In-situ polyelectrolyte as well as preparation method and application thereof
By using Sn-Beta molecular sieve initiators for in-situ polymerization in lithium-ion batteries, an in-situ polymerized electrolyte is formed, which solves the problems of interfacial contact and ionic conductivity of solid electrolytes and improves the cycle performance and stability of lithium metal batteries.
Patent Information
- Application Number
- CN202511136875.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-14
- Publication Date
- 2025-12-09
AI Technical Summary
Existing solid electrolytes cannot simultaneously possess excellent interfacial contact performance and high ionic conductivity in lithium-ion batteries, resulting in obstructed lithium-ion transport and affecting battery performance.
Using Sn-Beta molecular sieve as an initiator, an in-situ polymerized electrolyte is formed by in-situ polymerization of a mixed solution of lithium bis(trifluoromethanesulfonyl)imide and lithium difluoroborate at room temperature. This combines the advantages of inorganic solid electrolytes and polymers, thereby improving interfacial contact performance and ionic conductivity.
It significantly improves the cycle performance and stability of lithium metal batteries, with a specific capacity of 160.91 mAh·g-1 after 100 cycles, which is better than the electrolyte without Sn-Beta molecular sieve, thus improving the overall performance of the battery.
Smart Images
Figure CN121097191A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of in-situ polymerization electrolyte, and more particularly to an in-situ polymerization electrolyte, a preparation method and application thereof. BACKGROUND
[0002] The growing energy consumption has aroused widespread interest in energy storage and flexible energy conversion. The application demand of lithium ion batteries (LIBs) is experiencing unprecedented growth, and its application field is expanding from daily portable electronic devices to large-scale energy storage systems, showing its amazing potential as an energy storage solution. However, the current traditional LIBs also face many challenges in the growing demand, mainly including the bottleneck of energy density (about 300 Wh / kg) and the safety risk brought by the use of flammable liquid electrolyte. To effectively overcome these technical difficulties, solid-state batteries (SSBs) emerge as an innovative solution, which use in-situ polymerization electrolyte (SSE) to match with lithium (Li) metal anode. This design not only hopes to break through the existing upper limit of energy density, but also greatly reduces the safety risk caused by the flammability of liquid electrolyte, opening up a new way for the future development of lithium ion battery technology. All the time, the interface problem between SSE and electrode is one of the key difficulties hindering the commercialization process of SSB. Poor contact between SSE and electrode leads to large interface impedance, which hinders the effective transmission of lithium ions and seriously weakens the overall performance of the battery.
[0003] In-situ polymerization as a very potential method for preparing SSE shows significant advantages in processing and cost. Due to its unique advantage of converting liquid monomers into solid polymers under specific conditions, it effectively solves the problem of poor interface contact between in-situ polymerization electrolyte and solid-state electrode. However, its inherent low ionic conductivity limits its wide application. SUMMARY
[0004] The present application provides an in-situ polymerization electrolyte, a preparation method and application thereof, to solve the problem that the existing solid-state electrolyte cannot have excellent interface contact performance and ionic conductivity performance.
[0005] In the first aspect, the present application provides an in-situ polymerization electrolyte, which is obtained by the way of DOL in-situ polymerization based on Sn-Beta molecular sieve initiator.
[0006] As a possible implementation manner, its ionic conductivity at room temperature is 8.35 x 10 -4 S·cm -1 .
[0007] In a second aspect, the present invention provides a method for preparing the in-situ polymeric electrolyte according to any possible implementation of the first aspect, characterized by comprising the following steps: mixing and stirring lithium bis(trifluoromethanesulfonyl)imide and lithium difluoroborate in 1,3-dioxolane to obtain a mixed solution; adding Sn-Beta molecular sieve initiator to the mixed solution and stirring evenly to obtain a precursor solution; assembling a battery using the precursor solution as an electrolyte and placing it in a sealed container at room temperature to form the in-situ polymeric electrolyte.
[0008] As one possible implementation, the Sn-Beta molecular sieve in the precursor solution has a mass fraction of 1 wt% to 5 wt%.
[0009] As one possible implementation, the Sn-Beta molecular sieve has a mass fraction of 1 wt% in the precursor solution.
[0010] As one possible implementation, the time for which the room temperature is sealed is 24 hours.
[0011] As one possible implementation, the concentration of lithium bis(trifluoromethanesulfonyl)imide in the precursor solution is 1-2 mol / L; and / or, the concentration of lithium difluoroborate in the precursor solution is 0.1-0.2 mol / L.
[0012] Thirdly, the present invention provides a solid-state lithium metal battery, comprising the in-situ polymerized electrolyte described in any possible implementation of the first aspect.
[0013] As one possible implementation, the preparation method includes the steps of assembling a negative electrode shell, a positive electrode, an electrolyte, a separator, an electrolyte, a negative electrode (lithium metal sheet), a gasket, a spring sheet, and a positive electrode shell; wherein the electrolyte is an in-situ polymerized electrolyte as described in any possible implementation of the first aspect.
[0014] Compared with the prior art, the present invention can achieve the following beneficial effects:
[0015] The in-situ polymerization electrolyte provided by this invention is applied to solid-state lithium metal batteries, which significantly improves the cycle performance of the in-situ polymerization electrolyte that initiates DOL polymerization, and effectively solves the problems of short cycle life and poor cycle performance of solid-state lithium metal batteries.
[0016] A coin half-cell using the in-situ polymerized electrolyte provided by this invention, after activation at 0.1C for 2 cycles and then cycling at 0.5C for 100 cycles, exhibits a specific capacity of 160.91 mAh·g. -1 It exhibits excellent cycling stability, while the electrolyte without Sn-Beta molecular sieve retains a capacity of 151.78 mAh·g after 100 cycles at 0.5C.-1 This clearly demonstrates the significant improvement effect of the present invention.
[0017] The preparation method of this invention is simple, the materials are readily available, and it is convenient for large-scale industrial production. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 This is a schematic diagram of the curing of a solid polymer electrolyte provided in an embodiment of the present invention.
[0020] Figure 2 X-ray diffraction patterns of Sn-Beta molecular sieves, PL-Sn-Beta-1, PL-Sn-Beta-3 and PL-Sn-Beta-5 provided in the embodiments of the present invention.
[0021] Figure 3 The BET diagram of the Sn-Beta molecular sieve provided in the embodiments of the present invention.
[0022] Figure 4 The image shows an SEM image of the Sn-Beta molecular sieve provided in an embodiment of the present invention.
[0023] Figure 5 TEM image of Sn-Beta molecular sieve provided in an embodiment of the present invention.
[0024] Figure 6 The HAADF-STEM and elemental mapping diagram of Sn-Beta molecular sieve provided in the embodiments of the present invention.
[0025] Figure 7 The charge / discharge performance diagram of the Li / PL-Sn-Beta-1 / LFP battery provided in the embodiments of the present invention.
[0026] Figure 8 Battery cycle performance diagrams for Li / PL-Sn-Beta-1 / LFP, Li / PL-Sn-Beta-3 / LFP, Li / PL-Sn-Beta-5 / LFP and Li / LE / LFP batteries provided in embodiments of the present invention. Detailed Implementation
[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and 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.
[0028] To address the problem that solid electrolytes in the prior art cannot simultaneously possess excellent interfacial contact performance and ionic conductivity, this invention provides an experimental preparation and performance testing method for an in-situ polymerized electrolyte.
[0029] This invention relates to an in-situ polymeric electrolyte for DOL polymerization based on a molecular sieve initiator. The in-situ polymeric electrolyte is produced by adding Sn-Beta molecular sieve to DOL, causing it to polymerize. The Sn-Beta molecular sieve serves not only as a filler but also as an initiator for DOL polymerization. This combination of the advantages of inorganic solid electrolytes and polymeric in-situ polymeric electrolytes improves the cycling stability of this in-situ polymeric electrolyte.
[0030] The technical solution of the present invention will be further described below with reference to specific embodiments.
[0031] Example 1
[0032] This embodiment provides an experiment for the preparation of an in-situ polymeric electrolyte.
[0033] LiTFSI and LiDFOB were added to DOL liquid and stirred until homogeneous. Then, Sn-Beta molecular sieve was added to obtain the precursor solution. The ratio was: LiTFSI concentration was 1.9M, LiDFOB concentration was 0.1M, and Sn-Beta molecular sieve accounted for 1wt% of the total mass of the precursor solution.
[0034] 80 wt% active material (LFP), 10 wt% binder (PVDF) and 10 wt% conductive additive (SP) are uniformly dispersed in NMP solution and stirred at a constant speed to obtain a slurry; the obtained slurry is coated onto aluminum foil using a scraper, transferred to an oven to dry, and cut into 10 mm diameter discs, i.e. lithium metal discs, and stored in a glove box for later use.
[0035] Coin cells were assembled using the prepared precursor solution. The assembly process was as follows: CR2032 coin cells were assembled in the following order: negative electrode shell, positive electrode, electrolyte, separator, electrolyte (prepared precursor solution), negative electrode (prepared lithium metal sheet), gasket, spring sheet, and positive electrode shell. After assembly, the cells were placed at room temperature for 24 hours to allow the precursor solution to gradually polymerize under the action of the initiator. The resulting cells were named Li / PL-Sn-Beta-1 / LFP cells.
[0036] Example 2
[0037] The difference from Example 1 is that Sn-Beta molecular sieve accounts for 3 wt% of the total mass.
[0038] The resulting battery was named Li / PL-Sn-Beta-3 / LFP battery.
[0039] Example 3
[0040] The difference from Example 1 is that Sn-Beta molecular sieve accounts for 5 wt% of the total mass.
[0041] The resulting battery was named Li / PL-Sn-Beta-5 / LFP battery.
[0042] Comparative Example 1
[0043] The difference from Example 1 is that the concentration of LiTFSI is 1.8M, the concentration of LiDFOB is 0.2M, and Sn-Beta molecular sieve is not added.
[0044] The resulting battery was named a Li / LE / LFP battery.
[0045] Experimental Example 1
[0046] This experimental example provides characterization and testing experiments.
[0047] Figure 1 This is a schematic diagram of the solidification of the polymer electrolyte, where the left side is the mixed solution without Sn-Beta molecular sieve (Comparative Example 1), and the right side is the precursor solution of Example 1. Figure 1 As shown, the electrolyte prepared in Comparative Example 1 is transparent, while the electrolyte in Example 1 is white and has low transparency after polymerization.
[0048] Figure 2 The X-ray photoelectron spectrum of Sn-Beta molecular sieves is shown below. Figure 2 As shown, Sn-Beta molecular sieves exhibit high crystallization peaks at 7.64° and 22.36°. Observations revealed that with increasing amounts of Sn-Beta molecular sieve added to the electrolyte, the characteristic peak of Sn-Beta molecular sieves at 22.36° was enhanced in Examples 2 and 3.
[0049] like Figure 3 As shown, the BET diagram of Sn-Beta molecular sieve, namely the nitrogen adsorption-desorption isotherm and pore size distribution, indicates that the surface area of Sn-Beta molecular sieve is 471.39 m². 2 ·g -1It has a large contact area with the monomer DOL, and the pore size of 1.56 nm is larger than the diameter of TFSI- anion (0.79 nm), which can more effectively capture and adsorb TFSI- anion.
[0050] like Figure 4 As shown, the SEM image of Sn-Beta molecular sieve reveals a large number of interparticle voids due to disordered aggregation.
[0051] like Figure 5 and Figure 6 As shown, the TEM image of Sn-Beta molecular sieve can clearly capture the lattice of Sn-Beta molecular sieve crystal planes, and the mapping diagram shows that the elements of Sn-Beta molecular sieve are uniformly distributed inside it, especially Sn atoms are also uniformly distributed inside Sn-Beta molecular sieve.
[0052] Based on these experimental results, it has been demonstrated that Sn-Beta molecular sieves can initiate DOL polymerization; have a large contact area with monomer DOL, which can more effectively capture and adsorb TFSI- anions; generate a large number of interparticle voids; and have Sn atoms uniformly distributed inside Sn-Beta molecular sieves.
[0053] The electrolytes from Examples 1, 2, and 3, and the electrolyte from Comparative Example 1, were used in lithium metal batteries and their electrochemical performance was tested.
[0054] like Figure 7 As shown, the charge-discharge performance of the Li / PL-Sn-Beta-1 / LFP battery at 25℃ was measured. After Sn-Beta molecular sieve was added to the electrolyte as an initiator, the Li / PL-Sn-Beta-1 / LFP battery showed a stable charge-discharge curve in 25 cycles, and the capacity loss was negligible.
[0055] like Figure 8 As shown, the cycling performance of the electrolytes of Examples 1, 2, and 3, and the electrolyte of Comparative Example 1, was measured at 0.5C. The initial specific capacity of Comparative Example 1 reached 160.58 mAh·g at 0.5C. -1 However, after 100 cycles, it only has 151.78 mAh·g. -1 Specific capacity; Example 2 shows that the initial specific capacity reaches 152.3 mAh·g at 0.5C. -1 However, after 100 cycles, it has 127.98 mAh·g. -1 Specific capacity; Example 3 shows that the initial specific capacity reaches 156.89 mAh·g at 0.5C. -1 However, after 100 cycles, the energy content is 13.21 mAh·g. -1Specific capacity; Example 1: The initial specific capacity reached 163 mAh·g at 0.5C. -1 After 100 cycles, there is still 160.91 mAh·g remaining. -1 The specific capacity is significantly higher. Therefore, the cycling performance of Example 1 at 0.5C is far superior to that of Comparative Example 1, Example 2, and Example 3 in terms of both initial capacity and number of cycles.
[0056] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.
[0057] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. An in-situ polymeric electrolyte, characterized in that, It was obtained by in-situ polymerization of DOL based on Sn-Beta molecular sieve initiator.
2. The in-situ polymeric electrolyte according to claim 1, characterized in that, Its ionic conductivity at room temperature is 8.35 × 10⁻⁶. -4 S·cm -1 .
3. A method for preparing the in-situ polymeric electrolyte according to any one of claims 1 to 2, characterized in that, Includes the following steps: Lithium bis(trifluoromethanesulfonyl)imide and lithium difluoroborate were mixed and stirred in 1,3-dioxolane to obtain a mixed solution; Sn-Beta molecular sieve initiator was added to the mixed solution and stirred evenly to obtain a precursor solution; The precursor solution is used as an electrolyte to assemble a battery, which is then placed in a sealed container at room temperature to form the in-situ polymerized electrolyte.
4. The preparation method according to claim 3, characterized in that, In the precursor solution, the mass fraction of the Sn-Beta molecular sieve is 1 wt%.
5. The preparation method according to claim 3, characterized in that, The time for which the product is placed in a sealed container at room temperature is 24 hours.
6. The preparation method according to claim 3, characterized in that, In the precursor solution, the concentration of lithium bis(trifluoromethanesulfonyl)imide is 1–2 mol / L; And / or, in the precursor solution, the concentration of lithium difluoroborate is 0.1–0.2 mol / L.
7. A solid-state lithium metal battery, characterized in that, Includes the in-situ polymeric electrolyte as described in any one of claims 1 to 2.
8. The solid-state lithium metal battery according to claim 7, characterized in that, Its preparation method includes the following steps: assembly of negative electrode shell, positive electrode, electrolyte, separator, electrolyte, negative electrode (lithium metal sheet), gasket, spring and positive electrode shell; The electrolyte is the in-situ polymerized electrolyte according to any one of claims 1 to 2.