Preparation method of composite solid-state electrolyte and application thereof in solid-state lithium battery
By preparing a composite solid electrolyte membrane of Li5La3Nb2O12 and Ba0.5Sr0.5TiO3, the safety issues of traditional liquid electrolytes and the low conductivity of polymer-based electrolytes were solved, and the ionic conductivity and mechanical strength of high-performance all-solid-state lithium batteries were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUILIN UNIV OF ELECTRONIC TECH
- Filing Date
- 2026-03-18
- Publication Date
- 2026-06-05
AI Technical Summary
Traditional liquid electrolytes are flammable, prone to leakage, and have poor interfacial stability, while polymer-based solid electrolytes have low ionic conductivity, which limits the performance improvement of all-solid-state lithium batteries.
A composite solid electrolyte membrane was formed by mixing Li5La3Nb2O12 with ferroelectric materials Ba0.5Sr0.5TiO3 and polyvinylidene fluoride. The membrane was prepared by high-temperature sintering and solvent mixing, which enhanced the ionic conductivity and mechanical strength.
The prepared composite solid electrolyte membrane exhibits high ionic conductivity, high lithium-ion migration efficiency, good mechanical strength and thermal stability at room temperature, making it suitable for large-scale production.
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Figure CN122158674A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of solid electrolyte materials technology, and in particular to a method for preparing a composite solid electrolyte membrane, applicable to electrolyte components in all-solid-state lithium batteries. Background Technology
[0002] With the increasing demand for high-energy-density and high-safety lithium batteries, all-solid-state lithium batteries have attracted widespread attention as the next generation of energy storage systems. Traditional liquid electrolytes suffer from problems such as flammability, leakage, and poor interface stability, making them unsuitable for future battery safety requirements. Polymer-based solid electrolytes possess excellent flexibility, good film-forming properties, and processability; however, the low ionic conductivity of single polymers limits their practical applications.
[0003] Li5La3Nb2O 12 It possesses high ionic conductivity and good electrochemical stability, and can be used as an inorganic filler in polymer systems to enhance overall conductivity. On the other hand, ferroelectric materials such as barium strontium titanate (Ba...) 0.5 Sr 0.5 TiO3 has polarization properties, which can promote the directional migration of lithium ions through interfacial polarization effect, thereby further improving the performance of composite electrolytes.
[0004] Therefore, a method based on polyvinylidene fluoride and mixed Li5La3Nb2O was developed. 12 The composite solid electrolyte membrane made of ferroelectric ceramic materials was developed, and an efficient preparation process was proposed, which is of great significance for realizing high-performance all-solid-state lithium batteries. Summary of the Invention
[0005] To address the above problems, this invention provides a composite solid electrolyte and its preparation method:
[0006] A method for preparing a composite solid electrolyte includes the following steps:
[0007] S1. Preparation of composite electrolyte solution;
[0008] S1-1, Preparation of Li5La3Nb2O 12 Precursor;
[0009] S1-2. The above precursor is subjected to high-temperature sintering treatment to obtain Li5La3Nb2O 12 powder;
[0010] S1-3, The above powder is mixed with polyvinylidene fluoride and barium strontium titanate (Ba 0.5 Sr 0.5 TiO3 is mixed with an organic solvent to obtain a composite electrolyte solution.
[0011] S2, Coating Forming;
[0012] S3. Drying and curing;
[0013] S4. Demolding and cutting.
[0014] In some preferred embodiments of the present invention, step S1-1 of obtaining the precursor includes adding lithium nitrate, lanthanum nitrate hexahydrate, niobium pentachloride, citric acid and ethylene glycol to deionized water and mixing them evenly at 90°C to obtain a mixture.
[0015] In some preferred embodiments of the present invention, in step S1-1 of obtaining the precursor, the above mixture is placed in a forced-air drying oven and kept at 250°C for 6 hours to obtain Li5La3Nb2O. 12 Precursor.
[0016] In some preferred embodiments of the present invention, in step S1-1 of obtaining the precursor, an additional 10 wt.% lithium nitrate is added to the mixture to offset lithium loss at high temperature.
[0017] In some preferred embodiments of the present invention, in the preparation of Li5La3Nb2O 12 In step S1-2 of the powder, the precursor is subjected to high-temperature sintering by placing it in a muffle furnace and sintering at 900°C for 9 hours.
[0018] In some preferred embodiments of the present invention, in the preparation of Li5La3Nb2O 12 In step S1-2 of the powder process, Li5La3Nb2O 12 It is a powder material with a garnet-type crystal structure, and the particle size is preferably between 100 nm and 1 μm.
[0019] In some preferred embodiments of the present invention, the composite electrolyte solution further includes lithium bis(trifluoromethanesulfonylimide) (LiTFSI).
[0020] In some preferred embodiments of the present invention, in steps S1-3 of preparing the composite solid electrolyte solution, Li5La3Nb2O 12 Barium strontium titanate (Ba 0.5 Sr 0.5 After ultrasonic dispersion of TiO3 powder, the two are mixed with polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).
[0021] In some preferred embodiments of the present invention, in steps S1-3 of preparing the composite solid electrolyte solution, a small amount of lithium nitrate is added to the mixed solution to promote the decomposition of LiTFSI.
[0022] In some preferred embodiments of the present invention, the organic solvent of the composite solid electrolyte solution is N,N-dimethylformamide.
[0023] In some preferred embodiments of the present invention, in step S2, the composite electrolyte solution prepared in step S1 is uniformly coated onto a glass substrate by a doctor blade coating method, and the film thickness is controlled between 100 and 200 μm.
[0024] In some preferred embodiments of the present invention, in step S3, the coated sample is placed at 60°C for vacuum drying overnight to remove organic solvents and form a dense solid electrolyte membrane.
[0025] In some preferred embodiments of the present invention, step S4 involves peeling the dried and formed composite electrolyte membrane from the glass substrate using antistatic tweezers and cutting it into a size of 16 mm in diameter.
[0026] The principle and beneficial effects of this technical solution:
[0027] The composite electrolyte membrane prepared by this invention exhibits high ionic conductivity (>10) at room temperature. -5 (S / cm), which can meet the requirements for solid-state battery use;
[0028] The ferroelectric material Ba in this invention 0.5 Sr 0.5 The addition of TiO3 can form a micro electric field and promote lithium-ion migration, thereby improving the lithium-ion interface transport efficiency.
[0029] In this invention, Li5La3Nb2O 12 Mixed Ba 0.5 Sr 0.5 The ceramic framework structure of TiO3 enhances the mechanical strength and thermal stability of the membrane;
[0030] The preparation method of this invention is simple to operate and has mild conditions, making it suitable for large-scale preparation. Attached Figure Description
[0031] Figure 1 is a SEM image of the composite solid electrolyte membrane in this invention at 10,000x magnification;
[0032] Figure 2 The figure shows the test results of the solid-state lithium battery assembled with the composite solid-state electrolyte membrane in this invention.
[0033] Figure 3 shows the test results of the compatibility of the composite solid electrolyte in this invention. Detailed Implementation
[0034] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0035] Example 1
[0036] A composite solid electrolyte, the preparation method includes the following steps:
[0037] S1. Preparation of composite electrolyte solution:
[0038] Add 0.005 mol lithium nitrate, 0.003 mol lanthanum nitrate hexahydrate, 0.002 mol niobium pentachloride, 0.01 mol citric acid and 0.57 ml ethylene glycol to 10 ml deionized water, and add an additional 10 wt.% lithium nitrate. Stir and mix thoroughly at 90 °C to obtain a mixed solution.
[0039] The mixture was placed in a forced-air drying oven and kept at 250℃ for 6 hours to obtain Li5La3Nb2O. 12 Precursor. The precursor was sintered in a muffle furnace at 900℃ for 9 hours to obtain Li5La3Nb2O. 12 Powder. Mix 0.6g polyvinylidene fluoride, 0.4g LTFSI, and 0.2g Li5La3Nb2O. 12 and 0.02g Ba 0.5 Sr 0.5 TiO3 was mixed in 6 ml of N,N-dimethylformamide and stirred until homogeneous to obtain a composite electrolyte solution.
[0040] S2, Coating Forming:
[0041] The composite electrolyte solution prepared in step S1 was uniformly coated onto a glass substrate using a doctor blade coating method, with a film thickness of 180 μm.
[0042] S3. Drying and curing:
[0043] The coated sample was placed in a vacuum dryer at 60°C for 27 hours to remove organic solvents and form a dense solid electrolyte membrane.
[0044] S4. Demolding and Cutting:
[0045] Use antistatic tweezers to peel the film off the glass substrate and cut it into round pieces with a diameter of 16mm.
[0046] Example 2
[0047] A composite solid electrolyte, the preparation method includes the following steps:
[0048] S1. Preparation of composite electrolyte solution:
[0049] Add 0.005 mol lithium nitrate, 0.003 mol lanthanum nitrate hexahydrate, 0.002 mol niobium pentachloride, 0.01 mol citric acid and 0.57 ml ethylene glycol to 10 ml deionized water, and add an additional 10 wt.% lithium nitrate. Stir and mix thoroughly to obtain a mixture.
[0050] The mixture was placed in a forced-air drying oven and kept at 250℃ for 6 hours to obtain the Li5La3Nb2O12 precursor. The precursor was then sintered in a muffle furnace at 900℃ for 9 hours to obtain Li5La3Nb2O12 powder. 0.3g of polyvinylidene fluoride, 0.2g of LTFSI, and 0.1g of Li5La3Nb2O12 were then... 12 and 0.01g Ba 0.5 Sr 0.5 TiO3 was mixed in 4 ml of N,N-dimethylformamide and stirred until homogeneous to obtain a composite electrolyte solution.
[0051] S2, Coating Forming:
[0052] The composite electrolyte solution prepared in step S1 was uniformly coated onto a glass substrate using a doctor blade coating method, with a film thickness of 100 μm.
[0053] S3. Drying and curing:
[0054] The coated sample was placed in a vacuum dryer at 60°C for 24 hours to remove organic solvents and form a dense solid electrolyte membrane.
[0055] S4. Demolding and Cutting:
[0056] Use antistatic tweezers to peel the film off the glass substrate and cut it into round pieces with a diameter of 16mm.
[0057] Comparative Example 1
[0058] A composite solid electrolyte, the preparation method includes the following steps:
[0059] S1. Preparation of composite electrolyte solution:
[0060] Add 0.005 mol lithium nitrate, 0.003 mol lanthanum nitrate hexahydrate, 0.002 mol niobium pentachloride, 0.01 mol citric acid and 0.57 ml ethylene glycol to 10 ml deionized water, and add an additional 10 wt.% lithium nitrate. Stir and mix thoroughly to obtain a mixture.
[0061] The mixture was placed in a forced-air drying oven and kept at 250℃ for 6 hours to obtain Li5La3Nb2O. 12 Precursor. The precursor was sintered in a muffle furnace at 900℃ for 9 hours to obtain Li5La3Nb2O. 12 Powder. Mix 0.6g polyvinylidene fluoride, 0.4g LTFSI, and 0.1g Li5La3Nb2O. 12 and 0.02g Ba 0.5 Sr 0.5 TiO3 was mixed in 6 ml of N,N-dimethylformamide and stirred until homogeneous to obtain a composite electrolyte solution.
[0062] S2, Coating Forming:
[0063] The composite electrolyte solution prepared in step S1 was uniformly coated onto a glass substrate using a doctor blade coating method, with a film thickness of 150 μm.
[0064] S3. Drying and curing:
[0065] The coated sample was placed in a vacuum dryer at 60°C for 27 hours to remove organic solvents and form a dense solid electrolyte membrane.
[0066] S4. Demolding and Cutting:
[0067] Use antistatic tweezers to peel the film off the glass substrate and cut it into round pieces with a diameter of 16mm.
[0068] Table 1
[0069]
[0070] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.
Claims
1. A method for preparing a composite solid electrolyte, characterized in that, The preparation method includes the following steps: S1. Preparation of composite electrolyte solution: S1-1, Preparation of Li5La3Nb2O 12 Precursor; S1-2. The above precursor is subjected to high-temperature sintering treatment to obtain Li5La3Nb2O 12 powder; S1-3, The above powder is mixed with polyvinylidene fluoride and barium strontium titanate (Ba 0.5 Sr 0.5 TiO3 is mixed with an organic solvent to obtain a composite electrolyte solution. S2, Coating Forming; S3. Drying and curing; S4. Demolding and cutting.
2. The preparation method according to claim 1, characterized in that, Step S1-1 includes adding lithium nitrate, lanthanum nitrate hexahydrate, niobium pentachloride, citric acid and ethylene glycol to deionized water and mixing them evenly at 90°C to obtain a mixed solution.
3. The preparation method according to claim 2, characterized in that, In step S1-1, the above mixture is placed in a forced-air drying oven and kept at 250°C for 6 hours to obtain Li5La3Nb2O. 12 Precursor.
4. The preparation method according to claim 2, characterized in that, In step S1-1, an additional 10 wt.% lithium nitrate is added to the mixture to offset lithium loss at high temperatures.
5. The preparation method according to claim 1, characterized in that, The high-temperature sintering treatment of the precursor in step S1-2 includes sintering at 900°C in a muffle furnace for 9 hours.
6. The method according to claim 1, characterized in that, In steps S1-2, Li5La3Nb2O 12 It is a powder material with a garnet-type crystal structure, and the particle size is preferably between 100 nm and 1 μm.
7. The method according to claim 1, characterized in that, The composite electrolyte solution also includes lithium bis(trifluoromethanesulfonylimide) (LiTFSI).
8. The method according to claim 1, characterized in that, In steps S1-3, Li5La3Nb2O 12 Barium strontium titanate (Ba 0.5 Sr 0.5 After ultrasonic dispersion, TiO3 powder is mixed with polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).
9. The method according to claim 1, characterized in that, In steps S1-3, a small amount of lithium nitrate is added to the mixed solution to promote the decomposition of LiTFSI.
10. The method according to claim 1, characterized in that, The organic solvent is N,N-dimethylformamide.
11. The preparation method according to claim 1, characterized in that, In step S2, the composite electrolyte solution prepared in step S1 is uniformly coated onto the glass substrate using a doctor blade coating method, and the film thickness is controlled between 100 and 200 μm.
12. The preparation method according to claim 1, characterized in that, In step S3, the coated sample is placed at 60°C for vacuum drying overnight to remove organic solvents and form a dense solid electrolyte membrane.
13. The preparation method according to claim 1, characterized in that, In step S4, the dried composite electrolyte membrane is peeled off from the glass substrate using antistatic tweezers and cut into a size of 16mm in diameter.