An amorphous chalcogenide solid electrolyte, its preparation method, and its application in all-solid-state sodium batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-23
- Publication Date
- 2026-08-14
AI Technical Summary
[0008]本发明旨在解决现有晶态氧族卤化物固体电解质中Na+迁移势垒高、室温电导率低、界面稳定性差等问题，提供一种基于多阴离子无序骨架的非晶固体电解质及其简便制备方法
[0025]（1）超高离子传导：x=0.5时室温电导率达8.83×10−3 S·cm−1，接近液态电解质，活化能仅0.27 eV；
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Figure CN122576358A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of all-solid-state sodium battery (ASSSBs) technology, and relates to an amorphous oxohalide solid electrolyte, its preparation method, and its application in all-solid-state sodium batteries. Specifically, it relates to a method based on multiple anions (O2O3) 2− S 2− Cl - ,Br - I - The high-dimensional disordered structure of amorphous oxohalide superionic conductors, constructed by the joint efforts of [unclear], their mechanochemical preparation method, and their application in high-voltage, long-cycle all-solid-state sodium batteries. Background Technology
[0002] All-solid-state sodium batteries have become an ideal choice for large-scale energy storage due to their high safety and the low cost of sodium resources. Solid electrolytes are the core of all-solid-state batteries, and halide systems (such as chlorides, bromides, and iodides) have become core candidate materials for all-solid-state sodium batteries due to their advantages such as a wide electrochemical window, excellent mechanical flexibility, and the ability to be prepared by room-temperature mechanical ball milling. However, crystalline halide electrolytes have inherent drawbacks:
[0003] (1) Close-packed Cl - The skeleton makes Na + It can only transition between octahedral sites, and the transport path is a high-energy triangular coordination path, resulting in an extremely high ion migration barrier.
[0004] (2) The long-range ordered crystal structure enables the anionic framework to support Na + Strong Coulomb binding is generated, limiting the migration rate;
[0005] (3) Traditional heterovalent doping can only adjust Na + The vacancy concentration is insufficient to lower the intrinsic thermodynamic migration barrier, resulting in room temperature ionic conductivity generally below 10. −4 S·cm −1 However, this is far from meeting the requirements for practical application.
[0006] Recent studies have found that introducing anions with high polarizability (such as Br₂) can... - I - S 2− While ion exchange can effectively soften the lattice and reduce the migration barrier, the periodic barrier of crystalline materials remains difficult to completely eliminate. Therefore, constructing amorphous solid electrolytes that combine long-range disorder and short-range order and achieve synergistic regulation by multiple anions can break the ordered constraints of crystalline lattices, reduce the intrinsic migration barrier of ions, and build multidimensional continuous ion transport channels, becoming an important research direction for overcoming the bottleneck of room-temperature ionic conductivity.
[0007] In view of the above problems, this invention is proposed. Summary of the Invention
[0008] This invention aims to solve the problem of Na in existing crystalline chalcogenide solid electrolytes. + To address issues such as high migration barriers, low room temperature conductivity, and poor interface stability, this paper proposes an amorphous solid electrolyte based on a multi-anion disordered framework and its simple preparation method.
[0009] The first objective of this invention is to provide an amorphous chalcogenide solid electrolyte, the chemical composition of which includes sodium, at least one metal element selected from Ta and Nb, and at least two anions selected from Groups VI and VII; the solid electrolyte is amorphous, lacks a long-range ordered structure, and its local coordination environment exhibits disordered characteristics, with the general chemical formula NaMX. 6–2x Y x (M=Ta, Nb, etc., X=F, Cl, Br, I, etc., Y=S, O, Se, etc.).
[0010] Preferably, the anion is a combination of a halide ion and a Group 6 ion.
[0011] Using the above technical solution, the amorphous oxohalide solid electrolyte contains Na, at least one high field strength metal element (Ta, Nb, etc.), and at least two elements selected from O. 2− S 2− Cl - ,Br - I - The electrolyte is amorphous, lacking a long-range periodic lattice, and its short-range coordination environment (such as metal-anion bond length and coordination number) exhibits a broad distribution, i.e., short-range disorder. This dual disorder of long-range and short-range disorder, combined with large-volume, highly polarizable anions (such as Br₂), creates a highly polarizable electrolyte. - I - S 2− The combined effect of these factors can significantly weaken the Coulomb binding of sodium ions to the anionic framework, providing multidimensional low-barrier migration channels. The core mechanism is that the "paddle wheel effect" of the polyanionic framework rapidly weakens the inter-octahedral Na⁺ migration barrier, and the dual-scale disorder of amorphization and oxo group doping constructs multidimensional low-barrier transport channels.
[0012] A second objective of this invention is to provide a method for producing the aforementioned amorphous oxohalide solid electrolyte, comprising the following steps:
[0013] Sodium source, halogen source, sulfur source and / or oxygen source are mixed in a preset ratio (1:1:0.4-0.8) and subjected to high-energy mechanical ball milling under an inert atmosphere to directly obtain an amorphous solid electrolyte; the ball milling process is carried out at room temperature or 25-30°C, without the need for subsequent high-temperature crystallization treatment.
[0014] Preferably, the sodium source is one or more of NaCl, NaBr, NaI, Na2S, Na2O, and Na2O2; the metal source is one or more of TaCl5, NbCl5, Ta2O5, and Nb2O5; the halogen source is a metal halide or an alkali metal halide; the sulfur source is Na2S; and the oxygen source is an oxide or a peroxide.
[0015] Preferably, the high-energy mechanical ball mill uses a ZrO2 sealed ball mill jar as the wear-resistant ball milling medium, with a ball-to-material ratio of 20:1, and the ball milling speed and time are set to conditions sufficient to allow the precursor to undergo a mechanochemical reaction and achieve complete amorphization. The ball milling parameters are: ball milling at 500 rpm for 24 h, and the entire process is carried out in an argon glove box with a water and oxygen content of <0.5 ppm, without high-temperature annealing treatment.
[0016] Using the above-mentioned technical solution, compounds containing sodium, metals, halogens, and oxalates are used as precursors. High-energy mechanical ball milling is employed under an argon atmosphere. During the ball milling process, the precursors undergo repeated cold welding and fracture, resulting in a mechanochemical solid-state reaction that directly generates an amorphous product in one step. The anionic composition can be flexibly controlled by adjusting the type and proportion of the precursors. The ball milling conditions (500 rpm, 24 h, ball-to-material ratio of 20:1) are selected to ensure complete amorphization of the product, eliminating the need for subsequent high-temperature treatment.
[0017] A third objective of this invention is to provide the application of the aforementioned amorphous chalcogenide solid electrolyte in all-solid-state sodium batteries.
[0018] Preferably, the all-solid-state sodium battery includes a composite positive electrode, a negative electrode, a negative electrode electrolyte layer, and a positive electrode electrolyte layer; the positive electrode electrolyte layer or at least one electrolyte layer is the amorphous oxohalide solid electrolyte.
[0019] Preferably, the composite cathode comprises doped Na(Ni) 1 / 3 Fe 1 / 3 Mn 1 / 3 The cathode active material is O2 or Na3V2(PO4)3, the amorphous oxohalide solid electrolyte and the conductive agent (Super P, KB, MXene, VGCF); the anode is a sodium-tin alloy; the anode electrolyte layer is a sulfide solid electrolyte Na3PS4.
[0020] Preferably, in charge-discharge cycle tests, the all-solid-state sodium battery exhibits a capacity retention rate of 85.7% at room temperature and 0.2C for 550 cycles, with an average coulombic efficiency of approximately 99.99%, demonstrating stable cycle performance and high capacity retention. It also has low interfacial impedance and no significant side reaction products generated after cycling.
[0021] Using the above technical solution, the aforementioned all-solid-state sodium battery includes the aforementioned amorphous oxohalide solid electrolyte as the electrolyte layer. The battery configuration can adopt a design where the positive electrode electrolyte layer and the negative electrode electrolyte layer are separate to accommodate different electrode materials.
[0022] Battery configuration: Na(Ni) 1 / 3 Fe 1 / 3 Mn 1 / 3 O2 (or NVP)|| NaMX 6–2x Y x || Na3PS4 || Na-Sn;
[0023] Key design: Na3PS4 is used as the negative electrode isolation layer to avoid side reactions between the electrolyte and the negative electrode and improve interface stability.
[0024] The beneficial effects of this invention are:
[0025] (1) Ultra-high ion conductivity: The room temperature conductivity reaches 8.83×10 at x=0.5. −3 S·cm −1 It is close to a liquid electrolyte, with an activation energy of only 0.27 eV;
[0026] (2) Wide electrochemical window: The upper limit of oxidation stability is 4.2 V (vs Na9Sn4), which can be matched with high-voltage layered oxide cathodes;
[0027] (3) Long-term cycling stability: 85.7% capacity retention after 550 cycles at 0.2 C, high surface loading (20 mg·cm³). −2 It still cycles stably for 200 revolutions.
[0028] (4) Easy to scale up preparation: room temperature mechanical ball milling, no high temperature sintering, simple process, low cost and environmentally friendly;
[0029] (5) Excellent interface stability: The amorphous structure is in close contact with the electrode, and there are no obvious interface side reactions or structural collapse after cycling.
[0030] (6) This invention utilizes multiple anions (O 2− S 2− Cl - ,Br - I - The combination of these elements allows for the construction of strongly distorted, low-symmetry Na+ structures in an amorphous matrix. + The coordination environment significantly reduces the migration activation energy, and the amorphous structure eliminates grain boundary resistance, forming a tight solid-solid contact with the electrode material and reducing interfacial impedance. Attached Figure Description
[0031] Figure 1This describes the synthetic route for sodium-based oxychloride solid electrolytes.
[0032] Figure 2 In the figure, Figure (a) shows the XRD patterns of amorphous and crystalline electrolytes; Figure (b) shows the XRD patterns of NaTaO. x Cl 6–2x XRD patterns with different oxygen contents.
[0033] Figure 3 NaTaO x Cl 6–2x Schematic diagram of the main structural units.
[0034] Figure 4 In the middle, Figure (a) shows NaTaO 0.5 SEM and particle size distribution of Cl5 solid electrolyte; Figure (b) shows elemental mapping.
[0035] Figure 5 NaTaO x Cl 6–2x Correlation diagram of ion conduction performance of solid electrolytes.
[0036] Figure 6 In the figure, Figure (a) shows the charge-discharge curves with different number of cycles; Figure (b) shows the rate performance; and Figure (c) shows the long-cycle performance.
[0037] Figure 7 In the figure, (a) is the NaTaCl6 Nyquist plot; (b) is the Arrhenius plot. Detailed Implementation
[0038] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.
[0039] An amorphous chalcogenide solid electrolyte, the chemical composition of which includes sodium, at least one metal element selected from Ta and Nb, and at least two anions selected from Groups VI and VII; the solid electrolyte is amorphous, does not have a long-range ordered structure, and its local coordination environment exhibits disordered characteristics.
[0040] In some embodiments, the anion is a combination of a halide ion and a Group 6 ion.
[0041] The above-mentioned method for producing amorphous oxalide solid electrolytes includes the following steps:
[0042] Sodium source, halogen source, and sulfur source and / or oxygen source are mixed in a ratio of 1:1:0.4-0.8 and subjected to high-energy mechanical ball milling under an inert atmosphere to directly obtain an amorphous solid electrolyte. The ball milling process is carried out at room temperature or a controllable temperature, without the need for subsequent high-temperature crystallization treatment. The specific synthesis route is as follows: Figure 1 As shown.
[0043] In some embodiments, the sodium source is one or more of NaCl, NaBr, NaI, Na2S, Na2O, and Na2O2.
[0044] In some embodiments, the metal source is one or more of TaCl5, NbCl5, Ta2O5, and Nb2O5.
[0045] In some embodiments, the halogen source is a metal halide or an alkali metal halide.
[0046] In some embodiments, the sulfur source is Na2S.
[0047] In some embodiments, the oxygen source is an oxide or a peroxide.
[0048] In some embodiments, the high-energy mechanical ball milling uses a ZrO2 sealed ball milling jar as the wear-resistant ball milling medium, and the ball milling parameters are 500 rpm for 24 h, which is sufficient to cause the precursor to undergo a mechanochemical reaction and become completely amorphous. The ball milling is carried out entirely in an argon glove box with a water and oxygen content of <0.5 ppm, without high-temperature annealing treatment.
[0049] The above-mentioned amorphous chalcogenide solid electrolytes are used in all-solid-state sodium batteries.
[0050] In some embodiments, the all-solid-state sodium battery includes a composite positive electrode, a negative electrode, a negative electrode electrolyte layer, and a positive electrode electrolyte layer; the positive electrode electrolyte layer or at least one electrolyte layer is the aforementioned amorphous oxohalide solid electrolyte.
[0051] In some embodiments, the composite cathode comprises doped Na(Ni) 1 / 3 Fe 1 / 3 Mn 1 / 3 The cathode active material is O2 or Na3V2(PO4)3, the above-mentioned amorphous oxalide solid electrolyte and conductive agent (Super P, KB, MXene, VGCF); the anode is a sodium-tin alloy; the anode electrolyte layer is a sulfide solid electrolyte Na3PS4.
[0052] In some embodiments, the all-solid-state sodium battery exhibits stable cycling performance and high capacity retention in charge-discharge cycle tests at room temperature, 0.2C, and 550 cycles, with an average coulombic efficiency of approximately 99.99%. It also has low interfacial impedance and no significant side reaction products generated after cycling.
[0053] In the embodiments of this invention, all raw materials and reagents used are commercially available high-purity reagents, and all operations are performed in an argon glove box with water and oxygen content <0.5 ppm. The following describes the implementation of this invention through multiple examples. The above-described embodiments are merely preferred embodiments of this invention and are only used to explain the invention, not to limit the scope of the invention. For those skilled in the art, other implementation methods can be easily made by substitution or modification based on the technical content disclosed in this specification. Therefore, all changes and improvements made to the principles and process conditions of this invention should be included within the scope of this patent application.
[0054] Example 1
[0055] NaMX 0.5 Preparation of Y5 (M=Ta, Nb; X=O, S; Y=Cl, Br, I) solid electrolyte
[0056] The precursor was weighed according to the molar ratio of TaCl5 (NbCl5):NaCl (NaBr, NaI):Na2O (Na2O2 or Na2S) = 1:1:0.5, with a total mass of 2 g; 10 mm zirconia grinding balls were added, with a ball-to-material mass ratio of 20:1; after sealing, the mixture was placed in a ball mill and ball-milled at 500 rpm for 24 h to obtain an amorphous chalcogenide solid electrolyte, NaTaO. x Cl 6–2x Main structural units such as Figure 3 As shown.
[0057] Example 2
[0058] Preparation of electrolytes with x=0.4, 0.6, 0.7, 0.8 series
[0059] Except for adjusting the amount of Na2O (Na2O2 or Na2S) added to a molar ratio of 0.4, 0.6, 0.7, and 0.8, the other parameters were the same as in Example 1, and NaMX was prepared accordingly. 0.4 Y 5.2 NaMX 0.6 Y 4.8 NaMX 0.7 Y 4.6 NaMX 0.8 Y 4.4 .
[0060] Comparative Example 1
[0061] Preparation of crystalline NaMCl6 (M=Ta, Nb)
[0062] After ball milling TaCl5 (NbCl5):NaCl = 1:1 for 24 h, the mixture was annealed at high temperature to obtain crystalline NaMCl6.
[0063] Comparative Example 2
[0064] Annealed NaMX 0.5 Y5 preparation
[0065] The amorphous NaMX prepared in Example 1 0.5 Y5 solid electrolyte was vacuum sealed and then annealed at 200℃ for 2 hours to obtain a highly crystalline electrolyte material.
[0066] Material characterization and performance testing
[0067] (1) Structural characterization: such as Figure 2 As shown, XRD testing revealed that the electrolyte of this invention had no obvious diffraction peaks, indicating it was amorphous; Figure 4 As shown, SEM revealed a particle size of approximately 10 μm, and EDS indicated a uniform distribution of Na, Ta, O, and Cl elements; XPS, 23 Na SS-NMR and Ta L3-edge XAFS confirmed structural disorder and coordination distortion.
[0068] (2) Ionic conductivity: such as Figure 5 As shown, EIS testing revealed that the room temperature conductivity at x=0.5 was 8.83×10⁻⁶. −3 S·cm −1 With an activation energy of 0.27 eV, it is superior to existing oxyhalide electrolytes.
[0069] (3) Electrochemical stability: CV test confirmed that the stability window reached 4.2 V (vs Na9Sn4).
[0070] (4) Battery performance: such as Figure 6 As shown, the capacity retention rate is 85.7% after 550 cycles at 0.2°C and 60°C.
[0071] All the above characterization and testing were performed using NaTaO. 0.5 Taking Cl5 as an example, the attached diagram only shows NaTaO. 0.5 The relevant test results of Cl5 solid electrolyte material are provided, but are not intended to limit the scope of this invention.
[0072] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.
[0073] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. An amorphous chalcogenide solid electrolyte, characterized in that, Its chemical composition includes sodium, at least one metal element selected from Ta and Nb, and at least two anions selected from Groups 6 and 7; the solid electrolyte is amorphous, does not have a long-range ordered structure, and its local coordination environment exhibits disordered characteristics.
2. The amorphous chalcogenide solid electrolyte as described in claim 1, characterized in that, The anion is a combination of a halide ion and a Group 6 ion.
3. A method for preparing an amorphous chalcogenide solid electrolyte as described in any one of claims 1-2, characterized in that, Includes the following steps: Sodium source, halogen source, sulfur source and / or oxygen source are mixed in a preset ratio of 1:1:0.4-0.8 and subjected to high-energy mechanical ball milling under an inert atmosphere to directly obtain an amorphous solid electrolyte; the ball milling process is carried out at room temperature or within the range of 25-30°C, without the need for subsequent high-temperature crystallization treatment.
4. The method for preparing an amorphous chalcogenide solid electrolyte as described in claim 3, characterized in that, The sodium source is one or more of NaCl, NaBr, NaI, Na2S, Na2O, and Na2O2; the metal source is one or more of TaCl5, NbCl5, Ta2O5, and Nb2O5; the halogen source is a metal halide or an alkali metal halide; the sulfur source is Na2S; and the oxygen source is an oxide or a peroxide.
5. The method for preparing an amorphous oxalate halide solid electrolyte as described in claim 3, characterized in that, The high-energy mechanical ball mill uses a ZrO2 sealed ball mill jar as the wear-resistant ball milling medium, with a ball-to-material ratio of 20:
1. The ball milling parameters are 500 rpm for 24 h. The ball milling is carried out entirely in an argon glove box with a water and oxygen content of <0.5 ppm, without high-temperature annealing treatment.
6. The application of an amorphous chalcogenide solid electrolyte as described in any one of claims 1-2 in an all-solid-state sodium battery.
7. The application of an amorphous chalcogenide solid electrolyte in an all-solid-state sodium battery, characterized in that, The all-solid-state sodium battery includes a composite positive electrode, a negative electrode, a negative electrode electrolyte layer, and a positive electrode electrolyte layer; the positive electrode electrolyte layer or at least one electrolyte layer is the amorphous oxohalide solid electrolyte.
8. The application of the amorphous chalcogenide solid electrolyte as described in claim 7 in an all-solid-state sodium battery, characterized in that, The composite cathode comprises doped Na(Ni) 1 / 3 Fe 1 / 3 Mn 1 / 3 The positive electrode active material is O2 or Na3V2(PO4)3, the amorphous oxohalide solid electrolyte and the conductive agent; the negative electrode is a sodium-tin alloy; the negative electrode electrolyte layer is a sulfide solid electrolyte Na3PS4.
9. The application of an amorphous chalcogenide solid electrolyte as described in any one of claims 7-8 in an all-solid-state sodium battery, characterized in that, In charge-discharge cycle tests, the all-solid-state sodium battery maintained a capacity of 85.7% at room temperature and 0.2C for 550 cycles, with an average coulombic efficiency of approximately 99.99%.