Preparation method and application of in-situ poly-1,3-dioxolane solid-state electrolyte
By in-situ initiating 1,3-dioxolane polymerization with sulfide solid electrolyte, the problem of insufficient contact between conventional solid electrolyte and electrode is solved, thereby improving the ionic conductivity and electrochemical performance of lithium-ion batteries and reducing interfacial impedance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2024-12-13
- Publication Date
- 2026-06-23
AI Technical Summary
Insufficient interfacial contact between conventional solid electrolytes and electrodes leads to high interfacial impedance, increasing the likelihood of lithium dendrite formation. Furthermore, existing modification methods result in excessively rapid polymerization or residue degradation of the SEI.
In situ polymerization of 1,3-dioxolane was initiated using a sulfide solid electrolyte, and the ionic conductivity was improved by doping modification to prepare an in situ poly(1,3-dioxolane) solid electrolyte, which provides a lithium-ion transport channel and enhances the electrode interface contact.
It improves the ionic conductivity and lithium-ion transference number of the solid electrolyte membrane, enhances electrochemical performance, reduces interfacial impedance, and stabilizes the electrochemical performance of lithium-ion batteries.
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Figure CN122267286A_ABST
Abstract
Description
Technical Field
[0001] This application relates to a method for preparing and applying an in-situ poly(1,3-dioxolane) solid electrolyte, belonging to the field of solid polymer electrolyte membranes. Background Technology
[0002] Traditional liquid lithium-ion batteries (LIBs) are flammable, prone to leakage, and have poor safety performance. In contrast, solid-state electrolytes (SSEs) are non-flammable and have a wide electrochemical window, making them a more attractive option. Furthermore, the energy density of LIBs cannot meet the ever-growing demands for energy storage systems. Therefore, the development of solid-state lithium metal batteries (SSLMBs) has the potential to solve the leakage problems associated with conventional lithium-ion batteries and improve battery energy density by matching a high-voltage cathode with a solid-state electrolyte and a lithium metal anode. However, conventional SSEs do not provide good interfacial contact with the electrodes. This insufficient contact results in high interfacial resistance, which increases the likelihood of lithium dendrite formation due to inhomogeneous nucleation of Li+ ions.
[0003] Conventional solid electrolyte electrolytes (SSEs) do not provide good interfacial contact with the electrode. This insufficient contact results in high interfacial impedance, which increases the likelihood of lithium dendrite formation due to inhomogeneous nucleation of Li+ ions. Therefore, research in this area is challenging, seeking to develop stable solid electrolyte interphases (SEIs) while enhancing the interfacial contact between the SSE and the electrode. Previous studies have extensively investigated solid polymer electrolytes based on polymer matrices such as polyethylene oxide (PEO) and polyacrylonitrile (PAN). However, although the interfacial contact between conventional polymer electrolytes such as PEO or PAN and the electrode is much better than that between inorganic solid electrolytes and the electrode, many voids still exist between the electrolyte and the electrode, leading to high interfacial impedance.
[0004] In recent years, researchers have developed in-situ polymeric electrolytes, represented by poly(1,3-dioxolane) (PDOL), which can significantly improve the safety of battery systems while ensuring good interfacial contact. Existing technologies have proposed modifying traditional electrolytes using LiPF6 as an initiator and methoxymethane (DME) as a plasticizer to improve the conductivity of PDOL and thus enhance the electrochemical performance of the battery. However, the use of large amounts of LiPF6 leads to excessively rapid polymerization of 1,3-dioxolane (DOL), resulting in short PDOL chains and high residual DOL content. This residual DOL continuously reacts with Li metal, degrading the SEI (Sediment Injection Interchange). Therefore, developing novel Lewis acid initiators to initiate stable DOL polymerization at appropriate dosages has become a mainstream research direction. Summary of the Invention
[0005] To address the aforementioned problems in existing preparation techniques, the present invention aims to propose an effective method for initiating the ring-opening polymerization of DOL. This method involves obtaining a sulfide solid electrolyte with high ionic conductivity by conventionally ball milling and calcining raw materials Li2S, P2S5, and SnF2, thereby initiating the polymerization reaction of DOL and improving its ionic conductivity and various electrochemical properties.
[0006] According to one aspect of this application, a method for preparing an in-situ poly(1,3-dioxolane) solid electrolyte is provided. This method improves the ionic conductivity of the solid electrolyte membrane by doping and modifying the solid electrolyte to initiate DOL ring-opening polymerization. The in-situ poly(1,3-dioxolane) solid electrolyte prepared by this method provides a channel for lithium-ion transport, resulting in the co-migration of lithium ions and a higher lithium-ion transference number, thereby improving electrochemical performance.
[0007] The method for preparing the in-situ poly(1,3-dioxolane) solid electrolyte is characterized in that a sulfide solid electrolyte is used to initiate the polymerization reaction of 1,3-dioxolane in situ to prepare the in-situ poly(1,3-dioxolane) solid electrolyte.
[0008] The sulfide solid electrolyte is composed of Li 3+x P 1-x Sn x S 4-2x F 2x (0.05≤x≤0.2).
[0009] Preferably, the preparation method of the in-situ poly(1,3-dioxolane) solid electrolyte includes the following steps:
[0010] a) Prepared a composition of Li 3+x P 1-x Sn x S 4-2x F 2x (0.05≤x≤0.2) sulfide solid electrolyte;
[0011] b) The lithium-containing compound is dissolved in 1,3-dioxolane and then mixed with the sulfide solid electrolyte obtained in step a); the resulting mixture is stirred and polymerized, then spread on a substrate for further polymerization, and then vacuum dried to obtain the in-situ poly(1,3-dioxolane) solid electrolyte.
[0012] Preferably, step a) includes:
[0013] a1) Amorphous phase sulfide solid electrolyte material was obtained by high-energy ball milling of raw materials containing Li2S, P2S5 and SnF2.
[0014] a2) The amorphous phase sulfide solid electrolyte material obtained in step a1) is subjected to tableting, heat treatment, and pulverization to obtain the sulfide solid electrolyte.
[0015] Those skilled in the art can select the proportions of Li2S, P2S5, and SnF2 in the raw materials based on the composition of the sulfide solid electrolyte to be prepared.
[0016] Preferably, steps a) and b) are both performed under an inert atmosphere; the inert atmosphere is selected from at least one of nitrogen and an inert gas. More preferably, the inert atmosphere is selected from at least one of nitrogen, helium, and argon.
[0017] Those skilled in the art can select the conditions for high-energy ball milling according to actual needs. Preferably, the conditions for high-energy ball milling in step a1) are:
[0018] The high-energy ball mill speed is 400-600 r / min;
[0019] The ball-to-material ratio for high-energy ball milling is 20:1 to 50:1;
[0020] The high-energy ball milling time is 600–2400 min.
[0021] More preferably, the high-energy ball milling described in a1) is: first, ball milling at 100-300 r / min for 1-2 hours; then, ball milling at 300-500 r / min for 10-40 hours.
[0022] Those skilled in the art can select the tableting and heat treatment conditions according to actual needs. Preferably, the tableting pressure in step a2) is 5-15 MPa;
[0023] The heat treatment conditions described in step a2) are as follows:
[0024] The temperature is 200–300℃;
[0025] The heating rate is 1–10 °C / min;
[0026] The heat treatment time is 150–240 min.
[0027] Preferably, the lithium-containing compound in step b) is lithium bis(trifluoromethanesulfonylimide);
[0028] The substrate is glass fiber or polypropylene fiber paper.
[0029] Those skilled in the art can select the specific amounts of lithium-containing compound, 1,3-dioxolane, and sulfide solid electrolyte according to actual needs. Preferably, the mass ratio of lithium-containing compound, 1,3-dioxolane, and sulfide solid electrolyte in step b) is 0.5–0.8: 2–3.2: 0.027–0.048.
[0030] Those skilled in the art can select the conditions for stirred polymerization and vacuum drying according to actual needs. Preferably, the conditions for stirred polymerization in step b) are:
[0031] The stirring speed is 200-300 rpm, and the stirring time is 12-20 hours;
[0032] The vacuum drying conditions in step b) are:
[0033] The vacuum drying temperature is 20–30℃, and the vacuum drying time is 4–7 hours.
[0034] The further polymerization is carried out at room temperature for no less than 12 hours.
[0035] According to another aspect of this application, an all-solid-state lithium-ion battery is provided, characterized in that it contains an in-situ poly(1,3-dioxolane) solid electrolyte prepared by any of the above methods.
[0036] In this application, LiTFSI is an abbreviation for lithium bis(trifluoromethanesulfonylimide).
[0037] SSE is short for solid electrolyte;
[0038] SPE is short for solid polymer electrolyte;
[0039] SSLMBs is short for solid-state lithium metal batteries;
[0040] DOL is short for 1,3-dioxolane;
[0041] P-DOL is short for poly(1,3-dioxolane);
[0042] NMP is short for N-methylpyrrolidone.
[0043] The beneficial effects of this application include, but are not limited to:
[0044] (1) By doping and modifying the solid electrolyte, the ring-opening polymerization of DOL can be initiated, which can further improve the ionic conductivity of the solid electrolyte membrane.
[0045] (2) It provides a channel for lithium-ion transport, resulting in the co-migration of lithium ions and a higher lithium-ion transference number, thereby improving electrochemical performance. Attached Figure Description
[0046] Figure 1 This is the impedance curve spectrum of sample 1# prepared in Example 1. Detailed Implementation
[0047] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0048] Unless otherwise specified, all raw materials and reagents used in this application are commercially purchased and used directly without processing. The instruments and equipment used adopt the manufacturer's recommended scheme and parameters.
[0049] According to one specific embodiment, the preparation method of the in-situ poly(1,3-dioxolane) solid electrolyte includes the following steps:
[0050] 1) Under an inert atmosphere, according to the molecular formula Li 3+x P 1-x Sn x S 4-2x F 2x (0.05≤x≤0.2) Weigh the raw materials according to the corresponding molar ratio and obtain the amorphous phase sulfide solid electrolyte material by high-energy ball milling;
[0051] 2) Under an inert atmosphere, the ball-milled material was pressed, heat-treated, and pulverized to obtain a ceramic-phase high-ionic-conductivity sulfide solid electrolyte, Li. 3+x P 1-x Sn x S 4-2x F 2x .
[0052] 3) Under an inert atmosphere, weigh 0.5–0.8 g of LiTFSI and 2–3.2 g of DOL; weigh 0.027–0.046 g of the sulfide solid electrolyte Li. 3+x P 1-x Sn x S 4-2x F 2x， Stirring is performed using magnetic stirring.
[0053] 4) Under an inert atmosphere, the polymerized P-DOL is infiltrated into glass fiber or polypropylene fiber paper, and then further polymerized at room temperature, followed by vacuum drying to evaporate the unpolymerized DOL.
[0054] The raw materials mentioned in step 1) include Li2S, P2S5, and SnF2;
[0055] The inert atmosphere in step 1) includes at least one of nitrogen, helium, and argon.
[0056] In step 1), the high-energy ball milling speed is 400-600 r / min;
[0057] In step 1), the high-energy ball milling ball-to-material ratio is 20:1 to 50:1.
[0058] The high-energy ball milling time in step 1) is 600–2400 min.
[0059] The inert atmosphere in step 2) includes at least one of nitrogen, helium, and argon.
[0060] The tableting pressure in step 2) is 5-15 MPa;
[0061] The heat treatment temperature in step 2) is 200–300°C;
[0062] The heating rate in step 2) is 1–10 °C / min;
[0063] The heat treatment time in step 2) is 150–240 min.
[0064] The inert atmosphere in step 3) includes at least one of nitrogen, helium, and argon.
[0065] In step 3), the stirring speed is 200-300 rpm;
[0066] The stirring time in step 3) is 12-20 hours.
[0067] The inert atmosphere in step 4) includes at least one of nitrogen, helium, and argon.
[0068] The further drying time in step 4) is 10–16 hours;
[0069] The vacuum drying temperature in step 4) is 20–30°C.
[0070] The vacuum drying time in step 4) is 4 to 7 hours.
[0071] Example 1: Preparation of in-situ poly(1,3-dioxolane) solid electrolyte sample 1#
[0072] 1.143 g Li₂S, 1.605 g P₂S₅, and 0.2515 g SnF₂ in a molar ratio of 3.1:0.9:0.2 were placed in a ball mill jar (ball-to-material ratio 50:1). The mixture was pre-milled at 100 rpm for 1 hour, then ball-milled at 300 rpm for 10 hours. The resulting preform was cold-pressed (10 MPa) and placed in a quartz tube. The preform was heated to 210 °C at a heating rate of 5 °C / min for 4 hours. After cooling to room temperature, the solid electrolyte Li₂S₂ was obtained. 3.1 P 0.95 Sn 0.05 S 3.9 F0.1 0.57 g LiTFSI was dissolved in 2.0 g DOL, and then 0.027 g of ball-milled solid electrolyte was added as a catalyst. Polymerization was carried out by stirring at 200 rpm for 16 hours. The polymerized P-DOL was permeated into glass fiber or polypropylene fiber paper, and then further polymerized at room temperature for another 12 hours. Subsequently, it was vacuum dried at 25 °C for 4 hours to evaporate the unpolymerized DOL, yielding the in-situ poly(1,3-dioxolane) solid electrolyte, designated as sample 1#.
[0073] Example 2: Preparation of in-situ poly(1,3-dioxolane) solid electrolyte sample 2#
[0074] 1.143 g Li₂S, 1.605 g P₂S₅, and 0.2515 g SnF₂ in a molar ratio of 3.1:0.9:0.2 were placed in a ball mill jar (ball-to-material ratio 30:1). The mixture was pre-milled at 300 rpm for 2 hours, then ball-milled at 300 rpm for 10 hours. The resulting preform was cold-pressed (5 MPa) and placed in a quartz tube. The preform was heated to 200 °C at a rate of 1 °C / min from room temperature for 4 hours. After cooling to room temperature, the desired yield was obtained as a sulfide solid electrolyte, Li₂S. 3.1 P 0.95 Sn 0.05 S 3.9 F 0.1 0.57 g LiTFSI was dissolved in 2.0 g DOL, and then 0.036 g of ball-milled solid electrolyte was added as a catalyst. Polymerization was carried out by stirring at 300 rpm for 12 hours. The polymerized P-DOL was permeated into glass fiber or polypropylene fiber paper, and then further polymerized at room temperature for another 12 hours. Subsequently, it was vacuum dried at 20 °C for 4 hours to evaporate the unpolymerized DOL, thus obtaining the in-situ poly(1,3-dioxolane) solid electrolyte, designated as sample 2#.
[0075] Example 3: Preparation of in-situ poly(1,3-dioxolane) solid electrolyte sample #3
[0076] 1.143 g Li₂S, 1.605 g P₂S₅, and 0.2515 g SnF₂ in a molar ratio of 3.1:0.9:0.2 were placed in a ball mill jar (ball-to-material ratio of 20:1). The mixture was pre-milled at 100 rpm for 2 hours, then ball-milled at 500 rpm for 40 hours. The resulting preform was cold-pressed (15 MPa) and placed in a quartz tube. The preform was heated to 300 °C for 2.5 hours at a heating rate of 10 °C / min from room temperature. After cooling to room temperature, the desired yield was obtained as a sulfide solid electrolyte, Li₂S. 3.1 P 0.95 Sn 0.05 S 3.9 F 0.10.8 g LiTFSI was dissolved in 2.0 g DOL, and then 0.048 g of ball-milled solid electrolyte was added as a catalyst. Polymerization was carried out by stirring at 200 rpm for 20 hours. The polymerized P-DOL was permeated into glass fiber or polypropylene fiber paper, and then further polymerized at room temperature for another 12 hours. Subsequently, it was vacuum dried at 20 °C for 7 hours to evaporate the unpolymerized DOL, thus obtaining the in-situ poly(1,3-dioxolane) solid electrolyte, designated as sample 3#.
[0077] Example 4: Performance Testing of In-situ Poly(1,3-dioxolane) Solid Electrolyte Samples
[0078] A cathode slurry was prepared by mixing LiFePO4 and carbon black with PVDF at a weight ratio of 80:10:10 using NMP as a solvent. After coating the slurry onto aluminum foil, it was vacuum dried at room temperature for 6 hours and then transferred to a glove box for battery assembly.
[0079] Using the composite cathode material as the cathode and lithium foil as the anode, 2032 coin-type all-solid-state batteries were assembled using in-situ poly(1,3-dioxolane) solid electrolyte samples 1#, 2#, and 3# as electrolytes. The electrode sheets were cut into circular pieces with diameters of 18 mm, 16 mm, and 16 mm using a slicing machine, and sandwich-structured coin-type solid-state batteries were assembled. The assembled coin-type batteries were placed in an oven at 25°C for 12 hours. The AC impedance of the solid electrolyte was tested using a sandwich-structured solid-state battery assembled with a 16 mm diameter stainless steel sheet, and the solid electrolyte was tested using a long-cycle experiment at room temperature using a sandwich-structured solid-state battery assembled with a 16 mm diameter lithium metal sheet.
[0080] The results showed that the experimental results of samples 1#, 2# and 3# as electrolytes were similar.
[0081] Taking sample 1# prepared in Example 1 as a typical example, its impedance spectrum is as follows: Figure 1 As shown in the figure, the impedance is as low as 33.2Ω, indicating a low impedance result. Cyclic test results show that under a long-term cycling test at 0.5C, the capacitance retention is 80.1% after 300 stable cycles, demonstrating good cycling performance.
[0082] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.
Claims
1. A method for preparing an in-situ poly(1,3-dioxolane) solid electrolyte, characterized in that, The in-situ poly(1,3-dioxolane) solid electrolyte was prepared by in-situ initiating the polymerization reaction of 1,3-dioxolane using a sulfide solid electrolyte. The sulfide solid electrolyte is composed of Li 3+x P 1-x Sn x S 4-2x F 2x (0.05≤x≤0.2).
2. The preparation method according to claim 1, characterized in that, Includes the following steps: a) Prepared a composition of Li 3+x P 1-x Sn x S 4-2x F 2x (0.05≤x≤0.2) sulfide solid electrolyte; b) The lithium-containing compound is dissolved in 1,3-dioxolane and then mixed with the sulfide solid electrolyte obtained in step a); the resulting mixture is stirred and polymerized, then spread on a substrate for further polymerization, and then vacuum dried to obtain the in-situ poly(1,3-dioxolane) solid electrolyte.
3. The preparation method according to claim 2, characterized in that, Step a) includes: a1) Amorphous phase sulfide solid electrolyte material was obtained by high-energy ball milling of raw materials containing Li2S, P2S5 and SnF2. a2) The amorphous phase sulfide solid electrolyte material obtained in step a1) is subjected to tableting, heat treatment, and pulverization to obtain the sulfide solid electrolyte.
4. The preparation method according to claim 2, characterized in that, Both steps a) and b) are performed under a non-reactive atmosphere. The inactive atmosphere is selected from at least one of nitrogen and inert gases.
5. The preparation method according to claim 3, characterized in that, The conditions for high-energy ball milling described in step a1) are as follows: The high-energy ball mill speed is 400-600 r / min; The ball-to-material ratio for high-energy ball milling is 20:1 to 50:1; The high-energy ball milling time is 600–2400 min.
6. The preparation method according to claim 3, characterized in that, The pressure for compressing the tablet in step a2) is 5–15 MPa; The heat treatment conditions described in step a2) are as follows: The temperature is 200–300℃; The heating rate is 1–10 °C / min; The heat treatment time is 150–240 min.
7. The preparation method according to claim 2, characterized in that, The lithium-containing compound mentioned in step b) is lithium bis(trifluoromethanesulfonylimide); The substrate is glass fiber or polypropylene fiber paper.
8. The preparation method according to claim 2, characterized in that, The mass ratio of the lithium-containing compound, 1,3-dioxolane, and sulfide solid electrolyte in step b) is: 0.5～0.8：2～3.2：0.027～0.048。 9. The preparation method according to claim 2, characterized in that, The conditions for stirred polymerization described in step b) are: The stirring speed is 200-300 rpm, and the stirring time is 12-20 hours; The vacuum drying conditions in step b) are: The vacuum drying temperature is 20–30℃, and the vacuum drying time is 4–7 hours.
10. A fully solid-state lithium-ion battery, characterized in that, The in-situ poly(1,3-dioxolane) solid electrolyte is prepared by the method according to any one of claims 1 to 9.