A strong oxide solid electrolyte and a preparation method and application thereof

Abstract

The application discloses a kind of strong toughness oxide solid electrolyte and its preparation method and application, the present application is by inorganic non-metallic material and oxide solid electrolyte according to inorganic non-metallic material 0.5~15% of total mass of inorganic non-metallic material and oxide solid electrolyte with inorganic non-metallic material is mixed, by cold pressing tablet after again through high-temperature solid-phase sintering to obtain strong toughness oxide solid electrolyte.Based on inorganic non-metallic material does not react with oxide solid electrolyte at high temperature, and can be reticular structure in solid electrolyte, and it has high elastic coefficient, high mechanical strength and other excellent performance, can significantly enhance the toughness and mechanical strength of oxide solid electrolyte after modification, simultaneously can also improve the conductivity of solid electrolyte after modification.In addition, the preparation method of the present application also has the advantages of material convenient and easy to obtain, method is simple.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of solid electrolyte, and relates to a strong and tough oxide solid electrolyte material and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of electric vehicles and portable electronic devices, energy storage devices have become increasingly important. However, commercial lithium-ion batteries have low energy density and high manufacturing cost, and have been unable to meet the demand of the rapidly developing electronic device and electric vehicle industries for energy storage devices. Therefore, various energy storage systems such as lithium metal batteries, sodium-ion batteries and lithium-sulfur batteries have been developed. The current energy storage systems all use organic liquid electrolytes. The above liquid electrolytes are prone to interact with some components in the battery to cause side reactions, thereby resulting in low coulombic efficiency of the battery and easy formation of dendrites, which eventually pierces the separator to cause internal short circuit, thermal runaway, combustion and explosion and a series of accidents.

[0003] Solid electrolytes have the advantages of long service life, high energy density, wide temperature range and high safety, and are the best choice to replace liquid electrolytes. In particular, oxide ceramic electrolytes have the advantages of high pressure resistance, high temperature resistance, difficulty in causing side reactions and high room temperature ionic conductivity. However, the above oxide ceramic electrolytes are prone to brittle fracture, which further hinders the large-scale production and application of such electrolytes. SUMMARY

[0004] In order to improve the above technical problems, the present application provides a strong and tough oxide solid electrolyte, which comprises an oxide solid electrolyte and an inorganic non-metallic material.

[0005] According to an embodiment of the present application, the inorganic non-metallic material accounts for 0.5-15% of the total mass of the oxide solid electrolyte and the inorganic non-metallic material, preferably 1-12%, and exemplarily 0.5%, 1%, 5%, 8%, 10%, 12%, 15%.

[0006] According to an embodiment of the present application, the oxide solid electrolyte is one, two or more of a garnet-type solid electrolyte Li7La3Zr2O12, a NASICON structure electrolyte Li10Zr2(PO4)3, a Na3V2(PO4)3, a Na3Zr2Si2PO12, and a perovskite structure solid electrolyte Li3La2TiO7. 12 or Li7La3Ti2O12, 12 , a NASICON structure electrolyte Li10Zr2(PO4)3, 1+x M x (Ti / Ge) 2-x (PO4)3, Na3Zr2Si2PO12, and a perovskite structure solid electrolyte Li3La2TiO7. 12 and a perovskite structure solid electrolyte Li3La2TiO7. 3y La 2 / 3–y TiO3.

[0007] Wherein, M is selected from one, two or more of Al, Cr, Ca; 0≤x≤0.5; 0.04

[0008] The oxide solid electrolyte of the present application can be prepared by high-temperature solid-phase method, sol-gel method or purchased through commercial channels.

[0009] According to an embodiment of the present application, the oxide solid electrolyte is in powder form, for example, with a particle size of 0.1-0.5 μm.

[0010] According to an embodiment of the present application, the inorganic non-metallic material is one, two or more of glass fiber and its derivatives, SiO2 aerogel and nano-glass; preferably, the glass fiber and its derivatives are one, two or more of glass wool, glass filament and glass fiber cloth, for example, borosilicate glass fiber (GF).

[0011] The present application also provides a method for preparing the strong and tough oxide solid electrolyte as described above, comprising mixing the oxide solid electrolyte with the inorganic non-metallic material, drying, tabletting, sintering to obtain the strong and tough oxide solid electrolyte.

[0012] According to an embodiment of the present application, the oxide solid electrolyte and the inorganic non-metallic material have the meanings as described above.

[0013] According to an embodiment of the present application, the drying is performed in a blast drying oven. For example, the drying temperature is 50-90 °C, preferably 60-80 °C. Further, the drying time is 6-48 h, preferably 24 h.

[0014] According to an embodiment of the present application, the tabletting is performed by cold pressing. For example, the diameter of the cold pressing mold is 10-16 mm, for example 10 mm, 12 mm, 13 mm, 15 mm, 16 mm, preferably 13 mm.

[0015] According to an embodiment of the present application, the pressure for tabletting is 5-50 MPa, for example 5 MPa, 10 MPa, 15 MPa, 20 MPa, 30 MPa, 40 MPa, 50 MPa, preferably 15 MPa.

[0016] According to an embodiment of the present application, the sintering is performed in two steps. The first step sintering temperature is 300-600 °C, for example 300 °C, 400 °C, 500 °C, 600 °C, preferably 500 °C; the holding time is 0.5-4 h, for example 0.5 h, 1 h, 2 h, 3 h, 4 h, preferably 1 h; the heating rate is 0.5-3 °C / min, preferably 1 °C / min.

[0017] According to an embodiment of the present application, the second step sintering temperature is 800-1200℃, exemplarily 800℃, 900℃, 1000℃, 1050℃, 1100℃, 1200℃, preferably 1050℃; the holding time is 1-12h, exemplarily 1h, 2h, 3h, 4h, 6h, 8h, 10h, 12h, preferably 2h; the heating rate is 1-7℃ / min, preferably 2℃ / min.

[0018] According to an embodiment of the present application, the preparation method comprises the following steps:

[0019] (1) mixing the solid electrolyte powder with inorganic non-metallic material according to the mass ratio, then grinding and drying in a blast drying oven to obtain a mixed powder;

[0020] (2) putting the mixed powder into a cold pressing mold and pressing into a tablet by cold pressing to obtain a tablet material;

[0021] (3) putting the tablet material into a muffle furnace for sintering to obtain a modified oxide solid electrolyte tablet.

[0022] The present application also provides the use of the above oxide solid electrolyte in a secondary battery. Preferably, the secondary battery includes solid-state, solid-liquid mixed-state lithium ion and sodium ion battery systems.

[0023] The present application also provides a secondary battery containing the above oxide solid electrolyte.

[0024] Preferably, the secondary battery includes solid-state, solid-liquid mixed-state lithium ion and sodium ion battery systems.

[0025] According to an embodiment of the present application, the secondary battery further comprises a positive electrode material and a negative electrode material.

[0026] Preferably, the positive electrode material includes polyanion type material, transition metal oxide material, Prussian blue type material, and material composed of oxygen group elements.

[0027] Preferably, the negative electrode material includes silicon-carbon material, lithium metal, sodium metal, alloy or intermetallic compound formed by lithium metal or sodium metal and other metals.

[0028] The present application also provides a preparation method of the above secondary battery, which comprises assembling the above oxide solid electrolyte with a positive electrode material and a negative electrode material into a secondary battery.

[0029] The present application has the following beneficial effects:

[0030] The application can be prepared by mixing inorganic non-metallic materials and oxide solid electrolyte in a certain proportion, and then sintering by high-temperature solid phase method, so as to obtain a strong and tough oxide solid electrolyte which has high temperature resistance, high pressure resistance, high room temperature ionic conductivity, long service life and high safety, and can significantly enhance the toughness and mechanical strength of the oxide solid electrolyte without affecting the conductivity. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is an optical photo of the LATP@GF solid electrolyte prepared by mixing LATP and borosilicate glass fiber.

[0032] Figure 2 It is an XRD spectrum of the LATP@GF solid electrolyte prepared by mixing LATP and glass fiber in the test range of 10-70° of the application.

[0033] Figure 3 It is the charge-discharge curve of the LiFePO4 battery assembled by the LATP@GF solid electrolyte prepared by mixing LATP and borosilicate glass fiber in Example 1 at a rate of 0.1C.

[0034] Figure 4 It is the impedance spectrum of the battery assembled by the LATP@GF solid electrolyte prepared by mixing LATP and borosilicate glass fiber in Example 1 and LiFePO4.

[0035] Figure 5 It is the force and displacement curve of the LATP@GF solid electrolyte prepared by mixing LATP and borosilicate glass fiber. DETAILED DESCRIPTION

[0036] The technical solutions of the application will be further described in detail below in combination with specific examples. It should be understood that the following examples are only illustrative and explanatory of the application, and should not be interpreted as limiting the scope of protection of the application. Any technology realized based on the above description of the application is covered within the scope of protection intended by the application.

[0037] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods;

[0038] The borosilicate glass fibers used in the following examples are purchased from the Cybo Electrochemical Material Network.

[0039] Example 1

[0040] (1) Referring to the literature Wang S, Ding Y, Zhou G, et al. Durability of the Li 1+x Ti 2–x Al x(PO4)3Solid Electrolyte in Lithium–Sulfur Batteries[J]. ACS Energy Letters, 2016, 1(6): 1080-1085. This paper discloses a method for preparing Lithium-sulfur batteries. 1.4 Al 0.4 Ti 1.6 (PO4)3(LATP);

[0041] (2) The LATP powder with a particle size of 0.3-0.4 μm obtained in step (1) is mixed with borosilicate glass fiber at a ratio of 8% of the total mass of borosilicate glass fiber and LATP. The mixture is then ground in an agate mortar for 1 hour and then dried in a forced-air drying oven at 60°C for 24 hours to obtain the mixed powder.

[0042] (3) The mixture powder obtained in step (2) is cold-pressed under a pressure of 15 MPa to form a disc with a diameter of 13 mm and a thickness of 0.9 mm.

[0043] (4) The sheet material obtained in step (3) is placed in a muffle furnace for sintering. The first sintering step is to heat the material from room temperature to 500℃ for 1 hour at a heating rate of 1℃ / min. Then, the temperature is raised to 1050℃ for 2 hours at a heating rate of 2℃ / min. After cooling to room temperature, a dense ceramic sheet is obtained, which is the modified oxide solid electrolyte (LATP@GF solid electrolyte) sheet.

[0044] Optical photographs of the modified oxide solid electrolyte (LATP@GF) prepared in this embodiment are shown below. Figure 1 As shown in the figure, the particle size of the modified oxide solid electrolyte (LATP@GF) is significantly larger than that of the unmodified LATP oxide solid electrolyte.

[0045] The XRD pattern of the modified oxide solid electrolyte (LATP@GF) prepared in this embodiment is as follows: Figure 2 As shown in the figure, LATP@GF oxide solid electrolyte was successfully prepared by mixing LATP with borosilicate glass fiber.

[0046] The modified oxide solid electrolyte (LATP@GF solid electrolyte) and LATP oxide solid electrolyte prepared in this embodiment were respectively assembled into all-solid-state lithium batteries, using lithium metal as the negative electrode and lithium iron phosphate as the positive electrode, to assemble a lithium metal-oxide solid electrolyte-lithium iron phosphate battery. All assembly experiments were carried out in an argon-filled glove box.

[0047] The assembled battery was subjected to electrochemical performance test, and the charge-discharge curve of the LATP@GF assembled LiFePO4 battery mixed with borosilicate glass fiber at a rate of 0.1C is shown in the following figure. Figure 3 As can be seen from the results in the figure, the specific capacity of the LATP@GF solid electrolyte at a rate of 0.1C is above 150 Ah / g, which has better specific capacity than the LATP oxide solid electrolyte without mixing borosilicate glass.

[0048] Figure 4 The impedance spectrum of the battery assembled by the LATP@GF solid electrolyte mixed with borosilicate glass fiber and LiFePO4 in this embodiment is shown in the following figure. As can be seen from the results in the figure, the conductivity of the modified oxide solid electrolyte (LATP@GF solid electrolyte) and the conductivity of the pure oxide solid electrolyte (LATP) both remain at the level of 10 -4 Scm -1 .

[0049] Figure 5 The force and displacement curve of the LATP@GF solid electrolyte mixed with borosilicate glass fiber is shown in the following figure. As can be seen from the results in the figure, the toughness and mechanical strength of the modified oxide solid electrolyte (LATP@GF solid electrolyte) are significantly enhanced compared with the pure oxide solid electrolyte (LATP). It is thus shown that the modified oxide solid electrolyte prepared by mixing inorganic non-metallic materials with oxide solid electrolyte at a certain proportion and then sintering at high temperature can not only significantly enhance the toughness and mechanical strength of the electrolyte, but also improve the conductivity of the assembled battery.

[0050] Example 2

[0051] (1) Refer to the method disclosed in the literature Narayanan S, Reid S, Butler S, et al. Sintering temperature, excess sodium, and phosphorous dependencies on morphology and ionic conductivity of NASICON Na3Zr2Si2PO 12 [J]. Solid State Ionics, 2019, 331: 22-29 to prepare Na3Zr2Si2PO 12 (NZSP);

[0052] (2) The NZSP powder with a particle size of 0.4-0.5 μm prepared in step (1) is mixed with borosilicate glass fibers in a ratio of 8% of the borosilicate glass fibers to the total mass of the borosilicate glass fibers and the NZSP, and then ground in an agate mortar for 1 h, and then dried in a blast drying oven at 60°C for 24 h to obtain a mixed powder;

[0053] (3) The mixed powder prepared in step (2) is cold-pressed under a pressure of 15 MPa to form a disc with a diameter of 13 mm and a thickness of 0.9 mm;

[0054] (4) The disc-shaped material prepared in step (3) is sintered in a muffle furnace, and first sintered at a temperature rising rate of 1°C / min from room temperature to 500°C for 1 h. Then the temperature is raised to 1050°C at a temperature rising rate of 2°C / min for 2 h, and then cooled to room temperature to obtain a dense ceramic disc, i.e. a modified oxide solid electrolyte disc.

[0055] Example 3

[0056] (1) Li7La3Zr2O 12 (LLZO) with a particle size of 0.25-0.5 μm (purchased from Changsha Mining Research Institute Co., Ltd.) is dried in a blast drying oven at 60°C for 12 h;

[0057] (2) The LLZO powder prepared in step (1) is mixed with borosilicate glass fibers in a ratio of 8% of the borosilicate glass fibers to the total mass of the borosilicate glass fibers and the LLZO, and then ground in an agate mortar for 1 h, and then dried in a blast drying oven at 60°C for 24 h to obtain a mixed powder;

[0058] (3) The mixed powder prepared in step (2) is cold-pressed under a pressure of 15 MPa to form a disc with a diameter of 13 mm and a thickness of 0.9 mm;

[0059] (4) The disc-shaped material prepared in step (3) is sintered in a muffle furnace, and first sintered at a temperature rising rate of 1°C / min from room temperature to 500°C for 1 h. Then the temperature is raised to 1050°C at a temperature rising rate of 2°C / min for 2 h, and then cooled to room temperature to obtain a dense ceramic disc, i.e. a modified oxide solid electrolyte disc.

[0060] Example 4

[0061] (1) Li 1.4 Al 0.4 Ge 1.6 (PO4)3(LAGP) with a particle size of 0.1-0.2 μm (purchased from Changsha Mining Research Institute Co., Ltd.) is dried in a blast drying oven at 60°C for 12 h;

[0062] (2) The LAGP powder prepared in step (1) is mixed with borosilicate glass fibers in a ratio of 8% of the total mass of borosilicate glass fibers to LAGP in a marble mortar and ground for 1 h, and then dried in a blast drying oven at 60°C for 24 h to obtain a mixed powder;

[0063] (3) The mixed powder prepared in step (2) is cold-pressed at a pressure of 15 MPa to form a disc with a diameter of 13 mm and a thickness of 0.9 mm;

[0064] (4) The disc-shaped material prepared in step (3) is placed in a muffle furnace for sintering, and first sintering is performed at a temperature increasing rate of 1°C / min from room temperature to 500°C for 1 h. Subsequently, sintering is performed at a temperature increasing rate of 2°C / min from room temperature to 1050°C for 2 h, and a dense ceramic disc, i.e., a modified oxide solid electrolyte disc, is obtained after cooling to room temperature.

[0065] Example 5

[0066] (1) Li7La3Ti2O 12 (LLTO) (purchased from Changsha Mining Research Institute Co., Ltd.) with a particle size of 0.25-0.5 μm is dried in a blast drying oven at 60°C for 12 h;

[0067] (2) The LLTO powder prepared in step (1) is mixed with borosilicate glass fibers in a ratio of 8% of the total mass of borosilicate glass fibers to LLTO in a marble mortar and ground for 1 h, and then dried in a blast drying oven at 60°C for 24 h to obtain a mixed powder;

[0068] (3) The mixed powder prepared in step (2) is cold-pressed at a pressure of 15 MPa to form a disc with a diameter of 13 mm and a thickness of 0.9 mm;

[0069] (4) The disc-shaped material prepared in step (3) is placed in a muffle furnace for sintering, and first sintering is performed at a temperature increasing rate of 1°C / min from room temperature to 500°C for 1 h. Subsequently, sintering is performed at a temperature increasing rate of 2°C / min from room temperature to 1050°C for 2 h, and a dense ceramic disc, i.e., a modified oxide solid electrolyte disc, is obtained after cooling to room temperature.

[0070] The inventors have unexpectedly found through a large number of experimental studies that the modified oxide solid electrolyte prepared by mixing different types of oxide electrolytes with inorganic non-metallic materials and then sintering by high-temperature solid phase sintering has high toughness and mechanical strength and has substantially the same performance as that of Example 1.

[0071] Comparative Example 1

[0072] The other conditions are the same as in Example 1, except that in Step 2 the powder is only Li 1.4 Al 0.4 Ti 1.6 (PO4)3(LATP), without mixing borosilicate glass fibers Figure 1 ).

[0073] Comparative Example 2

[0074] The other conditions are the same as in Example 2, except that in Step 2 the powder is only Na3Zr2Si2(PO4)3(NZSP), without mixing borosilicate glass fibers.

[0075] Comparative Example 3:

[0076] The other conditions are the same as in Example 3, except that in Step 2 the powder is only Li7La3Zr2O 12 (LLZO), without mixing borosilicate glass fibers.

[0077] Comparative Example 4:

[0078] The other conditions are the same as in Example 4, except that in Step 2 the powder is only Li 1.4 Al 0.4 Ge 1.6 (PO4)3(LAGP), without mixing borosilicate glass fibers.

[0079] Comparative Example 5:

[0080] The other conditions are the same as in Example 5, except that in Step 2 the powder is only Li7La3Ti2O 12 (LLTO), without mixing borosilicate glass fibers.

[0081] The inventors have found through extensive experimental research that the oxide solid electrolytes of the inorganic non-metallic materials of Comparative Examples 2-5 all have substantially the same performance as Comparative Example 1.

[0082] The above describes embodiments of the present application. However, the present application is not limited to the above-described embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for producing a strong oxide solid electrolyte, characterized by, The preparation method comprises mixing, drying, tabletting and sintering the oxide solid electrolyte and inorganic non-metallic material to obtain the strong and tough oxide solid electrolyte. The sintering is divided into two steps, the first step is sintering at a temperature of 300-600 DEG C, and the holding time is 0.5-4 h. The heating rate is 0.5-3 DEG C / min. The second step is sintering at a temperature of 800-1200 DEG C, and the holding time is 1-12 h, and the heating rate is 1-7 DEG C / min. The oxide solid electrolyte comprises an oxide solid electrolyte and an inorganic non-metallic material. The inorganic non-metallic material accounts for 1-12% of the total mass of the oxide solid electrolyte and the inorganic non-metallic material. The oxide solid electrolyte is one, two or more of a garnet-type solid electrolyte Li7La3Zr2O 12 or Li7La3Ti2O 12 , a NASICON-structure electrolyte Li 1+x M x (Ti / Ge) 2-x (PO4)3, Na3Zr2Si2PO 12 and a perovskite-structure solid electrolyte Li 3y La 2 / 3–y TiO3 M is selected from one, two or more of Al, Cr and Ca; 0<=x<=0.5; 0.04<=y<=0.

16. The inorganic non-metallic material is borosilicate glass fiber.

2. The production method according to claim 1, wherein The oxide solid electrolyte is a powder with a particle size of 0.1-0.5 μm.

3. The method of claim 1, wherein the solid electrolyte is prepared by the steps of: preparing a solution of a lithium salt and a lithium alkoxyate; and adding a lithium alkoxyate to the solution of the lithium salt and the lithium alkoxyate. The drying is carried out in a blast drying oven at a drying temperature of 50-90 DEG C, and the drying time is 6-48 h.

4. The production method according to claim 1, wherein The tabletting is carried out by cold pressing, and the diameter of the cold pressing mold is 10-16 mm. And / or, the pressure of the tabletting is 5-50 MPa.

5. The production method according to any one of claims 1 to 4, wherein The preparation method comprises the following steps: (1) The solid electrolyte powder and the inorganic non-metallic material are mixed according to the above mass ratio, then ground, and then placed in a blast drying oven to obtain a mixed powder; (2) The mixed powder is placed in a cold pressing mold, and the tabletting is carried out by cold pressing to obtain a sheet material; (3) The sheet material is placed in a muffle furnace for sintering to obtain a modified oxide solid electrolyte sheet.

6. The application of the oxide solid electrolyte prepared by the preparation method of any one of claims 1-5 in a secondary battery. The secondary battery comprises a solid-state or solid-liquid hybrid lithium ion and sodium ion battery system.

7. A secondary battery characterized by comprising: The secondary battery comprises a solid-state or solid-liquid hybrid lithium ion and sodium ion battery system.

8. The secondary battery according to claim 7, wherein The secondary battery further comprises a positive electrode material and a negative electrode material.

9. The secondary battery according to claim 7, wherein the negative electrode is a lithium metal electrode. The positive electrode material comprises a polyanion material, a transition metal oxide material, a Prussian blue material and an oxygen group element material.

10. The secondary battery according to claim 9, wherein The negative electrode material comprises a silicon-carbon material, lithium metal, sodium metal, an alloy or intermetallic compound formed by lithium metal or sodium metal and other metals. The preparation method comprises assembling the oxide solid electrolyte prepared by the preparation method of any one of claims 1-5 with a positive electrode material and a negative electrode material to obtain a secondary battery.

11. The method of producing a secondary battery according to any one of claims 7 to 10, characterized by, ​

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