CN113611868A - Metal lithium composite electrode material, preparation method thereof and lithium ion battery - Google Patents

Metal lithium composite electrode material, preparation method thereof and lithium ion battery Download PDF

Info

Publication number
CN113611868A
CN113611868A CN202110884082.0A CN202110884082A CN113611868A CN 113611868 A CN113611868 A CN 113611868A CN 202110884082 A CN202110884082 A CN 202110884082A CN 113611868 A CN113611868 A CN 113611868A
Authority
CN
China
Prior art keywords
lithium
composite
dimensional structure
metal
electrode material
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.)
Granted
Application number
CN202110884082.0A
Other languages
Chinese (zh)
Other versions
CN113611868B (en
Inventor
李玉冰
徐雄文
黄成�
袁依婷
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.)
Hunan Lifang New Energy Science and Technology Co Ltd
Original Assignee
Hunan Lifang New Energy Science and 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 Hunan Lifang New Energy Science and Technology Co Ltd filed Critical Hunan Lifang New Energy Science and Technology Co Ltd
Priority to CN202110884082.0A priority Critical patent/CN113611868B/en
Publication of CN113611868A publication Critical patent/CN113611868A/en
Application granted granted Critical
Publication of CN113611868B publication Critical patent/CN113611868B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/043—Processes of manufacture in general involving compressing or compaction
    • H01M4/0435—Rolling or calendering
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • 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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/381—Alkaline or alkaline earth metals elements
    • H01M4/382—Lithium
    • 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
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • 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 lithium ion batteries, and particularly relates to a lithium metal composite negative electrode material, a preparation method thereof and a lithium ion battery. The metal lithium composite electrode material provided by the invention effectively prevents lithium from contacting with electrolyte, effectively reduces the consumption of the electrolyte, guides the uniform deposition of lithium ions, and inhibits the generation of lithium dendrites.

Description

Metal lithium composite electrode material, preparation method thereof and lithium ion battery
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a metal lithium composite negative electrode material, a preparation method thereof and a lithium ion battery.
Background
The lithium ion battery has been developed for more than half a century, and has the advantages of high energy density, small self-discharge, long service life and the like. However, with the rapid development of the modern society, it has become increasingly unable to meet the demand of people for high energy density batteries.
Compared with lithium ion batteries which are close to the theoretical specific energy limit, the lithium metal is considered to be an ideal negative electrode material of next generation high energy density lithium batteries due to the ultrahigh theoretical specific capacity (3860mAh/g) and the extremely low potential (-3.04V, relative to a standard hydrogen electrode). However, the uneven deposition/peeling behavior of lithium metal during charging and discharging is very likely to induce the growth of lithium dendrites, resulting in lower coulombic efficiency and potential safety hazard of the battery, which makes the secondary lithium metal battery to be not commercialized.
In order to solve the problem of lithium dendrite, researchers have tried various methods, and currently, the commonly used methods include adding functional additives (such as Cs salt, DTD, etc.) into an electrolyte, constructing an SEI film on the surface of lithium metal (including an in-situ method and an ex-situ method, wherein the in-situ method is a method of spontaneously forming SEI on the surface of a negative electrode by using lithium salt, functional additives, etc., and the ex-situ method is an artificial SEI), and constructing a three-dimensional framework structure. However, these methods all have certain limitations, and the electrolyte functional additives such as Cs salt have extremely high requirements on concentration accuracy. Artificial SEI film construction methods such as Atomic Layer Deposition (ALD) require the use of special equipment, are complicated in flow and expensive. And the methods mainly used for constructing the 3D negative electrode include electrochemical pretreatment, a melting method, and the like. Among them, electrochemical pretreatment requires the battery to be reassembled and disassembled, which is difficult to realize large-scale application, the melting method requires lithium to be in a molten state, the danger coefficient is large, and the material compounded with the lithium-philic pretreatment needs to have lithium-philic property.
In comparison, the method for preparing the composite cathode material by the rolling method is more convenient and more expected to realize large-scale production and application, and researchers directly roll and compound lithium metal with carbon paper, a copper/nickel net and the like by the method to obtain the composite material with excellent performance, but the materials such as the copper net/nickel net and the carbon paper are not superior in the aspects of weight, thickness and the like. There are also researchers who repeatedly fold and roll materials by sprinkling a metal oxide or the like on lithium, but it is obviously difficult to obtain a material with a uniformly distributed composite by this method. Therefore, it is of great significance to develop a simple preparation method of composite material which can be produced and applied in large scale.
Disclosure of Invention
One of the objects of the present invention is: in view of the disadvantages of the prior art, a lithium metal composite having a three-dimensional structure is provided, which has higher ionic conductivity. When the composite material is used as the battery cell anode, in the battery cell charge-discharge cycle process, the local current on the surface of the anode can be reduced, the electrolyte consumption is reduced, and meanwhile, lithium ions are effectively guided to deposit inside the three-dimensional structure of the material instead of on the surface of the material, so that the generation of lithium branches is inhibited, and the cycle life of the battery cell is prolonged.
In order to achieve the purpose, the invention adopts the following technical scheme:
a lithium metal composite electrode material comprises a lithium metal conducting layer, wherein the lithium metal conducting layer contains a three-dimensional structure material which is used for providing attachment sites for lithium metal and coating the lithium metal.
As an improvement of the metal lithium composite electrode material, the three-dimensional structure material comprises at least one of lithium nitride, lithium fluoride and aluminum lithium alloy.
As an improvement of the metal lithium composite electrode material, the metal lithium conducting layer further comprises carbon powder and a conducting agent, and the weight part ratio of the carbon powder to the conducting agent to the three-dimensional structure material is 5-8: 1-3: 2-5.
As an improvement of the metal lithium composite electrode material, the thickness of the metal lithium conducting layer is 40-60 mu m.
The second purpose of the invention is: aiming at the defects of the prior art, the preparation method of the metal lithium composite electrode material is provided, the controllability is good, the mass large-scale production can be realized, the practicability is strong, the cost is low, and the prepared metal lithium composite electrode material is more uniform and has more excellent performance.
In order to achieve the purpose, the invention adopts the following technical scheme:
a preparation method of a metal lithium composite electrode material comprises the following steps:
step (A): adding a solvent into the primary material with the three-dimensional structure to prepare slurry, coating the slurry on a bearing sheet, drying, and removing the bearing sheet to form a primary material composite layer with the three-dimensional structure;
step (B): taking a lithium belt and two layers of the three-dimensional structure primary material composite layers in the step (A), sequentially stacking the lithium belt and the three-dimensional structure primary material composite layers according to the sequence of the three-dimensional structure primary material composite layers, the lithium belt and the three-dimensional structure primary material composite layers, and rolling to form a first composite lithium belt;
step (C): taking another lithium belt and a layer of the three-dimensional structure primary material composite layer in the step (A), sequentially stacking the lithium belt and the three-dimensional structure primary material composite layer according to the three-dimensional structure primary material composite layer, the lithium belt and the first composite lithium belt, and rolling to form a second composite lithium belt;
step (D): taking the second composite lithium belt in the step (C) as a first composite lithium belt, and repeating the step (C) for more than two times to obtain a metal lithium mixture with a three-dimensional structure;
a step (E): and (D) heating the mixture of the lithium metal with the three-dimensional structure in the step (D) under the protection of inert gas to obtain the lithium metal composite electrode material containing the material with the three-dimensional structure.
As an improvement of the preparation method of the metal lithium composite electrode material, the solid content of the slurry in the step (A) is 3-10%, the drying temperature is 80-100 ℃, and the drying time is 20-30 hours.
As an improvement of the preparation method of the metal lithium composite electrode material, the heating temperature in the step (E) is 120-170 ℃.
As an improvement of the preparation method of the metal lithium composite electrode material, the conductive agent is one or a mixture of more than one of carbon fiber, carbon nano tube, graphene, acetylene black, Ketjen black and conductive carbon black.
As an improvement of the preparation method of the metal lithium composite electrode material, the rolling pressure is 150-300 kg.f/cm2。
The third purpose of the invention is that: aiming at the defects of the prior art, the lithium ion battery is provided, the dendritic crystal of lithium can be effectively avoided, the thickness increase is inhibited, and the electrochemical performance is better.
In order to achieve the purpose, the invention adopts the following technical scheme:
a lithium ion battery comprises a positive electrode, a negative electrode, a diaphragm, electrolyte and a shell, wherein the diaphragm is used for separating the positive electrode from the negative electrode, and the negative electrode comprises the metal lithium composite electrode material.
Compared with the prior art, the invention has the beneficial effects that:
1. the lithium metal composite electrode material disclosed by the invention contains a three-dimensional structure material, can provide attachment sites for lithium metal and coat the lithium metal, effectively avoids the direct contact of the lithium metal and electrolyte, effectively reduces the consumption of the electrolyte, and simultaneously guides the uniform deposition of lithium ions and inhibits the generation of lithium dendrites;
2. the preparation method of the metal lithium composite electrode material is simple to operate, good in controllability, capable of realizing large-scale mass production, strong in practicability and low in cost, and the prepared metal lithium composite electrode material is more uniform and has more excellent performance.
Drawings
FIG. 1 is a flow chart of the preparation of a lithium metal composite electrode material according to the present invention.
FIG. 2 is a representation of a lithium metal composite electrode material according to the present invention.
FIG. 3 is an XRD pattern of a lithium metal composite electrode material of the present invention.
FIG. 4 is a graph comparing the capacity retention rates of batteries prepared from a lithium metal composite electrode material, a lithium metal composite electrode material without a three-dimensional structure material and a 50 μm lithium metal negative electrode according to the present invention.
Detailed Description
1. A lithium metal composite electrode material comprises a lithium metal conducting layer, wherein the lithium metal conducting layer contains a three-dimensional structure material which is used for providing attachment sites for lithium metal and coating the lithium metal. According to the metal lithium composite electrode material, the metal lithium is protected through the three-dimensional structure material, so that the lithium is effectively prevented from contacting with the electrolyte, the consumption of the electrolyte is effectively reduced, the uniform deposition of lithium ions is guided, and the generation of lithium dendrites is inhibited.
Preferably, the three-dimensional structure material comprises at least one of lithium nitride, lithium fluoride and aluminum lithium alloy. The lithium nitride, the lithium fluoride and the aluminum lithium alloy are formed on the surface of the metal lithium conducting layer, so that a protective layer is effectively formed, the metal lithium is prevented from being directly contacted with electrolyte, the consumption of the electrolyte is effectively reduced, and meanwhile, the uniform deposition of lithium ions is guided, and the generation of lithium dendrites is inhibited.
Preferably, the lithium metal conducting layer further comprises carbon powder and a conducting agent, and the weight part ratio of the carbon powder to the conducting agent to the three-dimensional structure material is 5-8: 1-3: 2-5. The carbon powder, the conductive agent and the three-dimensional composite structure jointly form a cage for limiting the volume change of lithium in the circulation process, the thickness increase of a battery in the circulation process is effectively limited, and meanwhile, the metal lithium conductive layer has good conductivity by arranging the carbon powder, the conductive agent and the three-dimensional structure material in a certain ratio, and is favorable for the insertion and the extraction of lithium ions.
Preferably, the thickness of the metal lithium conducting layer is 40-60 μm. The thickness of the metallic lithium conducting layer is controlled, so that the metallic lithium conducting layer has good mechanical strength and electrochemical performance.
2. A preparation method of a metal lithium composite electrode material comprises the following steps:
step (A): adding a solvent into the primary material with the three-dimensional structure to prepare slurry, coating the slurry on a bearing sheet, drying, and removing the bearing sheet to form a primary material composite layer with the three-dimensional structure; the method mainly comprises the step of preparing the three-dimensional structure primary material into a layer for subsequent use, specifically, the solvent is deionized water or an organic solvent, and the step of preparing the multilayer three-dimensional structure primary material composite layer according to conditions so as to increase the number of layers during subsequent continuous rolling operation. The bearing sheet can be a diaphragm or a Mylar sheet, and after the slurry is dried, the slurry layer and the bearing sheet are separated to obtain a three-dimensional structure primary material composite layer. Preferably, the carbon powder, the conductive agent and the three-dimensional structure primary material are mixed and added into a solvent according to the weight part ratio of 5-8: 1-3: 2-5 to prepare slurry, the slurry is coated on a bearing sheet and dried, and the bearing sheet is removed to form a three-dimensional structure primary material composite layer, so that the ionic conductivity can be effectively improved.
Step (B): taking a lithium belt and two layers of the three-dimensional structure primary material composite layers in the step (A), sequentially stacking the lithium belt and the three-dimensional structure primary material composite layers according to the sequence of the three-dimensional structure primary material composite layers, the lithium belt and the three-dimensional structure primary material composite layers, and rolling to form a first composite lithium belt; the three-dimensional structure primary material composite layers are stacked on the two sides of the lithium belt, so that when the lithium belt is rolled, the three-dimensional structure primary materials on the two sides enter the lithium belt and are uniformly mixed with lithium particles, and the mixing uniformity is improved.
Step (C): taking another lithium belt and a layer of the three-dimensional structure primary material composite layer in the step (A), sequentially stacking the lithium belt and the three-dimensional structure primary material composite layer according to the three-dimensional structure primary material composite layer, the lithium belt and the first composite lithium belt, and rolling to form a second composite lithium belt; continuously rolling the first composite lithium belt subjected to one-time rolling, a newly taken lithium belt and a new primary material composite layer with a stereo structure, further mixing a stereo structure material, carbon powder, a conductive agent and lithium, and simultaneously rolling the mixed material in the first composite lithium belt again to make the mixed material thinner and more uniform; the invention continuously uses the mode of stacking, can improve the uniformity of the mixed material in the finished product, has better uniformity compared with the folding mode, and ensures that the prepared finished product has better electrochemistry and is not easy to generate the current concentration effect.
Step (D): taking the second composite lithium belt in the step (C) as a first composite lithium belt, and repeating the step (C) for more than two times to obtain a metal lithium mixture with a three-dimensional structure; after the lithium iron oxide particles pass through the roller for 10-50 times, the carbon powder, the conductive agent, the three-dimensional structure primary material and the particle lithium are uniformly mixed, so that the subsequent heating reaction is facilitated to generate a three-dimensional structure, a protective layer for protecting the particle lithium is formed, the uniform deposition of lithium ions is guided, and the generation of lithium dendrites is inhibited.
A step (E): and (D) heating the mixture of the lithium metal with the three-dimensional structure in the step (D) under the protection of inert gas to obtain the lithium metal composite electrode material containing the material with the three-dimensional structure. The inert gas may be helium or neon. Under the heating condition, a chemical reaction occurs, and the chemical reaction equation is as follows:
3Li+AlN(AlF)→Li3N(LiF)+Al (1)
Li+Al→LiAl (2)
li can be obtained from (1)3N (lithium nitride) or LiF (lithium fluoride). LiAl alloy (aluminum lithium alloy) can be obtained from the step (2), and products obtained from the two reaction formulas are core components of the material prepared by the invention, so that lithium is coated and protected, the direct contact with electrolyte is avoided, the uniform deposition of lithium ions is guided, the generation of lithium dendrites is inhibited, and the decisive effect is played on the electrochemical performance of the prepared material.
According to the preparation method of the metal lithium composite electrode material, disclosed by the invention, the composite material is prepared by using a rolling method, the controllability is good, the mass and large-scale production can be realized, the practicability is strong, the cost is low, and the prepared metal lithium composite electrode material is more uniform and has more excellent performance. When the compression roller is used, after the lithium belt and the two layers of three-dimensional structure primary material composite layers are subjected to multilayer overlapping and rolling, the three-dimensional structure primary material, the carbon powder and the conductive agent are liable to be embedded into the lithium belt, here, the lithium belt can be understood to be formed by agglomeration of numerous tiny lithium particles, the three-dimensional structure primary material, the carbon powder and the conductive agent mixture are embedded into the lithium belt to wrap the previous tiny particle lithium clusters to form a new lithium-containing mixture small particle, and the numerous lithium-containing mixture small particles are heated to form a composite product with a three-dimensional structure, so that the particle lithium is protected, direct contact between the lithium and electrolyte is avoided, and lithium dendrites are reduced.
Preferably, the solid content of the slurry in the step (A) is 3-10%, the drying temperature is 80-100 ℃, and the drying time is 20-30 hours. The solid content in the slurry is controlled to maintain the three-dimensional structure material at a certain content, so that the effectiveness is maintained when the three-dimensional structure material is combined with the lithium particles.
Preferably, the heating temperature of the step (E) is 120-170 ℃. And heating to enable the fully mixed materials to react, so that lithium in the metal lithium conducting layer reacts with the three-dimensional structure material to generate a three-dimensional composite structure. The temperature is not suitable to be too high, so that metal lithium is easy to melt, the metal lithium conducting layer is softened, the generation of a three-dimensional composite structure is not facilitated, the temperature is too low, the reaction is too slow, the internal reaction of the metal lithium conducting layer is insufficient, the deposition initiation of lithium ions is not facilitated, and the conductivity is poor.
Preferably, the conductive agent is one or a mixture of more than one of carbon fiber, carbon nanotube, graphene, acetylene black, ketjen black and conductive carbon black. The conductive agent can improve the conductive efficiency of the metal lithium conductive layer, and can limit the change of the lithium volume by cooperating with the carbon powder and the generated three-dimensional composite structure, thereby effectively inhibiting the increase of the thickness.
Preferably, the pressure of the rolling is 150-300 kg-f/cm2. The rolling pressure is controlled, so that carbon powder, a conductive agent, a three-dimensional structure primary material and metal lithium are uniformly mixed, uniform distribution of a three-dimensional composite structure is facilitated, current is prevented from being excessively concentrated, a heat effect is avoided, and the battery efficiency is improved. Preferably, the rolling pressure is 180 to 200 kg-f/cm2More preferably, the pressure of the rolling is 250kg · f/cm2。
3. A lithium ion battery comprises a positive electrode, a negative electrode, a diaphragm, electrolyte and a shell, wherein the diaphragm is used for separating the positive electrode from the negative electrode, and the negative electrode comprises the metal lithium composite electrode material.
The lithium ion battery can effectively avoid lithium dendrite, inhibit thickness increase and has better electrochemical performance.
Wherein, the positive electrode comprises a positive electrode current collector and a positive electrode active material arranged on the positive electrode current collector, and the positive electrode active material can be a chemical formula including but not limited to LiaNixCoyMzO2-bNb(wherein a is more than or equal to 0.95 and less than or equal to 1.2, x>0, y is more than or equal to 0, z is more than or equal to 0, x + y + z is 1,0 is more than or equal to b is less than or equal to 1, M is selected from one of Mn and AlOne or more combinations, N is selected from one or more combinations of F, P and S), the positive active material can also be selected from the group consisting of but not limited to LiCoO2、LiNiO2、LiVO2、LiCrO2、LiMn2O4、LiCoMnO4、Li2NiMn3O8、LiNi0.5Mn1.5O4、LiCoPO4、LiMnPO4、LiFePO4、LiNiPO4、LiCoFSO4、CuS2、FeS2、MoS2、NiS、TiS2And the like. The positive electrode active material may be further modified, and the method of modifying the positive electrode active material is known to those skilled in the art, for example, the positive electrode active material may be modified by coating, doping, and the like, and the material used in the modification may be one or a combination of more of Al, B, P, Zr, Si, Ti, Ge, Sn, Mg, Ce, W, and the like. 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 being used as a positive electrode current collector of a lithium ion battery in the field, 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.
The negative electrode comprises a negative electrode current collector and a negative electrode active substance arranged on the surface of the negative electrode current collector, wherein the negative electrode active substance can be one or more of graphite, soft carbon, hard carbon, carbon fiber, mesocarbon microbeads, silicon-based materials, tin-based materials, lithium titanate or other metals capable of forming alloys with lithium. Wherein, the graphite can be selected from one or more of artificial graphite, natural graphite and modified graphite; the silicon-based material can be one or more selected from simple substance silicon, silicon-oxygen compound, silicon-carbon compound and silicon alloy; the tin-based material can be one or more selected from simple substance tin, tin oxide compound and tin alloy. The negative electrode current collector is generally a structure or a part that collects current, and may be any material suitable for use as a negative electrode current collector of a lithium ion battery in the art, for example, the negative 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, a copper foil, a metal lithium foil, and the like.
The separator may be any material suitable for a lithium ion battery separator in the art, and for example, may be a combination including, but not limited to, one or more of polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester, natural fiber, and the like.
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 electrolyte6And/or LiBOB; or LiBF used in low-temperature electrolyte4、LiBOB、LiPF6At least one of; or LiBF used in anti-overcharge electrolyte4、LiBOB、LiPF6At least one of, LiTFSI; may also be LiClO4、LiAsF6、LiCF3SO3、LiN(CF3SO2)2At 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 electrolyte2At least one of additives of O and HF content, additives for improving low temperature performance, and multifunctional additives.
The material of the shell includes but is not limited to one of aluminum plastic film, aluminum plate, tin plate and stainless steel.
The present invention will be described in further detail with reference to the following detailed description and the accompanying drawings, but the embodiments of the invention are not limited thereto.
Example 1
1. A preparation method of a metal lithium composite electrode material comprises the following steps: as shown in figure 1 of the drawings, in which,
step (A): mixing carbon powder, a conductive agent VGCF and aluminum nitride (AlN) according to the mass part ratio of 6:2:3 to form a mixed solid, adding the mixed solid and water to prepare slurry, wherein the mass fraction of the solid is 10%, uniformly coating the slurry on a PP diaphragm by using a coating machine, and then placing the PP diaphragm in a vacuum drying oven to dry for 24 hours at 85 ℃ to form a primary material composite layer with a three-dimensional structure;
step (B): placing the dried three-dimensional structure primary material composite layer and the 50-micron metal lithium strip in an overlapped mode according to the three-dimensional structure primary material composite layer, the metal lithium strip and the three-dimensional structure primary material composite layer, and performing first rolling by using a rolling machine to obtain a composite material with a sandwich structure, namely a first composite lithium strip, comprising 2 layers of mixture containing AlN, carbon and a conductive agent and one layer of lithium strip;
step (C): taking another lithium belt and another three-dimensional structure primary material composite layer, stacking the lithium belt, the three-dimensional structure composite layer and the first composite lithium belt in sequence according to the three-dimensional structure composite layer, the lithium belt and the first composite lithium belt, and rolling the layered structure after placement to obtain a three-dimensional composite containing a mixture of 2 layers of lithium and 3 layers, namely a second composite lithium belt;
step (D): taking the second composite lithium belt in the step (C) as a first composite lithium belt, and repeating the step (C) for 10 times to obtain a three-dimensional mixture;
a step (E): and (D) heating the three-dimensional mixture in the step (D) at 150 ℃ under the protection of inert gas to obtain the metal lithium composite electrode material. As shown in fig. 2, (a)20 μm and (b)5 μm are SEM images of the prepared lithium metal composite electrode material, (C) an EDS image of the distribution of carbon (C) element in the lithium metal composite electrode material, (d) an EDS image of the distribution of nitrogen (N) element in the lithium metal composite electrode material, and (e) an EDS image of the distribution of aluminum (Al) element in the lithium metal composite electrode material. It is clear from the parts (c), (d) and (e) in the figure that the carbon nitrogen and aluminum in the lithium metal composite electrode material are uniformly distributed and have good uniformity. As can be seen from FIG. 3, the prepared lithium metal composite electrode material contains Li3N, LiAl and unreacted AlN and Li metal.
2. NCM811 is used as a positive electrode, the prepared metal lithium composite electrode material is used as a negative electrode, a PP diaphragm is used as the diaphragm, and Ethylene Carbonate (EC) is mixed with Ethylene Carbonate (EC) in a drying room,Uniformly mixing dimethyl carbonate (DMC) and fluoroethylene carbonate (FEC) according to the volume ratio of 45:45:10 to obtain the organic mixed solvent. Adding LiPF to the organic mixed solvent6Obtaining LiPF6And (3) electrolyte with the concentration of 1mol/L, and filling the positive electrode, the diaphragm, the negative electrode and the electrolyte into a shell to prepare the soft-package laminated battery with the capacity of 400 mAh.
Example 2
The difference from the embodiment 1 is that:
the weight part ratio of the carbon powder to the conductive agent to the three-dimensional structure material is 7:2: 3.
The rest is the same as embodiment 1, and the description is omitted here.
Example 3
The difference from the embodiment 1 is that:
the weight part ratio of the carbon powder to the conductive agent to the three-dimensional structure material is 8:2: 3.
The rest is the same as embodiment 1, and the description is omitted here.
Example 4
The difference from the embodiment 1 is that:
the weight part ratio of the carbon powder to the conductive agent to the three-dimensional structure material is 6:2: 4.
The rest is the same as embodiment 1, and the description is omitted here.
Example 5
The difference from the embodiment 1 is that:
the weight part ratio of the carbon powder to the conductive agent to the three-dimensional structure material is 6:2: 5.
The rest is the same as embodiment 1, and the description is omitted here.
Comparative example 1
The difference from the embodiment 1 is that:
a lithium metal strip having a thickness of 50 μm was used as the negative electrode.
The rest is the same as embodiment 1, and the description is omitted here.
Comparative example 2
The difference from the embodiment 1 is that: the lithium metal conductive layer does not contain a steric structural material.
The rest is the same as embodiment 1, and the description is omitted here.
And (3) performance testing:
1. the battery of example 1 and comparative example 1 was subjected to constant current charging to 4.3V at 0.2C at an ambient temperature of 25 ℃ on a blue tester, followed by charging to 0.05C under a constant voltage of 4.3V, respectively, followed by discharging to 3.0V at 0.5C, and the above-described charge and discharge processes were repeated N times to perform charge and discharge cycle life tests, the test results of which are shown in fig. 4;
2. the batteries prepared in examples 1 to 5 and comparative example 1 were subjected to constant current charge and discharge tests at 0.2C charge and 0.5C discharge rate, respectively, and the number of cycles at which the thickness of the battery increased by 0.2m, 0.5mm, 0.8mm, 1mm and short circuit occurred was recorded, and the test results are shown in table 1.
TABLE 1
Figure BDA0003193329320000111
As can be seen from table 1, the battery prepared by using the metal lithium composite electrode material prepared by the present invention as a negative electrode can well inhibit the increase of the thickness of the battery, because the metal lithium composite electrode material contains a three-dimensional structure, which can provide an attachment site for the particle lithium, so that the lithium is not directly contacted with the electrolyte under the protection of the three-dimensional framework, and the generation of lithium dendrites is avoided, thereby inhibiting the increase of the thickness, and further avoiding the short circuit caused by the penetration of the diaphragm by the excessively long-grown lithium dendrites. Moreover, as can be seen from examples 1 to 5, when the weight parts of the carbon powder, the conductive agent and the three-dimensional structure material are controlled to be 6:2:3, the prepared lithium metal composite electrode material and the battery have more excellent performance, better inhibit thickness growth, are not easy to short circuit and have long service life.
As can be seen from fig. 4, in comparative example 1, a 50 μm metal lithium tape is used as a negative electrode, in comparative example 2, a metal lithium composite electrode material prepared without a three-dimensional structure material is used as a negative electrode, and a battery prepared by using the metal lithium composite electrode material prepared in example 1 of the present invention as a negative electrode is subjected to a charge-discharge cycle test, when the comparative example 1 is charged and discharged for about 120 times, the capacity retention rate of the capacitor of the comparative example 1 is 90%, the capacity protection rate of the capacitor of the comparative example 2 is 98%, and the capacity retention rate of the battery is 98% in this embodiment, which means that the battery capacity protection rate can be effectively improved by adding a conductive agent and carbon powder into the lithium tape, when the number of charge and discharge times is increased to about 180 times, the capacity retention rate of the battery of the embodiment 1 is 92.5%, and the capacity protection rate of the comparative example 2 falls to 84%, which means that the carbon powder, the conductive agent and the three-dimensional structure material are compounded according to a certain weight portion, the prepared battery has good endurance, long battery performance, difficult occurrence of lithium dendrite and short circuit, and long service life.
Variations and modifications to the above-described embodiments may also occur to those skilled in the art, which fall within the scope of the invention as disclosed and taught herein. Therefore, the present invention is not limited to the above-mentioned embodiments, and any obvious improvement, replacement or modification made by those skilled in the art based on the present invention is 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. A lithium metal composite electrode material, characterized in that: the lithium metal conductive layer is provided with a three-dimensional structure material which is used for providing attachment sites for lithium metal and coating the lithium metal.
2. The lithium metal composite electrode material according to claim 1, wherein: the three-dimensional structure material comprises at least one of lithium nitride, lithium fluoride and aluminum lithium alloy.
3. The lithium metal composite electrode material according to claim 1, wherein: the lithium metal conducting layer further comprises carbon powder and a conducting agent, and the weight part ratio of the carbon powder to the conducting agent to the three-dimensional structure material is 5-8: 1-3: 2-5.
4. The lithium metal composite electrode material according to claim 1, wherein: the thickness of the metal lithium conducting layer is 40-60 mu m.
5. A preparation method of a metal lithium composite electrode material is characterized by comprising the following steps: the method comprises the following steps:
step (A): adding a solvent into the primary material with the three-dimensional structure to prepare slurry, coating the slurry on a bearing sheet, drying, and removing the bearing sheet to form a primary material composite layer with the three-dimensional structure;
step (B): taking a lithium belt and two layers of the three-dimensional structure primary material composite layers in the step (A), sequentially stacking the lithium belt and the three-dimensional structure primary material composite layers according to the sequence of the three-dimensional structure primary material composite layers, the lithium belt and the three-dimensional structure primary material composite layers, and rolling to form a first composite lithium belt;
step (C): taking another lithium belt and a layer of the three-dimensional structure primary material composite layer in the step (A), sequentially stacking the lithium belt and the three-dimensional structure primary material composite layer according to the three-dimensional structure primary material composite layer, the lithium belt and the first composite lithium belt, and rolling to form a second composite lithium belt;
step (D): taking the second composite lithium belt in the step (C) as a first composite lithium belt, and repeating the step (C) for more than two times to obtain a metal lithium mixture with a three-dimensional structure;
a step (E): and (D) heating the mixture of the lithium metal with the three-dimensional structure in the step (D) under the protection of inert gas to obtain the lithium metal composite electrode material containing the material with the three-dimensional structure.
6. The method for preparing a lithium metal composite electrode material according to claim 5, wherein: the solid content of the slurry in the step (A) is 3-10%, the drying temperature is 80-100 ℃, and the drying time is 20-30 hours.
7. The method for preparing a lithium metal composite electrode material according to claim 5, wherein: the heating temperature in the step (E) is 120-170 ℃.
8. The method for preparing a lithium metal composite electrode material according to claim 5, wherein: the conductive agent is one or a mixture of more than one of carbon fiber, carbon nano tube, graphene, acetylene black, Ketjen black and conductive carbon black.
9. The method for preparing a lithium metal composite electrode material according to claim 5, wherein: the rolling pressure is 150-300 kg.f/cm2。
10. A lithium ion battery, characterized by: comprising a positive electrode, a negative electrode, a separator for separating the positive electrode and the negative electrode, an electrolyte, and a case, the negative electrode comprising the lithium metal composite electrode material according to any one of claims 1 to 4.
CN202110884082.0A 2021-08-03 2021-08-03 Metal lithium composite electrode material, preparation method thereof and lithium ion battery Active CN113611868B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110884082.0A CN113611868B (en) 2021-08-03 2021-08-03 Metal lithium composite electrode material, preparation method thereof and lithium ion battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110884082.0A CN113611868B (en) 2021-08-03 2021-08-03 Metal lithium composite electrode material, preparation method thereof and lithium ion battery

Publications (2)

Publication Number Publication Date
CN113611868A true CN113611868A (en) 2021-11-05
CN113611868B CN113611868B (en) 2023-03-28

Family

ID=78339141

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110884082.0A Active CN113611868B (en) 2021-08-03 2021-08-03 Metal lithium composite electrode material, preparation method thereof and lithium ion battery

Country Status (1)

Country Link
CN (1) CN113611868B (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090123844A1 (en) * 2004-11-26 2009-05-14 Matsushita Electric Industrial Co., Ltd. Lithium Primary Battery and Manufacturing Method Therefor
WO2015027692A1 (en) * 2013-08-26 2015-03-05 华为技术有限公司 Composite negative electrode material of lithium-ion battery, preparation method therefor, and lithium-ion battery
CN109671908A (en) * 2018-12-17 2019-04-23 深圳先进技术研究院 Metal lithium electrode and preparation method thereof, lithium battery
CN111933888A (en) * 2020-06-30 2020-11-13 国网浙江省电力有限公司湖州供电公司 Fast ion conductor solid-state lithium battery cathode with SEI and preparation method thereof
CN112825354A (en) * 2019-11-20 2021-05-21 郑州宇通集团有限公司 Lithium negative electrode, preparation method thereof and lithium secondary battery
CN113066988A (en) * 2021-03-23 2021-07-02 远景动力技术(江苏)有限公司 Negative pole piece and preparation method and application thereof

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090123844A1 (en) * 2004-11-26 2009-05-14 Matsushita Electric Industrial Co., Ltd. Lithium Primary Battery and Manufacturing Method Therefor
WO2015027692A1 (en) * 2013-08-26 2015-03-05 华为技术有限公司 Composite negative electrode material of lithium-ion battery, preparation method therefor, and lithium-ion battery
CN109671908A (en) * 2018-12-17 2019-04-23 深圳先进技术研究院 Metal lithium electrode and preparation method thereof, lithium battery
CN112825354A (en) * 2019-11-20 2021-05-21 郑州宇通集团有限公司 Lithium negative electrode, preparation method thereof and lithium secondary battery
CN111933888A (en) * 2020-06-30 2020-11-13 国网浙江省电力有限公司湖州供电公司 Fast ion conductor solid-state lithium battery cathode with SEI and preparation method thereof
CN113066988A (en) * 2021-03-23 2021-07-02 远景动力技术(江苏)有限公司 Negative pole piece and preparation method and application thereof

Also Published As

Publication number Publication date
CN113611868B (en) 2023-03-28

Similar Documents

Publication Publication Date Title
CN112313819B (en) Method of manufacturing negative electrode for lithium secondary battery and method of manufacturing lithium secondary battery
JP4629027B2 (en) High capacity anode material for lithium secondary battery
KR102378583B1 (en) Separator Having Coating Layer of Lithium-Containing Composite, and Lithium Secondary Battery Comprising the Separator and Preparation Method Thereof
KR102502618B1 (en) Secondary battery, battery module including secondary battery, battery pack and device
KR101201804B1 (en) Negative active for rechargeable lithium battery, method of preparing the same, and rechargeable lithium battery including the same
US20110135982A1 (en) Negative electrode for non-aqueous electrolyte secondary battery and fabrication method thereof, and non-aqueous electrolyte secondary battery
CN111342137B (en) Electrolyte and electrochemical device
KR102660380B1 (en) Method for manufacturing lithium-ion type storage batteries
CN109449373A (en) Negative pole piece and battery
CN107565088B (en) Preparation method of negative electrode of lithium metal secondary battery
JPH08148185A (en) Nonaqueous electrolyte secondary battery and negative electrode therefor
WO2023040355A1 (en) Negative electrode plate and preparation method therefor, secondary battery, battery module, battery pack and power-consuming apparatus
CN115939309A (en) Positive electrode containing lithium supplement composition, preparation method thereof and lithium ion battery
KR20110056911A (en) Positive electrode for lithium rechargeable battery, method for manufacturing the same and lithium rechargeable battery including the same
CN112635766A (en) Metal lithium battery cathode, preparation method thereof and lithium secondary battery
CN114613963B (en) Negative electrode material, preparation method thereof, negative electrode sheet and secondary battery
CN116344742A (en) Fully lithiated negative electrode plate and preparation method thereof
CN113451547B (en) Composite metal lithium cathode and lithium ion battery comprising same
CN113611868B (en) Metal lithium composite electrode material, preparation method thereof and lithium ion battery
JP2022167890A (en) Negative electrode for lithium secondary battery and lithium secondary battery including the same
CN112216809B (en) Metal cathode, preparation method thereof and lithium ion battery
CN113707864A (en) Composite film-coated positive electrode material, and preparation method and application thereof
US20210104740A1 (en) Methods of prelithiating silicon-containing electrodes
WO2024040510A1 (en) Preparation method for secondary battery, secondary battery and electric device
CN117374390A (en) Electrolyte and lithium ion 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
GR01 Patent grant
GR01 Patent grant