Rapid purification and preparation method of sodium super-ion conductor solid electrolyte powder

Abstract

The invention relates to the field of sodium ion batteries, in particular to a method for rapidly purifying and preparing sodium super-ionic conductor solid electrolyte powder, which is used for solving the problem that the ionic conductivity of the sodium solid electrolyte is poor due to low purity of the existing sodium super-ionic conductor solid electrolyte. Adverse effects on the electrochemical performance and the safety of the sodium solid-state battery are caused; according to the invention, the sodium super-ionic conductor solid electrolyte powder with high ionic conductivity and high purity is prepared through the methods of doping, full mixing of materials and physical high pressure, and after the sodium super-ionic conductor solid electrolyte powder is applied to a sodium solid-state battery, the comprehensive electrochemical performance of the sodium solid-state battery can be improved to the same level as that of an organic electrolyte sodium-ion battery; the sodium super-ionic conductor solid electrolyte powder has the advantages that the defect of energy density of sodium-ion batteries is overcome, popularization of the sodium-ion batteries in new energy automobiles and energy storage markets is promoted, and the preparation method of the sodium super-ionic conductor solid electrolyte powder is simple and easy to implement, low in cost and suitable for large-scale production.

Description

Technical Field

[0001] The present invention relates to the field of sodium ion batteries, and specifically to a method for rapidly purifying and preparing sodium superionic conductor solid electrolyte powder. Background Art

[0002] With the continuous development of electric vehicles and energy storage, the application of lithium batteries has experienced exponential growth. The safety performance and energy density of batteries are inevitable requirements for the development of lithium batteries. Currently, the mainstream electrolyte for lithium ion batteries is organic electrolyte, which exhibits flammability and brings a large number of safety hazards. Therefore, the development of non-flammable solid electrolytes has become the technical route for the next generation of energy storage batteries. However, the proportion of lithium in the earth's crust is extremely low and cannot meet the wide application of electrochemical energy storage. Sodium, as a rich element in the earth's crust, can promote the wide application of electrochemical energy storage in life. However, sodium ion batteries also have problems such as low energy density and poor safety of the layered oxygen battery system. To solve the problems of insufficient safety and energy density of sodium ion batteries, sodium solid-state batteries are a good solution.

[0003] Sodium solid electrolytes are mainly divided into polymer solid electrolytes, oxide solid electrolytes, and sulfide solid electrolytes. Among them, the ionic conductivities of polymer solid electrolytes and sulfide solid electrolytes are relatively low, and sulfide solid electrolytes will produce poisonous gases during the preparation process. Therefore, the development of oxide solid electrolytes has become a primary choice. Oxide solid electrolytes are mainly sodium superionic conductor type solid electrolytes. However, during the preparation of sodium superionic conductor solid electrolyte powder, impure oxides are produced, the preparation process is difficult, and the improvement of ionic conductivity has also become an inevitable task. Therefore, how to rapidly produce high-purity and high-ionic-conductivity sodium superionic solid electrolyte powder in large quantities has become a difficult point in the research and development of sodium solid-state batteries.

[0004] Therefore, it is of great significance to develop a method for rapidly purifying and preparing sodium superionic conductor solid electrolyte powder. Summary of the Invention

[0005] In order to overcome the above technical problems, the purpose of the present invention is to provide a method for rapidly purifying and preparing sodium superionic conductor solid electrolyte powder, which solves the problems that the existing sodium superionic conductor type solid electrolyte has low purity, resulting in poor ionic conductivity of the sodium solid electrolyte, adversely affecting the electrochemical performance and safety of the sodium solid-state battery, and restricting the large-scale promotion of sodium ion batteries in the field of electrochemical energy storage.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A method for rapidly purifying and preparing sodium superionic conductor solid electrolyte powder includes the following steps:

[0008] Step 1: Add sodium carbonate, nano-silica, nano-zirconia, ammonium dihydrogen phosphate, and an additive into a ball milling tank. Then, add mixed zirconium beads according to a bead-to-material ratio of 2:1. Next, ball mill for 12 h under the condition that the ball milling speed is 300 - 400 r / min. After that, pass through a 200-mesh sieve to obtain a raw material mixture of solid electrolyte powder.

[0009] Step 2: Load the raw material mixture of solid electrolyte into an alumina crucible. Then, place the alumina crucible into a high-temperature furnace for calcination. After the calcination is completed, naturally cool it to room temperature to obtain a pre-calcined material of solid electrolyte powder.

[0010] Step 3: Add the pre-calcined material of solid electrolyte powder into a ball milling tank. Then, add mixed zirconium beads according to a bead-to-material ratio of 2:1. Next, ball mill for 12 h under the condition that the ball milling speed is 300 - 400 r / min. After that, pass through a 200-mesh sieve to obtain a pre-calcined, ball-milled, and sieved material.

[0011] Step 4: Put the pre-calcined, ball-milled, and sieved material into a tablet pressing mold, control the tablet pressing thickness to be 0.5 cm, and then perform tablet pressing to obtain a tablet of solid electrolyte powder.

[0012] Step 5: Load the tablet of solid electrolyte powder into an alumina crucible. Then, place the alumina crucible into a high-temperature furnace for calcination. After the calcination is completed, naturally cool it to room temperature, then perform crushing, then pass through a 300-mesh sieve, then add it to absolute ethanol for sand milling until the particle size is 100 - 300 nm, and then place it in a vacuum drying oven and vacuum dry at a temperature of 80 - 100 °C to obtain a sodium superionic conductor solid electrolyte powder.

[0013] As a preferred embodiment of the present invention, the molar ratio of the sodium carbonate, nano-silica, nano-zirconia, ammonium dihydrogen phosphate, and additive in Step 1 is 1.5 - 1.65:1.8 - 2.0:1.8 - 2.0:1.0 - 1.2:0 - 0.25.

[0014] As a preferred embodiment of the present invention, the additive in Step 1 is one or a mixture of two of zinc oxide and magnesium oxide in any molar ratio.

[0015] As a preferred embodiment of the present invention, the oxygen inlet flow rate during the calcination treatment in Step 2 is 20 - 50 mL / min, the heating rate is 1 - 5 °C / min, the calcination temperature is 950 °C, and the calcination time is 6 h.

[0016] As a preferred embodiment of the present invention, the mixed zirconium beads in Step 1 and Step 3 are composed of zirconium beads with particle sizes of 5 mm, 10 mm, and 20 mm mixed in an equal quantity ratio.

[0017] As a preferred embodiment of the present invention, the tableting process in step 4 has a pressure range of 5-35 MPa and a tableting time of 10-60 min.

[0018] As a preferred embodiment of the present invention, the oxygen inlet flow rate of the calcination treatment in step five is 10-30 mL / min, the heating rate is 1-3°C / min, the calcination temperature is 1200-1300°C and the calcination time is 20-36h.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The invention discloses a method for rapidly purifying and preparing sodium superion conductor solid electrolyte powder, which increases the content of different Na + The bottleneck size and tunnel size between bits reduce the Na + The migration energy wall can significantly improve the ionic conductivity of the sodium superion solid electrolyte. Then, by subjecting the powder to high pressure and long-term static tableting, the interparticle gaps between the nanoparticles are reduced, and the atomic migration energy during the high-temperature sintering process is reduced, thereby promoting the rapid formation of solid electrolyte crystals and reducing the generation of oxide impurities, effectively improving the purity of the final solid electrolyte powder product. This high-purity, high-ionic conductivity sodium superion solid electrolyte powder can be used in sodium solid-state batteries to effectively improve the electrochemical performance and safety of the battery.

[0021] In summary, a sodium superionic conductor solid electrolyte powder with high ionic conductivity and high purity is prepared by doping, sufficient material mixing, and physical high pressure. When used in sodium solid-state batteries, the comprehensive electrochemical performance of sodium solid-state batteries can be improved to the same level as that of organic electrolyte sodium-ion batteries, thereby providing key material support for sodium solid-state batteries with high safety, high energy density, and high electrochemical performance, filling the gap in energy density of sodium-ion batteries, and promoting the promotion of sodium batteries in new energy vehicles and energy storage markets. Moreover, the preparation method of the sodium superionic conductor solid electrolyte powder is simple, easy, low-cost, and suitable for large-scale production. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1.1

[0024] This embodiment is a method for rapidly purifying and preparing sodium superionic conductor solid electrolyte powder, comprising the following steps:

[0025] Step 1: Add 79.5 g of sodium carbonate, 120.2 g of nano-silica, 246.4 g of nano-zirconia, and 115 g of ammonium dihydrogen phosphate into a ball milling tank. Then, add a mixed zirconia bead mixture with a particle size of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to a bead-to-material ratio of 2:1. After that, ball mill for 12 h at a ball milling speed of 400 r / min, and then pass through a 200-mesh sieve to obtain the raw material mixture of the solid electrolyte powder;

[0026] Step 2: Load the raw material mixture of the solid electrolyte into an alumina crucible, and then place the alumina crucible into a high-temperature furnace. Heat it to 950 °C and calcine for 6 h under the conditions of an oxygen flow rate of 50 mL / min and a heating rate of 1 °C / min. After the calcination is completed, naturally cool it to room temperature to obtain the pre-calcined material of the solid electrolyte powder;

[0027] Step 3: Add the pre-calcined material of the solid electrolyte powder into a ball milling tank. Then, add a mixed zirconia bead mixture with a particle size of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to a bead-to-material ratio of 2:1. After that, ball mill for 12 h at a ball milling speed of 400 r / min, and then pass through a 200-mesh sieve to obtain the pre-calcined, ball-milled, and sieved material;

[0028] Step 4: Put the pre-calcined, ball-milled, and sieved material into a tablet press mold, control the tablet thickness to be 0.5 cm, and then perform tablet pressing treatment for 60 min under a pressure of 5 MPa to obtain the solid electrolyte powder tablet;

[0029] Step 5: Load the solid electrolyte powder tablet into an alumina crucible, and then place the alumina crucible into a high-temperature furnace. Heat it to 1250 °C and calcine for 36 h under the conditions of an oxygen flow rate of 10 mL / min and a heating rate of 2 °C / min. After the calcination is completed, naturally cool it to room temperature, then perform crushing treatment, then pass through a 300-mesh sieve, then add it to anhydrous ethanol and sand mill until the particle size is 100 - 200 nm, and then place it in a vacuum drying oven and vacuum dry at a temperature of 80 °C to obtain the sodium superionic conductor solid electrolyte powder.

[0030] Example 1.2

[0031] The difference between this embodiment and Example 1.1 is that the pressure in Step 4 is 10 MPa.

[0032] Example 1.3

[0033] This embodiment is different from Embodiment 1.1 in that the pressure in Step 4 is 20 MPa.

[0034] Embodiment 1.4

[0035] This embodiment is different from Embodiment 1.1 in that the pressure in Step 4 is 35 MPa.

[0036] Embodiment 2.1

[0037] This embodiment is a method for rapidly purifying and preparing sodium superionic conductor solid electrolyte powder, comprising the following steps:

[0038] Step 1: Add 84.8 g of sodium carbonate, 108.2 g of nano-silica, 246.4 g of nano-zirconia, and 138 g of ammonium dihydrogen phosphate into a ball milling tank, then add a mixed zirconia bead mixture with a particle size of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to a bead-to-material ratio of 2:1, and then ball mill for 12 h under the condition of a ball milling speed of 350 r / min, and then pass through a 200-mesh sieve to obtain a raw material mixture of solid electrolyte powder;

[0039] Step 2: Load the raw material mixture of solid electrolyte into an alumina crucible, then place the alumina crucible into a high-temperature furnace, and heat it to 950 °C and calcine for 6 h under the conditions of an oxygen flow rate of 30 mL / min and a heating rate of 2 °C / min. After calcination, naturally cool it to room temperature to obtain a pre-calcined solid electrolyte powder;

[0040] Step 3: Add the pre-calcined solid electrolyte powder into a ball milling tank, then add a mixed zirconia bead mixture with a particle size of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to a bead-to-material ratio of 2:1, and then ball mill for 12 h under the condition of a ball milling speed of 350 r / min, and then pass through a 200-mesh sieve to obtain a pre-calcined, ball-milled, and sieved material;

[0041] Step 4: Put the pre-calcined, ball-milled, and sieved material into a tablet press mold, control the tablet thickness to be 0.5 cm, and then perform tablet pressing treatment for 60 min under the condition of a pressure of 5 MPa to obtain a solid electrolyte powder tablet;

[0042] Step 5: Load the solid electrolyte powder tablet into an alumina crucible, then place the alumina crucible into a high-temperature furnace, and heat it to 1250 °C and calcine for 36 h under the conditions of an oxygen flow rate of 30 mL / min and a heating rate of 3 °C / min. After calcination, naturally cool it to room temperature, then perform crushing treatment, then pass through a 300-mesh sieve, then add it to anhydrous ethanol and perform sand milling until the particle size is 100 - 200 nm, and then place it in a vacuum drying oven and vacuum dry it at a temperature of 80 °C to obtain sodium superionic conductor solid electrolyte powder.

[0043] Example 2.2

[0044] The difference between this example and Example 2.1 is that the pressure in Step 4 is 10 MPa.

[0045] Example 2.3

[0046] The difference between this example and Example 2.1 is that the pressure in Step 4 is 20 MPa.

[0047] Example 2.4

[0048] The difference between this example and Example 2.1 is that the pressure in Step 4 is 35 MPa.

[0049] Example 3.1

[0050] This example is a method for rapidly purifying and preparing sodium superionic conductor solid electrolyte powder, including the following steps:

[0051] Step 1: Add 87.5 g of sodium carbonate, 108.2 g of nano-silica, 246.4 g of nano-zirconia, and 115 g of ammonium dihydrogen phosphate into a ball milling tank, then add a mixed zirconia bead mixture with a particle size of 5 mm, 10 mm, and 20 mm in a ratio of 2:1 by bead-to-material ratio and mixed in equal quantity ratio, and then ball mill for 12 h under the condition of a ball milling speed of 400 r / min, and then pass through a 200-mesh sieve to obtain the raw material mixture of solid electrolyte powder;

[0052] Step 2: Load the raw material mixture of solid electrolyte into an alumina crucible, then place the alumina crucible into a high-temperature furnace, and heat it to 950 °C and calcine for 6 h under the conditions of an oxygen flow rate of 20 mL / min and a heating rate of 5 °C / min. After calcination, naturally cool to room temperature to obtain the pre-calcined solid electrolyte powder;

[0053] Step 3: Add the pre-calcined solid electrolyte powder into a ball milling tank, then add a mixed zirconia bead mixture with a particle size of 5 mm, 10 mm, and 20 mm in a ratio of 2:1 by bead-to-material ratio and mixed in equal quantity ratio, and then ball mill for 12 h under the condition of a ball milling speed of 400 r / min, and then pass through a 200-mesh sieve to obtain the pre-calcined, ball-milled, and sieved material;

[0054] Step 4: Put the pre-calcined, ball-milled, and sieved material into a tablet press mold, control the tablet thickness to be 0.5 cm, and then perform tablet pressing treatment for 60 min under the condition of a pressure of 5 MPa to obtain the solid electrolyte powder tablet;

[0055] Step 5: Press the solid electrolyte powder into tablets and place them in an alumina crucible. Then, put the alumina crucible into a high-temperature furnace and heat it to 1250 °C at a heating rate of 2 °C / min with an oxygen flow rate of 30 mL / min for calcination for 36 h. After the calcination is completed, let it cool naturally to room temperature, then perform a crushing treatment, then pass through a 300-mesh sieve, then add it to absolute ethanol and grind it to a particle size of 100 - 200 nm, and then place it in a vacuum drying oven and vacuum dry it at a temperature of 80 °C to obtain the sodium superionic conductor solid electrolyte powder.

[0056] Example 3.2

[0057] The difference between this example and Example 3.1 is that the pressure in Step 4 is 10 MPa.

[0058] Example 3.3

[0059] The difference between this example and Example 3.1 is that the pressure in Step 4 is 20 MPa.

[0060] Example 3.4

[0061] The difference between this example and Example 3.1 is that the pressure in Step 4 is 35 MPa.

[0062] Example 4.1

[0063] This example is a method for rapidly purifying and preparing sodium superionic conductor solid electrolyte powder, including the following steps:

[0064] Step 1: Add 79.5 g of sodium carbonate, 108.2 g of nano-silica, 246.4 g of nano-zirconia, and 115 g of ammonium dihydrogen phosphate to a ball mill tank. Then, add a mixed zirconia bead mixture with a particle size of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to a bead-to-material ratio of 2:1. Then, ball mill for 12 h at a ball mill speed of 350 r / min, and then pass through a 200-mesh sieve to obtain the raw material mixture of the solid electrolyte powder;

[0065] Step 2: Load the raw material mixture of the solid electrolyte into an alumina crucible. Then, put the alumina crucible into a high-temperature furnace and heat it to 950 °C at a heating rate of 2 °C / min with an oxygen flow rate of 20 mL / min for calcination for 6 h. After the calcination is completed, let it cool naturally to room temperature to obtain the pre-calcined solid electrolyte powder;

[0066] Step 3: Add the pre-sintered solid electrolyte powder into a ball milling jar, then add mixed zirconium beads with diameters of 5 mm, 10 mm, and 20 mm, which are mixed in equal quantity ratios, according to a bead-to-material ratio of 2:1. Then, ball mill for 12 h under the condition of a ball milling speed of 350 r / min, and then pass through a 200-mesh sieve to obtain the pre-sintered, ball-milled, and sieved material;

[0067] Step 4: Put the pre-sintered, ball-milled, and sieved material into a tablet pressing mold, control the tablet pressing thickness to be 0.5 cm, and then perform tablet pressing treatment for 60 min under the condition of a pressure of 5 MPa to obtain a solid electrolyte powder tablet;

[0068] Step 5: Load the solid electrolyte powder tablet into an alumina crucible, then put the alumina crucible into a high-temperature furnace, heat it to 1250 °C and calcine for 36 h under the conditions of an oxygen flow rate of 30 mL / min and a heating rate of 5 °C / min. After calcination, naturally cool to room temperature, then perform crushing treatment, then pass through a 300-mesh sieve, then add it to absolute ethanol and sand mill until the particle size is 100 - 200 nm, and then place it in a vacuum drying oven and vacuum dry at a temperature of 90 °C to obtain a sodium superionic conductor solid electrolyte powder.

[0069] Example 4.2

[0070] The difference between this example and Example 4.1 is that the pressure in Step 4 is 10 MPa.

[0071] Example 4.3

[0072] The difference between this example and Example 4.1 is that the pressure in Step 4 is 20 MPa.

[0073] Example 4.4

[0074] The difference between this example and Example 4.1 is that the pressure in Step 4 is 35 MPa.

[0075] Example 5.1

[0076] This example is a method for rapidly purifying and preparing a sodium superionic conductor solid electrolyte powder, including the following steps:

[0077] Step 1: Add 87.5 g of sodium carbonate, 120.2 g of nano-silica, 246.4 g of nano-zirconia, and 126.5 g of ammonium dihydrogen phosphate into a ball milling jar, then add mixed zirconium beads with diameters of 5 mm, 10 mm, and 20 mm, which are mixed in equal quantity ratios, according to a bead-to-material ratio of 2:1. Then, ball mill for 12 h under the condition of a ball milling speed of 300 r / min, and then pass through a 200-mesh sieve to obtain a raw material mixture of solid electrolyte powder;

[0078] Step 2: Load the raw material mixture of the solid electrolyte into an alumina crucible, then place the alumina crucible into a high-temperature furnace, and heat it to 950 °C at a heating rate of 5 °C / min with an oxygen flow rate of 10 mL / min for calcination for 6 h. After the calcination is completed, naturally cool it to room temperature to obtain the pre-calcined material of the solid electrolyte powder;

[0079] Step 3: Add the pre-calcined material of the solid electrolyte powder into a ball mill tank, then add a mixed zirconia bead mixture composed of zirconia beads with particle sizes of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to the bead-to-material ratio of 2:1. Then, ball mill for 12 h under the condition of a ball mill speed of 400 r / min, and then pass through a 200-mesh sieve to obtain the pre-calcined, ball-milled, and sieved material;

[0080] Step 4: Place the pre-calcined, ball-milled, and sieved material into a tablet press mold, control the tablet thickness to be 0.5 cm, and then perform tablet pressing treatment for 60 min under the condition of a pressure of 5 MPa to obtain the solid electrolyte powder tablet;

[0081] Step 5: Load the solid electrolyte powder tablet into an alumina crucible, then place the alumina crucible into a high-temperature furnace, and heat it to 1250 °C at a heating rate of 3 °C / min with an oxygen flow rate of 20 mL / min for calcination for 36 h. After the calcination is completed, naturally cool it to room temperature, then perform crushing treatment, then pass through a 300-mesh sieve, then add it to anhydrous ethanol for sand milling until the particle size is 100 - 200 nm, and then place it in a vacuum drying oven and vacuum dry it at a temperature of 100 °C to obtain the sodium superionic conductor solid electrolyte powder.

[0082] Example 5.2

[0083] The difference between this example and Example 5.1 is that the pressure in Step 4 is 10 MPa.

[0084] Example 5.3

[0085] The difference between this example and Example 5.1 is that the pressure in Step 4 is 20 MPa.

[0086] Example 5.4

[0087] The difference between this example and Example 5.1 is that the pressure in Step 4 is 35 MPa.

[0088] Example 6.1

[0089] This example is a method for rapidly purifying and preparing sodium superionic conductor solid electrolyte powder, including the following steps:

[0090] Step 1: Add 79.5 g of sodium carbonate, 120.2 g of nano-silica, 221.8 g of nano-zirconia, and 115 g of ammonium dihydrogen phosphate into a ball milling tank. Then, add mixed zirconium beads with diameters of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to the bead-to-material ratio of 2:1. After that, ball mill for 12 h at a ball milling speed of 400 r / min, and then pass through a 200-mesh sieve to obtain the raw material mixture of the solid electrolyte powder;

[0091] Step 2: Load the raw material mixture of the solid electrolyte into an alumina crucible, and then put the alumina crucible into a high-temperature furnace. Heat it to 950 °C and calcine for 6 h under the conditions of an oxygen flow rate of 50 mL / min and a heating rate of 3 °C / min. After the calcination is completed, let it cool naturally to room temperature to obtain the pre-calcined material of the solid electrolyte powder;

[0092] Step 3: Add the pre-calcined material of the solid electrolyte powder into a ball milling tank. Then, add mixed zirconium beads with diameters of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to the bead-to-material ratio of 2:1. After that, ball mill for 12 h at a ball milling speed of 400 r / min, and then pass through a 200-mesh sieve to obtain the pre-calcined, ball-milled, and sieved material;

[0093] Step 4: Put the pre-calcined, ball-milled, and sieved material into a tablet press mold, control the tablet thickness to be 0.5 cm, and then perform tablet pressing for 60 min under a pressure of 5 MPa to obtain the pressed tablet of the solid electrolyte powder;

[0094] Step 5: Load the pressed tablet of the solid electrolyte powder into an alumina crucible, and then put the alumina crucible into a high-temperature furnace. Heat it to 1250 °C and calcine for 36 h under the conditions of an oxygen flow rate of 10 mL / min and a heating rate of 5 °C / min. After the calcination is completed, let it cool naturally to room temperature, then perform crushing treatment, then pass through a 300-mesh sieve, then add it to anhydrous ethanol and perform sand milling until the particle size reaches 100 - 200 nm, and then place it in a vacuum drying oven and vacuum dry at a temperature of 80 °C to obtain the sodium superionic conductor solid electrolyte powder.

[0095] Example 6.2

[0096] The difference between this example and Example 6.1 is that the pressure in Step 4 is 10 MPa.

[0097] Example 6.3

[0098] The difference between this example and Example 6.1 is that the pressure in Step 4 is 20 MPa.

[0099] Example 6.4

[0100] This embodiment is different from Embodiment 6.1 in that the pressure in Step 4 is 35 MPa.

[0101] Embodiment 7.1

[0102] This embodiment is a method for rapidly purifying and preparing sodium superionic conductor solid electrolyte powder, including the following steps:

[0103] Step 1: Add 79.5 g of sodium carbonate, 120.2 g of nano-silica, 234.1 g of nano-zirconia, 115 g of ammonium dihydrogen phosphate, and 8.1 g of zinc oxide into a ball milling tank. Then, add a mixed zirconia bead mixture with a particle size of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to a bead-to-material ratio of 2:1. After that, ball mill for 12 h under the condition of a ball milling speed of 300 r / min, and then pass through a 200-mesh sieve to obtain the raw material mixture of the solid electrolyte powder.

[0104] Step 2: Load the raw material mixture of the solid electrolyte into an alumina crucible, and then place the alumina crucible into a high-temperature furnace. Heat it to 950 °C and calcine for 6 h under the conditions of an oxygen flow rate of 20 mL / min and a heating rate of 2 °C / min. After the calcination is completed, naturally cool it to room temperature to obtain the pre-calcined material of the solid electrolyte powder.

[0105] Step 3: Add the pre-calcined material of the solid electrolyte powder into a ball milling tank. Then, add a mixed zirconia bead mixture with a particle size of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to a bead-to-material ratio of 2:1. After that, ball mill for 12 h under the condition of a ball milling speed of 300 r / min, and then pass through a 200-mesh sieve to obtain the pre-calcined, ball-milled, and sieved material.

[0106] Step 4: Put the pre-calcined, ball-milled, and sieved material into a tablet press mold, control the tablet thickness to be 0.5 cm, and then perform tablet pressing treatment for 60 min under the condition of a pressure of 5 MPa to obtain the solid electrolyte powder tablet.

[0107] Step 5: Load the solid electrolyte powder tablet into an alumina crucible, and then place the alumina crucible into a high-temperature furnace. Heat it to 1250 °C and calcine for 36 h under the conditions of an oxygen flow rate of 10 mL / min and a heating rate of 2 °C / min. After the calcination is completed, naturally cool it to room temperature, then perform crushing treatment, then pass through a 300-mesh sieve, then add it to absolute ethanol and grind it to a particle size of 100 - 200 nm, and then place it in a vacuum drying oven and vacuum dry it at a temperature of 80 °C to obtain the sodium superionic conductor solid electrolyte powder.

[0108] Embodiment 7.2

[0109] This embodiment is different from Embodiment 7.1 in that the pressure in Step 4 is 10 MPa.

[0110] Example 7.3

[0111] The difference between this example and Example 7.1 is that the pressure in Step 4 is 20 MPa.

[0112] Example 7.4

[0113] The difference between this example and Example 7.1 is that the pressure in Step 4 is 35 MPa.

[0114] Example 8.1

[0115] This example is a method for rapidly purifying and preparing sodium superionic conductor solid electrolyte powder, including the following steps:

[0116] Step 1: Add 84.8 g of sodium carbonate, 108.2 g of nano-silica, 234.1 g of nano-zirconia, 138 g of ammonium dihydrogen phosphate, and 8.1 g of zinc oxide into a ball mill tank. Then, add a mixed zirconia bead mixture with a particle size of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to a bead-to-material ratio of 2:1. Then, ball mill for 12 h under the condition of a ball mill speed of 400 r / min, and then pass through a 200-mesh sieve to obtain a raw material mixture of solid electrolyte powder;

[0117] Step 2: Load the raw material mixture of solid electrolyte into an alumina crucible, and then place the alumina crucible into a high-temperature furnace. Heat it to 950 °C and calcine for 6 h under the conditions of an oxygen flow rate of 30 mL / min and a heating rate of 2 °C / min. After calcination, naturally cool it to room temperature to obtain a pre-calcined solid electrolyte powder;

[0118] Step 3: Add the pre-calcined solid electrolyte powder into a ball mill tank. Then, add a mixed zirconia bead mixture with a particle size of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to a bead-to-material ratio of 2:1. Then, ball mill for 12 h under the condition of a ball mill speed of 350 r / min, and then pass through a 200-mesh sieve to obtain a pre-calcined, ball-milled, and sieved material;

[0119] Step 4: Put the pre-calcined, ball-milled, and sieved material into a tablet press mold, control the tablet thickness to be 0.5 cm, and then perform tablet pressing treatment for 60 min under the condition of a pressure of 5 MPa to obtain a solid electrolyte powder tablet;

[0120] Step 5: Press the solid electrolyte powder into tablets and place them in an alumina crucible. Then, put the alumina crucible into a high-temperature furnace and heat it to 1250 °C at a heating rate of 3 °C / min with an oxygen flow rate of 30 mL / min for 36 h. After the calcination is completed, let it cool naturally to room temperature, then perform a crushing treatment, then pass through a 300-mesh sieve, then add it to absolute ethanol and grind it until the particle size reaches 100 - 200 nm, and then place it in a vacuum drying oven and dry it under vacuum at a temperature of 80 °C to obtain the sodium superionic conductor solid electrolyte powder.

[0121] Example 8.2

[0122] The difference between this example and Example 8.1 is that the pressure in Step 4 is 10 MPa.

[0123] Example 8.3

[0124] The difference between this example and Example 8.1 is that the pressure in Step 4 is 20 MPa.

[0125] Example 8.4

[0126] The difference between this example and Example 8.1 is that the pressure in Step 4 is 35 MPa.

[0127] Example 9.1

[0128] This example is a method for rapidly purifying and preparing sodium superionic conductor solid electrolyte powder, which includes the following steps:

[0129] Step 1: Add 87.5 g of sodium carbonate, 108.2 g of nano-silica, 234.1 g of nano-zirconia, 115 g of ammonium dihydrogen phosphate, 4.05 g of zinc oxide, and 2.0 g of magnesium oxide into a ball mill tank. Then, add a mixed zirconia bead mixture with a particle size of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to a bead-to-material ratio of 2:1. Then, ball mill for 12 h at a ball mill speed of 400 r / min, and then pass through a 200-mesh sieve to obtain the raw material mixture of the solid electrolyte powder.

[0130] Step 2: Load the raw material mixture of the solid electrolyte into an alumina crucible. Then, put the alumina crucible into a high-temperature furnace and heat it to 950 °C at a heating rate of 5 °C / min with an oxygen flow rate of 20 mL / min for 6 h. After the calcination is completed, let it cool naturally to room temperature to obtain the pre-calcined solid electrolyte powder.

[0131] Step 3: Add the pre-sintered solid electrolyte powder into a ball milling jar, and then add mixed zirconium beads with diameters of 5 mm, 10 mm, and 20 mm in a 2:1 bead-to-material ratio, which are mixed in an equal quantity ratio. Then, ball mill for 12 h under the condition of a ball milling speed of 400 r / min, and then pass through a 200-mesh sieve to obtain the pre-sintered, ball-milled, and sieved material;

[0132] Step 4: Put the pre-sintered, ball-milled, and sieved material into a tablet press mold, control the tablet thickness to be 0.5 cm, and then perform tablet pressing for 60 min under the condition of a pressure of 5 MPa to obtain a solid electrolyte powder tablet;

[0133] Step 5: Load the solid electrolyte powder tablet into an alumina crucible, and then put the alumina crucible into a high-temperature furnace. Heat it to 1250 °C and calcine for 36 h under the conditions of an oxygen flow rate of 30 mL / min and a heating rate of 2 °C / min. After calcination, cool it naturally to room temperature, then perform crushing treatment, then pass through a 300-mesh sieve, then add it to absolute ethanol and sand mill until the particle size is 100 - 200 nm, and then place it in a vacuum drying oven and vacuum dry at a temperature of 80 °C to obtain sodium superionic conductor solid electrolyte powder.

[0134] Example 9.2

[0135] The difference between this example and Example 9.1 is that the pressure in Step 4 is 10 MPa.

[0136] Example 9.3

[0137] The difference between this example and Example 9.1 is that the pressure in Step 4 is 20 MPa.

[0138] Example 9.4

[0139] The difference between this example and Example 9.1 is that the pressure in Step 4 is 35 MPa.

[0140] Example 10.1

[0141] This example is a method for rapidly purifying and preparing sodium superionic conductor solid electrolyte powder, including the following steps:

[0142] Step 1: Add 79.5 g of sodium carbonate, 108.2 g of nano-silica, 234.1 g of nano-zirconia, 115 g of ammonium dihydrogen phosphate, 4.05 g of zinc oxide, and 2.0 g of magnesium oxide into a ball milling jar, and then add mixed zirconium beads with diameters of 5 mm, 10 mm, and 20 mm in a 2:1 bead-to-material ratio, which are mixed in an equal quantity ratio. Then, ball mill for 12 h under the condition of a ball milling speed of 350 r / min, and then pass through a 200-mesh sieve to obtain the raw material mixture of solid electrolyte powder;

[0143] Step 2: Load the solid electrolyte raw material mixture into an alumina crucible, then place the alumina crucible into a high-temperature furnace, and heat it to 950 °C for 6 h under the conditions of an oxygen flow rate of 20 mL / min and a heating rate of 2 °C / min. After the calcination is completed, let it cool naturally to room temperature to obtain a pre-calcined solid electrolyte powder;

[0144] Step 3: Add the pre-calcined solid electrolyte powder into a ball mill tank, then add a mixed zirconium bead composed of zirconium beads with particle sizes of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to the bead-to-material ratio of 2:1. Then ball mill for 12 h under the condition of a ball mill speed of 350 r / min, and then pass through a 200-mesh sieve to obtain a pre-calcined, ball-milled, and sieved material;

[0145] Step 4: Place the pre-calcined, ball-milled, and sieved material into a tablet press mold, control the tablet thickness to be 0.5 cm, and then perform tablet pressing treatment for 60 min under the condition of a pressure of 5 MPa to obtain a solid electrolyte powder tablet;

[0146] Step 5: Load the solid electrolyte powder tablet into an alumina crucible, then place the alumina crucible into a high-temperature furnace, and heat it to 1250 °C for 36 h under the conditions of an oxygen flow rate of 30 mL / min and a heating rate of 5 °C / min. After the calcination is completed, let it cool naturally to room temperature, then perform crushing treatment, then pass through a 300-mesh sieve, then add it to absolute ethanol and perform sand milling until the particle size reaches 100 - 200 nm, and then place it in a vacuum drying oven and vacuum dry at a temperature of 90 °C to obtain a sodium superionic conductor solid electrolyte powder.

[0147] Example 10.2

[0148] The difference between this example and Example 10.1 is that the pressure in Step 4 is 10 MPa.

[0149] Example 10.3

[0150] The difference between this example and Example 10.1 is that the pressure in Step 4 is 20 MPa.

[0151] Example 10.4

[0152] The difference between this example and Example 10.1 is that the pressure in Step 4 is 35 MPa.

[0153] Example 11.1

[0154] This example is a method for rapidly purifying and preparing a sodium superionic conductor solid electrolyte powder, including the following steps:

[0155] Step 1: Add 87.5 g of sodium carbonate, 120.2 g of nano-silica, 234.1 g of nano-zirconia, 126.5 g of ammonium dihydrogen phosphate, and 4.0 g of magnesium oxide into a ball mill tank. Then, add a mixed zirconia bead with a diameter of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to the bead-to-material ratio of 2:1. After that, ball mill for 12 h under the condition of a ball mill speed of 300 r / min, and then pass through a 200-mesh sieve to obtain a solid electrolyte powder raw material mixture;

[0156] Step 2: Load the solid electrolyte raw material mixture into an alumina crucible, and then place the alumina crucible into a high-temperature furnace. Heat it to 950 °C and calcine for 6 h under the conditions of an oxygen flow rate of 10 mL / min and a heating rate of 5 °C / min. After the calcination is completed, naturally cool it to room temperature to obtain a pre-calcined solid electrolyte powder;

[0157] Step 3: Add the pre-calcined solid electrolyte powder into a ball mill tank. Then, add a mixed zirconia bead with a diameter of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to the bead-to-material ratio of 2:1. After that, ball mill for 12 h under the condition of a ball mill speed of 400 r / min, and then pass through a 200-mesh sieve to obtain a pre-calcined ball milled and sieved material;

[0158] Step 4: Put the pre-calcined ball milled and sieved material into a tablet press mold, control the tablet thickness to be 0.5 cm, and then perform tablet pressing treatment for 60 min under the condition of a pressure of 5 MPa to obtain a solid electrolyte powder tablet;

[0159] Step 5: Load the solid electrolyte powder tablet into an alumina crucible, and then place the alumina crucible into a high-temperature furnace. Heat it to 1250 °C and calcine for 36 h under the conditions of an oxygen flow rate of 20 mL / min and a heating rate of 3 °C / min. After the calcination is completed, naturally cool it to room temperature, then perform crushing treatment, and then pass through a 300-mesh sieve. Then add it to anhydrous ethanol and sand mill until the particle size is 100 - 200 nm, and then place it in a vacuum drying oven and vacuum dry at a temperature of 100 °C to obtain a sodium superionic conductor solid electrolyte powder.

[0160] Example 11.2

[0161] The difference between this example and Example 11.1 is that the pressure in Step 4 is 10 MPa.

[0162] Example 11.3

[0163] The difference between this example and Example 11.1 is that the pressure in Step 4 is 20 MPa.

[0164] Example 11.4

[0165] This embodiment is different from Embodiment 11.1 in that the pressure in Step 4 is 35 MPa.

[0166] Embodiment 12.1

[0167] This embodiment is a method for rapidly purifying and preparing sodium superionic conductor solid electrolyte powder, comprising the following steps:

[0168] Step 1: Add 79.5 g of sodium carbonate, 120.2 g of nano-silica, 209.5 g of nano-zirconia, 115 g of ammonium dihydrogen phosphate, and 4.0 g of magnesium oxide into a ball milling tank, then add a mixed zirconia bead mixture with a particle size of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to a bead-to-material ratio of 2:1, and then ball mill for 12 h under the condition of a ball milling speed of 400 r / min, and then pass through a 200-mesh sieve to obtain a raw material mixture of solid electrolyte powder;

[0169] Step 2: Load the raw material mixture of solid electrolyte into an alumina crucible, then place the alumina crucible into a high-temperature furnace, and heat it to 950 °C and calcine for 6 h under the conditions of an oxygen flow rate of 50 mL / min and a heating rate of 3 °C / min. After calcination, naturally cool to room temperature to obtain a pre-calcined solid electrolyte powder;

[0170] Step 3: Add the pre-calcined solid electrolyte powder into a ball milling tank, then add a mixed zirconia bead mixture with a particle size of 5 mm, 10 mm, and 20 mm in an equal quantity ratio according to a bead-to-material ratio of 2:1, and then ball mill for 12 h under the condition of a ball milling speed of 400 r / min, and then pass through a 200-mesh sieve to obtain a pre-calcined, ball-milled, and sieved material;

[0171] Step 4: Put the pre-calcined, ball-milled, and sieved material into a tablet pressing mold, control the tablet thickness to be 0.5 cm, and then perform tablet pressing treatment for 60 min under the condition of a pressure of 5 MPa to obtain a solid electrolyte powder tablet;

[0172] Step 5: Load the solid electrolyte powder tablet into an alumina crucible, then place the alumina crucible into a high-temperature furnace, and heat it to 1250 °C and calcine for 36 h under the conditions of an oxygen flow rate of 10 mL / min and a heating rate of 5 °C / min. After calcination, naturally cool to room temperature, then perform crushing treatment, then pass through a 300-mesh sieve, then add it to anhydrous ethanol and perform sand milling until the particle size is 100 - 200 nm, and then place it in a vacuum drying oven and vacuum dry at a temperature of 80 °C to obtain sodium superionic conductor solid electrolyte powder.

[0173] Embodiment 12.2

[0174] This embodiment is different from Embodiment 12.1 in that the pressure in Step 4 is 10 MPa.

[0175] Example 12.3

[0176] The difference between this example and Example 12.1 is that the pressure in Step 4 is 20 MPa.

[0177] Example 12.4

[0178] The difference between this example and Example 12.1 is that the pressure in Step 4 is 35 MPa.

[0179] The sodium superionic conductor solid electrolyte powders of Examples 1.1 - 12.4 were pressed into wafers with a thickness of 1 mm and a radius of 6 mm using a tablet press at a pressure of 300 MPa, and were assembled into sodium / / sodium counter - electrode button cells as solid electrolytes. The impedance of the cells was tested using an electrochemical workstation, and the ionic conductivity of each sample was calculated by the calculation method of ionic conductivity. The test results are shown in the following table:

[0180]

[0181] Referring to the data in the above table, it can be known that the sodium superionic conductor solid electrolyte powder material of the present invention has good ionic conductivity, which is beneficial to the preparation of sodium solid - state batteries;

[0182] And according to the comparison between Examples 1.1, 2.1, 3.1, 4.1, 5.1, 6.1 and Examples 1.4, 2.4, 3.4, 4.4, 5.4, 6.4, it can be known that increasing the pressure of tablet pressing significantly improves the ionic conductivity of the sodium superionic solid electrolyte powder, and is beneficial to reducing the internal impurities of the sodium superionic conductor solid electrolyte powder and improving the yield of the sodium superionic conductor solid electrolyte powder;

[0183] And according to the comparison between Examples 1.4, 2.4, 3.4, 4.4, 5.4, 6.4, it can be known that different proportions of elements such as Na, Cr, Si, P, etc. have a great influence on the ionic conductivity of the prepared sodium superionic solid electrolyte powder;

[0184] And according to the comparison between Examples 1.4, 2.4, 3.4, 4.4, 5.4, 6.4 and Examples 7.4, 8.4, 9.4, 10.4, 11.4, 12.4, it can be known that the appropriate trace doping and element substitution of zinc and magnesium elements significantly improve the ionic conductivity of the sodium superionic conductor solid electrolyte powder.

[0185] The principle of the present invention is as follows:

[0186] First, use the high-speed rotation of ball milling technology to physically and uniformly mix the required nano-scale raw material oxides by the centrifugal force and shear force generated by the ball milling beads. To further improve the ionic conductivity of the solid electrolyte, replace the Zr, P, and Si elements in the solid electrolyte structure with trace elements such as magnesium and zinc to increase the Na-O bond length, increase the bottleneck size inside the crystal, and increase the + migration channels of Na + so as to reduce the migration impedance of Na

[0187] and improve the ionic conductivity. For the first time, sintering is carried out in an oxygen atmosphere at 950 °C to reduce the internal pores of the lattice, and then secondary ball milling is used to further improve the distribution uniformity of the material, and at the same time, the internal pores of the lattice are further reduced to promote the high crystallization of the crystal.

[0188] Before the secondary high-temperature oxygen sintering, the sample is subjected to high-pressure tablet pressing. By standing at high pressure for a long time, the gap between particles is reduced, the migration distance of atomic rearrangement during the melting and crystallization of metal oxides is reduced, and the high crystallization of the sample during the secondary sintering is improved to enhance the purity of the solid electrolyte powder.

[0189] In the description of this specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0190] The above content is only an example and explanation of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the invention or exceed the scope defined by this application, they should fall within the protection scope of the present invention.

Claims

1. A method for rapidly purifying and preparing sodium superion conductor solid electrolyte powder, characterized in that: The following steps are involved: Step 1: Sodium carbonate, nano silicon dioxide, nano zirconium dioxide, ammonium dihydrogen phosphate and additives are added to a ball mill, and then mixed zirconium beads are added at a ratio of 2:1, and then ball milled for 12 hours at a ball milling speed of 300-400r / min, and then passed through a 200-mesh sieve to obtain a solid electrolyte powder raw material mixture; Step 2: Load the solid electrolyte raw material mixture into an alumina sagger, then place the alumina sagger into a high-temperature furnace for calcination, and naturally cool to room temperature after calcination to obtain a solid electrolyte powder pre-sintered material; Step 3: add the pre-sintered solid electrolyte powder into a ball mill, then add mixed zirconium beads at a ratio of 2:1, then ball mill for 12 hours at a ball milling speed of 300-400r / min, and then pass through a 200-mesh sieve to obtain a pre-sintered ball mill sieve; Step 4: Place the pre-calcined ball-milled sieved material into a tableting mold, control the tableting thickness to be 0.5 cm, and then perform tableting to obtain a solid electrolyte powder tablet; Step 5: Press the solid electrolyte powder into an alumina sagger, then place the alumina sagger in a high-temperature furnace for calcination. After calcination, naturally cool to room temperature, crush, sieve through 300 mesh, add to anhydrous ethanol and sand grind to a particle size of 100-300nm, place in a vacuum drying oven, and vacuum dry at a temperature of 80-100°C to obtain a sodium superion conductor solid electrolyte powder.

2. The method for rapidly purifying and preparing a sodium superion conductor solid electrolyte powder according to claim 1, characterized in that: The molar ratio of the sodium carbonate, nano silicon dioxide, nano zirconium dioxide, diammonium phosphate and additives in step 1 is 1.5-1.65: 1.8-2.0: 1.8-2.0: 1.0-1.2: 0-0.

25.

3. The method for rapidly purifying and preparing a sodium superion conductor solid electrolyte powder according to claim 1, characterized in that: The additive in step 1 is one of zinc oxide and magnesium oxide or a mixture of the two in any molar ratio.

4. The method for rapidly purifying and preparing a sodium superion conductor solid electrolyte powder according to claim 1, characterized in that: The oxygen flow rate of the calcination treatment in step 2 is 20-50 mL / min, the heating rate is 1-5° C. / min, the calcination temperature is 950° C., and the calcination time is 6 h.

5. The method for rapidly purifying and preparing a sodium superion conductor solid electrolyte powder according to claim 1, characterized in that: The mixed zirconium beads in step 1 and step 3 are zirconium beads with particle sizes of 5 mm, 10 mm, and 20 mm mixed in equal quantitative ratios.

6. The method for rapidly purifying and preparing a sodium superion conductor solid electrolyte powder according to claim 1, characterized in that: The tableting process in step 4 has a pressure range of 5-35 MPa and a tableting time of 10-60 min.

7. The method for rapidly purifying and preparing a sodium superionic conductor solid electrolyte powder according to claim 1, characterized in that: The oxygen flow rate of the calcination treatment in step 5 is 10-30 mL / min, the heating rate is 1-3° C. / min, the calcination temperature is 1200-1300° C., and the calcination time is 20-36 h.

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