Recyclable turing structure polymer electrolyte, preparation method and application thereof

Abstract

The application belongs to the technical field of energy storage, and relates to a recyclable Turing structure polymer electrolyte as well as a preparation method and application thereof. The electrolyte comprises a solvent, a hydrogen bond donor, a lithium salt and a polymer monomer. Under the condition that the relative humidity is 1% to 40%, the electrolyte forms a periodic Turing structure through evaporation / diffusion driven instability at a gas / liquid / solid interface, and the Turing structure is a three-dimensional continuous and through lithium ion transmission network. Through the ion self-enrichment region in the periodic Turing structure, the electrolyte significantly improves the ionic conductivity and ion transference number of the electrolyte. Meanwhile, the electrolyte has self-healing ability, can repair damage during use, and has good flame retardant effect, thereby improving the safety and stability of the battery. In addition, the electrolyte exhibits excellent recyclability, and main components thereof can be efficiently extracted and reused through a closed-loop recycling process, thereby reducing resource waste, reducing production cost, and reducing environmental burden.

Description

Technical Field

[0001] This invention belongs to the field of energy storage technology, and relates to a recyclable Turing structure polymer electrolyte, its preparation method, and its application. Background Technology

[0002] Compared to traditional liquid lithium batteries, solid-state lithium batteries offer comprehensive advantages in energy density, safety, and wide temperature range adaptability, and are widely considered a key development direction for next-generation energy storage technology. Among various solid electrolyte systems, polymer electrolytes are regarded as ideal materials for achieving high-energy-density solid-state batteries due to their excellent flexibility and thin-film processability. However, polymer electrolytes currently face several key bottlenecks, mainly including: low room-temperature ionic conductivity and low ion transference number due to limitations in polymer chain kinetics and anion co-migration; easy induction of interfacial polarization under high voltage / high areal load conditions, affecting battery cycle stability; and, due to the complexity of the material system, difficulty in achieving both large-scale preparation and recycling, severely restricting its commercialization process.

[0003] To address these challenges, researchers both domestically and internationally have proposed various modification strategies, such as polymer composition regulation, chain segment motion optimization, and functional filler composites, aiming to improve ion dissociation and migration efficiency. However, these methods generally face problems such as the difficulty in synergistically improving electrical conductivity and mechanical properties, and the limited improvement in migration number due to complex system architecture, making it difficult to achieve a systematic breakthrough in performance. In recent years, research has gradually focused on the regulatory role of polymer morphology on ion transport behavior. By constructing ordered or heterogeneous ion migration channels, continuous migration paths with low tortuosity can be achieved at the nanometer to micrometer scale, effectively reducing diffusion barriers and improving ion migration efficiency. Typical examples include: composite polymer electrolytes with regular pore / skeleton structures, polymer systems containing ordered stacking of helical peptides and hydrogen bond networks, and liquid crystal / rigid chain polymer materials with columnar, layered orientations, or containing nanocrystalline channels. The above research shows that "morphology engineering" has become an important means of optimizing the performance of polymer electrolytes, providing new ideas for their structural design.

[0004] Turing structures are instability mechanisms originating in reaction-diffusion systems, forming periodic self-organized patterns through the interaction of activators and inhibitors with significantly different diffusion coefficients under non-equilibrium conditions. Their formation is typically accompanied by spatial concentration fluctuations and periodic enrichment of key species within the system, manifesting as alternating high and low concentration regions at the microscopic scale. This highly ordered, periodically symmetrical structural feature has not only demonstrated excellent performance in water purification and electrocatalysis but has also been proven to have unique advantages in enhancing ion migration rates. Compared to traditional microphase-separated structures, Turing structures can construct more interconnected, ordered, and spatially symmetrical ion transport pathways, significantly reducing migration barriers and improving lithium-ion conductivity and migration efficiency, possessing great potential as structural templates for high-performance electrolytes. However, the formation conditions of Turing structures are quite demanding, relying on the precise control of various reaction-diffusion parameters. Their construction in polymer electrolyte systems is still in the preliminary exploration stage, and the related mechanisms and engineering feasibility require further systematic research. Summary of the Invention

[0005] To address the shortcomings of existing solid-state polymer electrolytes in terms of ionic conductivity, ion transference number, and recyclability, this invention provides a recyclable Turing-structured polymer electrolyte. This electrolyte significantly improves the ionic conductivity and ion transference number of electrolytes in solid-state batteries by introducing ion self-enrichment domains from the Turing structure, and solves the problem of poor recyclability of existing electrolyte materials through an efficient recycling process.

[0006] The technical solution provided by this invention is as follows: a recyclable Turing structure polymer electrolyte, comprising a solvent, a hydrogen bond donor, a lithium salt, and a polymer monomer; the electrolyte forms a periodic Turing structure through evaporation / diffusion-driven instability at the gas / liquid / solid interface under relative humidity of 1%-40%, the Turing structure being a three-dimensional continuous lithium-ion transport network.

[0007] Furthermore, the hydrogen bond donor is selected from any one or more of urea compounds, alcohol compounds, amide compounds, amino acids and their derivatives, phenolic compounds, phosphoric acid compounds, and polymeric hydrogen bond donors, in order to change the diffusion rate of polymeric oligomers / monomers.

[0008] Further, the urea compound is selected from any one or more of urea, N,N'-dimethylurea, and N,N'-bis(2-ethylamino)urea; the alcohol compound is selected from any one or more of ethylene glycol, glycerol, propylene glycol, 1,3-propanediol, 2-methyl-2,4-pentanediol, mannitol, and sorbitol; the amide compound is selected from acetamide or acrylamide, etc.; the phenolic compound is selected from phenol or 2,4-dimethylphenol, etc.; the phosphoric acid compound is selected from phosphoric acid or dimethyl phosphate, etc.; and the polymeric hydrogen bond donor is selected from polyvinylpyrrolidone or polyoxyethylene, etc.

[0009] Furthermore, the lithium salt is selected from any one or more of lithium bis(trifluoromethane)sulfonylimide (LiTFSI), lithium bis(fluorosulfonylimide) (LiFSI), lithium difluoro(oxalate)borate (LiDFOB), lithium dioxalateborate (LiBOB), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium chloride (LiCl), and lithium perchlorate (LiClO4) to ensure the ionic conductivity of the electrolyte.

[0010] Furthermore, the polymer monomer is selected from any one or more of lithium polythiooctanoate (TA-Li), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyvinyl chloride (PVC), polyurethane (PU), polyacrylonitrile (PAN), polyimide (PI), polyvinylidene fluoride (PVDF), and polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), which serve as the polymer backbone and undergo self-assembly to enhance the stability of the Turing structure.

[0011] Furthermore, the present invention provides a method for preparing the recyclable Turing structure polymer electrolyte, the method comprising: uniformly mixing a hydrogen bond donor, a lithium salt and a polymer monomer in a solvent at a mass ratio of (3-6):(0.5-2):(2-8); controlling the relative humidity at 1% − 40%; and forming a periodic Turing structure by driving instability through evaporation / diffusion.

[0012] Furthermore, the present invention also provides the application of the recyclable Turing structure polymer electrolyte in the preparation of energy storage systems, wherein the energy storage system is a solid-state lithium-ion battery, a solid-state lithium metal battery, a solid-state lithium-sulfur battery, or a solid-state sodium metal battery, etc.

[0013] Furthermore, the electrolyte can be processed using a closed-loop recycling process to recover polymer monomers and lithium salts.

[0014] The recyclable Turing structure polymer electrolyte of this invention has the following key technical features: First, the Turing structure design is the core of this invention. A periodic Turing structure is formed through evaporation / diffusion-driven instability at the gas / liquid / solid interface. This structure provides the polymer electrolyte with a highly efficient ion transport interface and channels, forming a three-dimensional, continuous, interconnected lithium-ion transport network. The periodic lithium-ion self-enrichment domains significantly reduce the lithium-ion migration barrier. Second, ionic conductivity and lithium-ion transference number are significantly improved. The Turing structure electrolyte, through self-assembly forming spatially ordered ion channels, greatly enhances its ionic conductivity and lithium-ion transference number, resulting in excellent electrochemical performance at room temperature, meeting the requirements of high-performance solid-state batteries. Furthermore, this electrolyte possesses self-healing capabilities and flame-retardant properties. During battery use, the electrolyte can self-repair when subjected to mechanical damage, exhibiting excellent structural recovery ability and reversibility. Simultaneously, under extreme conditions such as high temperature and high rate, the electrolyte exhibits good flame-retardant effects, thereby improving battery safety and lifespan. Regarding recyclability, the Turing structure polymer electrolyte of this invention employs an efficient recycling process. Through a closed-loop recycling process, most polymer monomers and lithium salts can be efficiently recovered, thereby reducing production costs, minimizing resource waste, and meeting the requirements of green environmental protection and sustainable development. Furthermore, low-temperature stability is another outstanding feature of this invention. The electrolyte maintains stable cycle performance at low temperatures, making it suitable for solid-state battery applications under low-temperature conditions, further broadening the application range of solid-state batteries.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] (1) First, by constructing ion self-enrichment domains through a periodic Turing structure, the ionic conductivity and lithium-ion transference number of the electrolyte are significantly improved, meeting the requirements of high-performance solid-state batteries. Simultaneously, the electrolyte possesses self-healing capabilities, capable of repairing damage during use, and exhibits good flame retardant properties, thereby enhancing the safety and stability of the battery. This electrolyte maintains stable electrochemical performance even at low temperatures, broadening the application range of solid-state batteries. This recyclable Turing structure polymer electrolyte is not only suitable for solid-state lithium batteries but can also be widely applied to various battery systems such as solid-state lithium-sulfur batteries and solid-state sodium batteries, demonstrating enormous market application potential.

[0017] (2) Regarding the recycling process, this invention utilizes a closed-loop recycling process, enabling the efficient extraction and reuse of the recovered polymer monomers and lithium salts. Through methods such as chemical hydrolysis and solvent purification, more than 80% of the polymer monomers and lithium salts can be recovered, achieving sustainable recycling of electrolyte materials; reducing resource waste, lowering production costs, and reducing environmental pollution. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the formation of the Turing structure in an embodiment of the present invention;

[0019] Figure 2 This is a scanning electron microscope image of the Turing-structured polymer electrolyte (TPE) in an embodiment of the present invention; wherein: a. without the addition of hydrogen bond donors, no periodic structure was formed at relative humidity of 60%, 20%, and 1%; b. after the addition of hydrogen bond donors, as the relative humidity decreased from 60% to 40%, 20%, 15%, and 1%, the structure gradually evolved from a non-Turing-structured polymer electrolyte (NTPE) to typical Turing patterns such as wavy-TPE, striped-TPE, and spotted-TPE; c. the relationship between evaporation rate and hydrogen bonding synergistically regulating the structural morphology;

[0020] Figure 3 The ionic conductivity of TPE in this embodiment of the invention includes: a. a comparison of conductivity of the four structural electrolytes at different temperatures; b. activation energies of ion migration in the four structural electrolytes; c. migration number of NTPE at room temperature; d. migration number of Striped-TPE at room temperature.

[0021] Figure 4 This invention relates to battery performance testing of TPE in this embodiment; wherein, a. capacity retention of the Striped-TPE-based battery after 1580 cycles at 0.5 C; b. cycle performance of the Striped-TPE-based battery at a low temperature of −20 °C;

[0022] Figure 5 This is a test of the self-healing and flame-retardant properties of TPE in this embodiment of the invention;

[0023] Figure 6 This is a schematic diagram of the TPE recycling process in an embodiment of the present invention. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0025] Example 1: The recyclable TPE provided in this example is prepared by the following method:

[0026] (1) The preparation method of TA-Li / LiTFSI solution is as follows: TA-Li solution and LiTFSI are mixed at a mass ratio of 10:3 and stirred evenly to form a homogeneous solution. In addition, ethylene glycol and urea are mixed at a mass ratio of 8:5 and stirred evenly to form a hydrogen bond donor solution;

[0027] (2) Then the TA-Li / LiTFSI solution and the hydrogen bond donor solution were mixed at a mass ratio of 1:1 and stirred for 1 hour to obtain the precursor solution of TPE;

[0028] (3) Finally, the precursor solution was cast onto a polytetrafluoroethylene evaporating dish and placed in a drying oven with controlled relative humidity (1%, 5%, 10%, 15%, 20%, 30%, 40% or 60%) to regulate the solvent evaporation process and induce the formation of different film morphologies. All films were ensured to be in a consistent environment before being transferred to an argon-filled glove box for characterization.

[0029] Example 2: Scanning electron microscopy characterization of the electrolyte prepared in Example 1.

[0030] Figure 2 The surface morphology of TPE under different humidity conditions is shown. The results indicate that the synergistic regulation of relative humidity (RH) and hydrogen bond donors has a decisive influence on the formation of the Turing structure. Without the introduction of hydrogen bond donors and only adjusting RH, a periodic structure failed to form; with the introduction of hydrogen bond donors and at 60% RH, the film surface was smooth and NTPE was formed, as shown in the image. Figure 2 As shown in Figure a, when the RH decreases from 40% to 1%, the solvent evaporation rate accelerates, gradually forming typical Turing patterns such as wavy (40%, Wavy-TPE), striped (20%, Striped-TPE), and spotted (1%, Spotted-TPE), as shown in Figure a. Figure 2 As shown in Figures b and c, the experiment verified the controllable synthesis of Turing structures by regulating environmental parameters and intermolecular interactions.

[0031] Example 3: Ionic conductivity and transport number test of the electrolyte prepared in Example 1

[0032] Figure 3 The ionic conductivity of various TPEs and traditional NTPEs under different RH conditions was demonstrated. The test results show that Striped-TPE exhibits higher ionic conductivity at room temperature (1.6 × 10⁻⁶). −3 Its conductivity (S / cm) and lithium-ion transference number (0.61) are significantly better than those of traditional NTPE (conductivity 6.5 × 10⁻⁶). −4S / cm, with a migration number of 0.52). Arrhenius analysis showed that the Turing structure lowered the activation energy for lithium-ion migration, verifying the effectiveness of the synergistic mechanism of "periodic structure + ion enrichment" in improving electrolyte performance.

[0033] Example 4: Performance testing of the battery assembled using the electrolyte prepared in Example 1

[0034] Figure 4 The cycling performance of solid-state LiTi2(PO4)3||LiMn2O4 (LTPO||LMO) batteries fabricated using Striped-TPE and conventional NTPE at room temperature and low temperature (−20 °C) was demonstrated. Test results show that the Striped-TPE-based battery retains 80.7% of its capacity after 1580 cycles at 0.5C. Figure 4 As shown in Figure a, it significantly outperforms NTPE-based cells (which retain 61.5% capacity after 1100 cycles). Even at a low temperature of −20 °C, the Striped-TPE-based cell maintains stable cycle performance, retaining 85.0% capacity after 86 cycles. Figure 4 As shown in Figure b, its excellent performance under extreme conditions is demonstrated.

[0035] Example 5: Self-healing and flame-retardant performance tests of the electrolytes prepared in Example 1

[0036] Figure 5 Figure a demonstrates the self-healing process of TPE after mechanical damage. The electrolyte membrane, after being cut in half, can recover its original shape. The recovered membrane still possesses high strength, capable of withstanding a 10 g weight without breaking, proving the excellent self-healing ability of the Turing structure. Furthermore, this TPE also exhibits flame-retardant properties, effectively inhibiting the spread of fire under extreme conditions such as high temperature and high magnification. Figure 5 As shown in b.

[0037] Example 6, Schematic diagram of the electrolyte recovery process prepared in Example 1

[0038] Figure 6 A closed-loop recycling process for recyclable TPE was demonstrated. The process involves promoting electrolyte hydrolysis with lithium hydroxide solution, extracting polymer monomers (TA-Li) using dichloromethane, and then recovering lithium salts (LiTFSI) through an acidification process, ultimately restoring the electrolyte to its initial performance. This process can recover over 80% of the polymer monomers and lithium salts, and the regenerated electrolyte exhibits performance comparable to the original electrolyte, allowing for multiple recycling cycles, thereby reducing resource waste and environmental burden.

Claims

1. A recyclable Turing-structured polymer electrolyte, characterized in that, The polymer electrolyte is prepared from a solvent, a hydrogen bond donor, a lithium salt, and lithium polythiooctanoate. The hydrogen bond donor, lithium salt, and lithium polythiooctanoate are mixed uniformly in the solvent according to the mass ratio. Under the condition of relative humidity of 1%-40%, the instability driven by evaporation / diffusion at the gas / liquid / solid interface forms a periodic Turing structure, which is a three-dimensional continuous lithium-ion transport network.

2. The recyclable Turing-structured polymer electrolyte according to claim 1, characterized in that, The hydrogen bond donor is selected from any one or more of urea compounds, alcohol compounds, amide compounds, amino acids and their derivatives, phenolic compounds, phosphoric acid compounds, and polymeric hydrogen bond donors.

3. The recyclable Turing-structured polymer electrolyte according to claim 2, characterized in that, The urea compound is selected from any one or more of urea, N,N'-dimethylurea, and N,N'-bis(2-ethylamino)urea; the alcohol compound is selected from any one or more of ethylene glycol, glycerol, propylene glycol, 1,3-propanediol, 2-methyl-2,4-pentanediol, mannitol, and sorbitol; the amide compound is selected from acetamide or acrylamide; the phenolic compound is selected from phenol or 2,4-dimethylphenol; the phosphoric acid compound is selected from phosphoric acid or dimethyl phosphate; and the polymeric hydrogen bond donor is selected from polyvinylpyrrolidone or polyoxyethylene.

4. The recyclable Turing-structured polymer electrolyte according to claim 1, characterized in that, The lithium salt is selected from any one or more of lithium bis(trifluoromethane)sulfonylimide lithium, bis(fluorosulfonylimide) lithium, difluoro(oxalate)borate lithium, dioxalateborate lithium, lithium hexafluorophosphate lithium, tetrafluoroborate lithium, lithium chloride, and lithium perchlorate.

5. The method for preparing the recyclable Turing-structured polymer electrolyte according to any one of claims 1-4, characterized in that, include: In a solvent, hydrogen bond donors, lithium salts and lithium polythiooctanoate are mixed uniformly in a mass ratio of (3-6):(0.5-2):(2-8); the relative humidity is controlled at 1%-40%, and periodic Turing structures are formed by evaporation / diffusion-driven instability.

6. The application of the recyclable Turing structure polymer electrolyte according to any one of claims 1-4 in the preparation of energy storage systems, characterized in that, The energy storage system is a solid-state lithium-ion battery, a solid-state lithium metal battery, a solid-state lithium-sulfur battery, or a solid-state sodium metal battery.

7. The application according to claim 6, characterized in that, The electrolyte is processed using a closed-loop recycling process to recover lithium polythiooctanoate and lithium salts.

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