CN117976965B - Solid electrolyte material, composite solid electrolyte, preparation method of composite solid electrolyte, positive plate and battery - Google Patents
Solid electrolyte material, composite solid electrolyte, preparation method of composite solid electrolyte, positive plate and battery Download PDFInfo
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- CN117976965B CN117976965B CN202410391510.XA CN202410391510A CN117976965B CN 117976965 B CN117976965 B CN 117976965B CN 202410391510 A CN202410391510 A CN 202410391510A CN 117976965 B CN117976965 B CN 117976965B
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- 239000000463 material Substances 0.000 title claims abstract description 73
- 239000007784 solid electrolyte Substances 0.000 title claims abstract description 57
- 239000002131 composite material Substances 0.000 title claims abstract description 55
- 238000002360 preparation method Methods 0.000 title claims abstract description 15
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims abstract description 99
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 50
- 239000003792 electrolyte Substances 0.000 claims abstract description 43
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 37
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 19
- 229910001416 lithium ion Inorganic materials 0.000 claims abstract description 18
- 239000000654 additive Substances 0.000 claims abstract description 15
- 230000000996 additive effect Effects 0.000 claims abstract description 15
- 239000006258 conductive agent Substances 0.000 claims abstract description 15
- 239000011230 binding agent Substances 0.000 claims abstract description 13
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims abstract description 8
- 238000007731 hot pressing Methods 0.000 claims description 86
- 239000000460 chlorine Substances 0.000 claims description 76
- 239000000203 mixture Substances 0.000 claims description 52
- 239000006185 dispersion Substances 0.000 claims description 20
- 229910052801 chlorine Inorganic materials 0.000 claims description 15
- 239000003292 glue Substances 0.000 claims description 15
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 14
- 239000004709 Chlorinated polyethylene Substances 0.000 claims description 13
- 238000005303 weighing Methods 0.000 claims description 13
- 229910010272 inorganic material Inorganic materials 0.000 claims description 12
- 239000011147 inorganic material Substances 0.000 claims description 12
- 239000011888 foil Substances 0.000 claims description 11
- 229910003002 lithium salt Inorganic materials 0.000 claims description 11
- 159000000002 lithium salts Chemical class 0.000 claims description 11
- 238000002156 mixing Methods 0.000 claims description 11
- 239000007774 positive electrode material Substances 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 9
- 238000005096 rolling process Methods 0.000 claims description 8
- 239000011267 electrode slurry Substances 0.000 claims description 7
- 238000006243 chemical reaction Methods 0.000 claims description 5
- 239000011248 coating agent Substances 0.000 claims description 5
- 238000000576 coating method Methods 0.000 claims description 5
- 230000035484 reaction time Effects 0.000 claims description 5
- 239000007787 solid Substances 0.000 claims description 5
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 claims description 4
- 238000001035 drying Methods 0.000 claims description 4
- 239000002001 electrolyte material Substances 0.000 claims description 2
- 239000000126 substance Substances 0.000 claims description 2
- 150000002500 ions Chemical class 0.000 abstract description 3
- 150000001875 compounds Chemical class 0.000 abstract description 2
- 239000010405 anode material Substances 0.000 abstract 1
- QSZMZKBZAYQGRS-UHFFFAOYSA-N lithium;bis(trifluoromethylsulfonyl)azanide Chemical compound [Li+].FC(F)(F)S(=O)(=O)[N-]S(=O)(=O)C(F)(F)F QSZMZKBZAYQGRS-UHFFFAOYSA-N 0.000 description 34
- 229910003473 lithium bis(trifluoromethanesulfonyl)imide Inorganic materials 0.000 description 32
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 18
- 230000000052 comparative effect Effects 0.000 description 18
- 239000012528 membrane Substances 0.000 description 12
- 229920000642 polymer Polymers 0.000 description 10
- 238000012360 testing method Methods 0.000 description 10
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 9
- 229910052757 nitrogen Inorganic materials 0.000 description 9
- 229910052782 aluminium Inorganic materials 0.000 description 8
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 8
- 239000002033 PVDF binder Substances 0.000 description 7
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 7
- 229910018434 Mn0.5O2 Inorganic materials 0.000 description 6
- 229910004481 Ta2O3 Inorganic materials 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 5
- 238000005660 chlorination reaction Methods 0.000 description 5
- 238000000354 decomposition reaction Methods 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 239000005518 polymer electrolyte Substances 0.000 description 4
- 239000006256 anode slurry Substances 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 2
- 229910009178 Li1.3Al0.3Ti1.7(PO4)3 Inorganic materials 0.000 description 2
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000000498 ball milling Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- BPUBBGLMJRNUCC-UHFFFAOYSA-N oxygen(2-);tantalum(5+) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ta+5].[Ta+5] BPUBBGLMJRNUCC-UHFFFAOYSA-N 0.000 description 2
- 229910001936 tantalum oxide Inorganic materials 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- 208000019901 Anxiety disease Diseases 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910008514 Li1.2Mn0.54Ni0.13Co0.13O2 Inorganic materials 0.000 description 1
- 239000002228 NASICON Substances 0.000 description 1
- 230000036506 anxiety Effects 0.000 description 1
- 229910002113 barium titanate Inorganic materials 0.000 description 1
- -1 chlorine ions Chemical class 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000002223 garnet Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000011256 inorganic filler Substances 0.000 description 1
- 229910003475 inorganic filler Inorganic materials 0.000 description 1
- 230000037427 ion transport Effects 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- FUJCRWPEOMXPAD-UHFFFAOYSA-N lithium oxide Chemical class [Li+].[Li+].[O-2] FUJCRWPEOMXPAD-UHFFFAOYSA-N 0.000 description 1
- 229910001947 lithium oxide Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 230000032258 transport Effects 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
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- 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
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G65/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
- C08G65/02—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring
- C08G65/32—Polymers modified by chemical after-treatment
- C08G65/321—Polymers modified by chemical after-treatment with inorganic compounds
- C08G65/323—Polymers modified by chemical after-treatment with inorganic compounds containing halogens
- C08G65/3233—Molecular halogen
-
- 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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
- H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
-
- 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
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2300/00—Electrolytes
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0065—Solid electrolytes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2300/00—Electrolytes
- H01M2300/0088—Composites
- H01M2300/0091—Composites in the form of mixtures
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Organic Chemistry (AREA)
- Polymers & Plastics (AREA)
- Medicinal Chemistry (AREA)
- Primary Cells (AREA)
Abstract
The invention relates to a solid electrolyte material, a composite solid electrolyte, a preparation method of the composite solid electrolyte, a positive plate and a battery. The solid electrolyte material introduces chloride ions into the polyethylene oxide; the composite solid electrolyte is prepared from a solid electrolyte material and a lithium-containing oxide; the positive plate takes a solid electrolyte material as a binder, takes a lithium-rich positive material Li 1+nM1‑nO2 as a positive active main material, and further comprises a conductive agent and an additive; the solid-state battery comprises a positive plate, a composite solid-state electrolyte and a lithium metal negative electrode. According to the invention, chloride ions are introduced into the PEO material, so that the dielectric constant of the material and the attraction capability to lithium ions are increased, and the problems that the PEO material is difficult to compound oxide electrolyte, the solid-state battery is low in ion conductivity and the like are solved; the prepared solid-state battery anode has the lithium-rich anode material with high specific capacity, and the lithium metal cathode is matched with the composite electrolyte, so that the high energy density and the high safety performance of the lithium ion battery are realized.
Description
Technical Field
The invention belongs to the technical field of solid-state batteries, and relates to a solid-state electrolyte material, a composite solid-state electrolyte, a preparation method of the composite solid-state electrolyte, a positive plate and a battery.
Background
The electric automobile industry in China is vigorously developed, the sales volume of the electric automobile in China is rapidly increased from 2021, and the sales volume of the electric automobile in China is far and far advanced at present. However, with the rapid development of the electric vehicle market, the development of electric vehicles is hindered by problems, and the serious problem is mileage anxiety.
In order to solve the problems, besides the improvement of a battery module, the improvement of a lithium ion battery is very important, and a positive electrode material with high specific energy density, such as a lithium-rich material, is adopted, so that the positive electrode material has higher specific capacity and voltage, the specific capacity can reach 250mAh/g, and meanwhile, the cutoff voltage of the material can reach 4.8V, but the capacity of the material decays more quickly, because the higher cutoff voltage of the material has very high requirements on electrolyte; from the perspective of the negative electrode, a material with lighter weight or higher specific capacity, such as a lithium metal material, is more preferred, and the specific capacity can reach 3860mAh/g, but the safety problem is a serious problem when the lithium metal is used as the negative electrode. From the improvement of the above lithium ion positive and negative electrodes, the lithium ion battery with high energy density tends to be higher in voltage and worse in stability, so some researchers have proposed solid-state batteries, and use solid-state electrolyte instead of electrolyte and separator, because the solid-state electrolyte has decomposition potential greater than 5V and good mechanical strength, so that the problems of high voltage and safety can be well considered, and at present, the solid-state electrolyte is classified into three types: the oxide electrolyte has high mechanical strength, electrochemical window and lithium ion conductivity, but the interface between the oxide electrolyte and the electrode has high interface internal resistance; sulfide electrolytes have very high ionic conductivity, but the biggest impediment to their development is also the electrochemical instability of the material and the lower electrochemical window; the polymer electrolyte has good electrochemical stability and low internal resistance at the interface with the electrode, but is difficult to be applied to a battery due to low ionic conductivity and electrochemical window of the material. Some researchers in recent years propose semi-solid electrolytes, but the mechanical properties of the materials are greatly reduced due to the reduction of the crystallinity of the materials, so that the safety performance of batteries is greatly reduced; it has also been proposed to use polymer electrolyte in combination with oxide electrolyte, sulfide electrolyte or some inorganic filler, so that the characteristics of several electrolytes are considered, but the polymer electrolyte needs to be used as a substrate for the composite electrolyte, so that the polymer electrolyte has low polarity and less amount of other electrolytes to be compounded, and the effects of other electrolytes are difficult to be exerted.
Disclosure of Invention
The invention aims to overcome the defects and shortcomings of the prior art and provides a solid electrolyte material, a composite solid electrolyte, a preparation method of the composite solid electrolyte, a positive plate and a battery. The chlorine element introduced into PEO does not damage long-chain molecules of polyethylene oxide materials, and the prepared solid electrolyte membrane has good mechanical properties; after chlorine is introduced, the chlorine in the polymer attracts lithium on the lithium-containing oxide, so that oxygen vacancies can be generated, and the transmission of lithium ions is facilitated; meanwhile, the prepared Cl (x) -PEO is used as a binder for the positive plate, so that a better interface is formed between the positive plate and the solid electrolyte, and the prepared battery has lower internal resistance; the decomposition voltage of the composite solid electrolyte prepared from Cl (x) -PEO can reach the decomposition voltage of the lithium-containing oxide, so that the composite solid electrolyte is suitable for the next-generation high-energy-density positive electrode material lithium-rich positive electrode.
The aim of the invention can be achieved by the following scheme:
In a first aspect, the present invention provides a solid electrolyte material that incorporates chloride ions into polyethylene oxide to yield modified chlorinated polyethylene oxide Cl (x) -PEO; the chemical composition of the chlorinated polyethylene oxide may be represented as-CH (4-x)Cl(x) -O-; wherein x is more than 0 and less than or equal to 4.
In the invention, firstly, chlorine is selected for introduction, long-chain molecules of polyethylene oxide materials are not destroyed, and the solid electrolyte membrane prepared by the method has good mechanical properties; if other elements, such as fluorine element, are selected as strong polar elements, when more F element is introduced into PEO, the long chain molecules of the polymer can be destroyed, the viscosity of the polymer is influenced, and the mechanical property of the prepared solid electrolyte membrane is poor; secondly, when Cl (x) -PEO is used in combination with the lithium-containing oxide, the addition of the lithium-containing oxide can enhance the chain segment movement of the polymer, destroy the crystallinity of the material and accelerate the transmission rate of lithium ions, and after chlorine is introduced, the chlorine in the polymer can attract the lithium element on the lithium-containing oxide and generate oxygen vacancies, thereby being beneficial to the transmission of lithium ions; however, if fluorinated polyethylene oxide materials are adopted, more lithium is attracted by fluorine with strong polarity, and more lithium vacancies are formed, so that lithium-containing oxides are agglomerated, which is unfavorable for the transmission of lithium ions; in addition, cl (x) -PEO is used as a binder for the positive plate, so that a better interface is formed between the positive plate and the solid electrolyte, and the prepared battery has lower internal resistance; meanwhile, cl (x) -PEO is used as a binder, so that a better conductive network is formed on the positive plate, and lithium ion transmission is facilitated; whereas fluorinated polyethylene oxide materials have a lower viscosity and cannot be made into binders because of the lack of such advantages; finally, fluorinated polyethylene oxide is used as a pure polymer solid electrolyte and has excellent ionic conductivity, but the defect of the polymer cannot be avoided, and the problems of instability, low mechanical strength and the like under high potential exist, so that the fluorinated polyethylene oxide is difficult to apply to high-voltage positive electrode materials and difficult to match with next-generation high-energy-density positive electrode materials; the composite electrolyte prepared by adopting Cl (x) -PEO can reach the decomposition voltage of the lithium-containing oxide, so that the composite electrolyte is suitable for the next-generation high-energy-density positive electrode material lithium-rich positive electrode.
As an embodiment of the present invention, the method for preparing a solid electrolyte material includes:
PEO is reacted with chlorine to obtain a modified chlorinated polyethylene oxide, i.e., a solid electrolyte material.
As an embodiment of the present invention, the preparation method specifically includes: placing PEO in a chlorination device, and introducing nitrogen to remove air; and then introducing chlorine gas, turning on an ultraviolet lamp, and reacting to obtain the modified chlorinated polyethylene oxide material, namely the solid electrolyte material.
As an embodiment of the invention, the PEO has a molecular mass of 400000 to 700000. The higher the molecular mass, the better the performance, but the more difficult the preparation.
Preferably, the PEO has a molecular mass of 600000.
As one embodiment of the invention, the flow rate of nitrogen is 1-3ml/min, and the nitrogen introducing time is 2-5 hours; the flow rate of the chlorine is 0.5-1.5ml/min.
As one embodiment of the present invention, the reaction temperature is 63-70℃and the reaction time is 10-30 hours.
In the invention, the faster the flow rate of chlorine gas, the higher the reaction temperature and the longer the reaction time, the more hydrogen elements replaced by chloride ions can be caused; however, the time is too long, so that the polarity of the material is enhanced more, and the material is difficult to form a film.
In a second aspect, the present invention provides a composite solid state electrolyte comprising a combination of chlorinated polyethylene oxide, cl (x) -PEO, lithium-containing oxide, inert inorganic material, first lithium salt;
Wherein the mole fraction ratio of EO in Cl (x) -PEO to Li + in the first lithium salt is y1, and y1 is more than or equal to 8 and less than or equal to 16; the lithium-containing oxide accounts for y2 in mass percent of the whole composite solid electrolyte, and y2 is more than or equal to 30% and less than or equal to 50%; w represents the mass fraction of the inert inorganic material in the whole composite solid electrolyte, and w is more than or equal to 5% and less than or equal to 10%.
As an embodiment of the present invention, the lithium-containing oxide includes one of an oxide Li 6.75La3Zr1.75Ta0.25O12 (LLZTO) having a garnet structure, li 1.3Al0.3Ti1.7(PO4)3 (LATP) having a NASICON configuration.
As an embodiment of the present invention, the inert inorganic material comprises at least one of 3Al 2O3·2SiO2、Ta2O3、BaTiO3. The addition of inert inorganic materials can enhance the mechanical properties of the electrolyte.
As one embodiment of the present invention, the first lithium salt includes at least one of LiTFSI, liFSI, liCTFSI.
In a third aspect, the present invention provides a method for preparing the composite solid electrolyte, comprising the steps of:
s1: weighing chlorinated polyethylene oxide, lithium-containing oxide, inert inorganic material and first lithium salt, and uniformly mixing to obtain a mixture A;
S2: carrying out first hot pressing on the mixture A obtained in the step S1 (putting the mixture A into a hot press); and then carrying out multiple hot pressing on the mixture after the first hot pressing, wherein the specific steps of each hot pressing in the multiple hot pressing comprise: folding the mixture obtained by the last hot pressing, and hot pressing after folding; and finally, folding the mixture in half, and performing final hot pressing to obtain the composite solid electrolyte.
As an embodiment of the invention, in step S1, the molar mass of Li + in the first lithium salt to EO in Cl (x) -PEO is 1:8-16; the lithium-containing oxide accounts for 30-50% of the mass of the whole mixture A; the inert inorganic material accounts for 5-10% of the total mass fraction of the mixture A.
As an embodiment of the present invention, in step S1, the manner of mixing includes ball milling.
Further, the rotation speed of the ball milling is 50-100r/min, and the time is 5-12 hours.
As one embodiment of the present invention, in the step S2, the hot pressing temperature of the first hot pressing is 80-100 ℃, the hot pressing pressure is 5-8 tons, and the hot pressing time is 1-2 hours.
As one embodiment of the present invention, in the step S2, the temperature of each hot press is 100-120 ℃, the pressure of each hot press is 10-12 tons, the time of each hot press is 1-2 hours, and the times of the multiple times are 10-15 times.
As one embodiment of the invention, in the step S2, the hot pressing temperature of the last hot pressing is 120-140 ℃, the hot pressing pressure is 12-15 tons, and the hot pressing time is 3-5 hours.
As an embodiment of the present invention, in step S2, the film thickness of the composite solid electrolyte is 8 to 12 μm.
In a fourth aspect, the present invention provides a positive electrode sheet, the positive electrode sheet comprising a positive electrode film layer comprising a binder, a conductive agent, an additive, and a positive electrode active host; wherein, the solid electrolyte material Cl (x) -PEO is taken as a binder, the lithium-rich positive electrode material Li 1+nM1-nO2 is taken as a positive electrode active main material, and a conductive agent and an additive are added to prepare the positive electrode plate.
As one embodiment of the present invention, the conductive agent includes a provider P.
As an embodiment of the invention, the additive comprises a lithium-containing additive; the lithium-containing additive includes LiTFSI.
As one embodiment of the present invention, in Li 1+nM1-nO2, 0< n < 1, and M element includes at least one kind of Co, fe, ni, mn.
As one embodiment of the present invention, the method for preparing the positive electrode sheet includes the steps of:
Step 1: dispersing Cl (x) -PEO and an additive (placed in a dispersing tank), and adding NMP (N-methylpyrrolidone) to obtain a mixed glue solution A;
step 2: weighing Li 1+nM1-nO2, a conductive agent and a mixed glue solution A for dispersion to obtain positive electrode slurry;
Step 3: coating positive electrode slurry on a foil (controlling the double-sided density), drying (putting into an oven), and rolling the obtained pole piece to obtain the positive electrode piece.
As an embodiment of the invention, in step 1, the molar mass ratio of EO in Cl (x) -PEO to Li + in the lithium-containing additive is 8-16:1.
As one embodiment of the invention, NMP is added in step 1 in an amount of 19-20 times the total mass of Cl (x) -PEO, lithium-containing additive.
As one embodiment of the invention, in step 1, the dispersing speed is 200-500r/min and the dispersing time is 5-10 hours.
In the step 2, the mass ratio of Li 1+nM1-nO2 to Cl (x) -PEO in the mixed glue solution A to the conductive agent is 0.9-0.97:0.02-0.05:0.01-0.05.
As one embodiment of the invention, in the step2, the dispersing speed is 500-800r/min, and the dispersing time is 10-15 hours.
As an embodiment of the invention, in step 3, the foil comprises aluminum foil.
Further, the thickness of the aluminum foil is 10-15 μm.
As an embodiment of the invention, in step 3, the coated double sided density is 350-400g/m 2.
As one embodiment of the invention, in the step 3, the drying temperature is 100-120 ℃ and the drying time is 10-15 hours.
In step 3, as an embodiment of the present invention, the thickness of the positive electrode sheet after rolling is 120 to 130 μm.
In a fifth aspect, the present invention provides a solid-state battery comprising the positive electrode sheet, a composite solid-state electrolyte, and a lithium metal negative electrode. In order to ensure the electrochemical performance of the battery, the composite solid electrolyte is in direct contact with the positive plate and the lithium metal negative electrode, the structural unit of the battery is positive electrode-composite electrolyte-lithium metal, and the battery can be a winding type battery or a lamination type battery.
As an embodiment of the present invention, the lithium metal anode has a thickness of 70 to 80 μm.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the invention, chloride ions are introduced into the PEO material, so that the dielectric constant of the material is increased, and the polarity of the material is improved, so that the material can be compounded with more oxide electrolyte and inert inorganic material, and the problem that the PEO material is difficult to compound oxide electrolyte is solved.
2. According to the invention, chloride ions are introduced into the PEO material, so that the attraction capability of the material to lithium ions is enhanced, the ion conductivity of the solid electrolyte is improved, and the problem of low ion conductivity of the solid battery is solved.
3. According to the invention, on the basis of modifying the PEO material, the ionic conductivity of the material is increased by introducing the lithium-containing oxide material, and the mechanical property of the material is increased by adding the inert inorganic material, so that the material can be applied to a complex lithium-rich anode system, and the problem that the solid electrolyte material is difficult to apply to lithium ions is solved.
4. According to the invention, chlorine ions are introduced into the PEO material by using chlorine gas, and the composite electrolyte is prepared by matching with a hot pressing method, so that the whole preparation process is simple and convenient, and the industrial production is facilitated.
5. According to the invention, the lithium-rich positive electrode material with high specific capacity is used as the positive electrode, the lithium metal is used as the negative electrode, and the composite electrolyte is adopted in the invention, so that the high energy density and the high safety performance of the lithium ion battery are realized.
Drawings
Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, given with reference to the accompanying drawings in which:
FIG. 1 is a schematic diagram of a production apparatus for chlorinated PEO according to example 1 and example 2 of the present invention;
fig. 2 is an assembly drawing of an all-solid-state lithium ion battery according to embodiment 9 of the present invention;
FIG. 3 is a graph showing the dielectric constant of Cl (0.1) -PEO provided in example 1, cl (2) -PEO provided in example 2 and normal PEO at different frequencies according to the present invention;
FIG. 4 is a graph of ionic conductivity at various temperatures for LiTFSI/P (EO) 8-50LLZTO-10Ta2O3 provided in comparative example 1, liTFSI/Cl (2)-P(EO)16-50LLZTO-10Ta2O3、 provided in example 3, liTFSI/Cl (2)-P(EO)8-50LLZTO-10Ta2O3 provided in example 4, liTFSI/Cl (2)-P(EO)8-30LLZTO-10Ta2O3 provided in example 5, according to the present invention;
FIG. 5 shows tensile stretch curves of LiTFSI/Cl (2)-P(EO)8-50LLZTO-10Ta2O3 provided in example 4 and LiTFSI/Cl (2)-P(EO)8-50LLZTO-5Ta2O3 provided in example 6 according to the present invention;
Fig. 6 is a graph showing the sheet resistance of the positive electrode sheet provided in example 7, the positive electrode sheet provided in example 8, and the positive electrode sheet provided in comparative example 2 according to the present invention;
fig. 7 is a graph showing the charge and discharge curves at the first turn of the all-solid battery provided in example 9 and the all-solid battery provided in comparative example 3 in the present invention.
Detailed Description
The invention will now be described in detail with reference to the drawings and specific examples. The following examples, which are presented to provide those of ordinary skill in the art with a detailed description of the invention and to provide a further understanding of the invention, are presented in terms of implementation and operation. It should be noted that the protection scope of the present invention is not limited to the following embodiments, and several adjustments and improvements made on the premise of the inventive concept are all within the protection scope of the present invention.
Example 1
PEO with the molecular mass of 600000 is placed in a chlorination device (shown in figure 1), nitrogen is introduced to remove air, the flow rate of the nitrogen is 2ml/min, and the time for introducing the nitrogen is 3 hours; then chlorine is introduced, an ultraviolet lamp is turned on, the flow rate of the chlorine is 1ml/min, the reaction temperature is 65 ℃, the reaction time is 10 hours, the chlorinated polyethylene oxide material is obtained through analysis of XPS instruments, and the molar mass ratio of C, O, cl in the modified material is 1:1:0.1, the modified polyethylene oxide can thus be expressed as Cl (0.1) -PEO.
Example 2
PEO with the molecular mass of 600000 is placed in a chlorination device (shown in figure 1), nitrogen is introduced to remove air, the flow rate of the nitrogen is 2ml/min, and the time for introducing the nitrogen is 3 hours; then chlorine is introduced, an ultraviolet lamp is turned on, the flow rate of the chlorine is 1.5ml/min, the reaction temperature is 70 ℃, the reaction time is 30 hours, the chlorinated polyethylene oxide material is obtained through analysis of XPS instruments, and the molar mass ratio of C, O, cl in the modified material is 1:1:2, the polyethylene oxide thus modified may be expressed as Cl (2) -PEO.
Example 3
The Cl (2) -PEO material obtained in the above example 2 and LLZTO were used to prepare a composite solid electrolyte membrane (LiTFSI/Cl (2)-P(EO)16-50LLZTO-10Ta2O3) by the following steps:
S1: weighing required LiTFSI and Cl (2)-PEO、LLZTO、Ta2O3, wherein the molar mass of Li + in LiTFSI and EO in Cl (2) -PEO is 1:16, LLZTO accounts for 50% of the total mixture mass, ta 2O3 accounts for 10% of the total mixture mass fraction, putting the mixture into a ball mill, uniformly mixing at a low speed, and mixing at a rotating speed of 50r/min for 5 hours to obtain a mixture A;
S2: putting the mixture A into a hot press for first hot pressing, wherein the hot pressing temperature is 80 ℃, the hot pressing pressure is 8 tons, and the hot pressing time is 2 hours; folding the mixture after the first hot pressing in half, and carrying out the second hot pressing again, wherein the hot pressing temperature is 120 ℃, the hot pressing pressure is10 tons, the hot pressing time is1 hour, and the step of repeating the second hot pressing is10 times in total; and finally, performing final hot pressing on the mixture obtained by the second hot pressing, wherein the hot pressing temperature is 120 ℃, the hot pressing pressure is 12 tons, and the hot pressing time is 3 hours, so that the composite solid electrolyte membrane with the thickness of 10 mu m is obtained.
Example 4
Preparing a composite solid electrolyte membrane (LiTFSI/Cl (2)-P(EO)8-50LLZTO-10Ta2O3) from the Cl (2) -PEO material obtained in example 2 and LLZTO;
The preparation method comprises the following steps:
S1: weighing required LiTFSI and Cl (2)-PEO、LLZTO、Ta2O3, wherein the molar mass of Li + and Cl (the molar mass of EO in x) -PEO is between 1:8, LLZTO accounts for 50% of the total mixture mass, and Ta 2O3 accounts for 10% of the total mixture mass), putting the mixture into a ball mill, uniformly mixing at a low speed at a rotating speed of 100r/min for 12 hours to obtain a mixture A;
S2: 1) Putting the mixture A into a hot press for first hot pressing, wherein the hot pressing temperature is 100 ℃, the hot pressing pressure is 8 tons, and the hot pressing time is 2 hours; 2) Folding the mixture after the first hot pressing in half, carrying out hot pressing again, wherein the hot pressing temperature is 120 ℃, the hot pressing pressure is 12 tons, the hot pressing time is 2 hours, and repeating the operation of the step 2) for 15 times; 3) Finally, the mixture is subjected to final hot pressing at 140 ℃, the hot pressing pressure is 15 tons, and the hot pressing time is 5 hours, so that the composite electrolyte membrane with the thickness of 10 mu m is obtained.
Example 5
A composite solid electrolyte membrane (LiTFSI/Cl (2)-P(EO)8-30LLZTO-10Ta2O3) was prepared from the Cl (2) -PEO material obtained in example 2 above and LLZTO.
S1: weighing required LiTFSI and Cl (2)-PEO、LLZTO、Ta2O3, wherein the molar mass of Li + in LiTFSI and EO in Cl (2) -PEO is between 1:8, LLZTO accounts for 30% of the total mixture mass, 30Ta 2O3 accounts for 10% of the total mixture mass fraction, putting the mixture into a ball mill, uniformly mixing at a low speed, and mixing at a rotating speed of 80r/min for 10 hours to obtain a mixture A.
S2: 1) Putting the mixture A into a hot press for first hot pressing, wherein the hot pressing temperature is 90 ℃, the hot pressing pressure is 6 tons, and the hot pressing time is 1.5 hours; 2) Folding the mixture after the first hot pressing in half, carrying out hot pressing again, wherein the hot pressing temperature is 110 ℃, the hot pressing pressure is 11 tons, the hot pressing time is 1.5 hours, and repeating the operation of the step 2) for 12 times; 3) Finally, the mixture is subjected to final hot pressing at 130 ℃ under 13 tons for 4 hours to obtain the composite electrolyte membrane with the thickness of 10 mu m.
Example 6
A composite solid electrolyte membrane (LiTFSI/Cl (2)-P(EO)8-50LLZTO-5Ta2O3) was prepared from the Cl (2) -PEO material obtained in example 2 above and LLZTO.
The preparation method comprises the following steps:
S1: weighing required LiTFSI and Cl (2)-PEO、LLZTO、Ta2O3, wherein the molar mass of Li + in LiTFSI and EO in Cl (x) -PEO is between 1:8, LLZTO accounts for 50% of the total mixture mass, ta 2O3 accounts for 5% of the total mixture mass, putting the mixture into a ball mill, uniformly mixing at a low speed, and mixing at a rotating speed of 100r/min for 12 hours to obtain a mixture A.
S2: 1) Putting the mixture A into a hot press for first hot pressing, wherein the hot pressing temperature is 100 ℃, the hot pressing pressure is 8 tons, and the hot pressing time is 2 hours; 2) Folding the mixture after the first hot pressing in half, carrying out hot pressing again, wherein the hot pressing temperature is 120 ℃, the hot pressing pressure is 12 tons, the hot pressing time is 2 hours, and repeating the operation of the step 2) for 15 times; 3) Finally, the mixture is subjected to final hot pressing at 140 ℃, the hot pressing pressure is 15 tons, and the hot pressing time is 5 hours, so that the composite electrolyte membrane with the thickness of 10 mu m is obtained.
Example 7
Li 1.12(Ni0.425Co0.15Mn0.425)0.88O2 is used as a main material of the positive electrode, cl (2) -PEO obtained in the above example 2 is used as a binder, a loader P is used as a conductive agent, liTFSI is used as an additive, and the preparation method of the positive electrode sheet is as follows:
S1, weighing Cl (2) -PEO and LiTFSI well, ensuring that the molar mass ratio of EO in the Cl (2) -PEO to Li + in the LiTFSI is 8:1, putting the materials into a dispersion tank, adding NMP, wherein the adding amount of the NMP is 20 times of the total mass of the Cl (2) -PEO and the LiTFSI, the dispersion rotating speed is 200r/min, and the dispersion time is 5 hours, thus obtaining the mixed glue solution A.
S2: li 1.2Mn0.54Ni0.13Co0.13O2, a conductive agent supplier P and a mixed glue solution A are weighed and put into a dispersion tank, wherein the mass ratio of the Li 1.12(Ni0.425Co0.15Mn0.425)0.88O2 to the Cl (2) -PEO in the mixed glue solution A to the supplier P is 0.97:0.02:0.01, the dispersion rotating speed is 500r/min, and the dispersion time is 10 hours, so that the anode slurry is obtained.
S3: coating the positive electrode slurry on an aluminum foil with the thickness of 12 mu m, controlling the double-sided density to be about 400g/m 2, putting the aluminum foil into a baking oven for baking at the temperature of 110 ℃ for 10 hours, and rolling the obtained pole piece, wherein the thickness of the rolled positive electrode piece is 120 mu m, thus obtaining the positive electrode piece.
Example 8
Li 1.16Ni0.15Co0.19Mn0.5O2 is used as a main material of the positive electrode, cl (2) -PEO obtained in the above example 2 is used as a binder, a loader P is used as a conductive agent, liTFSI is used as an additive, and the preparation method of the positive electrode sheet is as follows:
S1, weighing Cl (2) -PEO and LiTFSI well, ensuring that the molar mass ratio of EO in the Cl (2) -PEO to Li + in the LiTFSI is 8:1, putting the materials into a dispersion tank, adding NMP, wherein the adding amount of the NMP is 20 times of the total mass of the Cl (2) -PEO and the LiTFSI, the dispersion rotating speed is 200r/min, and the dispersion time is 5 hours, thus obtaining the mixed glue solution A.
S2: li 1.16Ni0.15Co0.19Mn0.5O2, a conductive agent supplier P and a mixed glue solution A are weighed and put into a dispersion tank, wherein the mass ratio of the Li 1.16Ni0.15Co0.19Mn0.5O2 to the Cl (2) -PEO in the mixed glue solution A to the supplier P is 0.97:0.02:0.01, the dispersion rotating speed is 500r/min, and the dispersion time is 10 hours, so that the anode slurry is obtained.
S3: coating the positive electrode slurry on aluminum foil with the thickness of 12 mu m, controlling the double-sided density to be about 400g/m 2, putting the aluminum foil into a baking oven for baking at the temperature of 110 ℃ for 10 hours, rolling the obtained pole piece, and obtaining the positive electrode plate with the thickness of 120 mu m after rolling.
Example 9
The positive electrode sheet obtained in example 8 and the composite solid electrolyte obtained in example 4 were wound to prepare a battery having a lithium metal thickness of 75 μm as a negative electrode, and the battery was assembled as shown in fig. 2.
Comparative example 1
PEO material and LLZTO were used to prepare LiTFSI/P (EO) 8-50LLZTO-10Ta2O3 by the following method:
S1: weighing the required LiTFSI, PEO, LLZTO, ta 2O3, wherein the molar mass of Li + in LiTFSI and EO in PEO is between 1:8, LLZTO accounts for 50% of the mass of the whole mixture, ta 2O3 accounts for 10% of the mass fraction of the whole mixture, putting the mixture into a ball mill, uniformly mixing at a low speed at a rotating speed of 100r/min for 12 hours, and obtaining a mixture A;
S2: 1) Putting the mixture A into a hot press for first hot pressing, wherein the hot pressing temperature is 100 ℃, the hot pressing pressure is 8 tons, and the hot pressing time is 2 hours; 2) Folding the mixture after the first hot pressing in half, carrying out hot pressing again, wherein the hot pressing temperature is 120 ℃, the hot pressing pressure is 12 tons, the hot pressing time is 2 hours, and repeating the operation of the step 2) for 15 times; 3) Finally, the mixture is subjected to final hot pressing at 140 ℃, the hot pressing pressure is 15 tons, and the hot pressing time is 5 hours, so that the composite electrolyte membrane with the thickness of 10 mu m is obtained.
Comparative example 2
Li 1.16Ni0.15Co0.19Mn0.5O2 is used as a main material of the positive electrode, polyvinylidene fluoride (PVDF) is adopted as a binder, a feeder P is adopted as a conductive agent, liTFSI is used as an additive, and the preparation method of the positive electrode sheet is as follows:
And S1, weighing PVDF and LiTFSI, ensuring that the molar mass ratio of Li + in the PVDF and the LiTFSI is 8:1, putting the PVDF and the LiTFSI into a dispersion tank, adding NMP, wherein the adding amount of the NMP is 20 times of the total mass of the PVDF and the LiTFSI, the dispersion rotating speed is 200r/min, and the dispersion time is 5 hours, so as to obtain the mixed glue solution A.
S2: weighing Li 1.16Ni0.15Co0.19Mn0.5O2, a conductive agent and a mixed glue solution A, and putting the mixed glue solution A into a dispersion tank, wherein the mass ratio of Li 1.16Ni0.15Co0.19Mn0.5O2 to PVDF and a supplier P in the mixed glue solution A is 0.97:0.02:0.01, the dispersion rotating speed is 500r/min, and the dispersion time is 10 hours, so as to obtain the anode slurry.
S3: coating the positive electrode slurry on aluminum foil with the thickness of 12 mu m, controlling the double-sided density to be about 400g/m 2, putting the aluminum foil into a baking oven for baking at the temperature of 110 ℃ for 10 hours, rolling the obtained pole piece, and obtaining the positive electrode plate with the thickness of 120 mu m after rolling.
Comparative example 3
The positive electrode sheet obtained in comparative example 2 and the composite electrolyte obtained in example 4 were wound to prepare a battery using lithium metal as a negative electrode and a thickness of 75 μm.
Comparative example 4
The positive electrode sheet obtained in example 8 and the composite electrolyte obtained in comparative example 1 were wound to prepare a battery using lithium metal as a negative electrode and a thickness of 75 μm.
1. Dielectric constant test
The results obtained from the dielectric constant tests of Cl (0.1) -PEO obtained in example 1 and Cl (2) -PEO obtained in example 2 and the non-chlorinated PEO powder in comparative example 1, using a dielectric constant meter, with a frequency range of 0-1MHz, showed that at high frequencies, chlorinated PEO had a higher dielectric constant and Cl (2) -PEO had a higher dielectric constant than Cl (0.1) -PEO, indicating a higher chlorine content and a higher dielectric constant, as shown in FIG. 3; the higher dielectric constant represents a greater polarity of the material, indicating that PEO after chlorination has increased polarity, which allows for more of the first lithium salt and oxide electrolyte to be composited.
2. Lithium ion conductivity test
For LiTFSI/Cl (2)-P(EO)16-50LLZTO-10Ta2O3 obtained in example 3, liTFSI/Cl (2)-P(EO)8-50LLZTO-10Ta2O3 obtained in example 4, liTFSI/Cl (2)-P(EO)8-30LLZTO-10Ta2O3 obtained in example 5, liTFSI/P (EO) 8-50LLZTO-10Ta2O3 obtained in example 1 was tested for ionic conductivity at different temperatures, and the test criteria were NB/T10827-2021, as shown in FIG. 4 (experimental example in the figure, i.e., example), it can be seen that the ionic conductivity of the composite electrolyte in example 1 was the lowest, while the ionic conductivity details of the modified composite electrolyte in example 3 were higher, indicating that the composite electrolyte prepared by PEO after chlorination was more favorable for ionic transport, and that the composite electrolyte of example 4 was higher than that of the composite electrolyte in example 3, and that example 4 was also higher than that of the composite electrolyte obtained in example 5, indicating that the higher content of the first lithium salt, the higher content of LLZTO was more favorable for lithium ion transport.
3. Tensile test
The LiTFSI/Cl (2)-P(EO)8-50LLZTO-10Ta2O3 obtained in example 4 and LiTFSI/Cl (2)-P(EO)8-50LLZTO-5Ta2O3 obtained in example 6 were subjected to mechanical property test, the test standard is GB/T1040.3-2006, and the results obtained by using tensile test are shown as the graph, and as can be seen from FIG. 5, the maximum mechanical tensile stress of the added tantalum oxide in example 4 is 2.53MPa, then the mechanical strength in example 6 is 1.25MPa, and after the added tantalum oxide is obviously more, the mechanical strength in example 4 is better.
4. Diaphragm resistance test
The results of the sheet resistance tests (test standard GB/T41232.3-2023) performed on the positive electrode sheet obtained in example 7, the positive electrode sheet obtained in example 8 and the positive electrode sheet obtained in comparative example 2 are shown in FIG. 6 below, and it can be seen that the sheet resistance of the positive electrode sheet obtained in example 8 using PEO chloride as a binder is lower, and the sheet resistance of the positive electrode sheet obtained in example 8 is lower than that of the sheet resistance of the positive electrode sheet obtained in comparative example, and the sheet resistance of the positive electrode sheet obtained in example 7 is also lower, because the lithium-rich positive electrode used in example 8 contains higher lithium and has better conductivity, and thus the sheet resistance is lower.
5. Battery performance test
The battery obtained in example 9 (i.e., experimental example 9 in fig. 7), the battery obtained in comparative example 3, and the battery obtained in comparative example 4 were subjected to a first-cycle charge-discharge test, the charge-discharge rate was 0.1C, the charge-discharge interval was 2 to 4.8V, and the obtained data are shown in fig. 7, it can be seen that the battery capacity of comparative example 4 exhibited higher than that of comparative example 3; the capacity performance of the battery obtained in example 9 was higher than that of the batteries of comparative example 3 and comparative example 4.
The foregoing describes specific embodiments of the present invention. It is to be understood that the invention is not limited to the particular embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the claims without affecting the spirit of the invention.
Claims (9)
1. A solid electrolyte material for a lithium ion battery, characterized in that chloride ions are introduced into polyethylene oxide to obtain modified chlorinated polyethylene oxide Cl (x) -PEO; the chemical composition of the chlorinated polyethylene oxide may be represented as-CH (4-x)Cl(x) -O-; wherein x is more than 0 and less than or equal to 4;
the preparation method of the solid electrolyte material comprises the following steps: PEO and chlorine react to obtain modified chlorinated polyethylene oxide, namely a solid electrolyte material;
the reaction temperature is 63-70 ℃ and the reaction time is 10-30 hours.
2. The solid state electrolyte material of claim 1 wherein the PEO has a molecular mass of 400000 to 700000.
3. The solid electrolyte material of claim 1 wherein the flow rate of chlorine gas is 0.5-1.5ml/min.
4. A composite solid electrolyte comprising the solid electrolyte material of any one of claims 1-3, wherein the composite solid electrolyte comprises a combination of chlorinated polyethylene oxide Cl (x) -PEO, a lithium-containing oxide, an inert inorganic material, a first lithium salt;
Wherein the mole fraction ratio of EO in Cl (x) -PEO to Li + in the first lithium salt is y1, and y1 is more than or equal to 8 and less than or equal to 16; the lithium-containing oxide accounts for y2 in mass percent of the whole composite solid electrolyte, and y2 is more than or equal to 30% and less than or equal to 50%; w represents the mass fraction of the inert inorganic material in the whole composite solid electrolyte, and w is more than or equal to 5% and less than or equal to 10%.
5. A method of preparing the composite solid electrolyte of claim 4, comprising the steps of:
s1: weighing chlorinated polyethylene oxide, lithium-containing oxide, inert inorganic material and first lithium salt, and uniformly mixing to obtain a mixture A;
s2: carrying out first hot pressing on the mixture A obtained in the step S1; and carrying out multiple hot pressing on the mixture after the first hot pressing, wherein the specific steps of each hot pressing in the multiple hot pressing comprise: folding the mixture obtained by the last hot pressing, and hot pressing after folding; and finally, folding the mixture in half, and performing final hot pressing to obtain the composite solid electrolyte.
6. The method according to claim 5, wherein in step S1, the molar mass of Li + in the first lithium salt and EO in Cl (x) -PEO is 1:8-16; the lithium-containing oxide accounts for 30-50% of the mass of the whole mixture A; the inert inorganic material accounts for 5-10% of the total mass fraction of the mixture A.
7. A positive electrode sheet comprising the solid electrolyte material according to any one of claims 1 to 3, wherein the positive electrode sheet comprises a positive electrode film layer comprising a binder, a conductive agent, an additive, and a positive electrode active host material; wherein, the solid electrolyte material Cl (x) -PEO is taken as a binder, the lithium-rich positive electrode material Li 1+nM1-nO2 is taken as a positive electrode active main material, and a conductive agent and an additive are added to prepare a positive electrode plate; the lithium-rich positive electrode material Li 1+nM1-nO2 has n being more than 0 and less than 1, and M element includes at least one kind of Co, fe, ni, mn.
8. The positive electrode sheet according to claim 7, wherein the preparation method of the positive electrode sheet comprises the steps of:
step 1: dispersing Cl (x) -PEO and an additive, and adding NMP to obtain a mixed glue solution A;
step 2: weighing Li 1+nM1-nO2, a conductive agent and a mixed glue solution A for dispersion to obtain positive electrode slurry;
step 3: and coating the positive electrode slurry on a foil, drying, and rolling the obtained pole piece to obtain the positive electrode piece.
9. A solid-state battery comprising the composite solid-state electrolyte according to claim 4 or the composite solid-state electrolyte produced by the method according to claim 5 or 6, and the positive electrode sheet according to claim 7 or 8, characterized in that the solid-state battery further comprises a lithium metal negative electrode.
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