction at high temperature to generate the-C bond, so that the coating material and the matrix material are combined more tightly, the coating layer is stable and is not easy to fall off in the circulating process, and the circulating performance of the graphite cathode material is improved.
In some embodiments, the coating rate of the manganese pyrophosphate material layer is 60% to 90%. The manganese pyrophosphate material layer is coated on the surface of the graphite, and a certain carbon coating rate is set, so that the rapid charging function and excellent stability of the manganese pyrophosphate can be exerted, and the influence of the overhigh carbon coating rate on the performance of the graphite can be avoided. Preferably, the coating rate of the manganese pyrophosphate material layer is 60% to 70%, 70% to 80%, 80% to 90%, and specifically, the coating rate of the manganese pyrophosphate material layer is 60%, 63%, 65%, 68%, 69%, 70%, 75%, 78%, 80%, 82%, 85%, 86%, 87%, 89%, 90%.
In some embodiments, the layer of manganese pyrophosphate material has a thickness of 10 to 120nm. The thickness of the layer of manganese pyrophosphate material has some effect on the properties of the graphite. The thickness of the manganese pyrophosphate material layer is too thick, so that the ion moving distance is increased, and the manganese pyrophosphate material layer is too thin and is easy to fall off in the process of charging and discharging for many times, so that the cycle performance is influenced. The thickness of the manganese pyrophosphate material layer is 10-50 nm, 50-90 nm, 90-100 nm and 100-120 nm, and specifically, the thickness of the manganese pyrophosphate material layer is 50nm, 53nm, 54nm, 55nm, 58nm, 60nm, 64nm, 65nm, 68nm, 70nm, 72nm, 74nm, 75nm, 78nm, 80nm, 82nm, 84nm, 85nm, 88nm, 90nm, 93nm, 95nm, 98nm, 100nm, 110nm, 113nm, 115nm, 118nm and 120nm.
A preparation method of a negative electrode material comprises the steps of mixing liquid phases, heating and sintering, and generating manganese pyrophosphate on the surface of graphite in situ to form a manganese pyrophosphate material layer, so that the manganese pyrophosphate material layer can be uniformly dispersed on the surface of the graphite, and the performance is more stable.
A preparation method of the anode material comprises the following steps:
step S1, adding a manganese source and a phosphorus source into a solvent, mixing and stirring to obtain a mixed solution;
s2, adding graphite into the mixed solution, stirring and dispersing, carrying out vacuum filtration, heating, and carrying out vacuum drying to obtain a pre-product;
and S3, heating and sintering the pre-product in an inert atmosphere, cooling, and disintegrating to obtain the cathode material.
The method uses a liquid method to generate the manganese pyrophosphate material layer on the surface of the graphite, has the advantages of more uniformity, better coating rate and good thickness controllability, and is convenient for reaction to produce corresponding cathode materials. Ultrasonic waves can be used to accelerate the dissolution speed during mixing and stirring. The gas in the inert atmosphere can be one or two of nitrogen and argon.
In some embodiments, the weight ratio of the manganese source to the phosphorus source in step S1 is 1 to 3. The weight ratio of the manganese source to the phosphorus source is 1-2, 3-5, 2-3. Certain manganese source and phosphorus source are arranged, so that the reaction is more uniform.
In some embodiments, the temperature of the vacuum drying in the step S2 is 70 to 80 ℃, and the vacuum drying time is 5 to 15 hours. The vacuum drying temperature is 70 ℃, 72 ℃, 75 ℃, 76 ℃, 78 ℃ and 80 ℃, and the vacuum drying time is 5-8 h, 8-10 h, 10-12 h and 12-15 h, concretely, the vacuum drying time is 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h and 15h.
In some embodiments, the heating process in step S3 is specifically to first increase the temperature to 150-300 ℃ at a heating rate of 5-10 ℃/min, then increase the temperature to 900-1000 ℃ at a heating rate of 2-5 ℃/min, and keep the temperature for 4-12 h. Two-stage heating is adopted in the heating process, the temperature is quickly raised to a certain temperature, the heating time is shortened, meanwhile, the raw materials are quickly dried, and then the temperature is increased to a higher temperature in a buffering way for sintering, so that the raw materials are reacted under a high-temperature condition. Preferably, the first stage heating rate is 5-8 ℃/min and 8-10 ℃/min, specifically, the first stage heating rate is 5 ℃/min, 6 ℃/min, 7 ℃/min, 8 ℃/min, 9 ℃/min and 10 ℃/min, the first stage heating temperature is 150 ℃, 180 ℃, 200 ℃, 220 ℃, 250 ℃, 280 ℃ and 300 ℃, the second stage heating rate is 2-5 ℃/min, specifically, the second stage heating rate is 2 ℃/min, 3 ℃/min, 4 ℃/min and 5 ℃/min, the second stage heating temperature is 900 ℃, 910 ℃, 920 ℃, 930 ℃, 940 ℃, 950 ℃, 960 ℃, 970 ℃, 980 ℃, 990 ℃ and 1000 ℃.
In some embodiments, the particle size after the crushing in step S3 is 100 to 250 mesh. The grain diameter is 100-150 meshes, 150-200 meshes and 200-250 meshes. Specifically, the particle size is 100 mesh, 130 mesh, 150 mesh, 180 mesh, 190 mesh, 200 mesh, 250 mesh. The negative electrode material with a certain particle size is set, so that the thickness and the performance of the negative electrode material are influenced after the negative electrode material is prepared into slurry.
The negative pole piece has good rate performance and cycle performance. Specifically, the negative electrode plate comprises the negative electrode material.
The secondary battery has good rate capability and cycle performance. Specifically, a secondary battery includes the anode material described above.
A secondary battery may be a lithium ion battery, a sodium ion battery, a magnesium ion battery, a calcium ion battery, a potassium ion battery, or the like. Preferably, the following secondary battery is exemplified by a lithium ion battery, which includes a positive plate, a negative plate, a separator, an electrolyte, and a case, wherein the separator separates the positive plate from the negative plate, and the case is used for mounting the positive plate, the negative plate, the separator, and the electrolyte. The negative pole piece is the negative pole piece.
Positive electrode
The positive plate comprises a positive current collector and a positive active material layer arranged on at least one surface of the positive current collector, wherein the positive active material layer comprises a positive active material, and the positive active material can be a compound including but not limited to a chemical formula such as Li a Ni x Co y M z O 2-b N b (wherein 0.95. Ltoreq. A.ltoreq.1.2>0,y ≧ 0, z ≧ 0, and x + y + z =1,0 ≦ b ≦ 1, M is selected from one or more combinations of Mn, al, N is selected from one or more combinations of F, P, S), the positive electrode active material may also be a combination including but not limited to LiCoO 2 、LiNiO 2 、LiVO 2 、LiCrO 2 、LiMn 2 O 4 、LiCoMnO 4 、Li 2 NiMn 3 O 8 、LiNi 0.5 Mn 1.5 O 4 、LiCoPO 4 、LiMnPO 4 、LiFePO 4 、LiNiPO 4 、LiCoFSO 4 、CuS 2 、FeS 2 、MoS 2 、NiS、TiS 2 And the like. The positive electrode active material may also be subjected to a modification treatment, and a method of modifying the positive electrode active material should be known to those skilled in the art, for example, may beThe positive electrode active material is modified by coating, doping, etc., and the material used in the modification treatment may be one or a combination of more of Al, B, P, zr, si, ti, ge, sn, mg, ce, W, etc., but is not limited thereto. And the positive electrode current collector is generally a structure or a part for collecting current, and the positive electrode current collector may be any material suitable for use as a positive electrode current collector of a lithium ion battery in the art, for example, the positive electrode current collector may include, but is not limited to, a metal foil and the like, and more specifically, may include, but is not limited to, an aluminum foil and the like.
Negative electrode
The negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer arranged on the surface of the negative electrode current collector, the negative electrode current collector is generally a structure or part for collecting current, the negative electrode current collector can be various materials suitable for serving as a negative electrode current collector of a lithium ion battery in the field, for example, the negative electrode current collector can include but is not limited to metal foils and the like, and more specifically, the negative electrode current collector can include but is not limited to copper foils and the like.
Electrolyte solution
The lithium ion battery also comprises electrolyte, and the electrolyte comprises an organic solvent, electrolyte lithium salt and an additive. Wherein the electrolyte lithium salt may be LiPF used in a high-temperature electrolyte 6 And/or LiBOB; or LiBF used in low-temperature electrolyte 4 、LiBOB、LiPF 6 At least one of (a); also can be LiBF adopted in anti-overcharging electrolyte 4 、LiBOB、LiPF 6 At least one of LiTFSI; may also be LiClO 4 、LiAsF 6 、LiCF 3 SO 3 、LiN(CF 3 SO 2 ) 2 At least one of (1). And the organic solvent may be a cyclic carbonate including PC, EC; or chain carbonates including DFC, DMC, or EMC; and also carboxylic acid esters including MF, MA, EA, MP, etc. And additives include, but are not limited to, film forming additives, conductive additives, flame retardant additives, overcharge prevention additives, control of H in the electrolyte 2 At least one of additives of O and HF content, additives for improving low temperature performance, and multifunctional additives.
And the separator may be various materials suitable for lithium ion battery separators in the art, and for example, may be one or a combination of more of polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester, natural fiber, and the like, including but not limited thereto.
Preferably, the material of the shell is one of stainless steel and an aluminum plastic film. More preferably, the housing is an aluminum plastic film.
Example 1
The first step is as follows: preparing a manganese pyrophosphate pre-coated graphite cathode;
weighing required mass of ethylene diamine tetraacetic acid disodium manganese (organic manganese source) and ammonium dihydrogen phosphate (phosphorus source) according to the molar ratio of manganese element to phosphorus element of 1, placing the weighed mass into a certain amount of deionized water, and ultrasonically accelerating the dissolution speed; according to the proportion of graphite: manganese pyrophosphate =1: 5g of graphite was weighed in a mass ratio of 0.03 and poured into the above solution, thereby obtaining a mixed solution. Stirring at room temperature at 320rpm/min for 11h to uniformly disperse the graphite material; the mixture was vacuum filtered through a teflon membrane to give a mixture, which was then vacuum dried in an oven at 78 ℃ for 10h.
The second step is that: preparing a manganese pyrophosphate-coated graphite cathode;
transferring the dried pre-coated graphite into a tube furnace at the speed of 5L/min N 2 Raising the temperature to 200 ℃ at a heating rate of 8 ℃/min under the atmosphere of (non-oxidizing gas), raising the temperature to 950 ℃ at a heating rate of 3 ℃/min, keeping the temperature for 8h, and naturally cooling. And (3) crushing the obtained sample, and screening by 150 meshes to finally obtain the manganese pyrophosphate-coated graphite cathode material, wherein the coating rate of the manganese pyrophosphate material layer is 85%, and the thickness of the manganese pyrophosphate material layer is 80nm.
The third step: the manganese pyroenoate-coated graphite cathode material prepared in the above way is mixed with a conductive agent Super-conductive carbon (Super-P), a thickening agent sodium carboxymethyl cellulose (CMC) and a binder Styrene Butadiene Rubber (SBR) according to a mass ratio of 96:2.0:1.0:1.0, preparing slurry, coating the slurry on a current collector copper foil, drying at 85 ℃, cutting edges, cutting pieces, dividing strips, drying for 4 hours at 110 ℃ under a vacuum condition after dividing the strips, and welding tabs to prepare a negative plate.
The fourth step: lithium cobaltate, conductive agent superconducting carbon (Super-P) and binder polyvinylidene fluoride (PVDF) are mixed according to the mass ratio of 97:1.5:1.5, uniformly mixing to prepare lithium ion battery anode slurry with certain viscosity, coating the slurry on a current collector aluminum foil, drying at 85 ℃, and then carrying out cold pressing; then trimming, cutting into pieces, slitting, drying for 4 hours at 110 ℃ under the vacuum condition after slitting, and welding the tabs to prepare the positive plate.
The fifth step: lithium hexafluorophosphate (LiPF) 6 ) Dissolved in a mixed solvent composed of Ethylene Carbonate (EC), dimethyl carbonate (DMC) and Ethyl Methyl Carbonate (EMC) (the mass ratio of the three is 1:2: 1) To obtain the electrolyte with the concentration of 1 mol/L.
And a sixth step: winding the positive plate, the isolating membrane and the negative plate into a battery cell, wherein the isolating membrane is positioned between the positive plate and the negative plate, the positive electrode is led out by spot welding of an aluminum tab, and the negative electrode is led out by spot welding of a nickel tab; and then placing the battery core in an aluminum-plastic packaging bag, injecting the electrolyte, and carrying out processes such as packaging, formation, capacity and the like to prepare the lithium ion battery.
Example 2
The difference from example 1 is that: the coating rate of the manganese pyrophosphate material layer is 60%.
The rest is the same as embodiment 1, and the description is omitted here.
Example 3
The difference from example 1 is that: the coating rate of the manganese pyrophosphate material layer is 70%.
The rest is the same as embodiment 1, and the description is omitted here.
Example 4
The difference from example 1 is that: the coating rate of the manganese pyrophosphate material layer is 80%.
The rest is the same as embodiment 1, and the description is omitted here.
Example 5
The difference from example 1 is that: the coating rate of the manganese pyrophosphate material layer is 90%.
The rest is the same as embodiment 1, and the description is omitted here.
Example 6
The difference from example 1 is that: the coating rate of the manganese pyrophosphate material layer is 95%.
The rest is the same as embodiment 1, and the description is omitted here.
Example 7
The difference from example 1 is that: the thickness of the manganese pyrophosphate material layer is 10nm.
The rest is the same as embodiment 1, and the description is omitted here.
Example 8
The difference from example 1 is that: the thickness of the manganese pyrophosphate material layer is 60nm.
The rest is the same as embodiment 1, and the description is omitted here.
Example 9
The difference from example 1 is that: the thickness of the manganese pyrophosphate material layer is 100nm.
The rest is the same as embodiment 1, and the description is omitted here.
Example 10
The difference from example 1 is that: the thickness of the manganese pyrophosphate material layer is 120nm.
The rest is the same as embodiment 1, and the description is omitted here.
Comparative example 1
The difference from example 1 is that: the negative electrode material is graphite, and a manganese pyrophosphate material layer is not arranged on the surface of the negative electrode material.
The rest is the same as embodiment 1, and the description is omitted here.
And (3) performance testing: the batteries of examples 1 to 10 and comparative example 1 were subjected to performance tests, and the test results are reported in table 1.
TABLE 1
Figure BDA0003855842270000091
Figure BDA0003855842270000101
As can be seen from table 1, the prepared negative electrode material has a better capacity retention rate compared with the secondary battery in the prior art, the first capacity retention rate is as high as 93.5%, and the capacity retention rate is maintained at 81.3% after 500 times of charging and discharging. Also, as shown by comparison of examples 1 to 6, when the coating rate of the manganese pyrophosphate material layer was set to 85%, the prepared anode material was more excellent in performance when applied to a secondary battery. The manganese pyrophosphate material layer can maintain the stability that improves graphite, makes the negative electrode material can not take place structural change at quick charge-discharge in-process, leads to the performance variation, sets up the manganese pyrophosphate material layer of certain cladding rate moreover, avoids the cladding rate too high, influences graphite material's performance, also avoids the cladding rate to hang down, and manganese pyrophosphate does not provide sufficient ion channel, and the multiplying power performance improves limitedly.
From comparison of examples 1 and 7-10, when the thickness of the manganese pyrophosphate material layer is set to be 80nm, the prepared anode material has better performance when applied to a secondary battery. The performance of the graphite is affected by the excessively thick manganese pyrophosphate material layer, the manganese pyrophosphate material layer is excessively thin and is easy to fall off when generated on the surface of the graphite in situ, and the structure is not stable after multiple cycles.
Variations and modifications to the above-described embodiments may become apparent to those skilled in the art to which the invention pertains based upon the disclosure and teachings of the above specification. Therefore, the present invention is not limited to the above-mentioned embodiments, and any obvious modifications, substitutions or alterations based on the present invention will fall within the protection scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims (10)

1. The negative electrode material is characterized by comprising graphite and a manganese pyrophosphate material layer coated on the surface of the graphite.
2. The negative electrode material according to claim 1, wherein the coating rate of the manganese pyrophosphate material layer is 60% to 95%.
3. The anode material according to claim 1, wherein the thickness of the manganese pyrophosphate material layer is 10 to 120nm.
4. A method for preparing the negative electrode material according to any one of claims 1 to 3, characterized by comprising the steps of:
step S1, adding a manganese source and a phosphorus source into a solvent, mixing and stirring to obtain a mixed solution;
s2, adding graphite into the mixed solution, stirring and dispersing, vacuum filtering, heating, and vacuum drying to obtain a pre-product;
and S3, heating and sintering the pre-product in an inert atmosphere, cooling, and breaking to obtain the cathode material.
5. The method for preparing the negative electrode material of claim 4, wherein the weight ratio of the manganese source to the phosphorus source in the step S1 is 1-3.
6. The method for preparing the anode material according to claim 4, wherein the temperature of the vacuum drying in the step S2 is 70 to 80 ℃, and the time of the vacuum drying is 5 to 15 hours.
7. The method for preparing the anode material according to claim 4, wherein the heating in the step S3 is performed by heating to 150-300 ℃ at a heating rate of 5-10 ℃/min, heating to 900-1000 ℃ at a heating rate of 2-5 ℃/min, and maintaining the temperature for 4-12 hours.
8. The method for producing the anode material according to claim 4, wherein the particle size after the crushing in the step S3 is 100 to 250 mesh.
9. A negative electrode sheet comprising the negative electrode material according to any one of claims 1 to 3.
10. A secondary battery comprising the negative electrode sheet according to claim 9.
CN202211148518.0A 2022-09-21 2022-09-21 Negative electrode material, preparation method thereof, negative electrode plate and secondary battery Pending CN115425203A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211148518.0A CN115425203A (en) 2022-09-21 2022-09-21 Negative electrode material, preparation method thereof, negative electrode plate and secondary battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211148518.0A CN115425203A (en) 2022-09-21 2022-09-21 Negative electrode material, preparation method thereof, negative electrode plate and secondary battery

Publications (1)

Publication Number Publication Date
CN115425203A true CN115425203A (en) 2022-12-02

Family

ID=84204844

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211148518.0A Pending CN115425203A (en) 2022-09-21 2022-09-21 Negative electrode material, preparation method thereof, negative electrode plate and secondary battery

Country Status (1)

Country Link
CN (1) CN115425203A (en)

Similar Documents

Publication Publication Date Title
CN110265627B (en) Positive electrode plate and lithium ion secondary battery
CN110010903B (en) Positive pole piece and battery
CN101699590B (en) Hybrid supercapacitor
EP2677569B1 (en) Active material for composite electrode of lithium secondary battery for increased output, and lithium secondary battery including same
US9745194B2 (en) Method of producing cathode active material for lithium secondary battery
CN103392250B (en) Anode of secondary cell mixture and containing its secondary cell
CN104604014A (en) Non-aqueous electrolyte and lithium secondary battery comprising same
US11677074B2 (en) Positive electrode plate, method for preparing the same and lithium-ion secondary battery
EP2876722B1 (en) Lithium secondary battery
CN101295780B (en) Anode active material composition of lithium ion secondary battery and battery
US20150318571A1 (en) Lithium-ion secondary battery
CN113140731B (en) All-solid-state lithium battery and preparation method thereof
CN111834620A (en) Lithium metal battery positive electrode, lithium metal battery and preparation method thereof
CN111710911A (en) Electrolyte and lithium ion battery
CN101783401A (en) Cathode and Li-ion battery comprising same
CN113748550B (en) Secondary battery and device containing the same
KR20210143863A (en) Composite graphite material, secondary battery, device and manufacturing method
KR20200126781A (en) Non-aqueous electrolyte for lithium secondary battery and lithium secondary battery comprising the same
CN114976218A (en) Composite isolating membrane, preparation method thereof and secondary battery
CN115425203A (en) Negative electrode material, preparation method thereof, negative electrode plate and secondary battery
CN104756302B (en) Electrolyte for lithium secondary batteries and the lithium secondary battery comprising it
EP3930070A1 (en) Electrolyte for lithium ion battery, lithium ion battery, battery module, battery pack, and device
KR20220064385A (en) Composite graphite material and manufacturing method thereof, secondary battery and device
CN114497483B (en) Negative plate, preparation method thereof and lithium ion battery
CN115632106B (en) Composite negative plate and secondary battery

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination