A tungsten and halogen co-doped solid electrolyte with high electrical conductivity and its preparation method

Abstract

The tungsten and halogen co-doped high-conductivity solid electrolyte disclosed by the present invention is a sodium-ion chalcogenide electrolyte, and its main crystal structure is the cubic phase c-Na3SbS4. This solid electrolyte is a glass-ceramic structure in which a high-conductivity c-Na3SbS4 crystal is wrapped by a glass matrix. The composition formula of the solid electrolyte is aNa2S-bSb2S3-cWS2-dS-eNaM, where M is any one of the elements Cl, Br, and I, and a, b, c, d, and e are all molar ratios, 0.3 ≤ a ≤ 1.2, 0.1 ≤ b ≤ 0.4, 0.2 ≤ c ≤ 0.8, d = 1, and e = c. The solid electrolyte of the present invention has a high room-temperature ionic conductivity, good stability, and a low activation energy, greatly improving the ion transport efficiency. The sodium-ion chalcogenide electrolyte prepared by the preparation method of the present invention has a dense structure, few impurities, higher crystallinity, a high room-temperature ionic conductivity, and strong performance controllability.

Description

Technical Field

[0001] The present invention belongs to the technical field of sodium ion solid electrolytes and their preparation, and particularly relates to a highly conductive solid electrolyte co-doped with tungsten and halogen and a preparation method thereof. Background Art

[0002] With the rapid development of the new energy vehicle industry, the demand for lithium-ion batteries is increasing day by day. However, due to the approaching exhaustion of global effective lithium resources, lithium-ion batteries are insufficient to support the large-scale development of the new energy vehicle industry. At the same time, traditional lithium-ion batteries use liquid organic electrolytes, and there are safety problems such as internal thermal runaway of the battery caused by overcharging, fire sources, extrusion, puncture, short circuits, etc., resulting in inflammability and explosiveness. Therefore, it is urgent to develop new electrolyte materials.

[0003] On the one hand, sodium ion solid-state batteries use solid electrolytes, which can effectively avoid problems such as short-circuit thermal runaway caused by electrolyte leakage inside the battery, and have higher safety than lithium-ion liquid electrolytes. On the other hand, sodium resources are abundant, raw materials are easy to obtain, and the price is lower than that of lithium ions. Against the background of the continuous rise in lithium prices and resource shortages, sodium ion solid-state batteries have emerged and are gradually developing rapidly in fields with lower energy density requirements such as grid energy storage, low-speed electric vehicles, and home energy storage. However, as a new type of battery, the development and application of solid-state sodium batteries still face challenges in terms of technology, materials, etc. In particular, the performance of solid electrolyte materials such as ionic conductivity and air stability needs to be further improved.

[0004] Inorganic chalcogenide electrolyte materials have become a key research direction for solid electrolyte materials due to their high room temperature ionic conductivity and excellent processing performance. However, as a key material for sodium ion batteries, the room temperature conductivity of sodium ion chalcogenide electrolytes is relatively low, which greatly limits the application of sodium ion chalcogenide solid-state batteries. Based on Na 3 SbS 4 The sodium ion chalcogenide solid electrolyte of the system is the most common sodium ion superionic conductor electrolyte at present, and is also restricted by problems such as low ionic conductivity and poor air stability. Among them, Na + In Na 3 SbS 4 The transmission path and rate in the lattice are the main reasons restricting ionic conductivity. Some specifically prepared Na 3 SbS 4 Contains two crystal structures, tetragonal t-Na 3 SbS 4 And cubic c-Na 3 SbS 4 Among them, in tetragonal t-Na 3 SbS 4 In SbS 43- A slight rotation of the polyhedron about the

[111] axis results in two crystallographically independent Na + positions (i.e. Wyckoff 4d and 2a). Due to polyhedral rotation and Na + displacement, the lattice parameter increases away from unity compared to c / a, resulting in a tetragonal structure. 3 Sb 4 SbS in the structure 4 3- The polyhedra are arranged in a body-centered cubic lattice with a crystallographic Na + position (Wyckoff 6b), resulting in a large amount of Na + A jump at this point generates Na + The interstitial site (Wyckoff12d), c-Na 3 Sb 4 Therefore, it has a higher defect concentration, making Na + It is more conductive in the crystal lattice.

[0005] At present, there are two main methods for preparing sulfide solid electrolytes. One is the common high-energy ball milling method. The microstructure of the solid electrolyte prepared by this method is not dense enough, the crystal growth is not enough, and c-Na 3 Sb 4 The other is the high-temperature melting method. Although this method can improve the density of the solid electrolyte, its high-temperature treatment time is long (> 10 hours), the energy consumption is high, and the S in the raw material is easily released at high temperature, resulting in c-Na 3 Sb 4 Structural collapse is not conducive to the stability of the ion transport structure, so the optimized preparation process has an important influence on the improvement of ion conductivity.

[0006] In order to improve the ionic conductivity, the method used also includes heterovalent element doping, that is, in the original c-Na 3 Sb 4 The original structure of the crystal is destroyed by adding other elements in the raw material ratio to expand the structural space of ion transmission and obtain higher ion transmission efficiency. However, most of the existing methods are single element doping methods, and the room temperature ion conductivity is mostly 10 -3 S / cm, it is difficult to further improve the conductivity performance, resulting in great limitations on the development and application of sodium-ion solid-state batteries with high energy density, long cycle life, and mechanical and thermal stability. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a highly conductive solid electrolyte co-doped with tungsten and halogen with high room temperature ionic conductivity and good stability, in view of the deficiencies of the prior art.

[0008] The technical solution adopted by the present invention to solve the above technical problems is as follows: A highly conductive solid electrolyte co-doped with tungsten and halogen, wherein the solid electrolyte is a sodium-ion chalcogenide electrolyte co-doped with tungsten and halogen, and its main crystal structure is cubic phase c-Na 3 SbS 4 ; the solid electrolyte is a glass-ceramic structure in which a high-conductivity c-Na 3 SbS 4 crystal is wrapped by a glass matrix; the composition formula of the solid electrolyte is aNa 2 S-bSb 2 S 3 -cWS 2 -dS-eNaM, where M is any one of the elements Cl, Br, and I, and a, b, c, d, and e are all molar ratios, 0.3 ≤ a ≤ 1.2, 0.1 ≤ b ≤ 0.4, 0.2 ≤ c ≤ 0.8, d = 1, and e = c.

[0009] In the present invention, two elements, tungsten and halogen, are co-doped in the sodium-ion chalcogenide electrolyte. The incorporation of tungsten can effectively introduce Na 3 SbS 4 vacancies into the lattice by replacing Sb in c-Na + SbS + . Similarly, since the halogen replaces the S element, Na + vacancies can also be formed in the lattice, accelerating the generation of Na + vacancies, promoting the effect of ion transport, and at the same time reducing the activation energy and increasing the transport rate of sodium ions. With the increase in the doping amounts of tungsten and halogen, the generated Na 3 SbS 4 vacancies are divided into two sites on the a–b plane around the Na1 site in c-Na -2 SbS -3 and form a 2D conduction channel with Na1. Along the c-axis, the Na1 connected by Na2 forms a 1D Na chain of Na-Na1-Na2, constructing a sodium-ion migration path based on a 3D migration network. The size of such an ion transport path (especially along the c-axis) increases, raising the room temperature ionic conductivity of the solid electrolyte to above 10

[0010] The inventors of the present invention also have the following three findings:

[0011] First, the high-conductivity solid electrolyte co-doped with tungsten and halogen of the present invention is not a completely crystallized structure, but mainly shows a c-Na 3 SbS 4 glass-ceramic solid electrolyte. Due to the glass-ceramic structure of the solid electrolyte of the present invention, which is a glass matrix encapsulating high-conductivity c-Na 3 SbS 4 crystals, this solid electrolyte not only has high conductivity, but also good mechanical properties, and can be cold-pressed into shape at room temperature with high density.

[0012] Second, when the element M in the solid electrolyte of the present invention is selected as Cl element, the room-temperature ionic conductivity can be as high as 16.1×10 -3 S / cm, which is related to the strong electronegativity and smaller ionic radius of Cl ions. The Cl element can efficiently replace the S element, and the smaller radius causes less damage to the original electrolyte structure, maintaining the good structural compactness of the electrolyte.

[0013] Third, when the solid electrolyte of the present invention is exposed to air, the release of H 2 S can be reduced. This benefits from the crystal structure of c-Na 3 SbS 4 itself, which follows the Hard-Soft-Acid-Base principle. Based on the strong electrostatic attraction between the soft acid Sb 5+ and the soft base S 2- , the SbS 4 2- ionic group is more stable in air.

[0014] The preparation method of the high-conductivity solid electrolyte co-doped with tungsten and halogen of the present invention includes the following steps:

[0015] (1) Weigh the raw materials Na 2 S, Sb 2 S 3 , WS 2 , S and NaM in proportion, and respectively crush and screen them under the condition of anhydrous and anaerobic protected by inert gas to obtain the powdery raw materials Na 2 S, Sb 2 S 3 , WS 2 , S and NaM. Put the above powdery raw materials into a ball mill for ball milling, and after screening under the condition of anhydrous and anaerobic protected by inert gas, the obtained mixed powder is the precursor;

[0016] (2) Press the precursor into shape, put it into a quartz tube, evacuate the quartz tube to 10 -3 Pa, and then seal the quartz tube;

[0017] (3) Place the sealed quartz tube into an annealing furnace for high-temperature heat treatment. First, heat it at a heating rate of 1 °C / min to 300 - 700 °C, then anneal it at 300 - 700 °C for 6 - 12 h, and then cool it to room temperature at a cooling rate of 1 °C / min. Open the quartz tube to obtain a high-conductivity solid electrolyte co-doped with tungsten and halogen.

[0018] The preparation method of the high-conductivity solid electrolyte co-doped with tungsten and halogen in the present invention optimizes the process by combining mechanical ball milling and high-temperature heat treatment in the sodium-ion chalcogenide electrolyte c-Na 3 SbS 4 and simultaneously dopes it with two elements, tungsten and halogen. By controlling the ball milling parameters and heat treatment parameters, the cubic phase c-Na 3 SbS 4 is efficiently synthesized. The annealing treatment at 300 - 700 °C can make the electrolyte fully crystallize, compensating for the problem that the crystals of the electrolyte prepared by the single ball milling method are not dense enough; controlling the annealing time at 6 - 12 h can avoid the desulfurization reaction of the electrolyte at high temperature, thereby synthesizing a sufficient amount of c-Na 3 SbS 4 .

[0019] Preferably, in step (1), the anhydrous and anaerobic condition is: the water content is lower than 1 ppm and the oxygen content is lower than 1 ppm.

[0020] Preferably, in step (1), the conditions for the mixed ball milling treatment are: the rotation speed is 300 - 700 rpm and the ball milling time is 5 - 30 h.

[0021] Preferably, in step (1), the conditions for the mixed ball milling treatment are: the rotation speed is 400 - 500 rpm, the ball-to-material ratio is 7:5, the ball milling time is 10 - 20 h, and during the ball milling, scraping treatment is carried out every 5 h.

[0022] Preferably, in step (2), the pressure for pressing the precursor into a mold is 480 MPa, and before vacuum pumping, the body of the quartz tube is wound with a heating tape and the quartz tube is sealed with a blowtorch.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. High room-temperature ionic conductivity

[0025] In the present invention, two elements, tungsten and halogen, are simultaneously doped in the sodium-ion chalcogenide electrolyte. Through the co-substitution strategy of anions and cations, Sb and S in c-Na 3 SbS 4 are replaced, generating a large number of sodium-ion vacancies, which greatly improves the room-temperature ionic conductivity of the sodium-ion chalcogenide electrolyte, up to 16.1×10-3 S / cm, and has a low activation energy of 0.0805 eV, greatly improving the ion transport efficiency. The present invention solves the energy density problem of sodium-ion chalcogenide electrolytes, provides new ideas for the development of sodium-ion chalcogenide electrolyte materials, and can support the large-scale development of sodium-ion solid-state batteries.

[0026] 2. Good stability

[0027] In the solid electrolyte of the present invention, c-Na 3 SbS 4 its crystal structure itself follows the Hard-Soft-Acid-Base principle. Due to the strong electrostatic attraction between the soft acid Sb 5+ and the soft base S 2- the bS 4 2- ionic group is more stable in air. Thus, the solid electrolyte of the present invention only releases a small amount of H 2 S in air. And the introduction of halogen, on the one hand, replaces the S element, which can reduce the content of the SbS 4 2- ionic group and increase the air stability; on the other hand, halogen has a strong electronegativity and has an attraction to the matrix ions in the electrolyte structure, so that the activation energy of the sample can be reduced to 0.0805 eV, and the electronic conductivity can be reduced to 4.97×10 -7 mS / cm. Thus, it can avoid the dendrite growth and subsequent internal short-circuit problems caused by component reasons in all-solid-state sodium-ion batteries.

[0028] 3. Optimization of the preparation process

[0029] The preparation method of the present invention uses an optimized process combining mechanical ball milling and high-temperature heat treatment. The prepared sodium-ion chalcogenide electrolyte has a dense structure, few impurities, higher crystallinity, high room-temperature ionic conductivity, and strong performance controllability. This benefits from the fact that the raw materials before high-temperature heat treatment react sufficiently by high-energy ball milling to form a uniform precursor, so that not only c-Na 3 SbS 4 with a higher crystal growth degree is formed under high-temperature heat treatment conditions, but also the doping of tungsten and halogen is promoted, solving the problem of efficient synthesis of c-Na 3 SbS 4 . BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 XRD patterns of the samples of Examples 1 to 4;

[0031] Figure 2 XRD patterns of the samples of Comparative Examples 1 to 4;

[0032] Figure 3 XRD patterns of the samples of Comparative Examples 7 to 10;

[0033] Figure 4 Raman spectra of the samples of Examples 1 to 4;

[0034] Figure 5 Raman spectra of the samples of Comparative Examples 1 to 4;

[0035] Figure 6 Raman spectra of the samples of Comparative Examples 7 to 10;

[0036] Figure 7 3D transport path of sodium ions in c-Na 3 SbS 4 simulated by computer software;

[0037] Figure 8 Mapping results of different elements on the surface of the cylindrical sheet samples of Examples 1 to 4;

[0038] Figure 9 Nyquist plots of the samples of Comparative Examples 1 to 6;

[0039] Figure 10 Nyquist plots of the samples of Comparative Examples 7 to 10;

[0040] Figure 11 Nyquist plots of the samples of Examples 1 to 3;

[0041] Figure 12 H of the sample powders of Examples 1 to 4 at 48% relative humidity 2 S release amount vs. exposure time;

[0042] Figure 13 Change in resistance value shown by the Nyquist plot after the samples of Examples 1 to 4 are exposed to air for 1 h. Detailed implementation mode

[0043] The present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0044] Four examples and ten comparative examples were selected. The specific molar composition formulas are shown in Table 1. Among them, Comparative Examples 1 to 6 are not doped with halogens, and Comparative Examples 7 to 10 are not doped with tungsten.

[0045] The solid electrolytes of the examples and comparative examples were respectively processed into cylindrical sheets with a diameter of 10 mm and a thickness of about 1 - 2 mm by the preparation method of the present invention. The specific preparation method includes the following steps:

[0046] (1) Weigh the raw materials proportionally: Na with a purity of 95%, 2 Sb with a purity of 99%, 2 S 3 WS with a purity of 99% (if any), 2 S with a purity of 99.99% and NaM with a purity of 99.99% (if any). Crush and sieve them respectively under the condition of anhydrous and anaerobic protected by inert gas to obtain powdery raw materials. Then put the powdery raw materials into a ball mill for mixed ball milling. After sieving under the condition of anhydrous and anaerobic protected by inert gas, the obtained mixed powder is the precursor;

[0047] Among them, in step (1), the anhydrous and anaerobic condition is: the water content is lower than 1 ppm and the oxygen content is lower than 1 ppm. The conditions for the mixed ball milling are: the rotation speed is 500 rpm, the ball-to-material ratio is 7:5, and the ball milling time is 10 h. And during the ball milling, scraping treatment is carried out every 5 h;

[0048] (2) Press the precursor into a mold at a pressure of 480 MPa, put it into a quartz tube. First, wind the heating tape around the tube body of the quartz tube to prevent deliquescence and assist in vacuum pumping. Then pump the quartz tube to a vacuum of 10 -3 Pa, and seal the quartz tube with a blowtorch. The above operations are all carried out in a glove box filled with argon;

[0049] (3) Put the sealed quartz tube into an annealing furnace for high-temperature heat treatment. First, heat it at a heating rate of 1 °C / min to 600 °C, then anneal it at 600 °C for 6 h, and then cool it to room temperature at a cooling rate of 1 °C / min. Transfer the quartz tube to a glove box filled with argon, and open the quartz tube to obtain the solid electrolyte.

[0050] Table 1 The molar composition formulas of the examples and comparative examples of the present invention

[0051] Sample Number Molar Composition Formula Abbreviation Example 1 <![CDATA[1.125Na 2 S-0.325Sb 2 S 3 -0.25WS 2 -1S-0.25NaI]]> <![CDATA[WI 0.25 > Example 2 <![CDATA[1.125Na 2 S-0.325Sb 2 S 3 -0.25WS 2 -1S-0.25NaBr]]> <![CDATA[WBr 0.25 > Example 3 <![CDATA[1.125Na 2 S-0.325Sb 2 S 3 -0.25WS 2 -1S-0.25NaCl]]> <![CDATA[WCl 0.25 > Example 4 <![CDATA[0.9Na 2 S - 0.3Sb 2 S 3 - 0.4WS 2 - 1S - 0.4NaCl]]> <![CDATA[WCl 0.4 > Comparative Example 1 <![CDATA[1.45Na 2 S-0.45Sb 2 S 3 -0.1WS 2 -1S]]> <![CDATA[W 0.1 <!-- 4 -->]]> Comparative Example 2 <![CDATA[1.4Na 2 S-0.4Sb 2 S 3 -0.2WS 2 -1S]]> <![CDATA[W 0.2 > Comparative Example 3 <![CDATA[1.35Na 2 S-0.35Sb 2 S 3 -0.3WS 2 -1S]]> <![CDATA[W 0.3 > Comparative Example 4 <![CDATA[1.3Na 2 S-0.3Sb 2 S 3 -0.4WS 2 -1S]]> <![CDATA[W 0.4 > Comparative Example 5 <![CDATA[1.2Na 2 S-0.2Sb 2 S 3 -0.6WS 2 -1S]]> <![CDATA[W 0.6 > Comparative Example 6 <![CDATA[1.1Na 2 S - 0.1Sb 2 S 3 -0.8WS 2 -1S]]> <![CDATA[W 0.8 > Comparative Example 7 <![CDATA[1.25Na 2 S-0.5Sb 2 S 3 -0.5S-0.25NaI]]> <![CDATA[I 0.25 > Comparative Example 8 <![CDATA[1.25Na 2 S - 0.5Sb 2 S 3 - 0.5S - 0.25NaBr]]> <![CDATA[Br 0.25 > Comparative Example 9 <![CDATA[1.25Na 2 S - 0.5Sb 2 S 3 -0.5S - 0.25NaCl]]> <![CDATA[Cl 0.25 > Comparative Example 10 <![CDATA[1.1Na 2 S - 0.5Sb 2 S 3 -0.5S - 0.4NaCl]]> <![CDATA[Cl 0.4 >

[0052] Grind the electrolyte samples obtained from Example 1 to Example 4 and Comparative Example 1 to Comparative Example 10 into powder in a glove box filled with argon, and conduct structure tests, electrochemical performance tests and air stability tests respectively to obtain various performance parameters such as the microstructural information and conductivity of the samples.

[0053] Use an X-ray diffraction system (D2 PHASER, Germany) to evaluate the microstructure of each electrolyte sample. Use Cu-Kα target as the X-ray source and scan in the angle range of 10° - 70° at a step size of 0.06° / min. The XRD patterns of the samples of Example 1 to Example 4 are shown in Figure 1 , and the XRD patterns of the samples of Comparative Example 1 to Comparative Example 4 are shown in Figure 2, the XRD patterns of the samples of Comparative Examples 7 to 10 are shown in Figure 3 . From the comparative XRD patterns, it can be seen that under the action of tungsten and / or halogen, new diffraction peaks appear in the XRD pattern of the sodium-ion chalcogenide electrolyte.

[0054] Raman spectroscopy was used to evaluate the structure of each electrolyte sample. The Raman spectra were measured by a Renishaw inVia system with an excitation source of a 785 nm light source, and the range was 100 - 700 cm -1 . The Raman spectra of the samples of Examples 1 to 4 are shown in Figure 4 , the Raman spectra of the samples of Comparative Examples 1 to 4 are shown in Figure 5 , the Raman spectra of the samples of Comparative Examples 7 to 10 are shown in Figure 6 . From the comparative Raman spectra, it can be seen that under the action of tungsten and / or halogen, new chemical bonds appear in the Raman pattern.

[0055] Figure 7 is the 3D transmission path of sodium ions in c-Na 3 SbS 4 simulated by computer software. As can be seen from Figure 7 , the Na + vacancies generated by tungsten and halogen are divided into two sites on the a–b plane around the Na1 site and form a 2D conduction channel with Na1. Along the c-axis, Na1 connected by Na2 forms a 1D Na chain of Na-Na1-Na2. Therefore, a sodium-ion migration path based on a 3D migration network is constructed.

[0056] Figure 8 is the mapping of different elements on the surface of the cylindrical sheet sample detected by an energy dispersive spectrometer (Oxford EDS Inca Energy Coater), and it can be seen that different elements are evenly distributed on the surface of the sample. Figure 8 The four small figures (d), (e), (f), and (g) in

[0057] correspond to the cylindrical sheet samples of Examples 1, 2, 3, and 4 respectively. 6 On an electrochemical workstation (CHI660e), the electrochemical performance was studied using AC complex impedance with an amplitude of 10 mV and a frequency range of 1 - 10 Figure 9 is the Nyquist plot of the samples of Comparative Examples 1 to 6, Figure 10 is the Nyquist plot of the samples of Comparative Examples 7 to 10, Figure 11 is the Nyquist plot of the samples of Examples 1 to 3. It can be seen that when the M element is selected as the Cl element and the e value is 0.25, the lowest resistance obtained is 5.55 Ω, and the corresponding conductivity is 16.1×10 -3 S / cm.

[0058] Figure 12 The H 2 S release amounts of the sample powders of Examples 1 to 4 at 48% relative humidity versus exposure time. H 2 S gas sensor (Drager PAC6500 H 2 S) was used to detect the H 2 S release amount in the sample. Under the conditions of an ambient temperature of 25°C and a humidity of 48%, 140 mg of the sample powder was placed in a sealed container with a tester. From Figure 12 It can be seen that the solid electrolyte of the present invention doped with tungsten and halogen has good air stability.

[0059] Figure 13 For the change in the resistance values shown by the Nyquist plots after the samples of Examples 1 to 4 were exposed to air for 1 h. From Figure 13 It can be seen that the solid electrolyte of the present invention doped with tungsten and halogen can still maintain a low impedance after contacting air.

Claims

1. A high-conductivity solid electrolyte co-doped with tungsten and halogen, characterized in that, The solid electrolyte described is a sodium-ion chalcogenide electrolyte doped with both tungsten and halogen, and its main crystal structure is the cubic phase c-Na 3 SbS 4 , the solid electrolyte is a glass-ceramic structure with a high-conductivity c-Na 3 SbS 4 crystal encapsulated by a glass matrix. The composition formula of the solid electrolyte is aNa 2 S-bSb 2 S 3 -cWS 2 -dS-eNaM, where M is any one element of Cl, Br, and I, and a, b, c, d, and e are all molar ratios, 0.3 ≤ a ≤ 1.2, 0.1 ≤ b ≤ 0.4, 0.2 ≤ c ≤ 0.8, d = 1, and e = c.

2. A method for preparing the high-conductivity solid electrolyte co-doped with tungsten and halogen according to claim 1, characterized in that, it includes the following steps: (1) Weigh the raw materials Na 2 S, Sb 2 S 3 , WS 2 , S and NaM proportionally, and crush and sieve them respectively under the condition of anhydrous and anaerobic with inert gas protection to obtain the powdery raw materials Na 2 S, Sb 2 S 3 , WS 2 , S and NaM. Put the above powdery raw materials into a ball mill for ball milling, and after sieving under the condition of anhydrous and anaerobic with inert gas protection, the obtained mixed powder is the precursor; (2) Press the precursor into a mold, place it in a quartz tube, evacuate the quartz tube to 10 -3 Pa, and then seal the quartz tube hermetically; (3) Put the sealed quartz tube into an annealing furnace for high-temperature heat treatment. First, heat it at a heating rate of 1 °C / min to 300-700 °C, then anneal it at a temperature of 300-700 °C for 6-12 h, and then cool it to room temperature at a cooling rate of 1 °C / min. Open the quartz tube to obtain the high-conductivity solid electrolyte co-doped with tungsten and halogen.

3. According to the method for preparing the high-conductivity solid electrolyte co-doped with tungsten and halogen according to claim 2, characterized in that, in step (1), the anhydrous and oxygen-free condition is: the water content is lower than 1 ppm and the oxygen content is lower than 1 ppm.

4. According to the method for preparing the high-conductivity solid electrolyte co-doped with tungsten and halogen according to claim 2, characterized in that, in step (1), the conditions for the mixed ball milling treatment are: the rotation speed is 300-700 rpm and the ball milling time is 5-30 h.

5. According to the method for preparing the high-conductivity solid electrolyte co-doped with tungsten and halogen according to claim 4, characterized in that, in step (1), the conditions for the mixed ball milling treatment are: the rotation speed is 400-500 rpm, the ball-to-material ratio is 7:5, the ball milling time is 10-20 h, and during the ball milling, scraping treatment is carried out every 5 h.

6. According to the method for preparing the high-conductivity solid electrolyte co-doped with tungsten and halogen according to claim 2, characterized in that, in step (2), the pressure used for pressing the precursor into shape is 480 MPa, and before vacuum pumping, the body of the quartz tube is wound with a heating tape and the quartz tube is sealed with a blowtorch.

Images