CN113764667A - Lithium-supplementing functional electrolyte membrane for solid lithium battery - Google Patents

Lithium-supplementing functional electrolyte membrane for solid lithium battery Download PDF

Info

Publication number
CN113764667A
CN113764667A CN202110922764.6A CN202110922764A CN113764667A CN 113764667 A CN113764667 A CN 113764667A CN 202110922764 A CN202110922764 A CN 202110922764A CN 113764667 A CN113764667 A CN 113764667A
Authority
CN
China
Prior art keywords
lithium
layer
inorganic solid
battery
electrolyte
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
CN202110922764.6A
Other languages
Chinese (zh)
Other versions
CN113764667B (en
Inventor
杨杰
林久
许晓雄
崔言明
张永龙
楼凯
戈志敏
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.)
Zhejiang Funlithium New Energy Tech Co Ltd
Original Assignee
Zhejiang Funlithium New Energy Tech 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 Zhejiang Funlithium New Energy Tech Co Ltd filed Critical Zhejiang Funlithium New Energy Tech Co Ltd
Priority to CN202110922764.6A priority Critical patent/CN113764667B/en
Publication of CN113764667A publication Critical patent/CN113764667A/en
Application granted granted Critical
Publication of CN113764667B publication Critical patent/CN113764667B/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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • 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
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • 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
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • 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

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Secondary Cells (AREA)

Abstract

The invention discloses a lithium-supplementing functional electrolyte membrane for a solid lithium battery, which consists of a framework layer, a reinforcing layer and a lithium-supplementing electrolyte layer, wherein the framework layer has a three-dimensional porous structure, and part of the lithium-supplementing electrolyte layer is filled in the porous structure of the framework layer. The lithium-supplementing functional electrolyte membrane for the solid-state lithium battery replaces the traditional lithium ion battery diaphragm, the first-circle charging and lithium ion supplementing can be realized after the battery is assembled, the cycle performance of the battery is improved, and the first-circle charging can not damage the performance of the battery. The lithium supplement electrolyte layer is filled in the framework layer and between the enhancement layers, so that good lithium supplement can be realized, and the reduction of lithium supplement efficiency caused by the fact that a lithium supplement agent falls off into the electrolyte can be avoided. Meanwhile, the lithium supplement electrolyte layer has controllable thickness, and the lithium supplement amount is adjusted according to the positive and negative electrode systems. The inorganic solid electrolyte particles in the lithium-supplementing electrolyte layer can not only increase lithium ion conduction, but also enhance the heat resistance of the diaphragm and reduce the thermal shrinkage and thermal puncture of the diaphragm.

Description

Lithium-supplementing functional electrolyte membrane for solid lithium battery
Technical Field
The invention belongs to the technical field of lithium batteries, and particularly relates to an electrolyte membrane with a lithium supplementing function for a solid-state lithium battery.
Background
The lithium ion battery has the advantages of high energy density, long cycle life and the like, and is widely applied to the fields of portable electronic products, electric automobiles and the like. In the first charging process of the lithium ion battery, an SEI film is formed on the surface of a negative electrode, active lithium in a positive electrode is consumed, irreversible capacity loss is caused, the irreversible capacity loss of the graphite negative electrode which is most widely used at present can reach 10%, and the irreversible capacity loss of silicon-based and tin-based negative electrodes with high specific capacity can even reach more than 30%, so that the energy density of the lithium ion battery is greatly reduced. For this problem, it is currently acknowledged in academia and industry that the irreversible loss of lithium ions is compensated by a lithium supplementing method, so that the capacity of the positive electrode can be recovered, and the energy density of the lithium ion battery is greatly improved.
From the technical path, the currently mainstream lithium supplement schemes can be divided into three main categories: 1) the negative pole is supplemented with lithium, mainly inert metal lithium powder and metal lithium foil, and the lithium is supplemented by vacuum winding and evaporation; 2) the positive electrode being lithium-supplemented, primarily by some lithium-containing oxides, e.g. Li5FeO4Etc.; 3) and (3) lithium is supplemented by the third electrode, and the purpose of lithium supplementation is achieved by charging and discharging between the negative electrode and the third electrode (such as a metal lithium electrode and a high-capacity lithium-containing oxide electrode).
The lithium is supplemented by the metal lithium in the negative electrode, so that the lithium supplementing efficiency is high, no residue is left after reaction, but the activity of the metal lithium is very high, the requirement on environmental control is high, large-scale equipment is required, the cost investment is large, and the influence on the existing production process is large. Meanwhile, the adoption of the lithium metal also has a great safety risk, and particularly, the lithium metal powder is suspended in the air and can cause the risks of dust explosion and the like. Meanwhile, if the lithium supplement is insufficient, the energy density is not obviously improved; if lithium is excessively supplied, a lithium metal plating layer is formed on the surface of the negative electrode, and the battery performance is impaired.
The lithium supplement of the positive electrode has the advantages of simple process, low price, high safety and the like, and has attracted wide attention in recent years. Patent CN110120493A provides a positive electrode lithium-supplementing method for preparing a smear by pulping a lithium-supplementing material, a positive electrode material, a conductive agent and a binder together, but in this method, a lithium-supplementing sacrificial agent has a certain influence on the mass transfer inside the whole pole piece after the lithium-removing decomposition of the positive electrode side. Patent CN109755448A will contain Li5FeO4The lithium supplementing coating containing the lithium compound, the nano inert inorganic filler and the binder is coated on the diaphragm substrate to prepare the lithium battery diaphragm with the lithium supplementing coating, the heat shrinkage of the diaphragm is reduced while the lithium is supplemented, but the bonding between the lithium supplementing layer and the diaphragm substrate can be influenced after the lithium supplementing agent is removed, and the lithium supplementing efficiency is reduced after the lithium supplementing agent is removed into the electrolyte.
Therefore, it is important to develop lithium batteries to provide an electrolyte membrane with lithium supplementing function for solid lithium batteries, which has high-efficiency and controllable lithium supplementing effect, prolongs the battery cycle life, and has better temperature resistance.
Disclosure of Invention
The invention aims to solve the technical problem of providing a lithium-supplementing functional electrolyte membrane for a solid lithium battery, and solves the problems that a lithium-supplementing diaphragm in the prior art is poor in temperature resistance and a lithium supplementing layer can fall off into an electrolyte.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the electrolyte membrane consists of a framework layer, a reinforcing layer and a lithium supplement electrolyte layer positioned between the framework layer and the reinforcing layer, wherein the framework layer has a three-dimensional porous structure, and part of the lithium supplement electrolyte layer is filled in the porous structure of the framework layer.
Preferably, the lithium-supplement electrolyte layer includes a lithium-containing compound, inorganic solid electrolyte particles, a binder, and a conductive agent.
Preferably, the content of the lithium-containing compound is 10% to 45%, the content of the inorganic solid electrolyte particles is 50% to 80%, the content of the binder is 3.5% to 10%, and the content of the conductive agent is 0.5% to 2%.
Preferably, the lithium-containing compound includes at least one of lithium iron oxide, lithium nickel oxide, lithium cobalt oxide, organic lithium salt, lithium oxide, lithium sulfide, lithium phosphide, and lithium nitride.
Preferably, the lithium-containing compound is Li5FeO4、Li5Fe5O8、Li6CoO4、Li2NiO2、 Li2O、Li2S、Li3P、Li3N、Li2O2、Li2C2O4、Li2At least one of DHBN.
Preferably, the lithium-containing compound has a particle size of 0.1 to 2 μm.
Preferably, the inorganic solid electrolyte particles have a NASICON type structure, and the chemical formula of the inorganic solid electrolyte particles is LiM2(PO4)3、Li1+xAlxTi2-x(PO4)3And Li1+xAlxGe2-x(PO4)3Wherein M is one of Ti, Ge and Hf, and 0 < x < 2;
or the inorganic solid electrolyte particles are in a perovskite structure, and the chemical formula of the inorganic solid electrolyte particles is Li0.34La0.56TiO3And/or Li0.5La0.5TiO3；
Or the inorganic solid electrolyte particles are of a LISICON type structure, and the chemical formula of the inorganic solid electrolyte particles is Li14Zn(GeO4)4；
Or the inorganic solid electrolyte particles are of garnet structure, the chemistry of the inorganic solid electrolyte particlesIs represented by the formula Li5La3R2O12、Li6ALa2R2O12、Li5.5La3R1.75D0.25O12、 Li7La3Zr2O12And Li7.06E3Y0.06Zr1.94O12Wherein, R is Nb or Ta, A is one of Ca, Sr and Ba, D is In or Zr, and E is one of La, Nb and Ta;
or the inorganic solid electrolyte particles are of an anti-perovskite structure, and the chemical formula of the inorganic solid electrolyte particles is Li3OX, wherein X is F, Cl or Br;
or the inorganic solid electrolyte particles are in a glass state or a glass ceramic state, and the inorganic solid electrolyte particles are sulfide Li10GeP2S12、Li2S-SiS2、Li2S-P2S5、 70Li2S-30P2S5One or more of (a).
Preferably, the inorganic solid electrolyte particles have a particle size of 0.1 to 2 μm.
Preferably, the binder is at least one of PVDF, PVDF-HFP, PVP, PEO, PAN, EVA and PMMA;
the conductive agent is one or more of Super-P, Ketjen black, CNTs and graphene;
the framework layer is a three-dimensional porous non-woven membrane and comprises a first polymer base material, and the first polymer base material is one of cellulose, PET, PI, PVDF, PA and PVC.
Preferably, the reinforcement layer comprises a second polymeric substrate, the second polymeric substrate being one of PE, PP, PE/PP/PE.
Compared with the prior art, the electrolyte membrane with the lithium supplementing function for the solid lithium battery has the advantages that,
1) the lithium-containing compound in the lithium-supplementing functional electrolyte membrane for the solid lithium battery can be used for extracting more lithium ions in the process of charging the battery and participating in the formation of an SEI layer, so that the loss of the lithium ions in the positive active material is reduced, more lithium ions can be ensured to participate in the extraction, the discharge capacity of the lithium battery is improved, and the charge-discharge cycle life of the lithium battery can be prolonged;
2) because the inorganic solid electrolyte has higher ionic conductivity, the rate capability of the battery can be greatly improved;
3) the lithium supplement electrolyte layer is filled in the framework layer and between the framework layer and the enhancement layer, and the framework layer and the enhancement layer are tightly bonded through the lithium supplement electrolyte layer, so that good lithium supplement can be realized, and the problem that the lithium supplement effect is influenced because a lithium supplement agent is separated in the lithium supplement process to cause the electrolyte layer to fall into the electrolyte can be avoided;
4) the enhancement layer is arranged, so that the overall mechanical strength of the film is far greater than that of a film structure which only has the framework layer and is provided with the lithium-supplement electrolyte layer on one side of the framework layer, and therefore the whole film can meet the strength specification of equipment pulling in the manufacturing process of the battery cell and meet the subsequent tests of safety performances of the battery cell such as heavy object impact resistance and the like;
5) the heat resistance of the electrolyte membrane is improved through the synergistic effect of the framework layer, the enhancement layer and the lithium-supplement electrolyte layer, the thermal shrinkage and the thermal puncture are reduced, and the safety problem caused by puncture or thermal runaway is prevented.
Drawings
FIG. 1 is an electron micrograph of a surface of a lithium-doped electrolyte layer according to the present example;
fig. 2 is a cycle life curve in the 1C (1C ═ 5A) charge-discharge mode in this example;
FIG. 3 is a photograph of the present example (example 1, comparative example 1 and comparative example 2, respectively, from top to bottom) before heat treatment at 180 ℃;
FIG. 4 is a photograph showing the heat treatment at 180 ℃ for 1 hour in this example (example 1, comparative example 1 and comparative example 2, respectively, from the top).
Detailed Description
The invention is described in further detail below with reference to the accompanying examples.
The electrolyte membrane consists of a framework layer, a reinforcing layer and a lithium-supplementing electrolyte layer positioned between the framework layer and the reinforcing layer, wherein the framework layer has a three-dimensional porous structure, and part of the lithium-supplementing electrolyte layer is filled in the porous structure of the framework layer.
Lithium ions are extracted in the battery charging and discharging process through the lithium supplementing electrolyte layer, the lithium ions participate in forming the SEI layer, the loss of the lithium ions in the positive active material is reduced, the lithium supplementing electrolyte layer is located between the framework layer and the enhancement layer, even if the structure of the lithium supplementing electrolyte layer is changed due to lithium removal in the lithium supplementing process, the lithium supplementing electrolyte layer cannot fall into electrolyte due to falling, and the lithium supplementing effect is guaranteed.
And the arrangement of the reinforced layer enables the overall mechanical strength of the membrane to be higher. Experiments show that the inorganic electrolyte layer is arranged on one side of the framework layer, the mechanical strength of the lithium-supplement electrolyte membrane obtained by arranging the composite electrolyte layer on the other side is only 50Mpa at most, the lithium-supplement electrolyte layer of the lithium-supplement function electrolyte membrane for the solid lithium battery in the embodiment is filled in the framework layer and between the framework layer and the reinforcing layer, the framework layer and the reinforcing layer are tightly bonded through the lithium-supplement electrolyte layer, and the integral mechanical strength of the membrane is greater than 100Mpa, so that the whole membrane can meet the strength specification of equipment pulling in the manufacturing process of the battery cell, and meanwhile, the tests of the safety performances of the follow-up battery cell, such as heavy object impact resistance and the like, can be met.
Specifically, the lithium-supplement electrolyte layer includes a lithium-containing compound, inorganic solid electrolyte particles, a binder, and a conductive agent.
The lithium-containing compound in the lithium supplement functional electrolyte membrane for the solid lithium battery can be used for releasing and inserting more lithium ions in the battery charging process to participate in the formation of an SEI layer, so that the loss of the lithium ions in the positive active material is reduced, more lithium ions can be ensured to participate in the insertion and release, the discharge capacity of the lithium battery is improved, and the charge-discharge cycle life of the lithium battery can be prolonged.
The content of the lithium-containing compound is 10-45%, the content of the inorganic solid electrolyte particles is 50-80%, the content of the binder is 3.5-10%, and the content of the conductive agent is 0.5-2%.
The lithium-containing compound is a lithium-containing compound having a high irreversible capacity in a certain voltage range, and includes at least one of lithium iron oxide, lithium nickel oxide, lithium cobalt oxide, organic lithium salt, lithium oxide, lithium sulfide, lithium phosphide, and lithium nitride.
Specifically, the lithium-containing compound is Li5FeO4、Li5Fe5O8、Li6CoO4、Li2NiO2、Li2O、Li2S、Li3P、Li3N、Li2O2、Li2C2O4、Li2At least one of DHBN.
The activity of the lithium-containing compound increases with the decrease of the particle size, and the lithium-containing compound is more likely to react with moisture, a binder and a solution in the environment, so that the slurry gel is accelerated. The large-particle lithium-containing compound has poor dynamics, so that the lithium supplementing efficiency is reduced, the particle size of the lithium-containing compound is moderate, and the particle size of the lithium-containing compound is preferably 0.1-2 mu m, so that the stability of the slurry can be improved, the exertion of the lithium supplementing efficiency can be facilitated, and the energy density and the electrochemical performance of the battery can be further improved.
The inorganic solid electrolyte particles have NASICON type structure, and the chemical formula of the inorganic solid electrolyte particles is LiM2(PO4)3、Li1+xAlxTi2-x(PO4)3(LATP) and Li1+xAlxGe2-x(PO4)3(LAGP), wherein M is one of Ti, Ge and Hf, and 0 < x < 2;
or the inorganic solid electrolyte particles are in a perovskite structure, and the chemical formula of the inorganic solid electrolyte particles is Li0.34La0.56TiO3And/or Li0.5La0.5TiO3；
Or the inorganic solid electrolyte particles are of a LISICON type structure and have a chemical formula of Li14Zn(GeO4)4；
OrThe inorganic solid electrolyte particles have a garnet structure and have a chemical formula of Li5La3R2O12、Li6ALa2R2O12、Li5.5La3R1.75D0.25O12、Li7La3Zr2O12And Li7.06E3Y0.06Zr1.94O12Wherein, R is Nb or Ta, A is one of Ca, Sr and Ba, D is In or Zr, and E is one of La, Nb and Ta;
or the inorganic solid electrolyte particles are of an anti-perovskite structure, and the chemical formula of the inorganic solid electrolyte particles is Li3OX, X is F, Cl or Br;
or the inorganic solid electrolyte particles are in a glass state or a glass ceramic state, and the inorganic solid electrolyte particles are sulfide Li10GeP2S12、Li2S-SiS2、Li2S-P2S5、70Li2S-30P2S5One or more of (a).
The particle size of the inorganic solid electrolyte particles is preferably 0.1 μm to 2 μm so as to match the particle size of the lithium-containing compound for coating.
The binder is at least one of PVDF, PVDF-HFP, PVP, PEO, PAN, EVA and PMMA.
The conductive agent is one or more of Super-P, Ketjen black, CNTs and graphene.
The framework layer is a three-dimensional porous non-woven membrane and comprises a first polymer base material, and the first polymer base material is one of cellulose, PET, PI, PVDF, PA and PVC.
The reinforced layer comprises a second polymer substrate, and the second polymer substrate is one of PE, PP and PE/PP/PE.
A preparation method of an electrolyte membrane with a lithium supplementing function for a solid lithium battery comprises the following specific steps:
s1, respectively weighing a lithium-containing compound, an inorganic solid electrolyte, a binder and a conductive agent, respectively dispersing the weighed lithium-containing compound and the weighed inorganic solid electrolyte in NMP, and respectively preparing a lithium-containing compound dispersion liquid and an inorganic solid electrolyte dispersion liquid by ball milling; simultaneously, stirring and dissolving the weighed adhesive in NMP to prepare an adhesive solution;
s2, mixing the lithium-containing compound dispersion liquid and the inorganic solid electrolyte dispersion liquid according to the mass ratio, adding a conductive agent into the mixture, and continuously performing ball milling dispersion and mixing to prepare a mixed dispersion liquid;
s3, adding the binder solution obtained in the step S1 into the mixed dispersion liquid obtained in the step S2, and performing ball milling and mixing to obtain uniform slurry;
and S4, simultaneously coating the uniform slurry obtained in the step S3 on the surface of one side of the reinforcing layer opposite to the framework layer through a double-unwinding mode, drying the uniform slurry in an oven of a coating machine, and further forming a lithium-supplement electrolyte layer between the reinforcing layer and the framework layer, so that the lithium-supplement functional electrolyte membrane for the solid lithium battery is obtained.
Specifically, in step S1, the binder was dissolved in NMP with stirring at a solid content of 10%, to prepare a binder solution. The particle size of the lithium-containing compound after ball milling in step S1 is 0.1 to 2 μm, and the particle size of the inorganic solid electrolyte particles after ball milling in step S1 is 0.1 to 2 μm.
The temperature of the oven in the step S4 is 60 to 80 ℃, the content of the lithium-containing compound in the lithium-supplement electrolyte layer obtained in the step S4 is 10 to 45%, the content of the inorganic solid electrolyte particles is 50 to 80%, the content of the binder is 3.5 to 10%, and the content of the conductive agent is 0.5 to 2%.
The dispersing and ball milling equipment in the steps S1, S2 and S3 comprises a double-planet dispersing machine, a planet ball mill and a horizontal ball mill.
Examples 1,
A preparation method of an electrolyte membrane with a lithium supplementing function for a solid lithium battery comprises the following specific steps:
s1, respectively weighing Li2NiO2LATP, PVP and Super-P, weighing Li2NiO2And LATP is respectively dispersed in NMP according to the solid content of 45 percent and respectively ball-milledPreparing a lithium-containing compound dispersion liquid and an inorganic solid electrolyte dispersion liquid, and ball-milling at 300rpm to obtain Li in the lithium-containing compound dispersion liquid2NiO2The particle size range was 0.8 μm, and the particle size of LATP in the inorganic solid electrolyte dispersion was 0.3 μm; simultaneously stirring and dissolving the weighed binder in NMP to prepare a binder solution;
s2, mixing the lithium-containing compound dispersion liquid and the inorganic solid electrolyte dispersion liquid according to the mass ratio, adding a conductive agent, continuing ball milling dispersion, and mixing to prepare a mixed dispersion liquid, wherein the ball milling rotation speed is 300rpm, and the ball milling time is 1 h;
s3, adding the binder solution obtained in the step S1 into the mixed dispersion liquid obtained in the step S2, and performing ball milling and mixing to obtain uniform slurry, wherein the ball milling speed is 300 rpm;
and S4, simultaneously coating the uniform slurry obtained in the step S3 on the surface of one side of the reinforcing layer opposite to the framework layer through a double-unwinding mode, drying the uniform slurry in an oven of a coating machine at the temperature of 60-80 ℃, and further forming a lithium-supplement electrolyte layer between the reinforcing layer and the framework layer, so that the lithium-supplement functional electrolyte membrane for the solid lithium battery is obtained. Wherein the first polymer base material of the framework layer is PET, the second polymer base material of the enhancement layer is PE, and Li in the prepared lithium-supplement electrolyte layer2NiO2The contents of LATP, PVP and Super-P were 30%, 64.5%, 4% and 1.5%, respectively.
Examples 2,
A preparation method of an electrolyte membrane with a lithium supplementing function for a solid lithium battery comprises the following specific steps:
s1, respectively weighing Li5FeO4LLZTO, PVDF and Super-P/CNTs, weighing Li5FeO4And respectively dispersing LLZTO in NMP according to 45% of solid content, and respectively preparing lithium-containing compound dispersion liquid and inorganic solid electrolyte dispersion liquid by ball milling, wherein the ball milling rotating speed is 300rpm, so that Li in the lithium-containing compound dispersion liquid5FeO4The particle size range was 0.1 μm, and the particle size of LLZTO in the inorganic solid electrolyte dispersion was 0.3 μm; simultaneously, the weighed binder is stirred and dissolved in NMP to prepare a binder solutionLiquid;
s2, mixing the lithium-containing compound dispersion liquid and the inorganic solid electrolyte dispersion liquid according to the mass ratio, adding a conductive agent, continuing ball milling dispersion, and mixing to prepare a mixed dispersion liquid, wherein the ball milling rotation speed is 300rpm, and the ball milling time is 1 h;
s3, adding the binder solution obtained in the step S1 into the mixed dispersion liquid obtained in the step S2, and performing ball milling and mixing to obtain uniform slurry, wherein the ball milling speed is 300 rpm;
and S4, simultaneously coating the uniform slurry obtained in the step S3 on the surface of one side of the reinforcing layer opposite to the framework layer through a double-unwinding mode, drying the uniform slurry in an oven of a coating machine at the temperature of 60-80 ℃, and further forming a lithium-supplement electrolyte layer between the reinforcing layer and the framework layer, so that the lithium-supplement functional electrolyte membrane for the solid lithium battery is obtained. Wherein the first polymer base material of the framework layer is PI, the second polymer base material of the enhancement layer is PE, and Li in the prepared lithium-supplement electrolyte layer5FeO4The contents of LLZTO, PVDF and Super-P/CNTs were 20%, 73.5%, 5% and 1.5%, respectively.
Examples 3,
A preparation method of an electrolyte membrane with a lithium supplementing function for a solid lithium battery comprises the following specific steps:
s1, respectively weighing Li2DHBN, LLZNO, PVDF-HFP and graphene/CNTs, namely the weighed Li2Respectively dispersing DHBN and LLZNO in NMP according to the solid content of 45 percent, respectively preparing a lithium-containing compound dispersion liquid and an inorganic solid electrolyte dispersion liquid by ball milling, wherein the ball milling rotating speed is 300rpm, so that Li in the lithium-containing compound dispersion liquid2The particle size range of DHBN is 0.3 mu m, so that the particle size of LLZNO in the inorganic solid electrolyte dispersion liquid is 0.8 mu m; simultaneously stirring and dissolving the weighed binder in NMP to prepare a binder solution;
s2, mixing the lithium-containing compound dispersion liquid and the inorganic solid electrolyte dispersion liquid according to the mass ratio, adding a conductive agent, continuing ball milling dispersion, and mixing to prepare a mixed dispersion liquid, wherein the ball milling rotation speed is 300rpm, and the ball milling time is 1 h;
s3, adding the binder solution obtained in the step S1 into the mixed dispersion liquid obtained in the step S2, and performing ball milling and mixing to obtain uniform slurry, wherein the ball milling speed is 300 rpm;
and S4, simultaneously coating the uniform slurry obtained in the step S3 on the surface of one side of the reinforcing layer opposite to the framework layer through a double-unwinding mode, drying the uniform slurry in an oven of a coating machine at the temperature of 60-80 ℃, and further forming a lithium-supplement electrolyte layer between the reinforcing layer and the framework layer, so that the lithium-supplement functional electrolyte membrane for the solid lithium battery is obtained. Wherein the first polymer base material of the framework layer is cellulose, the second polymer base material of the enhancement layer is PE, and Li in the prepared lithium-supplement electrolyte layer2The contents of DHBN, LLZNO, PVDF-HFP and graphene/CNTs are 40%, 52.2%, 7% and 0.8% respectively.
Examples 4,
A preparation method of an electrolyte membrane with a lithium supplementing function for a solid lithium battery comprises the following specific steps:
s1, respectively weighing Li6CoO4LAGP, EAV and CNTs, weighing Li6CoO4And respectively dispersing LAGP in NMP according to the solid content of 45 percent, and respectively preparing a lithium-containing compound dispersion liquid and an inorganic solid electrolyte dispersion liquid by ball milling, wherein the ball milling rotating speed is 300rpm, so that Li in the lithium-containing compound dispersion liquid6CoO4The particle size range was 1.5 μm, and the particle size of LAGP in the inorganic solid electrolyte dispersion was 0.6 μm; simultaneously stirring and dissolving the weighed binder in NMP to prepare a binder solution;
s2, mixing the lithium-containing compound dispersion liquid and the inorganic solid electrolyte dispersion liquid according to the mass ratio, adding a conductive agent, continuing ball milling dispersion, and mixing to prepare a mixed dispersion liquid, wherein the ball milling rotation speed is 300rpm, and the ball milling time is 1 h;
s3, adding the binder solution obtained in the step S1 into the mixed dispersion liquid obtained in the step S2, and performing ball milling and mixing to obtain uniform slurry, wherein the ball milling speed is 300 rpm;
s4, coating the uniform slurry obtained in the step S3 on the surface of the reinforcing layer and the framework layer on the opposite side simultaneously through a double-unwinding mode, and placing the reinforcing layer and the framework layer in an oven of a coating machineAnd drying at 60-80 ℃ to form a lithium-supplement electrolyte layer between the enhancement layer and the framework layer, thereby obtaining the lithium-supplement functional electrolyte membrane for the solid lithium battery. Wherein the first polymer base material of the framework layer is PA, the second polymer base material of the enhancement layer is PP, and Li in the prepared lithium-supplement electrolyte layer6CoO4LAGP, EAV and CNTs were 15%, 78%, 6% and 1%, respectively.
Examples 5,
A preparation method of an electrolyte membrane with a lithium supplementing function for a solid lithium battery comprises the following specific steps:
s1, respectively weighing Li2C2O4LLTO, PAN and graphene/CNTs, weighing Li2C2O4And respectively dispersing LLTO in NMP according to the solid content of 45 percent, and respectively preparing a lithium-containing compound dispersion liquid and an inorganic solid electrolyte dispersion liquid by ball milling, wherein the ball milling rotating speed is 300rpm, so that Li in the lithium-containing compound dispersion liquid2C2O4Particle size range of 1.5 μm, particle size of LLTO in inorganic solid electrolyte dispersion is 0.6 μm; simultaneously stirring and dissolving the weighed binder in NMP to prepare a binder solution;
s2, mixing the lithium-containing compound dispersion liquid and the inorganic solid electrolyte dispersion liquid according to the mass ratio, adding a conductive agent, continuing ball milling dispersion, and mixing to prepare a mixed dispersion liquid, wherein the ball milling rotation speed is 300rpm, and the ball milling time is 1 h;
s3, adding the binder solution obtained in the step S1 into the mixed dispersion liquid obtained in the step S2, and performing ball milling and mixing to obtain uniform slurry, wherein the ball milling speed is 300 rpm;
and S4, simultaneously coating the uniform slurry obtained in the step S3 on the surface of one side of the reinforcing layer opposite to the framework layer through a double-unwinding mode, drying the uniform slurry in an oven of a coating machine at the temperature of 60-80 ℃, and further forming a lithium-supplement electrolyte layer between the reinforcing layer and the framework layer, so that the lithium-supplement functional electrolyte membrane for the solid lithium battery is obtained. Wherein the first polymer base material of the framework layer is PET, the second polymer base material of the reinforced layer is PP, and the prepared lithium-supplement electrolyteLi in the layer2C2O4LLTO, PAN and graphene/CNTs contents were 40%, 54.2%, 5% and 0.8%, respectively.
Lithium batteries were prepared by using the lithium-supplement functional electrolyte membranes and ceramic coating membranes for solid-state lithium batteries obtained in examples 1 to 5, respectively, and the specific steps were as follows:
step 1, preparing a positive plate, namely mixing nickel cobalt lithium manganate, carbon black and a binder (PVDF) according to a mass ratio of 95:2:3 to prepare slurry, uniformly coating the slurry on a carbon-coated aluminum foil current collector, drying the carbon-coated aluminum foil current collector in an air-blowing oven at 80 ℃, and then drying the carbon-coated aluminum foil current collector in vacuum at 80 ℃ for 8 hours to prepare the positive plate;
step 2, preparing a negative plate, namely mixing SiOx/graphite (SiOx: graphite is 3:7, x is more than 0 and less than or equal to 2), carbon black and a butylbenzene emulsion binder in a mass ratio of 94:1.8:4.2, taking water as a solvent, pulping, uniformly coating the slurry on a copper foil current collector, drying the copper foil current collector in a blast oven at the temperature of 55 ℃, and then performing vacuum drying at the temperature of 60 ℃ for 12 hours to prepare the negative plate;
step 3, respectively adopting the lithium-supplement functional electrolyte membrane and the proportional ceramic coating membrane for the solid-state lithium battery prepared in the embodiments 1-5 to laminate the positive electrode and the negative electrode according to the condition that n/p is 1.05, preparing a 5Ah soft package battery cell, welding a tab, performing side sealing and performing top sealing on one side of a framework layer, wherein the tab is opposite to the positive electrode;
step 4, in a glove box under the protection of argon, an interfacial wetting agent (1M LiPF6 dissolved in an organic solvent with a volume ratio of EC: DEC: DMC ═ 1:1: 1) is added, and the mixture is sealed.
And 5, forming, secondary sealing and capacity grading to prepare the lithium battery.
The lithium-supplement functional electrolyte membrane for a solid lithium battery and the common ceramic coating membrane prepared in the above manner were subjected to heat shrinkage and hot puncture tests.
Heat shrinkage Performance test with reference to ISO 14616-1997 test for film shrinkage stress in heat-shrinkable of polyethylene, ethylene copolymers and mixtures thereof, cutting the test specimens into 120mm x 120mm square test specimens using an image measuring apparatus, drawing 10cm lines in the MD and TD directions on the test specimens, and testing the heat shrinkage of the films in the MD and TD directions after heat treatment at 180 ℃ for 60 min.
The hot puncture performance test is that a steel needle heated to 300 ℃ penetrates through the membrane surface on a tensile machine at a speed of 100mm/min, and the aperture of the membrane surface is measured by an image measuring instrument.
TABLE 1,
300 ℃ hot puncture test, pore size of membrane surface (mm)
Example 1 2.69
Comparative example 1(PE ceramic coating film) 4.99
Comparative example 2(PP ceramic coating film) 5.284
As can be seen from fig. 3 and 4, the comparison between the electrolyte membrane of example 1 and the electrolyte membrane before and after heat treatment at 180 ℃ for 1 hour shows that the electrolyte membrane of example 1 has a temperature resistance significantly superior to that of the conventional ceramic coating membrane, particularly, the PE ceramic coating membrane, and the membrane is completely broken and not formed after baking at 180 ℃.
According to the hot puncture performance test, the pore size of the membrane surface of the lithium-supplement functional electrolyte membrane is obviously smaller than that of a comparative example after the lithium-supplement functional electrolyte membrane is subjected to hot puncture at 300 ℃, and the puncture performance of the battery can be further improved.
In a cycle stability test, a cycle life curve in a 1C (1C ═ 5A) charge-discharge mode is shown in fig. 2, and it can be seen from the cycle performance of the example 1 and the comparative example battery that, by supplementing redundant lithium ions provided by the first circle of the lithium compound in the lithium-supplementing electrolyte membrane, the lithium ion battery can realize more stable cycle, and the example 1 can still have 100% capacity retention rate after 360 circles of 1C cycle; in contrast, in the comparative example, since the utilization efficiency of lithium ions was low, the cycle performance was poor, and the retention rate was only 77.41% after 243 cycles.
Compared with the prior art, the lithium supplement function electrolyte membrane for the solid lithium battery replaces the traditional lithium ion battery diaphragm, the first circle of lithium ion supplement can be realized after the battery is assembled, the cycle performance of the battery is improved, and the performance of the battery cannot be damaged after the first circle of charging. The lithium supplement electrolyte layer is filled in the framework layer and between the enhancement layers, so that good lithium supplement can be realized, and the lithium supplement agent can be prevented from falling into the electrolyte, so that the lithium supplement efficiency is reduced. Meanwhile, the lithium supplement electrolyte layer has controllable thickness, and the lithium supplement amount can be easily adjusted according to a positive and negative electrode system. The inorganic solid electrolyte particles in the lithium-supplementing electrolyte layer can not only increase lithium ion conduction, but also enhance the heat resistance of the diaphragm and reduce the thermal shrinkage and thermal puncture of the diaphragm.
Although preferred embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that modifications and variations of the present invention are possible to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A lithium-supplementing functional electrolyte membrane for a solid-state lithium battery, characterized in that: the electrolyte membrane consists of a framework layer, a reinforcing layer and a lithium supplement electrolyte layer positioned between the framework layer and the reinforcing layer, wherein the framework layer has a three-dimensional porous structure, and part of the lithium supplement electrolyte layer is filled in the porous structure of the framework layer.
2. The lithium replenishing functional electrolyte membrane for a solid lithium battery as claimed in claim 1, wherein: the lithium-supplementing electrolyte layer includes a lithium-containing compound, inorganic solid electrolyte particles, a binder, and a conductive agent.
3. The lithium replenishing functional electrolyte membrane for a solid lithium battery as claimed in claim 2, wherein: the content of the lithium-containing compound is 10-45%, the content of the inorganic solid electrolyte particles is 50-80%, the content of the binder is 3.5-10%, and the content of the conductive agent is 0.5-2%.
4. The lithium replenishing functional electrolyte membrane for a solid lithium battery as claimed in claim 2, wherein: the lithium-containing compound includes at least one of lithium iron oxide, lithium nickel oxide, lithium cobalt oxide, organic lithium salt, lithium oxide, lithium sulfide, lithium phosphide and lithium nitride.
5. The lithium replenishing functional electrolyte membrane for a solid lithium battery as claimed in claim 4, wherein: the lithium-containing compound is Li5FeO4、Li5Fe5O8、Li6CoO4、Li2NiO2、Li2O、Li2S、Li3P、Li3N、Li2O2、Li2C2O4And Li2At least one of DHBN.
6. The lithium replenishing functional electrolyte membrane for a solid lithium battery as claimed in claim 4, wherein: the particle size of the lithium-containing compound is 0.1-2 μm.
7. The lithium replenishing functional electrolyte membrane for a solid lithium battery as claimed in claim 2, wherein: the inorganic solid electrolyte particles are of NASICON type structure and the chemical formula of the inorganic solid electrolyte particles is LiM2(PO4)3、Li1+ xAlxTi2-x(PO4)3And Li1+xAlxGe2-x(PO4)3Wherein M is one of Ti, Ge and Hf, and 0 < x < 2;
or the inorganic solid electrolyte particles areA perovskite-type structure, the inorganic solid electrolyte particles having a chemical formula of Li0.34La0.56TiO3And/or Li0.5La0.5TiO3；
Or the inorganic solid electrolyte particles are of a LISICON type structure, and the chemical formula of the inorganic solid electrolyte particles is Li14Zn(GeO4)4；
Or the inorganic solid electrolyte particles have a garnet structure and have a chemical formula of Li5La3R2O12、Li6ALa2R2O12、Li5.5La3R1.75D0.25O12、Li7La3Zr2O12And Li7.06E3Y0.06Zr1.94O12Wherein, R is Nb or Ta, A is one of Ca, Sr and Ba, D is In or Zr, and E is one of La, Nb and Ta;
or the inorganic solid electrolyte particles are of an anti-perovskite structure, and the chemical formula of the inorganic solid electrolyte particles is Li3OX, wherein X is F, Cl or Br;
or the inorganic solid electrolyte particles are in a glass state or a glass ceramic state, and the inorganic solid electrolyte particles are sulfide Li10GeP2S12、Li2S-SiS2、Li2S-P2S5、70Li2S-30P2S5One or more of (a).
8. The lithium replenishing functional electrolyte membrane for a solid lithium battery as claimed in claim 2, wherein: the particle size of the inorganic solid electrolyte particles is 0.1-2 μm.
9. The lithium replenishing functional electrolyte membrane for a solid lithium battery as claimed in claim 2, wherein: the binder is at least one of PVDF, PVDF-HFP, PVP, PEO, PAN, EVA and PMMA;
the conductive agent is at least one of Super-P, Ketjen black, CNTs and graphene;
the framework layer is a three-dimensional porous structure non-woven membrane and comprises a first polymer base material, and the first polymer base material is one of cellulose, PET, PI, PVDF, PA and PVC.
10. The lithium replenishing functional electrolyte membrane for a solid lithium battery as claimed in claim 2, wherein: the reinforced layer comprises a second polymer substrate, and the second polymer substrate is one of PE, PP and PE/PP/PE.
CN202110922764.6A 2021-08-12 2021-08-12 Lithium supplementing functional electrolyte membrane for solid lithium battery Active CN113764667B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110922764.6A CN113764667B (en) 2021-08-12 2021-08-12 Lithium supplementing functional electrolyte membrane for solid lithium battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110922764.6A CN113764667B (en) 2021-08-12 2021-08-12 Lithium supplementing functional electrolyte membrane for solid lithium battery

Publications (2)

Publication Number Publication Date
CN113764667A true CN113764667A (en) 2021-12-07
CN113764667B CN113764667B (en) 2023-07-14

Family

ID=78789096

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110922764.6A Active CN113764667B (en) 2021-08-12 2021-08-12 Lithium supplementing functional electrolyte membrane for solid lithium battery

Country Status (1)

Country Link
CN (1) CN113764667B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114497439A (en) * 2022-01-07 2022-05-13 珠海冠宇电池股份有限公司 Negative plate and battery comprising same
CN115842097A (en) * 2022-07-22 2023-03-24 宁德时代新能源科技股份有限公司 Positive plate, secondary battery, battery module, battery pack and electric device

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106654362A (en) * 2016-12-07 2017-05-10 珠海光宇电池有限公司 Composite solid electrolyte membrane, preparation method and lithium-ion battery
CN109786667A (en) * 2017-11-15 2019-05-21 北京卫蓝新能源科技有限公司 A kind of composite high-molecular three-dimensional structure metal lithium electrode and lithium ion battery
CN112886011A (en) * 2021-01-04 2021-06-01 昆山宝创新能源科技有限公司 Composite lithium supplementing film and preparation method and application thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106654362A (en) * 2016-12-07 2017-05-10 珠海光宇电池有限公司 Composite solid electrolyte membrane, preparation method and lithium-ion battery
CN109786667A (en) * 2017-11-15 2019-05-21 北京卫蓝新能源科技有限公司 A kind of composite high-molecular three-dimensional structure metal lithium electrode and lithium ion battery
CN112886011A (en) * 2021-01-04 2021-06-01 昆山宝创新能源科技有限公司 Composite lithium supplementing film and preparation method and application thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114497439A (en) * 2022-01-07 2022-05-13 珠海冠宇电池股份有限公司 Negative plate and battery comprising same
CN115842097A (en) * 2022-07-22 2023-03-24 宁德时代新能源科技股份有限公司 Positive plate, secondary battery, battery module, battery pack and electric device

Also Published As

Publication number Publication date
CN113764667B (en) 2023-07-14

Similar Documents

Publication Publication Date Title
CN108963327B (en) Inorganic filler composite PEO solid electrolyte material, preparation method and all-solid-state battery
CN103956458B (en) A kind of composite lithium ion battery anode and preparation method thereof and the application in all-solid-state battery
CN110556611A (en) Pre-lithiation of negative electrodes for high performance capacitor-assisted batteries
CN103904290B (en) Aquo-lithium ion battery combination electrode and preparation method thereof, aquo-lithium ion battery
CN107275673B (en) Lithium battery solid electrolyte membrane and preparation method and application thereof
US9397365B2 (en) Solid electrolyte material and all solid-state lithium secondary battery
CN110380133A (en) A kind of transition zone design method of inorganic solid electrolyte and positive interpolar
CN111864181A (en) Pre-lithiated silicon negative electrode and preparation method and application thereof
CN104241598A (en) Composite negative electrode, preparation method of negative electrode and lithium-sulfur secondary battery with negative electrode
WO2022077371A1 (en) Secondary battery, manufacturing method for same, and related thereto, battery module, battery pack, and device
CN105932209A (en) Ceramic coating diaphragm for lithium ion battery and preparation method thereof
CN110690440A (en) Metal ion supplementing additive and preparation method and application thereof
CN113764667B (en) Lithium supplementing functional electrolyte membrane for solid lithium battery
CN103346292B (en) A kind of composite lithium ion battery anode and its preparation method and application
JP2016184483A (en) All solid-state lithium secondary battery
CN108172893A (en) A kind of lithium ion battery
CN114361711A (en) Composite coating diaphragm of metal lithium battery, preparation method of composite coating diaphragm and corresponding lithium battery
CN112993233A (en) Lithium supplement material of lithium ion battery and preparation method and application thereof
CN113300051A (en) Method for compounding pole piece and diaphragm of lithium ion battery and lithium ion battery
CN114242942A (en) Composite buffer layer with stable negative electrode interface and solid-state lithium metal battery thereof
CN107565088A (en) A kind of preparation method of lithium metal secondary battery negative pole
KR101664629B1 (en) Method for preparing bi-polar all solid battery
CN111384390A (en) Acidification reaction modification method for solid electrolyte surface
CN115548270A (en) Processing method of positive pole piece of solid-state lithium battery and lithium battery
CN113782823B (en) Preparation method of lithium supplementing functional electrolyte membrane for solid-state lithium 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