CN112635814B - Electrolyte membrane for sulfide solid-state battery and preparation method and application thereof - Google Patents

Electrolyte membrane for sulfide solid-state battery and preparation method and application thereof Download PDF

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CN112635814B
CN112635814B CN202011597001.0A CN202011597001A CN112635814B CN 112635814 B CN112635814 B CN 112635814B CN 202011597001 A CN202011597001 A CN 202011597001A CN 112635814 B CN112635814 B CN 112635814B
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electrolyte
sulfide
state battery
electrolyte membrane
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CN112635814A (en
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黄海强
陈少杰
王磊
李瑞杰
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Svolt Energy Technology Co Ltd
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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
    • 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
    • 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
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

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Abstract

The invention provides an electrolyte membrane for a sulfide solid-state battery, and a preparation method and application thereof. The electrolyte membrane comprises a base membrane, a nano ceramic particle layer and a sulfide electrolyte layer; wherein the pores of the base film contain electrolyte, the nano ceramic particle layer is positioned on the surface of two opposite sides of the base film, and the sulfide electrolyte layer is positioned on the surface of the nano ceramic particle layer. The electrolyte membrane for the sulfide solid-state battery provided by the invention has high interface contact property, high strength and high ionic conductivity, and can effectively solve the problems of large interface contact resistance between an electrode and the electrolyte membrane, insufficient conductivity of the electrolyte membrane, poor battery processability and the like, thereby optimizing the rate capability and the cycle performance of the sulfide solid-state battery, simplifying the subsequent manufacturing process and improving the qualified rate of the battery.

Description

Electrolyte membrane for sulfide solid-state battery and preparation method and application thereof
Technical Field
The invention belongs to the technical field of solid-state batteries, and relates to an electrolyte membrane for a sulfide solid-state battery, and a preparation method and application thereof.
Background
With the requirements of the new energy power battery field on the safety and high energy density of the battery technology becoming higher and higher, the traditional liquid battery can not meet the use requirements of consumers more and more, especially on the aspect of safety performance, so that the development of the all-solid-state lithium battery with high energy density and good safety becomes the trend of future development of the industry. The current all-solid-state batteries mainly comprise polymer-based all-solid-state batteries, organic-inorganic composite all-solid-state batteries and sulfide-based all-solid-state batteries. The development of the sulfide-based all-solid-state battery is the best seen by the industry, but the existing sulfide-based all-solid-state battery has the problems that the ion conductive network inside a positive electrode and a negative electrode is poor, the interface between an electrolyte membrane and an electrode plate is large in resistance due to solid-solid contact, the conductivity of the dielectric membrane is low, sulfide and an active substance are in contact to generate interface reaction, and the like, so that the rate capability and the cycle performance of the sulfide-based all-solid-state battery hardly meet the commercial requirements.
The main structure and process of the sulfide all-solid-state battery reported at present are as follows: the negative electrode adopts a lithium metal or silicon carbon composite pole piece, the electrolyte layer is a sulfide electrolyte membrane coated by a wet method, the positive electrode is a NCM, LCO or LFP pole piece coated by the wet method, then the independent film-forming positive and negative pole pieces and the electrolyte membrane are compacted together by flat plate hot pressing or other pressurizing modes, and then a plurality of independent small units are assembled into the high-capacity soft package battery in an internal parallel connection mode. The assembly method of the above-described sulfide solid-state battery has the following problems: 1. in order to ensure that the general electrolyte membrane with high energy density of the solid-state battery can preferably reduce the thickness of the control electrolyte membrane, so that the mechanical strength of the electrolyte membrane is reduced, the electrolyte membrane is easy to crack in the process of being combined with an electrode to cause short circuit, and the consistency and the yield of the battery are low; 2. when lithium metal is used as a negative electrode, pressurization is needed to improve the interface contact between the electrolyte membrane and the lithium metal in order to ensure the contact between the lithium metal and the electrolyte membrane, at the moment, the high ductility of the lithium metal can cause the short circuit of the battery cell in the manufacturing process easily to cause the failure of the battery cell, and meanwhile, the dendritic crystal growth of the lithium metal negative electrode easily breaks through the electrolyte layer in the charging and discharging processes to cause the short circuit; 3. the sulfide electrolyte membrane has poor physical and mechanical properties, so that the whole manufacturing process is complex in process flow, low in success rate, high in cost and high in mass production difficulty.
CN109661743A discloses ion-conducting solid-state compositions comprising ion-conducting inorganic particles in a matrix of an organic material. The obtained composite material has high ionic conductivity and mechanical properties convenient for processing. In some embodiments of this document, an electrolyte membrane is provided that, while effective in enhancing the flexibility of the electrolyte layer, greatly reduces the room temperature ionic conductivity due to the presence of the non-ionic conductor polymer.
CN109148944A discloses a composite solid electrolyte with high ionic conductivity and a preparation method thereof, belonging to the technical field of solid electrolytes of lithium ion batteries. The composite solid electrolyte consists of an inorganic solid electrolyte, a polymer electrolyte and a lithium salt, wherein the mass ratio of the inorganic solid electrolyte to the polymer electrolyte to the lithium salt is 0.2-0.8: 0.2-0.8: 0.05 to 0.5. The invention prepares inorganic solid electrolyte nano-fiber by electrostatic spinning, and prepares a vertically oriented inorganic solid electrolyte framework by a freeze casting method, and the composite solid electrolyte is formed by pouring polymer and lithium salt. However, the preparation method in the process is complex and has high cost, and the inorganic solid electrolytes adopted in the embodiment are oxides, so that the problems of severe preparation, storage and transportation conditions and high cost exist if the common sulfide solid electrolyte is adopted.
Therefore, how to develop an electrolyte membrane which has ultra-thin, high conductivity and excellent physical and mechanical properties and is suitable for a sulfide all-solid-state system to improve the process feasibility of the sulfide all-solid-state battery and improve the performance of the sulfide all-solid-state battery is a technical problem which needs to be solved urgently at present.
Disclosure of Invention
The invention aims to provide an electrolyte membrane for a sulfide solid-state battery, and a preparation method and application thereof. The electrolyte membrane for the sulfide solid-state battery has high interface contact property, high strength and high ionic conductivity, and can effectively solve the problems of large interface contact resistance between an electrode and the electrolyte membrane, insufficient electrolyte membrane conductivity, poor battery processability and the like, thereby optimizing the rate capability and the cycle performance of the sulfide solid-state battery, simplifying the subsequent manufacturing process and improving the battery qualification rate.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides an electrolyte membrane for a sulfide solid-state battery, the electrolyte membrane including a base membrane, a nanoceramic particle layer, and a sulfide electrolyte layer; wherein the pores of the base film contain electrolyte, the nano ceramic particle layer is positioned on the surface of two opposite sides of the base film, and the sulfide electrolyte layer is positioned on the surface of the nano ceramic particle layer.
The nano ceramic particle layer on the surface of the basement membrane has the main function of increasing the liquid retention and absorption capacity of the basement membrane after absorbing liquid so as to ensure that the solvent cannot volatilize to cause the reduction of the conductivity of the electrolyte membrane.
The sulfide electrolyte layer aims to utilize the characteristics of soft particles and high conductivity of the sulfide electrolyte layer, so that the interface impedance of the battery is lower when the positive and negative pole piece batteries are formed in the subsequent pressurizing composite mode.
The electrolyte membrane for the sulfide solid-state battery provided by the invention has high interface contact property, high strength and high ionic conductivity, and can effectively solve the problems of large interface contact resistance between an electrode and the electrolyte membrane, insufficient electrolyte membrane conductivity, poor battery processability and the like, thereby optimizing the rate capability and the cycle performance of the sulfide solid-state battery, simplifying the subsequent manufacturing process and improving the battery qualification rate.
Preferably, the porosity of the base film is 40 to 60%, such as 40%, 45%, 50%, 55%, or 60%, and the like.
In the invention, the porosity of the basal membrane is too small, which is not beneficial to absorbing electrolyte liquid and influencing conductivity; too much porosity of the base film may result in insufficient film support strength, possibly resulting in short circuits.
Preferably, the base film has a thickness of 5 to 12 μm, such as 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, or the like.
Preferably, the base film comprises any one of or a combination of at least two of a polyethylene barrier film, a polypropylene barrier film, a polyethylene-polypropylene composite barrier film, a polyethylene terephthalate non-woven fabric barrier film or a polyimide electrospinning barrier film.
Compared with other types of isolating membranes, the polyethylene terephthalate non-woven fabric is more beneficial to absorbing electrolyte liquid, ensures high porosity and has good supporting strength, thereby preventing lithium dendrite short circuit.
Preferably, the thickness of the layer of nanoceramic particles is 300nm to 1 μm, such as 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm or 1 μm, etc.
Preferably, the median particle diameter of the nano ceramic particles in the nano ceramic particle layer is 50-100 nm, such as 50nm, 60nm, 70nm, 80nm, 90nm or 100 nm.
Preferably, the nano-ceramic particles comprise any one of LATP, LLZTO or LTO or a combination of at least two thereof.
Wherein LATP is Li1.3Al0.3Ti1.7P3O12LLZTO is Li7La3Zr2O12LTO being Li4Ti5O12。
Preferably, the thickness of the sulfide electrolyte layer is 15 to 25 μm, for example, 15 μm, 16 μm, 17 μm, 18 μm, 20 μm, 22 μm, 23 μm, or 25 μm.
Preferably, the sulfide electrolyte in the sulfide electrolyte layer is a thio-LISICON structure and derivatives thereof, preferably any one of LPSCL, LPSBr, LSPS or LPSI or a combination of at least two thereof.
In a second aspect, the present invention provides a production method for an electrolyte membrane for a sulfide solid-state battery as described in the first aspect, the production method comprising:
(1) coating nano ceramic particles on the surface of a base film to obtain the base film coated with the nano ceramic particles;
(2) soaking the base membrane coated with the nano ceramic particles in an electrolyte solution, and draining after the soaking to obtain an electrolyte membrane soaked with the electrolyte solution;
(3) and casting the sulfide electrolyte slurry on the surface of the electrolyte membrane soaked with the electrolyte solution in a curtain coating manner to obtain the electrolyte membrane for the sulfide solid-state battery.
The preparation method provided by the invention is simple to operate, so that the electrolyte solution can be immersed into the pores of the base film, and the liquid retention and absorption capacities of the base film after liquid absorption are increased, so that the solvent is prevented from volatilizing to reduce the conductivity, the rate capability and the cycle performance of the sulfide solid-state battery are optimized, the subsequent manufacturing process is simplified, and the qualified rate of the battery is improved.
Preferably, the electrolyte solution of step (2) includes LiTFSi.
Preferably, the electrolyte solution further comprises triethylene glycol dimethyl ether.
Triethylene glycol dimethyl ether (G3) has the characteristics of high boiling point, low volatility, low fluidity, low polarity and stability to sulfide electrolyte, and the characteristics are favorable for maintaining the state of the basement membrane after imbibing and the stability of the sulfide electrolyte after casting coating.
Preferably, the preparation method of the sulfide electrolyte slurry of step (3) includes:
and mixing the sulfide electrolyte, the binder and the solvent to obtain sulfide electrolyte slurry.
Preferably, the sulfide electrolyte comprises a thio-LISICON structure and derivatives thereof, preferably any one of LPSCL, LPSBr, LSPS or LPSI or a combination of at least two thereof.
Preferably, the solvent comprises any one of n-hexane, n-heptane, xylene, trimethylbenzene, tetrahydrofuran or anisole or a combination of at least two thereof.
Preferably, the content of the binder in the sulfide electrolyte slurry is 2-5%, such as 2%, 3%, 4%, or 5%.
In the invention, the content of the binder is too high, which causes the conductivity of the electrolyte membrane to be low and the charge-discharge polarization to be large, and the content of the binder is too low, which causes the strength and the flexibility of the sulfide electrolyte membrane to be poor and is not beneficial to film formation.
Preferably, the binder comprises any one of SBR, NBR, HNBR or PVDF or a combination of at least two of these.
As a preferable aspect, the method for producing an electrolyte membrane for a sulfide solid-state battery includes:
(1) coating nano ceramic particles on the surface of a base film to obtain the base film coated with the nano ceramic particles;
(2) soaking the base membrane coated with the nano ceramic particles in electrolyte solution of triethylene glycol dimethyl ether containing LiTFSi, and draining after soaking to obtain an electrolyte membrane soaked with the electrolyte solution;
(3) mixing sulfide electrolyte, a binder and a solvent to obtain sulfide electrolyte slurry; casting the sulfide electrolyte slurry on the surface of the electrolyte membrane soaked with the electrolyte solution to obtain the electrolyte membrane for the sulfide solid-state battery;
wherein the sulfide electrolyte comprises a thio-LISICON structure and derivatives thereof, preferably any one or a combination of at least two of LPSCL, LPSBr, LSPS or LPSI; the solvent comprises any one or the combination of at least two of n-hexane, n-heptane, xylene, trimethylbenzene, tetrahydrofuran or anisole; the content of the binder in the sulfide electrolyte slurry is 2-5%; the binder comprises any one or a combination of at least two of SBR, NBR, HNBR or PVDF.
In a third aspect, the present invention also provides a sulfide solid-state battery including a positive electrode, the electrolyte membrane for a sulfide solid-state battery according to the first aspect, and a negative electrode.
Preferably, the negative electrode comprises a copper foil and lithium metal electroplated on the surface of the copper foil.
Preferably, the thickness of the lithium metal is 1 to 10 μm, such as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm.
The lithium metal obtained by electroplating is thin, so that the lithium metal is favorable for preventing short circuit caused by pressure extension in the manufacturing process of the battery, and the microscopic surface is very flat.
Compared with the prior art, the invention has the following beneficial effects:
the electrolyte membrane for the sulfide solid-state battery provided by the invention has high interface contact property, high strength and high ionic conductivity, and can effectively solve the problems of large interface contact resistance between an electrode and the electrolyte membrane, insufficient electrolyte membrane conductivity, poor battery processability and the like, thereby optimizing the rate capability and the cycle performance of the sulfide solid-state battery, simplifying the subsequent manufacturing process, improving the qualification rate of the battery, ensuring that the capacity retention rate of the battery is still 87.9% or more after the cycle performance of the battery can reach 0.1C for fifty weeks, and the specific discharge capacity under 3C can reach 171.8mAh/g or more.
Drawings
Fig. 1 is a graph showing a cycle curve of the solid-state battery provided in example 1.
Fig. 2 is a charge-discharge curve diagram of the solid-state battery provided in comparative example 1.
Fig. 3 is a graph showing a cycle curve of the solid-state battery provided in comparative example 2.
Detailed Description
The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitation of the present invention.
Example 1
The present embodiment provides an electrolyte membrane for a sulfide solid-state battery, the electrolyte membrane including a PET (polyethylene terephthalate) nonwoven fabric separator having a porosity of 51%, a LATP ceramic particle layer, and a sulfide electrolyte layer; wherein the pores of the base film contain an electrolyte solution of LiTFSi-G3, the LATP ceramic particle layer is positioned on the surface of two opposite sides of the PET (polyethylene terephthalate) non-woven fabric separation film, and the sulfide electrolyte layer is positioned on the surface of the nano ceramic particle layer.
The preparation method of the electrolyte membrane for the sulfide solid-state battery comprises the following steps:
(1) coating two sides of a PET non-woven fabric isolating membrane with the thickness of 8 mu m with LATP ceramic particle layers with the thickness of 1 mu m and the median particle size of 50nm to obtain a base membrane coated with nano ceramic particles;
(2) fully soaking the base membrane coated with the nano ceramic particles in 0.5mol/L electrolyte solution of LiTFSi-G3 for 10min, taking out the base membrane after pores in the base membrane are fully absorbed with the electrolyte solution, and draining residual electrolyte solution on the surface to obtain an electrolyte membrane soaked with the electrolyte solution;
(3) mixing LPSCL and LPSI in a mass ratio of 7:3, and 5% of NBR and trimethylbenzene to obtain sulfide electrolyte slurry; and coating a layer of electrolyte membrane with the thickness of 20 mu m and soaked with electrolyte solution on the two sides of the sulfide electrolyte slurry by tape casting to obtain the electrolyte membrane for the sulfide solid-state battery.
Example 2
The present embodiment provides an electrolyte membrane for a sulfide solid-state battery, the electrolyte membrane including a PE (polyethylene) separator having a porosity of 40%, a LLZTO ceramic particle layer, and a sulfide electrolyte layer; wherein the pores of the base film contain an electrolyte solution of LiTFSi-G3, the LLZTO ceramic particle layer is positioned on the surface of the PE (polyethylene) separator on the opposite sides, and the sulfide electrolyte layer is positioned on the surface of the nano ceramic particle layer.
The preparation method of the electrolyte membrane for the sulfide solid-state battery comprises the following steps:
(1) coating a PE (polyethylene) isolating film with the thickness of 5 mu m on two sides with 500 nm-thick LLZTO ceramic particle layers with the median particle size of 100nm to obtain a base film coated with nano ceramic particles;
(2) fully soaking the base membrane coated with the nano ceramic particles in 0.5mol/L electrolyte solution of LiTFSi-G3 for 10min, taking out the base membrane after pores in the base membrane are fully absorbed with the electrolyte solution, and draining residual electrolyte solution on the surface to obtain an electrolyte membrane soaked with the electrolyte solution;
(3) mixing LPSCL, 3.5% PVDF and n-hexane to obtain sulfide electrolyte slurry; and coating a layer of electrolyte membrane with the thickness of 25 mu m and soaked with electrolyte solution on the two sides of the sulfide electrolyte slurry by tape casting to obtain the electrolyte membrane for the sulfide solid-state battery.
Example 3
The present embodiment provides an electrolyte membrane for a sulfide solid-state battery, the electrolyte membrane including a PI polyimide electrospun separator having a porosity of 60%, an LTO ceramic particle layer, and a sulfide electrolyte layer; wherein the pores of the base film contain an electrolyte solution of LiTFSi-G3, the LTO ceramic particle layer is positioned on the surface of two opposite sides of the PI polyimide electrospinning isolating film, and the sulfide electrolyte layer is positioned on the surface of the nano ceramic particle layer.
The preparation method of the electrolyte membrane for the sulfide solid-state battery comprises the following steps:
(1) coating LTO ceramic particle layers with the thickness of 300nm and the median particle size of 85nm on two sides of a PI polyimide electrospinning isolating membrane with the thickness of 12 mu m to obtain a base membrane coated with nano ceramic particles;
(2) fully soaking the base membrane coated with the nano ceramic particles in 0.5mol/L electrolyte solution of LiTFSi-G3 for 10min, taking out the base membrane after pores in the base membrane are fully absorbed with the electrolyte solution, and draining residual electrolyte solution on the surface to obtain an electrolyte membrane soaked with the electrolyte solution;
(3) mixing the LPSBr, 2% of SBR and anisole to obtain sulfide electrolyte slurry; and coating a layer of electrolyte membrane with the thickness of 15 mu m and soaked with electrolyte solution on the two sides of the sulfide electrolyte slurry by tape casting to obtain the electrolyte membrane for the sulfide solid-state battery.
Example 4
The present example is different from example 1 in that the porosity of the PET (polyethylene terephthalate) nonwoven fabric separator in the present example is 35%.
The remaining preparation methods and parameters were in accordance with example 1.
Example 5
The difference between this example and example 1 is that the porosity of the PET (polyethylene terephthalate) nonwoven separator film in this example is 65%.
The remaining preparation methods and parameters were in accordance with example 1.
Comparative example 1
This comparative example provides an electrolyte membrane for a sulfide solid-state battery, the electrolyte membrane having a thickness of 100 μm.
The preparation method of the electrolyte membrane comprises the following steps:
mixing LPSCL and LPSI in a mass ratio of 7:3, and 5% of NBR and trimethylbenzene to obtain sulfide electrolyte slurry, and preparing the slurry into an electrolyte membrane with the thickness of 100 mu m.
Comparative example 2
This comparative example was identical to the electrolyte membrane provided in comparative example 1, but the method of preparing the battery was different.
Sulfide solid-state batteries were prepared by using the electrolyte membranes provided in examples 1 to 5 and comparative examples 1 to 2, and the method for preparing the solid-state batteries included:
mixing the components in a mass ratio of 60: 5: 30: 5 NCM 811: SP sulfide electrolyte: mixing the binder in a wet ball milling mode, uniformly mixing, coating and vacuum drying, wherein the sulfide electrolyte in the positive electrode is prepared by matching LPCLC and LPSI, and the matching ratio is 7: 3; the negative electrode was a 3 μm electroplated lithium copper composite tape and the electrolyte membranes were provided by examples 1-5 and comparative examples 1-2.
Cutting the positive electrode provided in examples 1 to 5 and comparative example 1 into 3 × 3cm, cutting the electrolyte membrane into 3.2 × 3.2cm, cutting the negative electrode into 3.1 × 3.1, respectively attaching the positive and negative electrode plates to both sides of the electrolyte membrane, fixing the shape and position by green glue, primarily forming in a glove box by using a shaping die with a heating function, then packaging in an aluminum plastic film Pocket, performing secondary flat plate pressure forming under a large pressure press, and then locking in a testing die by 10Mpa force at 60 ℃.
Cutting the anode provided by the comparative example 2 into 3 × 3cm size by using a cutting die, cutting the electrolyte membrane into 3.2 × 3.2cm size, cutting the cathode into 3.1 × 3.1 size, respectively attaching the anode and cathode plates to two sides of the electrolyte membrane, fixing the positions by using green glue, primarily forming by using a shaping die with a heating function in a glove box, then packaging into an aluminum plastic membrane Pocket bag, carrying out secondary pressure forming by using large-pressure cold isostatic pressing, and then testing in a testing die by locking at 60 ℃ under 10 MPa.
As can be seen from fig. 1, the electrolyte membrane described in example 1 is used, and a simple flat plate hot pressing process is used to assemble and compact the soft package battery, so that the battery has good cycle performance while no short circuit occurs during charging and discharging.
As can be seen from fig. 2, the battery was assembled and pressurized using the flat hot press process using the sulfide electrolyte membrane alone described in comparative example 1 as an electrolyte layer, and the battery was short-circuited during charge and discharge.
As can be seen from fig. 3, the battery can also operate normally in comparative example 1 after the complicated and cost-effective cold isostatic pressing process is used, but the manufacturing process cost and difficulty of the battery are far more than those of the battery of example 1.
The solid-state batteries prepared in examples 1 to 5 and comparative examples 1 to 2 were subjected to cycle performance tests including specific charge/discharge capacity and capacity retention at 0.1C and specific discharge capacity at 0.3C, and the test results after 50 cycles are shown in table 1.
TABLE 1
Figure BDA0002866669710000111
Figure BDA0002866669710000121
As is clear from the data results of examples 1, 4 and 5, when the porosity of the base film is too small or too large, the electrolyte membrane is affected, and as a result, the charge/discharge performance is lowered due to the increase in polarization, or the risk of short-circuiting is present, while when too small, the capacity is lowered due to the increase in polarization, and when too large, the risk of short-circuiting of the battery is increased, which is advantageous for the exertion of capacity.
As can be seen from the data results of example 1 and comparative example 1, the conventional solid-state battery manufacturing process cannot solve the problems that the internal interface of the battery is not uniform, and the electrolyte membrane is easily deformed by pressure to cause short circuit, so that the electrolyte membrane is easily short-circuited during the charging process.
As can be seen from the data results of example 1 and comparative example 2, the battery in comparative example 2 is manufactured by a more complicated manufacturing process, and a complicated operation process of cold isostatic pressing is required, and although the result is better, the manufacturing process is more complicated and increases the production cost, but the electrolyte membrane provided by the present invention has a simple manufacturing method, and in the process of manufacturing the battery, a result comparable to that of comparative example 2 can be realized without complicated operation, so that a novel electrolyte membrane capable of solving the difficulty in the processing process of the solid-state battery is provided, which is of great help to save the range economic cost and the time cost of the solid-state battery.
In conclusion, the electrolyte membrane provided by the invention can effectively solve the problems of large interface contact resistance between an electrode and the electrolyte membrane, insufficient conductivity of the electrolyte membrane, poor battery processability and the like, thereby optimizing the rate capability and the cycle performance of the sulfide solid-state battery, simplifying the subsequent manufacturing process, improving the qualification rate of the battery, ensuring that the capacity retention rate of the battery is still 87.9% or more after the cycle performance of the battery can reach 0.1C for fifty weeks, and the specific discharge capacity under 3C can reach 171.8mAh/g or more.
The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.

Claims (20)

1. An electrolyte membrane for a sulfide solid-state battery, characterized in that the electrolyte membrane comprises a base membrane, a layer of nanoceramic particles, and a sulfide electrolyte layer; wherein the pores of the base film contain electrolyte, the nano ceramic particle layer is positioned on the surface of two opposite sides of the base film, and the sulfide electrolyte layer is positioned on the surface of the nano ceramic particle layer; the sulfide electrolyte in the sulfide electrolyte layer is of a thio-LICION structure and derivatives thereof; the nano ceramic particles comprise any one of LATP, LLZTO or LTO or a combination of at least two of the same.
2. The electrolyte membrane for a sulfide solid-state battery according to claim 1, wherein a porosity of the base membrane is 40 to 60%.
3. The electrolyte membrane for a sulfide solid-state battery according to claim 1, wherein the base membrane has a thickness of 5 to 12 μm.
4. The electrolyte membrane for a sulfide solid-state battery according to claim 1, wherein the base membrane comprises any one of a polyethylene separator, a polypropylene separator, a polyethylene-polypropylene composite separator, a polyethylene terephthalate non-woven fabric separator, or a polyimide electrospun separator, or a combination of at least two thereof.
5. The electrolyte membrane for a sulfide solid state battery according to claim 1, wherein the thickness of the nanoceramic particle layer is 300nm to 1 μm.
6. The electrolyte membrane for a sulfide solid-state battery according to claim 1, wherein a median particle diameter of the nano ceramic particles in the nano ceramic particle layer is 50 to 100 nm.
7. The electrolyte membrane for a sulfide solid state battery according to claim 1, wherein a thickness of the sulfide electrolyte layer is 15 to 25 μm.
8. The electrolyte membrane for a sulfide solid state battery according to claim 1, wherein a sulfide electrolyte in the sulfide electrolyte layer is any one of LPSCL, LPSBr, LSPS, or LPSI or a combination of at least two thereof.
9. The production method of the electrolyte membrane for a sulfide solid state battery according to any one of claims 1 to 8, characterized by comprising:
(1) coating nano ceramic particles on the surface of a base film to obtain the base film coated with the nano ceramic particles;
(2) soaking the base membrane coated with the nano ceramic particles in an electrolyte solution, and draining after soaking to obtain an electrolyte membrane soaked with the electrolyte solution;
(3) casting the sulfide electrolyte slurry on the surface of an electrolyte membrane soaked with an electrolyte solution to obtain the electrolyte membrane for the sulfide solid-state battery; the sulfide electrolyte includes a thio-LISICON structure and derivatives thereof.
10. The production method of an electrolyte membrane for a sulfide solid state battery according to claim 9, wherein LiTFSi is included in the electrolyte solution in step (2).
11. The production method of an electrolyte membrane for a sulfide solid-state battery according to claim 9, characterized in that triethylene glycol dimethyl ether is further included in the electrolyte solution.
12. The production method of the electrolyte membrane for a sulfide solid state battery according to claim 9, characterized in that the production method of the sulfide electrolyte slurry of step (3) includes:
and mixing the sulfide electrolyte, the binder and the solvent to obtain sulfide electrolyte slurry.
13. The method for producing an electrolyte membrane for a sulfide solid state battery according to claim 9, wherein the sulfide electrolyte is any one of LPSCL, LPSBr, LSPS or LPSI or a combination of at least two thereof.
14. The production method of an electrolyte membrane for a sulfide solid state battery according to claim 12, wherein the solvent includes any one of n-hexane, n-heptane, xylene, trimethylbenzene, tetrahydrofuran, or anisole, or a combination of at least two thereof.
15. The method for producing an electrolyte membrane for a sulfide solid state battery according to claim 12, wherein a content of the binder in the sulfide electrolyte slurry is 2 to 5%.
16. The production method of the electrolyte membrane for a sulfide solid state battery according to claim 12, wherein the binder includes any one of SBR, NBR, HNBR, or PVDF, or a combination of at least two of them.
17. The production method of the electrolyte membrane for a sulfide solid-state battery according to claim 9, characterized by comprising:
(1) coating nano ceramic particles on the surface of a base film to obtain the base film coated with the nano ceramic particles;
(2) soaking the base membrane coated with the nano ceramic particles in electrolyte solution of triethylene glycol dimethyl ether containing LiTFSi, and draining after soaking to obtain an electrolyte membrane soaked with the electrolyte solution;
(3) mixing sulfide electrolyte, a binder and a solvent to obtain sulfide electrolyte slurry; casting the sulfide electrolyte slurry on the surface of the electrolyte membrane soaked with the electrolyte solution to obtain the electrolyte membrane for the sulfide solid-state battery;
wherein the sulfide electrolyte is any one of or a combination of at least two of LPSCL, LPSBr, LSPS or LPSI; the solvent comprises any one or the combination of at least two of n-hexane, n-heptane, xylene, trimethylbenzene, tetrahydrofuran or anisole; the content of the binder in the sulfide electrolyte slurry is 2-5%; the binder comprises any one or a combination of at least two of SBR, NBR, HNBR or PVDF.
18. A sulfide solid-state battery characterized by comprising a positive electrode, the electrolyte membrane for a sulfide solid-state battery according to any one of claims 1 to 8, and a negative electrode.
19. The sulfide solid-state battery according to claim 18, wherein the negative electrode comprises a copper foil and lithium metal plated on a surface of the copper foil.
20. The sulfide solid state battery according to claim 19, wherein the lithium metal has a thickness of 1 to 10 μm.
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