A sodium-ion cathode-derived multi-active-site solid electrolyte, its preparation method and application

Abstract

This invention belongs to the field of all-solid-state sodium-ion battery technology, specifically disclosing a multi-active-site solid electrolyte derived from a sodium-ion cathode, its preparation method, and its applications. This solid electrolyte is obtained through mechanochemical treatment using sodium-ion cathode materials and active metal chlorides as raw materials, and possesses an amorphous sodium halide oxide structure. The solid electrolyte contains Na, O, Cl, and at least two variable-valence metal elements. These at least two variable-valence metal elements include a first active metal element derived from the sodium-ion cathode material and a second active metal element derived from the active metal chloride. The first and second active metal elements are distributed within the amorphous sodium halide oxide structure, forming multiple variable-valence metal active sites. This invention can solve the problems of high proportion of non-capacity-contributing components, reduced proportion of cathode active materials, and limited capacity utilization and energy density in existing all-solid-state sodium-ion battery composite cathodes.

Description

Technical Field

[0001] This invention belongs to the field of all-solid-state sodium-ion battery technology, specifically relating to a multi-active-site solid electrolyte derived from a sodium-ion cathode, its preparation method, and its application. Background Technology

[0002] While traditional lithium-ion batteries are widely used, lithium resources are relatively concentrated, the cost of some key raw materials fluctuates significantly, and commonly used organic liquid electrolytes pose safety hazards such as flammability, leakage, and thermal runaway. Sodium-ion batteries, due to the abundance of sodium resources and relatively low cost, are gradually becoming an important candidate system for large-scale energy storage. Furthermore, all-solid-state sodium-ion batteries, which use solid electrolytes instead of liquid electrolytes, are beneficial for improving battery safety and provide the possibility of matching high-voltage positive electrodes and low-potential negative electrodes.

[0003] In existing all-solid-state sodium-ion batteries, common solid electrolytes include oxides, sulfides, halides, halide oxides, polymers, and their composite systems. Oxide solid electrolytes generally have good chemical stability, but their high material hardness makes it difficult to form sufficient contact between particles and between particles and electrodes, resulting in high interfacial impedance. Sulfide solid electrolytes have high ionic conductivity and good compactibility, but they are sensitive to air and moisture, and interfacial side reactions are significant when in contact with high-voltage positive electrodes or metallic sodium negative electrodes. Polymers or quasi-solid-state electrolytes have good processability, but their room-temperature ionic conductivity, high-voltage performance, and long-term thermal stability are still limited. Halide and halide oxide solid electrolytes have attracted attention in recent years due to their wide operating voltage range and good positive electrode interfacial compatibility; however, in practical composite positive electrode applications, most still primarily perform ion transport functions, with limited direct contribution to positive electrode capacity.

[0004] In the composite cathode of all-solid-state batteries, because the solid electrolyte cannot fully wet the cathode particles like a liquid electrolyte, a higher proportion of solid electrolyte is usually required to construct a continuous sodium ion transport network. This approach helps improve ion transport within the cathode, but the addition of a large amount of solid electrolyte reduces the relative content of the cathode active material and increases the proportion of inactive mass in the composite cathode, thereby weakening the capacity utilization per unit mass of cathode and the overall energy density of the battery. Simultaneously, the solid-solid contact between the solid electrolyte and the cathode particles and conductive agent is significantly affected by particle morphology, compaction degree, and cycle volume changes, easily leading to uneven local ion transport, increased interfacial impedance, and decreased cycle performance.

[0005] To address these issues, existing technologies have attempted to improve performance by optimizing the composite cathode ratio, introducing interface modification layers, controlling the particle size of the solid electrolyte, employing flexible or glassy electrolytes, and improving the cathode / electrolyte interface contact. These methods can reduce interfacial impedance or improve ion transport to some extent, but they often increase preparation steps, require high levels of control over battery structure or process, and offer limited improvement over the energy density loss caused by a high proportion of solid electrolytes. Some studies have also attempted to use solid electrolytes with certain electrochemical activity to improve the effective utilization rate of electrolyte components; however, these materials still require a balance between ion conduction, electronic insulation, reversible redox activity, operating voltage range, and interfacial stability, demanding high standards in material design and performance stability.

[0006] Therefore, in existing all-solid-state sodium-ion batteries, the problems of high solid electrolyte content in composite cathodes, insufficient interfacial contact, and low effective utilization of electrolyte components are still prominent. It is necessary to further study solid electrolyte materials and their construction methods suitable for composite cathodes in order to improve sodium ion transport, interfacial stability, and capacity utilization. Summary of the Invention

[0007] The purpose of this invention is to provide a multi-active-site solid electrolyte derived from sodium-ion cathode, its preparation method, and its application, which can solve the problems of high proportion of non-capacity-contributing components, reduced proportion of cathode active materials, and limited capacity utilization and energy density in existing all-solid-state sodium-ion battery composite cathodes.

[0008] To achieve the above objectives, the present invention employs the following technical solution: According to a first aspect of the present invention, a multi-active-site solid electrolyte derived from a sodium-ion cathode is provided. The solid electrolyte is obtained by mechanochemical treatment of sodium-ion cathode material and active metal chloride as raw materials, and has an amorphous sodium halide oxide structure. The solid electrolyte contains Na, O, Cl and at least two variable-valence metal elements; the at least two variable-valence metal elements include a first active metal element derived from sodium electrode material and a second active metal element derived from active metal chloride. The first and second active metal elements are distributed in the amorphous sodium halide oxide structure and form multiple variable valence metal active sites.

[0009] The operating voltage range of the aforementioned solid electrolyte is 1.5V-4.1V; The aforementioned solid electrolyte serves as the active positive electrode electrolyte in the composite positive electrode, simultaneously providing sodium ion transport channels and contributing to redox capacity.

[0010] Using the above technical solution, the sodium-ion battery cathode material is a sodium-containing material with a variable-valence transition metal element. This allows the raw material to simultaneously provide both a sodium source and a variable-valence metal source, thereby improving the functional integration of the resulting solid-state electrolyte. The first and second active metal elements are distributed in the amorphous sodium halide oxide structure, forming multiple variable-valence metal active sites. This allows the solid-state electrolyte to function as both a sodium ion transport channel and a redox capacity contributor in the composite cathode, ensuring sodium ion transport capacity in the composite cathode and reducing capacity limitations caused by insufficient ion transport. Furthermore, the above-mentioned solid-state electrolyte exhibits strong voltage compatibility with various sodium-ion battery cathode materials, improving the operational stability of all-solid-state sodium-ion batteries within the corresponding voltage range.

[0011] According to one embodiment of the present invention, the sodium electrode material includes at least one of layered oxide sodium electrode material, Prussian blue sodium electrode material, phosphate sodium electrode material, fluorophosphate sodium electrode material, fluorooxyphosphate sodium electrode material, and pyrophosphate sodium electrode material.

[0012] Furthermore, sodium-ion battery cathode materials include NaNi. 1 / 3 Fe 1 / 3 Mn 1 / 3 At least one of the following: O2 (NNFM), Prussian blue analogue (PBA), sodium vanadium phosphate, sodium vanadium fluorophosphate (NVPF), sodium vanadium fluorophosphate, sodium nickel iron manganese zinc, and iron pyrophosphate.

[0013] According to one embodiment of the present invention, the active metal chloride includes at least one of NbCl5, TaCl5, TiCl4, FeCl3, NiCl2 and VCl3.

[0014] Furthermore, the first active metal element includes at least one of Ni, Fe, Mn, V, Co, Cu, and Zn; The second active metal element includes at least one of Nb, Ta, Ti, Fe, Ni, and V.

[0015] The first active metal element can serve as a variable-valence transition metal in sodium-ion battery cathode materials, forming first-type active sites. This allows the sodium-ion battery cathode material to not only provide sodium but also participate in the formation of capacity-contributing centers. Active metal chlorides can simultaneously provide Cl and a second active metal element to the reaction system, thereby promoting the formation of amorphous sodium halide structures and multiple active sites.

[0016] According to one embodiment of the present invention, the first active metal element and the second active metal element are dispersed in the amorphous sodium halide oxide structure and participate in the reversible redox reaction during the charging and discharging process.

[0017] This reduces the risk of structural inhomogeneity caused by localized enrichment of active metal elements, and improves the uniformity of the composition and reactivity distribution of the solid electrolyte. The first and second active metal elements participate in reversible redox reactions during charge and discharge, enabling the solid electrolyte to provide additional capacity contributions, thereby reducing the ineffective mass impact of traditional inert solid electrolytes.

[0018] According to one embodiment of the present invention, the raw materials for preparing the solid electrolyte further include a sodium supplement, which includes at least one of NaCl, Na2CO3, NaOH, Na2O2 and Na2O.

[0019] Sodium supplementation agents can adjust the sodium content for different combinations of sodium-ion cathode materials and active metal chlorides, thereby improving the sodium ion carrier conditions in amorphous sodium halide oxide structures. Furthermore, sodium supplementation agents can regulate the amorphization degree and sodium ion conductivity of solid-state electrolytes, thus increasing the flexibility of compositional control in the resulting solid-state electrolytes.

[0020] According to a second aspect of the present invention, a method for preparing a sodium-ion cathode-derived multi-active-site solid electrolyte is provided, comprising the following steps: Sodium-ion cathode material is mixed with active metal chloride to obtain a precursor mixture; the sodium-ion cathode material contains Na, O and a first active metal element, and the active metal chloride contains Cl and a second active metal element. Mechanochemical treatment of the precursor mixture causes mechanochemical reconstruction of the sodium-ion cathode material and the active metal chloride, resulting in a multi-active-site solid electrolyte derived from the sodium-ion cathode. The resulting solid electrolyte has an amorphous sodium halide oxide structure and contains Na, O, Cl, a first active metal element, and a second active metal element. The first and second active metal elements are distributed in the amorphous sodium halide oxide structure and form multiple variable-valence metal active sites.

[0021] Mechanochemical treatment can disrupt the original ordered structure of sodium-ion cathode materials and promote their structural reconstruction with active metal chlorides, thereby forming an amorphous sodium halide oxide structure. It also promotes the formation of a dual-source multi-active-site structure of the first and second active metal elements in the resulting solid electrolyte, thus enabling it to contribute to both sodium ion transport and redox capacity.

[0022] Furthermore, the sodium electrode material includes at least one of layered oxide sodium electrode materials, Prussian blue sodium electrode materials, phosphate sodium electrode materials, fluorophosphate sodium electrode materials, fluorooxyphosphate sodium electrode materials, and pyrophosphate sodium electrode materials; the active metal chloride includes at least one of NbCl5, TaCl5, TiCl4, FeCl3, NiCl2, and VCl3; When sodium-ion battery cathode material is mixed with active metal chloride, a sodium supplement is also added. The sodium supplement includes at least one of NaCl, Na2CO3, NaOH, Na2O2, and Na2O.

[0023] Furthermore, when the sodium electrode material is a layered oxide sodium electrode material, the molar ratio of the sodium electrode material to the active metal chloride is (2:3)-(7:4).

[0024] Furthermore, the mechanochemical treatment is mechanical ball milling, with a ball milling speed of 600rpm-1000rpm, a ball milling time of 6h-24h, and a ball-to-material ratio of (20-60):1.

[0025] According to a third aspect of the present invention, an application of a sodium-ion battery with multiple active sites derived from a sodium-ion cathode is provided.

[0026] Furthermore, the positive electrode of the all-solid-state ion battery is prepared by mixing the multi-active-site solid electrolyte derived from the above-mentioned sodium-electric positive electrode with sodium-electric positive electrode material and vapor-grown carbon fiber (VGCF).

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention forms a solid electrolyte using sodium-ion battery cathode material and active metal chloride as raw materials, and introduces a first and a second active metal element into the amorphous sodium halide oxide structure, thereby forming a solid electrolyte material with dual-source variable-valence metal active sites. The multi-active-site solid electrolyte derived from the sodium-ion battery cathode forms multiple variable-valence metal active sites, which can contribute to the redox capacity in the composite cathode; and can also form effective sodium ion transport channels in the composite cathode, thereby improving the ion transport efficiency on the cathode side.

[0028] 2. This invention obtains a multi-active-site solid electrolyte derived from sodium-electric cathode by mechanically and chemically treating sodium-electric cathode material and active metal chloride, and reconstructs an amorphous sodium halide oxide structure, which is beneficial to the dispersion and distribution of the first and second active metal elements in the obtained solid electrolyte, thereby improving the sodium ion migration environment and enhancing structural uniformity.

[0029] 3. The sodium-ion cathode-derived multi-active-site solid electrolyte of the present invention has an operating voltage range of 1.5V-4.1V and a sodium-ion conductivity of up to 2.9mS / cm at room temperature, which can improve its voltage matching with various sodium-ion cathode materials, thereby improving the working adaptability of all-solid-state sodium-ion batteries. Attached Figure Description

[0030] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 The X-ray diffraction patterns of the solid electrolytes obtained in Examples 1-3 and NNFM and NbCl5 are shown below. Figure 2 The X-ray diffraction patterns of the solid electrolytes obtained in Examples 4-7 and NNFM and TaCl5 are shown. Figure 3 The X-ray diffraction patterns of the solid electrolytes obtained in Examples 8-9 are shown below. Figure 4 The X-ray diffraction patterns of the solid electrolytes obtained in Examples 11-13 and NVPF and TaCl5 are shown below. Figure 5 The X-ray diffraction patterns of the solid electrolytes obtained in Examples 14-16, as well as NVPF and NbCl5; Figure 6 The X-ray diffraction patterns of the solid electrolytes obtained in Examples 17-20 and PBA and TaCl5 are shown. Figure 7 The X-ray diffraction pattern of NZCO obtained as a comparative example; Figure 8 The results are the ionic conductivity test results of the solid electrolytes obtained in Examples 1-3; Figure 9 The results are the ionic conductivity test results of the solid electrolytes obtained in Examples 4-7; Figure 10 The results are the ionic conductivity test results of the solid electrolytes obtained in Examples 11-13; Figure 11 The results are the ionic conductivity test results of the solid electrolytes obtained in Examples 14-16; Figure 12 The results are the ionic conductivity test results of the solid electrolytes obtained in Examples 17-20; Figure 13 The results are the ionic conductivity test results of the solid electrolytes obtained in Examples 8-9; Figure 14 The results show the ionic conductivity of the solid electrolyte obtained in the comparative example. Figure 15 The energy density test results of each all-solid-state ion battery obtained from Example 1 are shown. Figure 16 The test results of the all-solid-state ion battery obtained in Example 2 are shown. Figure 17 The EIS results of the all-solid-state ion battery NNFM-NNNFM after charge-discharge cycles obtained in Example 1 are shown. Figure 18 The results are EDS measurements of the solid electrolyte NNNFM-3 obtained in Example 3. Figure 19 The results of EDS testing of the solid electrolyte NTNFM-2 obtained in Example 5 are shown below. Figure 20 The results are EDS test results for the solid electrolyte NTVPF-3 obtained in Example 13. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0032] The following detailed descriptions are exemplary and intended to provide further detailed explanation of the present invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used in this invention is for the purpose of describing specific embodiments only and is not intended to limit the scope of exemplary embodiments according to the present invention. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in the art, or in accordance with the product instructions. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased through legitimate channels.

[0033] This invention involves mixing a sodium-ion battery cathode material with an active metal chloride to obtain a precursor mixture. The sodium-ion battery cathode material contains Na, O, and a first active metal element, while the active metal chloride contains Cl and a second active metal element. The precursor mixture is subjected to mechanochemical treatment to cause mechanochemical reconstruction of the sodium-ion battery cathode material and the active metal chloride, resulting in a sodium-ion battery-derived multi-active-site solid electrolyte. The obtained solid electrolyte has an amorphous sodium halide oxide structure and contains Na, O, Cl, a first active metal element, and a second active metal element. The first and second active metal elements are distributed in the amorphous sodium halide oxide structure and form multiple variable-valence metal active sites.

[0034] The sodium-ion cathode-derived multi-active-site solid electrolyte obtained by this invention has a wide voltage window, can match most sodium-ion cathodes, can greatly improve solid-solid interface contact, and can adapt to cathode volume changes during charging and discharging.

[0035] Example 1 Preparation of multi-active-site solid electrolyte derived from sodium-ion cathode S1. Preparation of precursor mixture.

[0036] Sodium-ion cathode material is mixed with an active metal chloride to obtain a precursor mixture. The sodium-ion cathode material is NaNi. 1 / 3 Fe 1 / 3 Mn 1 / 3 O2 (NNFM), with the active metal chloride being NbCl5; the molar ratio of NNFM to NbCl5 is 3:2.

[0037] S2. Preparation of solid electrolytes.

[0038] In a glove box (H2O < 0.01 ppm, O2 < 0.01 ppm), the precursor mixture obtained in step S1 was placed into a ball mill jar, followed by the addition of grinding beads. The jar was then vacuum-sealed and placed in a ball mill for mechanical ball milling. The grinding beads were 5 mm in diameter and made of ZrO2; the ball-to-material ratio was 40:1; the milling speed was 800 rpm; and the milling time was 8 hours. During the mechanical ball milling process, the grinding was followed by a 5-minute rest period.

[0039] After mechanical ball milling, the ball mill jar was opened in the glove box, the product was collected, and the product was pulverized using a mortar and pestle to obtain a sodium-ion cathode-derived multi-active-site solid electrolyte, denoted as NNNNFM-1.

[0040] Example 2 The difference between this embodiment and Embodiment 1 is that: In step S1, the molar ratio of NNFM to NbCl5 is 1:1.

[0041] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NNNNFM-2.

[0042] Example 3 The difference between this embodiment and Embodiment 1 is that: In step S1, the molar ratio of NNFM to NbCl5 is 2:3.

[0043] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NNNNFM-3.

[0044] Example 4 The difference between this embodiment and Embodiment 1 is that: In step S1, when the sodium electrode positive electrode material is mixed with the active metal chloride, a sodium supplement is added simultaneously. The sodium supplement is Na2CO3; the active metal chloride is TaCl5; and the molar ratio of Na2CO3, NNFM and TaCl5 is 1:4:4.

[0045] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NTNFM-1.

[0046] Example 5 The difference between this embodiment and Embodiment 1 is that: In step S1, when the sodium electrode material is mixed with the active metal chloride, a sodium supplement is added simultaneously. The sodium supplement is Na2CO3; the active metal chloride is TaCl5; and the molar ratio of Na2CO3, NNFM and TaCl5 is 1:5:4.

[0047] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NTNFM-2.

[0048] Example 6 The difference between this embodiment and Embodiment 1 is that: In step S1, when the sodium electrode positive electrode material is mixed with the active metal chloride, a sodium supplement is added simultaneously. The sodium supplement is Na2CO3; the active metal chloride is TaCl5; and the molar ratio of Na2CO3, NNFM and TaCl5 is 1:6:4.

[0049] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NTNFM-3.

[0050] Example 7 The difference between this embodiment and Embodiment 1 is that: In step S1, when the sodium electrode positive electrode material is mixed with the active metal chloride, a sodium supplement is added simultaneously. The sodium supplement is Na2CO3; the active metal chloride is TaCl5; and the molar ratio of Na2CO3, NNFM and TaCl5 is 1:7:4.

[0051] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NTNFM-4.

[0052] Example 8 The difference between this embodiment and Embodiment 1 is that: In step S1, when the sodium electrode material is mixed with the active metal chloride, a sodium supplement is added simultaneously. The sodium supplement is NaOH; the active metal chloride is TaCl5; and the molar ratio of NaOH, NNFM and TaCl5 is 1:5:4.

[0053] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NTNFM-5.

[0054] Example 9 The difference between this embodiment and Embodiment 1 is that: In step S1, when the sodium electrode material is mixed with the active metal chloride, a sodium supplement is added simultaneously. The sodium supplement is NaCl; the active metal chloride is TaCl5; and the molar ratio of NaCl, NNFM and TaCl5 is 1:5:4.

[0055] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NTNFM-6.

[0056] Example 10 The difference between this embodiment and Embodiment 1 is that: In step S1, the active metal chloride is TaCl5; the molar ratio of NNFM to TaCl5 is 3:2.

[0057] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NTNFM-7.

[0058] Example 11 The difference between this embodiment and Embodiment 1 is that: In step S1, the sodium electrode material is sodium vanadium fluorophosphate (NVPF); the active metal chloride is TaCl5; and the molar ratio of NVPF to TaCl5 is 3:2.

[0059] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NTVPF-1.

[0060] Example 12 The difference between this embodiment and Embodiment 1 is that: In step S1, the sodium electrode material is NVPF; the active metal chloride is TaCl5; and the molar ratio of NVPF to TaCl5 is 1:1.

[0061] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NTVPF-2.

[0062] Example 13 The difference between this embodiment and Embodiment 1 is that: In step S1, the sodium electrode material is NVPF; the active metal chloride is TaCl5; and the molar ratio of NVPF to TaCl5 is 2:3.

[0063] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NTVPF-3.

[0064] Example 14 The difference between this embodiment and Embodiment 1 is that: In step S1, the sodium electrode material is NVPF; the molar ratio of NVPF to NbCl5 is 3:2.

[0065] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NNVPF-1.

[0066] Example 15 The difference between this embodiment and Embodiment 1 is that: In step S1, the sodium electrode material is NVPF; the molar ratio of NVPF to NbCl5 is 1:1.

[0067] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NNVPF-2.

[0068] Example 16 The difference between this embodiment and Embodiment 1 is that: In step S1, the sodium electrode material is NVPF; the molar ratio of NVPF to NbCl5 is 2:3.

[0069] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as NNVPF-3.

[0070] Example 17 The difference between this embodiment and Embodiment 1 is that: In step S1, the sodium-ion battery cathode material is a Prussian blue analogue (PBA); the active metal chloride is TaCl5; PBA was purchased from Canrd, model number: MA-EN-CA-008201. When mixing the sodium-ion battery cathode material and the active metal chloride, a sodium supplement agent, Na2CO3, is added simultaneously; the mass ratio of Na2CO3, PBA, and TaCl5 is 6:12.7:81.3.

[0071] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as TPBA-1.

[0072] Example 18 The difference between this embodiment and Embodiment 1 is that: In step S1, the sodium-ion battery cathode material is a Prussian blue analogue (PBA); the active metal chloride is TaCl5; the PBA was purchased from Canrd, model number: MA-EN-CA-008201. When mixing the sodium-ion battery cathode material and the active metal chloride, a sodium supplement agent, Na2CO3, is added simultaneously; the mass ratio of Na2CO3, PBA, and TaCl5 is 5.6:17.9:76.5.

[0073] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as TPBA-2.

[0074] Example 19 The difference between this embodiment and Embodiment 1 is that: In step S1, the sodium-ion battery cathode material is a Prussian blue analogue (PBA); the active metal chloride is TaCl5; the PBA was purchased from Canrd, model number: MA-EN-CA-008201. When mixing the sodium-ion battery cathode material and the active metal chloride, a sodium supplement agent, Na2CO3, is added simultaneously; the mass ratio of Na2CO3, PBA, and TaCl5 is 5.3:22.4:73.2.

[0075] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as TPBA-3.

[0076] Example 20 The difference between this embodiment and Embodiment 1 is that: In step S1, the sodium-ion battery cathode material is a Prussian blue analogue (PBA); the active metal chloride is TaCl5; the PBA was purchased from Canrd, model number: MA-EN-CA-008201. When mixing the sodium-ion battery cathode material and the active metal chloride, a sodium supplement agent, Na2CO3, is added simultaneously; the mass ratio of Na2CO3, PBA, and TaCl5 is 5.1:26.6:68.3.

[0077] The remaining steps and conditions are the same. The resulting sodium-ion cathode-derived multi-active-site solid electrolyte is denoted as TPBA-4.

[0078] Example 21 The difference between this embodiment and Embodiment 1 is that: In step S2, the ball-to-material ratio is 20:1; the ball mill speed is 600 rpm; the ball milling time is 24 hours, during which the ball milling time is 8 minutes and the rest time is 8 minutes.

[0079] The remaining steps and conditions are the same.

[0080] Example 22 The difference between this embodiment and Embodiment 1 is that: In step S2, the ball-to-material ratio is 60:1; the ball mill speed is 1000 rpm; the ball milling time is 6 hours, with a 3-minute grinding period followed by a 5-minute rest period.

[0081] The remaining steps and conditions are the same.

[0082] Example 23 The difference between this embodiment and Embodiment 1 is that: In step S2, the ball-to-material ratio is 60:1; the ball mill speed is 900 rpm; and the ball milling time is 12 hours.

[0083] The remaining steps and conditions are the same.

[0084] Comparative Example Preparation of inert zirconium-based solid electrolytes In a glove box (H2O < 0.01 ppm, O2 < 0.01 ppm), ZrCl4 and Na2CO3 were placed in a ball mill jar, followed by the addition of grinding beads. The jar was then vacuum-sealed and placed in a ball mill for mechanical ball milling. The molar ratio of ZrCl4 to Na2CO3 was 1:2. The grinding beads were 5 mm in diameter and made of ZrO2; the ball-to-material ratio was 40:1; the milling speed was 800 rpm; and the milling time was 8 hours. During the mechanical ball milling process, there was a 5-minute milling rest period followed by a 5-minute rest period.

[0085] After mechanical ball milling, the ball mill jar is opened in the glove box, the product is collected, and the product is pulverized using a mortar to obtain an inert zirconium-based solid electrolyte, denoted as NZCO.

[0086] Application Example 1 S(11) is used to prepare composite cathode materials.

[0087] The NNNNFM-1 prepared in Example 1, the NTNFM-1 prepared in Example 4, the NTVPF-1 prepared in Example 11, and the NZCO prepared in the comparative example were used as target solid electrolytes to prepare composite cathode materials. Specifically, the target solid electrolyte was mixed with NNFM and VGCF at a mass ratio of 50:45:5 and ground uniformly in a mortar for 30 minutes to obtain the composite cathode material.

[0088] S(12) Assemble an all-solid-state ion battery.

[0089] Using the NZCO prepared in the comparative example as the interlayer, the composite cathode material obtained in step S(11) above is the cathode, and Na... 15 Sn4 is used as the negative electrode in the assembly of an all-solid-state ion battery. Specifically, 50 mg of inert zirconium-based solid electrolyte (NZCO) is weighed and placed in a battery mold, and a pressure of 200 MPa is applied. Then, 10 mg of composite positive electrode material and 40 mg of Na3PS4 are added to both sides of the inert zirconium-based solid electrolyte, respectively, and spread evenly with a spatula, while applying a pressure of 200 MPa. Finally, 30 mg of Na3PS4 is added to the Na3PS4 side. 15The Sn4 negative electrode was flattened with a spatula, and then a pressure of 300 MPa was applied. After standing for 3 hours, an all-solid-state ion battery was obtained. Corresponding to the target solid electrolyte in each composite positive electrode material, the obtained all-solid-state ion batteries were designated as NNFM-NNNFM, NNFM-NTNFM, NNFM-NTVPF, and NNFM-NZCO, respectively.

[0090] Application Example 2 The difference between this application example and application 1 is that: In step S(11), when preparing the composite cathode material, the target solid electrolyte is the inert zirconium-based solid electrolyte NZCO prepared in the comparative example, without the addition of NNFM. NZCO and VGCF are mixed at a mass ratio of 95:5 and ground uniformly in a mortar for 30 minutes to obtain the composite cathode material.

[0091] The remaining steps and conditions are the same. The resulting all-solid-state ion battery is denoted as NZCO-VGCF.

[0092] Test Example 1 X-ray diffraction was performed on the solid electrolytes obtained in Examples 1-3, as well as NNFM and NbCl5. The results are shown in [reference needed]. Figure 1 ; X-ray diffraction was performed on the solid electrolytes obtained in Examples 4-7, as well as NNFM and TaCl5. The results are shown in [reference needed]. Figure 2 ; X-ray diffraction was performed on the solid electrolytes obtained in Examples 8-9, and the results are shown in [reference]. Figure 3 ; X-ray diffraction was performed on the solid electrolytes obtained in Examples 11-13, as well as NVPF and TaCl5. The results are shown in [reference needed]. Figure 4 ; X-ray diffraction was performed on the solid electrolytes obtained in Examples 14-16, as well as NVPF and NbCl5. The results are shown in [reference needed]. Figure 5 ; X-ray diffraction was performed on the solid electrolytes obtained in Examples 17-20, as well as PBA and TaCl5. The results are shown in [reference needed]. Figure 6 ; X-ray diffraction was performed on the NZCO obtained in the comparative example, and the results are shown in [reference needed]. Figure 7 .

[0093] Combination Figure 1 , Figure 2 , Figures 4-6It can be seen that NNFM, NVPF, PBA, NbCl5, and TaCl5, as raw materials for preparing sodium-ion cathode-derived multi-active-site solid electrolytes, all exhibit obvious crystal phase diffraction peaks. However, the sodium-ion cathode-derived multi-active-site solid electrolytes prepared in Examples 1-9 and 11-20 mainly exhibit broad and diffuse peaks in the range of 10°-80°. The characteristic diffraction peaks of the raw materials are significantly weakened or even disappear. This indicates that the mechanochemical treatment effectively destroys the original ordered crystal structure of the precursor and reconstructs it into an amorphous sodium halide oxide structure.

[0094] Specifically, Figure 1 Compared to NNFM and NbCl5, NNNFM-1, NNNFM-2, and NNNFM-3... Figure 2 Compared to NNFM and TaCl5, NTNFM-1 to NTNFM-4 in the middle Figure 4 Compared to NVPF and TaCl5, NTVPF-1 to NTVPF-3 are... Figure 5 Compared to NVPF and NbCl5, NNVPF-1 to NNVPF-3 are... Figure 6 Compared to PBA and TaCl5, TPBA-1 to TPBA-4 all exhibit the same broad and diffuse peak characteristics, indicating that the mechanochemical reconstruction strategy of the present invention has good applicability to different types of sodium electrode cathode materials such as layered oxides, fluorophosphates and Prussian blue, and can universally obtain the target amorphous sodium halide oxide solid electrolyte.

[0095] also, Figure 3 The results show that, under different sodium supplementation conditions, NTNFM-5 and NTNFM-6 still maintain diffraction characteristics dominated by broad diffuse peaks, indicating that changes in the type of sodium supplementation do not disrupt the formation of amorphous sodium halide oxide structures. Figure 2 and Figure 3 The comparison further demonstrates that the introduction of sodium supplementation can regulate the amorphization degree of the resulting sodium-ionized, multi-active-site solid electrolyte. Specifically, Figure 3 The broad diffusion peak morphology of NTNFM-5 and NTNFM-6 obtained after adding sodium supplement is similar to... Figure 2 The differences in NTNFM-2 indicate that different sodium supplements can alter the degree of formation of amorphous sodium halide oxide structures, thereby enabling the regulation of the amorphization degree and local structure of the material.

[0096] Figure 7 Although the NZCO shown in the comparative example also exhibits amorphous characteristics, it is only an inert zirconium-based system and does not contain variable-valence metal elements from both sodium-ion battery cathode materials and active metal chlorides. Figure 7 This further illustrates that mechanochemical treatment can destroy the original ordered crystal structure of the precursor and reconstruct an amorphous sodium halide oxide structure.

[0097] Test Example 2 (1) Ionic conductivity test The ionic conductivity of the solid electrolytes obtained in Examples 1-9, Examples 11-20, and the comparative examples was tested using cold pressing technology.

[0098] The specific testing method is as follows: In a glove box (H2O < 0.01 ppm, O2 < 0.01 ppm), 200 mg of the target solid electrolyte was weighed and then poured into a solid battery mold (10 mm in diameter). A pressure of 200 MPa was then applied for cold pressing, and the pressure was held for 2 minutes. Subsequently, an AC impedance test was performed on the sample using a Bio-Logic VMP3 electrochemical workstation at 25°C (room temperature) within a frequency range of 1 Hz to 7 MHz.

[0099] The ionic conductivity test results of the solid electrolytes obtained in Examples 1-3 are shown in [reference]. Figure 8 ; The ionic conductivity test results of the solid electrolytes obtained in Examples 4-7 are shown in [reference]. Figure 9 ; The ionic conductivity test results of the solid electrolytes obtained in Examples 11-13 are shown in [reference]. Figure 10 ; The ionic conductivity test results of the solid electrolytes obtained in Examples 14-16 are shown in [reference]. Figure 11 ; The ionic conductivity test results of the solid electrolytes obtained in Examples 17-20 are shown in [reference]. Figure 12 ; The ionic conductivity test results of the solid electrolytes obtained in Examples 8-9 are shown in [reference]. Figure 13 ; The ionic conductivity test results of the solid electrolyte obtained in the comparative example are shown in [reference]. Figure 14 .

[0100] Combination Figures 8-14 It can be seen that different precursor combinations and ratios have a significant impact on the ion conduction performance of the resulting solid electrolyte.

[0101] Figure 8 The results show that the room temperature ionic conductivity of NNNNFM-1, NNNNFM-2 and NNNNFM-3 obtained in Examples 1-3 are 0.05 mS / cm, 0.15 mS / cm and 0.20 mS / cm, respectively. This indicates that with the optimization of the ratio of NNFM to NbCl5, the sodium ion transport capacity of the materials is significantly improved, and NNNNFM-3 exhibits the best ion transport performance among the three.

[0102] Figure 9The results show that the room temperature ionic conductivity of NTNFM-1, NTNFM-2, NTNFM-3 and NTNFM-4 obtained in Examples 4-7 are 0.96 mS / cm, 2.98 mS / cm, 1.50 mS / cm and 1.26 mS / cm, respectively. Among them, NTNFM-2 has the highest ionic conductivity, reaching 2.98 mS / cm. This indicates that by introducing a sodium supplement and optimizing the raw material ratio in the NNFM-TaCl5 system, the ionic conductivity of the obtained solid electrolyte can be significantly improved.

[0103] Figure 10 and Figure 11 Further, it was shown that using NVPF as a sodium-ion cathode material precursor can also yield a multi-active-site solid electrolyte with sodium ion conductivity. Specifically, the room-temperature ionic conductivity of NTVPF-1, NTVPF-2, and NTVPF-3 were 0.09 mS / cm, 0.24 mS / cm, and 0.29 mS / cm, respectively; while the room-temperature ionic conductivity of NTVPF-1, NTVPF-2, and NTVPF-3 were 0.015 mS / cm, 0.029 mS / cm, and 0.035 mS / cm, respectively. Therefore, under the same sodium-ion cathode material precursor conditions, the ionic conductivity of the material obtained via the TaCl5 route is generally superior to that via the NbCl5 route.

[0104] Figure 12 The results show that when PBA is used as the precursor for sodium-ion batteries, the room-temperature ionic conductivity of TPBA-1, TPBA-2, TPBA-3, and TPBA-4 are 0.28 mS / cm, 0.60 mS / cm, 0.63 mS / cm, and 0.16 mS / cm, respectively, with TPBA-3 being the highest. This indicates that even if the precursor is switched from layered oxide or multi-anion cathode to Prussian blue cathode, the technical solution of this invention can still obtain a target solid electrolyte with good ionic conductivity.

[0105] and Figure 9 Compared to NTNFM-2 in the middle, Figure 13 NTNFM-5 and NTNFM-6 prepared with different sodium supplements both exhibited low impedance characteristics, indicating that adding different types of sodium supplements can effectively regulate the ionic conductivity of multi-active-site solid electrolytes derived from sodium electrodes.

[0106] Figure 14The results show that the room-temperature ionic conductivity of the comparative example NZCO is only 0.23 mS / cm. In comparison, the ionic conductivity of NTNFM-2 reaches 2.98 mS / cm, approximately 13 times that of NZCO; TPBA-3 reaches 0.63 mS / cm, approximately 2.7 times that of NZCO; and NTVPF-3 reaches 0.29 mS / cm, also higher than NZCO. These comparisons demonstrate that this invention, by introducing a dual-source variable-valence metal element derived from both sodium cathode materials and active metal chlorides to form multiple active sites, can significantly improve sodium ion transport capacity while maintaining the amorphous structure, thereby providing a more efficient ion transport channel for the composite cathode.

[0107] (2) Electrochemical testing The all-solid-state ion batteries NNFM-NNNFM, NNFM-NTNFM, NNFM-NTVPF, and NNFM-NZCO obtained in Application Example 1, and the all-solid-state ion battery NZCO-VGCF obtained in Application Example 2, were subjected to electrochemical tests on the Blue Electric testing system under the following conditions: 25°C and a voltage window of 1.5V–4.1V. The energy density test results for each all-solid-state ion battery obtained in Application Example 1 are shown below. Figure 15 The test results of the all-solid-state ion battery obtained from Example 2 can be found in [reference]. Figure 16 .

[0108] Figure 15 The table shows the energy density test results for each all-solid-state ion battery after charging to 4.1V and then discharging. Those marked "(1.5V)" are the results after fully discharging to 1.5V, and the rest are the results after discharging to 1.8V. Additionally, Figure 15 The energy density obtained from NNFM calculations and the results calculated based on the corresponding composite cathode materials are presented for each all-solid-state ion battery.

[0109] Combination Figure 15It is evident that after constructing a composite cathode using the multi-active-site solid-state electrolyte derived from the sodium-ion cathode of this invention, the energy density of the all-solid-state sodium-ion battery is significantly higher than that of the control system using the inert zirconium-based solid-state electrolyte NZCO. Specifically, the energy density of the NNFM-NZCO battery, calculated based on NNFM, is 491.9 Wh / kg, and the energy density calculated based on the composite cathode material is 233.6 Wh / kg; while the NNFM-NNNFM battery using the solid-state electrolyte of this invention increases to 763.0 Wh / kg and 362.4 Wh / kg, respectively, and further increases to 879.6 Wh / kg and 417.8 Wh / kg when the discharge cutoff voltage is reduced to 1.5V. Furthermore, the energy densities of the NNFM-NTNFM and NNFM-NTVPF batteries, calculated based on NNFM, are 701.1 Wh / kg and 677.1 Wh / kg, respectively, and the energy densities calculated based on the composite cathode material are 333.1 Wh / kg and 322.4 Wh / kg, respectively, all significantly higher than those of the NNFM-NZCO system. This demonstrates that the solid electrolyte of the present invention does not merely exist as an inert ion transport medium, but can simultaneously provide ion transport channels and redox capacity contributions in the composite cathode, thereby reducing the proportion of non-capacity contributing components and improving the effective utilization rate of cathode active materials and the overall energy density of the battery.

[0110] Combination Figure 16 It can be seen that the NZCO-VGCF battery constructed using the inert zirconium-based solid electrolyte NZCO and VGCF maintains a discharge specific capacity close to zero during cycling, while the coulombic efficiency remains close to 100%, indicating that NZCO itself does not provide a significant capacity contribution. Figure 16 and Figure 15 The comparison can further prove this: Figure 15 The significant improvement in the energy density of the corresponding all-solid-state ion battery is mainly due to the additional capacity contribution and synergistic effect of the multi-active-site solid electrolyte provided by the present invention, rather than simply relying on the conductive agent or inert electrolyte to construct the transport network. It can be seen that the multi-active-site solid electrolyte derived from the sodium electrode provided by the present invention can effectively solve the problems of high proportion of non-capacity contributing components, limited capacity utilization and energy density in the existing all-solid-state sodium-ion battery composite cathode.

[0111] Furthermore, in conjunction with the electrochemical testing conditions of Test Example 2 and Figure 15 and Figure 16 It can be seen that the all-solid-state sodium-ion battery obtained in Application Example 1 was tested within a voltage range of 1.5V-4.1V. Figure 15The results show that the all-solid-state sodium-ion battery constructed using the multi-active-site solid-state electrolyte derived from the sodium electrode of this invention, after being charged to 4.1V, can output a significant energy density at a discharge lower limit of 1.5V or 1.8V, and is significantly higher than the NNFM-NZCO system using an inert zirconium-based solid-state electrolyte. On the other hand, Figure 16 The results show that the control system, which uses only the inert zirconium-based solid electrolyte NZCO and the conductive agent VGCF, exhibits almost no effective discharge capacity under near-the same upper voltage limit. This indicates that the solid electrolyte of this invention can achieve a stable match with sodium-ion cathode materials within a voltage range of 1.5V-4.1V and supports reversible charge-discharge of all-solid-state sodium-ion batteries, thus demonstrating its electrochemical stability and redox compatibility suitable for the 1.5V-4.1V operating range.

[0112] In addition, EIS testing was performed on the all-solid-state ion battery NNFM-NNNFM obtained in Case 1 on the Blue Electric testing system, and the results are shown in [link to results]. Figure 17 After 800 cycles, the battery impedance increased only slightly, indicating good interfacial contact. This demonstrates that the solid electrolyte prepared using the method of this invention helps improve solid-solid interface contact.

[0113] Test Example 3 EDS (Energy Dispersive X-ray Spectroscopy) test EDS tests were performed on NNNNFM-3 obtained in Example 3, NTNFM-2 obtained in Example 5, and NTVPF-3 obtained in Example 13, respectively. The test results are shown in [link to results]. Figures 18-20 See also Figure 18 ,in Figure 18 (g) shows the SEM results for NNNFM-3. Figure 18 (h)- Figure 18 (n) represents the EDS surface scan distribution of the corresponding element in NNNNFM-3. See also Figure 19 ,in Figure 19 (a) shows the SEM results for NTNFM-2. Figure 19 (b)- Figure 19 (h) shows the EDS surface scan distribution of the corresponding elements in NTNFM-2. See also Figure 20 ,in Figure 20 (a) shows the SEM results for NTVPF-3. Figure 20 (b)- Figure 20 (h) is the EDS surface scan distribution map of the corresponding element in NTVPF-3. Combined with... Figures 18-20Even with variations in the type and proportion of sodium-ion cathode material and active metal chloride, the solid electrolytes prepared using the method of this invention exhibit excellent structural uniformity. Both the main phase elements and dopant elements are uniformly distributed within the particles, with no obvious elemental segregation or phase separation. This demonstrates that the method of this invention enables the first and second active metal elements to be dispersed within the resulting solid electrolyte, thereby improving the sodium ion migration environment and enhancing structural uniformity. Particularly in NNNNFM-3, the distribution profiles of elements such as Na, Nb, O, Cl, Ni, Mn, and Fe highly overlap with the morphology of the SEM matrix particles, exhibiting a continuous and uniform distribution throughout the particles, without any independent element enrichment regions detached from the matrix; there are no obvious elemental agglomerations, clusters, or local deficiencies. Therefore, the compositional distribution of NNNNFM-3 obtained in Example 3 is highly uniform, with no obvious phase separation or elemental migration.

[0114] The applicant declares that the detailed method of the present invention is illustrated by the above embodiments, but the present invention is not limited to the above detailed method, that is, it does not mean that the present invention must rely on the above detailed method to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A sodium-ion cathode-derived multi-active-site solid electrolyte, characterized in that, The solid electrolyte is obtained by mechanochemical treatment of sodium electrode material and active metal chloride as raw materials, and has an amorphous sodium halide oxide structure. The solid electrolyte contains Na, O, Cl and at least two variable-valence metal elements; the at least two variable-valence metal elements include a first active metal element derived from the sodium electrode material and a second active metal element derived from the active metal chloride. The first and second active metal elements are distributed in the amorphous sodium halide oxide structure and form multiple variable valence metal active sites.

2. The solid electrolyte according to claim 1, characterized in that, The sodium electrode material includes at least one of layered oxide sodium electrode materials, Prussian blue sodium electrode materials, phosphate sodium electrode materials, fluorophosphate sodium electrode materials, fluorooxyphosphate sodium electrode materials, and pyrophosphate sodium electrode materials.

3. The solid electrolyte according to claim 1, characterized in that, The first active metal element includes at least one of Ni, Fe, Mn, V, Co, Cu, and Zn; The second active metal element includes at least one of Nb, Ta, Ti, Fe, Ni and V.

4. The solid electrolyte according to claim 1, characterized in that, The first and second active metal elements are dispersed in the amorphous sodium halide oxide structure and participate in reversible redox reactions during charging and discharging.

5. The solid electrolyte according to claim 1, characterized in that, The raw materials for preparing the solid electrolyte also include a sodium supplement, which includes at least one of NaCl, Na2CO3, NaOH, Na2O2, and Na2O.

6. A method for preparing a sodium-ion cathode-derived multi-active-site solid electrolyte, characterized in that, Includes the following steps: A sodium-ion cathode material is mixed with an active metal chloride to obtain a precursor mixture; the sodium-ion cathode material contains Na, O and a first active metal element, and the active metal chloride contains Cl and a second active metal element. The precursor mixture is subjected to mechanochemical treatment to cause the sodium-ion cathode material and the active metal chloride to undergo mechanochemical reconstruction, resulting in a sodium-ion cathode-derived multi-active-site solid electrolyte. The resulting solid electrolyte has an amorphous sodium halide oxide structure and contains Na, O, Cl, a first active metal element, and a second active metal element. The first active metal element and the second active metal element are distributed in the amorphous sodium halide oxide structure and form multiple variable-valence metal active sites.

7. The preparation method according to claim 6, characterized in that, The sodium electrode material includes at least one of layered oxide sodium electrode materials, Prussian blue sodium electrode materials, phosphate sodium electrode materials, fluorophosphate sodium electrode materials, fluorooxyphosphate sodium electrode materials, and pyrophosphate sodium electrode materials; the active metal chloride includes at least one of NbCl5, TaCl5, TiCl4, FeCl3, NiCl2, and VCl3. When the sodium electrode material is mixed with an active metal chloride, a sodium supplement is also added, wherein the sodium supplement includes at least one of NaCl, Na2CO3, NaOH, Na2O2, and Na2O.

8. The preparation method according to claim 6, characterized in that, The mechanochemical treatment is mechanical ball milling, with a ball milling speed of 600 rpm to 1000 rpm, a ball milling time of 6 h to 24 h, and a ball-to-material ratio of (20-60):

1.

9. The application of a multi-active-site solid electrolyte derived from the sodium-ion cathode as described in claim 1 in an all-solid-state sodium-ion battery.

10. The application of the sodium-ion battery with multiple active sites derived from the sodium-ion cathode according to claim 9 in an all-solid-state sodium-ion battery, characterized in that, The positive electrode of the all-solid-state ion battery is prepared by mixing a multi-active-site solid electrolyte derived from the sodium electrode positive electrode with sodium electrode positive electrode material and vapor-grown carbon fiber.

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