A high-entropy lead-free energy storage ceramic material, its preparation method and application

Abstract

This invention discloses a high-entropy lead-free energy storage ceramic material, its preparation method, and its application. The preparation method includes the following steps: S1, weighing: weighing each precursor raw material according to the stoichiometric ratio and setting aside; S2, first ball milling: mixing the weighed precursor raw materials and then ball milling; S3, pre-firing: pre-firing the ball-milled slurry; S4, second ball milling: ball milling the pre-firing raw materials again, drying them to obtain pre-fired ceramic powder; S5, molding: adding a binder to the pre-fired ceramic powder, and then pressing it to obtain a ceramic preform; S6, debinding and sintering: heating the obtained ceramic preform and then holding it at a heat source to obtain a debinded green preform; subsequently, sintering the debinded green preform. The magnesium-lanthanum co-doped high-entropy ceramic strategy in this invention significantly increases the relaxation behavior and voltage breakdown resistance of the ceramic material, improves the polarization intensity, and simultaneously achieves high energy storage density and high energy storage efficiency. The resulting high-entropy ceramic exhibits excellent comprehensive performance.

Description

Technical Field

[0001] This invention belongs to the field of energy storage material preparation technology, specifically relating to a high-entropy lead-free energy storage ceramic material, its preparation method, and its application. Background Technology

[0002] With the rapid development of renewable energy, the research and development of energy storage materials has become a focus of social attention and research. Ceramic dielectric materials are insulators that can store energy. When an external electric field is applied to them, internal charges accumulate on the electrode surface to form a built-in electric field for energy storage. They have outstanding advantages such as ultra-high power density, ultra-fast charge and discharge rate, and no risk of combustion and explosion, and have broad application prospects in pulse power systems, hybrid vehicles, microwave communications, electromagnetic catapults, and other fields.

[0003] Compared to traditional low-entropy lead-free energy storage ceramic materials (e.g., Bi 0.5 Na 0.5 High-entropy ceramics (TiO3, (K,Na)NbO3, and BiFeO3-based ceramics) are ceramic materials containing five or more elements at a single site, with these elements randomly and uniformly distributed in the crystal lattice. Due to the disordered arrangement of atoms with different radii and valence states, their long-range ferroelectric order is broken, resulting in a series of unique effects such as kinetic hysteresis, structural distortion, and cocktail effects, which are beneficial for improving their energy storage performance. In existing technologies, many researchers have studied high-entropy ceramics. For example, patent document CN103288348A provides a high-energy-density barium strontium titanate-based glass-ceramic energy storage material and its preparation and application. Through composite modification, the dielectric constant of the glass-ceramic is improved, and the breakdown field strength is also enhanced, but its energy density is only 2.81 J / cm³. 3 .

[0004] Yuan-Hua Lin's team synthesized Bi with a novel pyrochlore structure through high-entropy design. 1.5 Zn 0.75 Mg 0.25 Nb 0.75 Ta 0.75 O7 high-entropy ceramic has an energy storage efficiency of 91% and an energy storage density of 2.72 J / cm³. 3 .

[0005] Jiu-Jun Xu's team will use Bi(Li 0.2 Y 0.2 Mg 0.2 Ti 0.2 Ta 0.2 High-entropy compounds of O3 were introduced into BaTiO3-(Bi 0.5 Na 0.5In a TiO3 matrix, a ceramic material with a storage density of 4.89 J / cm³ was obtained. 3 The energy storage efficiency is 91.2%. Although the energy storage efficiency of the above-mentioned high-entropy ceramics is relatively high, their energy storage density is generally low.

[0006] In recent years, Professor Chen Jun's team has prepared relaxor ferroelectric ceramics ([(K)) by simultaneously introducing high-entropy design at sites A and B. 0.2 Na 0.8 ) 0.8 Li 0.08 Ba 0.02 Bi 0.1 ](Nb 0.68 Sc 0.02 Hf 0.08 Zr 0.1 Ta 0.08 Sb 0.04 )O3), and obtained 10.06 J / cm 3 It boasts an ultra-high recoverable energy density and a high energy storage efficiency of 90.8%. However, this strategy of simultaneously doping at both A and B sites involves a wide variety of elements, which greatly increases the complexity of the material preparation process and the manufacturing cost.

[0007] Therefore, developing high-entropy energy storage ceramics that simultaneously possess high energy storage density, high energy storage efficiency, and low preparation cost remains a challenge. In view of this, the present invention is proposed. Summary of the Invention

[0008] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a high-entropy lead-free energy storage ceramic material, its preparation method and application. The obtained ceramic material has the advantages of high energy storage density and high energy storage efficiency, and the preparation method involves few types of elements, which has great cost advantages.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a method for preparing a high-entropy lead-free energy storage ceramic material, comprising the following steps:

[0011] S1. Weighing: According to the measurement formula (Ca 0.2 Sr 0.2 Ba 0.2 Mg x La x Bi 0.2-x Na 0.2-x Precursor raw materials for TiO3, namely calcium salt, strontium salt, barium salt, bismuth salt, sodium salt, titanium salt, magnesium salt, and lanthanum salt, were weighed and set aside; wherein, 0.02≤x≤0.06

[0012] S2, First ball milling: Mix the precursor raw materials weighed in step S1 and then ball mill them;

[0013] S3. Pre-calcination: Pre-calcining the slurry after ball milling in step S2;

[0014] S4. Secondary ball milling: The pre-fired raw material from step S3 is ball-milled again and dried to obtain pre-fired ceramic powder.

[0015] S5: Molding: Add a binder to the pre-fired ceramic powder obtained in step S4, and then press it to form a ceramic blank.

[0016] S6. Debinding and Sintering: The ceramic blank obtained in step S5 is heated and then kept warm to obtain a debinded green blank; the debinded green blank is then sintered to obtain a high-entropy lead-free energy storage ceramic material.

[0017] As a preferred embodiment of the technical solution of the present invention, in step S1, the precursor raw materials for calcium salt, strontium salt, barium salt, bismuth salt, sodium salt, titanium salt, magnesium salt, and lanthanum salt are CaO, SrCO3, BaCO3, and Bi2O, respectively. 3、 Na2CO3, TiO2, MgO, La2O3.

[0018] As a preferred embodiment of the technical solution of the present invention, in step S2, the ball milling is carried out using zirconium dioxide ball milling, and 70-90% of the total mass of each precursor raw material is added with anhydrous ethanol before ball milling; the ball milling time is 0.5-5h.

[0019] As a preferred embodiment of the technical solution of the present invention, in step S3, the pre-firing temperature is 1100-1200℃ and the pre-firing time is 0.5-5h.

[0020] As a preferred embodiment of the technical solution of the present invention, in step S4, the secondary ball milling time is 3 to 8 hours.

[0021] As a preferred embodiment of the technical solution of the present invention, in step S5, the pressing pressure is 2-4 MPa and the pressing time is 10-20 s.

[0022] As a preferred embodiment of the technical solution of the present invention, in step S6, the heat preservation temperature is 600-700℃ and the heat preservation time is 0.5-5h.

[0023] As a preferred embodiment of the technical solution of the present invention, in step S6, the sintering temperature is 1230-1330℃ and the sintering time is 2-8h.

[0024] Secondly, this invention aims to protect the high-entropy lead-free energy storage ceramic material prepared by the above method.

[0025] Thirdly, the present invention aims to protect the application of the above-obliquity high-entropy lead-free energy storage ceramic material in energy storage materials in any form.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The high-entropy lead-free energy storage ceramic material provided by this invention preferably uses specific element types and modification / doping types, and only involves the modification / doping of (Ca). 0.2 Sr 0.2 Ba 0.2 Bi 0.2 Na 0.2 The co-doping of TiO3 high-entropy ceramics with a small amount of magnesium and lanthanum successfully fabricated CSBBNT-xML high-entropy energy storage ceramics. This magnesium-lanthanum co-doping strategy further increases the material's configurational entropy, leading to lattice distortion and a reduction in the size of nano-ferroelectric domains, thus significantly enhancing relaxation behavior. On the other hand, it suppresses grain growth, increasing the number of grain boundaries per unit volume, resulting in increased volume resistivity and significantly improving the material's voltage breakdown resistance. Therefore, magnesium-lanthanum co-doping is beneficial for simultaneously achieving high energy density and high energy efficiency. Especially when x = 0.05, the prepared high-entropy ceramic exhibits excellent overall performance, with energy density and efficiency reaching as high as 10.1 J / cm³. 3 And 90%, with a breakdown voltage as high as 540kV / cm.

[0028] (2) The high-entropy lead-free energy storage ceramic material provided by this invention has significant economic benefits. Compared with the A-site and B-site high-entropy strategies, this invention adopts the A-site high-entropy doping strategy, which significantly reduces the types of metal elements used and has a small magnesium and lanthanum doping content, resulting in a significant reduction in overall manufacturing costs and good prospects for promotion and application. Attached Figure Description

[0029] Figure 1 XRD pattern of CSBBNT-xML ceramic and magnified view of (200) diffraction peak;

[0030] Figure 2 The natural surface grain morphology of CSBBNT-xML ceramic;

[0031] Figure 3 The curves showing the relationship between the density and relative density of CSBBNT-xML ceramic and x;

[0032] Figure 4 The polarization intensity-polarization electric field curves of CSBBNT-xML ceramics;

[0033] Figure 5 The energy storage density and energy storage efficiency of CSBBNT-xML ceramic. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] This invention provides a high-entropy lead-free energy storage ceramic material with the chemical formula (Ca). 0.2 Sr 0.2 Ba 0.2 Mg x La x Bi 0.2-x Na 0.2-x TiO3 (where x = 0.02–0.06), abbreviated as CSBBNT-xML, is prepared by the following steps:

[0036] S1. Weighing: Weigh the precursor raw materials of calcium salt, strontium salt, barium salt, bismuth salt, sodium salt, titanium salt, magnesium salt, and lanthanum salt according to the stoichiometric ratio, and set aside for later use;

[0037] S2, First ball milling: Mix the precursor raw materials weighed in step S1 and then ball mill them;

[0038] S3. Pre-calcination: Pre-calcining the slurry after ball milling in step S2;

[0039] S4. Secondary ball milling: The pre-fired raw material from step S3 is ball-milled again and dried to obtain pre-fired ceramic powder.

[0040] S5: Molding: Add a binder to the pre-fired ceramic powder obtained in step S4, and then press it to form a ceramic blank.

[0041] S6. Debinding and Sintering: The ceramic blank obtained in step S5 is heated and then kept warm to obtain a debinded green blank; the debinded green blank is then sintered to obtain a high-entropy lead-free energy storage ceramic material.

[0042] In the above technical solution, only by modifying (Ca) 0.2 Sr 0.2 Ba 0.2 Bi 0.2 Na 0.2 By co-doping TiO3 high-entropy ceramics with a small amount of magnesium and lanthanum, a high-entropy energy storage ceramic material with both high energy density and high energy storage efficiency was successfully prepared. Moreover, the above synthesis strategy also has the advantages of fewer element types and lower manufacturing cost.

[0043] In some embodiments, in step S1, the precursor raw materials for calcium salt, strontium salt, barium salt, bismuth salt, sodium salt, titanium salt, magnesium salt, and lanthanum salt are CaO, SrCO3, BaCO3, and Bi2O, respectively. 3、 Na₂CO₃, TiO₂, MgO, La₂O₃; stoichiometric formula expressed as (Ca... 0.2 Sr 0.2 Ba 0.2 Mg x La x Bi 0.2-x Na 0.2-x TiO3 (where x = 0.02 to 0.06).

[0044] In some embodiments, in step S2, the ball milling is performed using zirconium dioxide ball milling, and anhydrous ethanol of 70-90% of the total mass of each precursor raw material is added before ball milling; the ball milling time is 0.5-5 hours. Preferably, the amount of anhydrous ethanol added is 80% of the total mass of each precursor raw material, and the ball milling time is 2 hours.

[0045] In some embodiments, in step S3, the pre-firing temperature is 1100–1200°C, and the pre-firing time is 0.5–5 hours. It is understood that the pre-firing temperature can be any value from 1100°C, 1110°C, 1120°C, 1130°C, 1140°C, 1150°C, 1160°C, 1170°C, 1180°C, 1190°C, and 1200°C, or any value within the aforementioned range; similarly, the pre-firing time can be any value from 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, and 5 hours, or any value within the aforementioned range.

[0046] In some embodiments, the secondary ball milling time in step S4 is 3–8 hours. The ball milling is also performed using zirconia ball milling, and the milling time can be any value selected from 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, and 8 hours, or any value within the aforementioned range. Preferably, the milling time is 4 hours. The drying temperature is preferably 80°C.

[0047] In some embodiments, in step S5, the pressing pressure is 2–4 MPa; the pressing time is 10–20 s. It is understood that the pressing pressure can be any value from 2 MPa, 2.1 MPa, 2.2 MPa, 2.3 MPa, 2.4 MPa, 2.5 MPa, 2.6 MPa, 2.7 MPa, 2.8 MPa, 2.9 MPa, 3 MPa, 3.1 MPa, 3.2 MPa, 3.3 MPa, 3.4 MPa, 3.5 MPa, 3.6 MPa, 3.7 MPa, 3.8 MPa, 3.9 MPa, and 4 MPa, or any value within the aforementioned range; the pressing time can be any value from 10 s, 11 s, 12 s, 13 s, 14 s, 15 s, 16 s, 17 s, 18 s, 19 s, and 20 s, or any value within the aforementioned range. Preferably, the pressing pressure is 3 MPa; the pressing time is 15 s.

[0048] In some embodiments, in step S6, the heat preservation temperature is 600–700°C, and the heat preservation time is 0.5–5 hours. It is understood that the heat preservation temperature can be any value from 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, 690°C, and 700°C, or any value within the aforementioned range; the heat preservation time can be any value from 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, and 5 hours, or any value within the aforementioned range. Preferably, the heat preservation temperature is 650°C, and the heat preservation time is 1 hour.

[0049] In some embodiments, in step S6, the sintering temperature is 1230–1330°C, and the sintering time is 2–8 hours. It is understood that the sintering temperature can be any value from 1230°C, 1240°C, 1250°C, 1260°C, 1270°C, 1280°C, 1290°C, 1300°C, 1310°C, 1320°C, and 1330°C, or any value within the aforementioned range; the sintering time can be any value from 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, and 8 hours, or any value within the aforementioned range.

[0050] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0051] Example 1

[0052] A method for preparing a high-entropy lead-free energy storage ceramic material includes the following steps:

[0053] (1) Weighing: Weigh the metal precursor compound raw materials, including CaO, SrCO3, BaCO3, Bi2O3, Na2CO3, TiO2, MgO, and La2O3, according to the stoichiometric ratio of each component in the chemical formula (CSBBNT-0.02ML).

[0054] (2) One-time ball milling: The weighed precursor raw material and zirconium dioxide ball milling beads are placed in a ball milling jar, and anhydrous ethanol of 80% of the total mass of the drug is added for ball milling. The speed is increased to 50, 100, 150, 200 and up to 250 r / min every 5 minutes. Finally, the ball milling is carried out at 250 r / min for 2 hours.

[0055] (3) Pre-calcination: After grinding, the slurry is placed in a constant temperature drying oven at 80°C to completely evaporate the alcohol in the medicine. Then, it is placed in a crucible and transferred to a muffle furnace for pre-calcination at 1100°C for 3 hours.

[0056] (4) Secondary ball milling: The pre-fired powder is mixed with anhydrous ethanol again and ball milled for 4 hours. The slurry after ball milling is dried at 80°C to obtain the final pre-fired ceramic powder.

[0057] (5) Molding: Add an appropriate amount of 8wt% polyvinyl alcohol ethanol solution as a binder to an appropriate amount of pre-fired ceramic powder and mix them evenly. Fill the mold with the evenly mixed powder and press it into shape using a tablet press. The applied pressure is 3MPa and the constant pressure is 15s to obtain a ceramic blank disc with a flat and delicate surface and no internal layering. Its diameter is about 8mm and its thickness is about 0.9mm.

[0058] (6) Debinding and sintering: The pressed ceramic green body is placed in a muffle furnace and heated to 650℃, and held for 1 hour to debind the green body. The debinded green body is then placed in a muffle furnace for sintering at 1230℃ for 4 hours to obtain a high-entropy ceramic with a magnesium-lanthanum co-doping content of 2%.

[0059] Example 2

[0060] A method for preparing a high-entropy lead-free energy storage ceramic material includes the following steps:

[0061] (1) Weighing: Weigh the metal precursor compound raw materials, including CaO, SrCO3, BaCO3, Bi2O3, Na2CO3, TiO2, MgO, and La2O3, according to the stoichiometric ratio of each component in the chemical formula (CSBBNT-0.03ML).

[0062] (2) One-time ball milling: The weighed precursor raw material and zirconium dioxide ball milling beads are placed in a ball milling jar, and anhydrous ethanol of 80% of the total mass of the drug is added for ball milling. The speed is increased to 50, 100, 150, 200 and up to 250 r / min every 5 minutes. Finally, the ball milling is carried out at 250 r / min for 2 hours.

[0063] (3) Pre-calcination: After grinding, the slurry is placed in a constant temperature drying oven at 80°C to completely evaporate the alcohol in the medicine. Then, it is placed in a crucible and transferred to a muffle furnace for pre-calcination at 1100°C for 3 hours.

[0064] (4) Secondary ball milling: The pre-fired powder is mixed with anhydrous ethanol again and ball milled for 4 hours. The slurry after ball milling is dried at 80°C to obtain the final pre-fired ceramic powder.

[0065] (5) Molding: Add an appropriate amount of 8wt% polyvinyl alcohol ethanol solution as a binder to an appropriate amount of pre-fired ceramic powder and mix them evenly. Fill the mold with the evenly mixed powder and press it into shape using a tablet press. The applied pressure is 3MPa and the constant pressure is 15s to obtain a ceramic blank disc with a flat and delicate surface and no internal layering. Its diameter is about 8mm and its thickness is about 0.9mm.

[0066] (6) Debinding and sintering: The pressed ceramic green body is placed in a muffle furnace and heated to 650℃, and held for 1 hour to debind the green body. The debinded green body is then placed in a muffle furnace for sintering at 1230℃ for 4 hours to obtain a high-entropy ceramic with a magnesium-lanthanum co-doping content of 3%.

[0067] Example 3

[0068] A method for preparing a high-entropy lead-free energy storage ceramic material includes the following steps:

[0069] (1) Weighing: Weigh the metal precursor compound raw materials, including CaO, SrCO3, BaCO3, Bi2O3, Na2CO3, TiO2, MgO, and La2O3, according to the stoichiometric ratio of each component in the chemical formula (CSBBNT-0.04ML).

[0070] (2) One-time ball milling: The weighed precursor raw material and zirconium dioxide ball milling beads are placed in a ball milling jar, and anhydrous ethanol of 80% of the total mass of the drug is added for ball milling. The speed is increased to 50, 100, 150, 200 and up to 250 r / min every 5 minutes. Finally, the ball milling is carried out at 250 r / min for 2 hours.

[0071] (3) Pre-calcination: After grinding, the slurry is placed in a constant temperature drying oven at 80°C to completely evaporate the alcohol in the medicine. Then, it is placed in a crucible and transferred to a muffle furnace for pre-calcination at 1150°C for 3 hours.

[0072] (4) Secondary ball milling: The pre-fired powder is mixed with anhydrous ethanol again and ball milled for 4 hours. The slurry after ball milling is dried at 80°C to obtain the final pre-fired ceramic powder.

[0073] (5) Molding: Add an appropriate amount of 8wt% polyvinyl alcohol ethanol solution as a binder to an appropriate amount of pre-fired ceramic powder and mix them evenly. Fill the mold with the evenly mixed powder and press it into shape using a tablet press. The applied pressure is 3MPa and the constant pressure is 15s to obtain a ceramic blank disc with a flat and delicate surface and no internal layering. Its diameter is about 8mm and its thickness is about 0.9mm.

[0074] (6) Debinding and sintering: The pressed ceramic green body is placed in a muffle furnace and heated to 650℃, and held for 1 hour to remove the binder. The debinded green body is then placed in a muffle furnace for sintering at 1280℃ for 4 hours to obtain a high-entropy ceramic with a magnesium-lanthanum co-doping content of 4%.

[0075] Example 4

[0076] A method for preparing a high-entropy lead-free energy storage ceramic material includes the following steps:

[0077] (1) Weighing: Weigh the metal precursor compound raw materials, including CaO, SrCO3, BaCO3, Bi2O3, Na2CO3, TiO2, MgO, and La2O3, according to the stoichiometric ratio of each component in the chemical formula (CSBBNT-0.05ML).

[0078] (2) One-time ball milling: The weighed precursor raw material and zirconium dioxide ball milling beads are placed in a ball milling jar, and anhydrous ethanol of 80% of the total mass of the drug is added for ball milling. The speed is increased to 50, 100, 150, 200 and up to 250 r / min every 5 minutes. Finally, the ball milling is carried out at 250 r / min for 2 hours.

[0079] (3) Pre-calcination: After grinding, the slurry is placed in a constant temperature drying oven at 80°C to completely evaporate the alcohol in the medicine. Then, it is placed in a crucible and transferred to a muffle furnace for pre-calcination at 1150°C for 3 hours.

[0080] (4) Secondary ball milling: The pre-fired powder is mixed with anhydrous ethanol again and ball milled for 4 hours. The slurry after ball milling is dried at 80°C to obtain the final pre-fired ceramic powder.

[0081] (5) Molding: Add an appropriate amount of 8wt% polyvinyl alcohol ethanol solution as a binder to an appropriate amount of pre-fired ceramic powder and mix them evenly. Fill the mold with the evenly mixed powder and press it into shape using a tablet press. The applied pressure is 3MPa and the constant pressure is 15s to obtain a ceramic blank disc with a flat and delicate surface and no internal layering. Its diameter is about 8mm and its thickness is about 0.9mm.

[0082] (6) Debinding and sintering: The pressed ceramic green body is placed in a muffle furnace and heated to 650℃, and held for 1 hour to debind the green body. The debinded green body is then placed in a muffle furnace for sintering at 1280℃ for 4 hours to obtain a high-entropy ceramic with a magnesium-lanthanum co-doping content of 5%.

[0083] Example 5

[0084] A method for preparing a high-entropy lead-free energy storage ceramic material includes the following steps:

[0085] (1) Weighing: Weigh the metal precursor compound raw materials, including CaO, SrCO3, BaCO3, Bi2O3, Na2CO3, TiO2, MgO, and La2O3, according to the stoichiometric ratio of each component in the chemical formula (CSBBNT-0.06ML).

[0086] (2) One-time ball milling: The weighed precursor raw material and zirconium dioxide ball milling beads are placed in a ball milling jar, and anhydrous ethanol of 80% of the total mass of the drug is added for ball milling. The speed is increased to 50, 100, 150, 200 and up to 250 r / min every 5 minutes. Finally, the ball milling is carried out at 250 r / min for 2 hours.

[0087] (3) Pre-calcination: After grinding, the slurry is placed in a constant temperature drying oven at 80°C to completely evaporate the alcohol in the medicine. Then, it is placed in a crucible and transferred to a muffle furnace for pre-calcination at a temperature of 1200°C for 3 hours.

[0088] (4) Secondary ball milling: The pre-fired powder is mixed with anhydrous ethanol again and ball milled for 4 hours. The slurry after ball milling is dried at 80°C to obtain the final pre-fired ceramic powder.

[0089] (5) Molding: Add an appropriate amount of 8wt% polyvinyl alcohol ethanol solution as a binder to an appropriate amount of pre-fired ceramic powder and mix them evenly. Fill the mold with the evenly mixed powder and press it into shape using a tablet press. The applied pressure is 3MPa and the constant pressure is 15s to obtain a ceramic blank disc with a flat and delicate surface and no internal layering. Its diameter is about 8mm and its thickness is about 0.9mm.

[0090] (6) Debinding and sintering: The pressed ceramic green body is placed in a muffle furnace and heated to 650℃, and held for 1 hour to debind the green body. The debinded green body is then placed in a muffle furnace for sintering at 1330℃ for 4 hours to obtain a high-entropy ceramic with a magnesium-lanthanum co-doping content of 6%.

[0091] Comparative Example 1

[0092] A method for preparing a high-entropy lead-free energy storage ceramic material includes the following steps:

[0093] (1) Weighing: Weigh the metal precursor compound raw materials, including CaO, SrCO3, BaCO3, Bi2O3, Na2CO3, and TiO2, according to the stoichiometric ratio of each component in the chemical formula (CSBBNT-0ML).

[0094] (2) One-time ball milling: The weighed precursor raw material and zirconium dioxide ball milling beads are placed in a ball milling jar, and anhydrous ethanol of 80% of the total mass of the drug is added for ball milling. The speed is increased to 50, 100, 150, 200 and up to 250 r / min every 5 minutes. Finally, the ball milling is carried out at 250 r / min for 2 hours.

[0095] (3) Pre-calcination: After grinding, the slurry is placed in a constant temperature drying oven at 80°C to completely evaporate the alcohol in the medicine. Then, it is placed in a crucible and transferred to a muffle furnace for pre-calcination at 1100°C for 3 hours.

[0096] (4) Secondary ball milling: The pre-fired powder is mixed with anhydrous ethanol again and ball milled for 4 hours. The slurry after ball milling is dried at 80°C to obtain the final pre-fired ceramic powder.

[0097] (5) Molding: Add an appropriate amount of 8wt% polyvinyl alcohol ethanol solution as a binder to an appropriate amount of pre-fired ceramic powder and mix them evenly. Fill the mold with the evenly mixed powder and press it into shape using a tablet press. The applied pressure is 3MPa and the constant pressure is 15s to obtain a ceramic blank disc with a flat and delicate surface and no internal layering. Its diameter is about 8mm and its thickness is about 0.9mm.

[0098] (6) Debinding and sintering: The pressed ceramic green body is placed in a muffle furnace and heated to 650℃, and held for 1 hour to debind the green body. The debinded green body is then placed in a muffle furnace for sintering at 1230℃ for 4 hours to obtain high-entropy ceramics without magnesium and lanthanum doping.

[0099] The performance of the ceramic materials prepared in each embodiment and comparative example was tested, see [link to relevant documentation]. Figures 1-5 .

[0100] from Figure 1As can be seen, all ceramics exhibit a single perovskite structure, indicating that Mg and La are completely dissolved in the CSBBNT-xML ceramic lattice. According to the magnified view of the (200) diffraction peak, no splitting is observed, and the peak symmetry is good, indicating that each ceramic possesses a long-range pseudo-cubic structure. With increasing x, the (200) diffraction peak gradually shifts towards lower angles, indicating that the introduction of Mg and La causes cell expansion.

[0101] from Figure 2 The image shows a natural surface SEM image of the CSBBNT-xML ceramics. All ceramics have a dense microstructure with tightly bonded grains and no obvious large pores, indicating that the samples have good sintering quality. Furthermore, the grain size gradually decreases as x increases.

[0102] from Figure 3 As x increases, the density of the ceramic gradually decreases, while the relative density remains at a high level, always above 95%.

[0103] from Figure 4 As can be seen, for the ceramic sample with x = 0, approximately 62 μC / cm was obtained under an electric field of 300 kV / cm. 2 It has an ultra-high polarization intensity and a value of 8 μC / cm. 2 The residual polarization intensity is relatively low, but due to rapid polarization saturation, the polarization value changes from linear to parabolic growth at an electric field of around 100 kV / cm. This results in a high maximum polarization value but a small area enclosed along the Y-axis, leading to a low calculated recoverable energy density. Furthermore, the low maximum breakdown strength also contributes to the low energy storage density. As x increases, the polarization value decreases further under the same electric field, but the breakdown field strength initially increases and then decreases. When x = 0.05, the breakdown electric field reaches a high of 540 kV / cm, and the maximum polarization intensity is 53 μC / cm. 2 It has the best energy density and energy storage efficiency.

[0104] from Figure 5 As can be seen, the sample's energy density first increases and then decreases with increasing x. The energy density reaches its maximum of 10.1 J / cm³ when x = 0.05. 3 Moreover, its energy storage efficiency is as high as 90%.

[0105] The present invention has been illustrated through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of individual raw materials in the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a high-entropy lead-free energy storage ceramic material, characterized in that, Includes the following steps: S1. Weighing: According to the measurement formula (Ca... 0.2 Sr 0.2 Ba 0.2 Mg x La x Bi 0.2-x Na 0.2-x Precursor raw materials of calcium salt, strontium salt, barium salt, bismuth salt, sodium salt, titanium salt, magnesium salt, and lanthanum salt were weighed out for later use; wherein, 0.02≤x≤0.06; S2, First ball milling: Mix the precursor raw materials weighed in step S1 and then ball mill them; S3. Pre-calcination: Pre-calcining the slurry after ball milling in step S2; S4. Secondary ball milling: The pre-fired raw material from step S3 is ball-milled again and dried to obtain pre-fired ceramic powder. S5: Molding: Add a binder to the pre-fired ceramic powder obtained in step S4, and then press it to form a ceramic blank. S6. Debinding and Sintering: The ceramic blank obtained in step S5 is heated and then kept warm to obtain a debinded green blank; the debinded green blank is then sintered to obtain a high-entropy lead-free energy storage ceramic material.

2. The method for preparing a high-entropy lead-free energy storage ceramic material according to claim 1, characterized in that, In step S1, the precursor raw materials for calcium salts, strontium salts, barium salts, bismuth salts, sodium salts, titanium salts, magnesium salts, and lanthanum salts are CaO, SrCO3, BaCO3, and Bi2O, respectively. 3、 Na2CO3, TiO2, MgO, La2O3.

3. The method for preparing a high-entropy lead-free energy storage ceramic material according to claim 1, characterized in that, In step S2, the ball milling is carried out using zirconium dioxide ball milling. Before ball milling, 70-90% of the total mass of each precursor raw material is added in anhydrous ethanol; the ball milling time is 0.5-5 hours.

4. The method for preparing a high-entropy lead-free energy storage ceramic material according to claim 1, characterized in that, In step S3, the pre-firing temperature is 1100-1200℃ and the pre-firing time is 0.5-5h.

5. The method for preparing a high-entropy lead-free energy storage ceramic material according to claim 1, characterized in that, In step S4, the secondary ball milling time is 3 to 8 hours.

6. The method for preparing a high-entropy lead-free energy storage ceramic material according to claim 1, characterized in that, In step S5, the pressing pressure is 2-4 MPa; the pressing time is 10-20 s.

7. The method for preparing a high-entropy lead-free energy storage ceramic material according to claim 1, characterized in that, In step S6, the heat preservation temperature is 600-700℃ and the heat preservation time is 0.5-5h.

8. The method for preparing a high-entropy lead-free energy storage ceramic material according to claim 1, characterized in that, In step S6, the sintering temperature is 1230–1330℃ and the sintering time is 2–8 hours.

9. A high-entropy lead-free energy storage ceramic material prepared by the method according to any one of claims 1 to 8.

10. The application of the high-entropy lead-free energy storage ceramic material of claim 9 in the preparation of energy storage materials.

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