B-site controllable doped perovskite energetic material and preparation method thereof

Abstract

The invention belongs to the technical field of energetic materials, and discloses a B-site controllable doped perovskite energetic material and a preparation method thereof, the structural general formula of the perovskite energetic material compound is AB (1-x) B'x (ClO4) 3, 0 lt; xlt; 1, the positive ion A is selected from nitrogen-containing organic positive ions, and the positive ion B and the positive ion B'are different monovalent positive ions. The preparation method comprises the following steps that an original AB (ClO4) 3 energetic material is put into a B'salt solution and heated to be dissolved, the AB (1-x) B'x (ClO4) 3 energetic material is obtained through cooling, and the proportion of B and B'ions in the product can be controlled through synthesis conditions. The preparation method of the material is simple, the synthesis condition is mild, and the final performance of the perovskite energetic material can be regulated and controlled by changing the type, doping amount and the like of B'ions.

Description

Technical Field

[0001] The present application belongs to the technical field of energetic materials, and specifically relates to a B-site controllably doped perovskite energetic material and a preparation method thereof. Background Art

[0002] Energetic materials are compounds or mixtures that can undergo redox reactions and rapidly release large amounts of gas and heat under sufficient external stimulation. They usually refer to explosives, propellants, and pyrotechnics. Energy and safety are two very important properties of energetic materials; energy determines their ability to do work, and safety guarantees their reliability. In practical applications, high energy insensitivity is the main goal of research and development of energetic materials (Cryst. Growth. Des. 2018, 18(10), 5713-5726.). However, traditional covalently synthesized energetic molecules often face a contradiction between energy and safety. As the number of nitro groups in the molecule and the tension of the carbon skeleton increase, their energy can be increased, but their sensitivity increases greatly, which greatly affects their safety and reliability in use. Therefore, designing energetic materials with new structures is one of the research hotspots in the field of energetic materials.

[0003] Molecular perovskite energetic materials, with a general structural formula of ABX3, are a new class of energetic materials with great application prospects. They are structurally stable and have high detonation performance, comparable to the current high-energy explosive HMX, and most of them are superior to the commonly used explosive RDX (Sci. China Mater. 2018, 61(8), 1123-1128; Energetic Materials Frontiers 2020, 1(3-4), 123-135). As described in patent documents with patent application numbers CN107722022A and CN106278771A, ABX3-type perovskite energetic materials are ternary crystal materials self-assembled from oxidizing and reducing molecules / ions based on crystal engineering strategies and energetic material design at the supramolecular level. The electrostatic Coulomb force between the ionic components stabilizes the perovskite framework structure, and the oxidant and reductant are closely arranged in space, which can achieve fast and efficient redox reactions and have the advantages of both high energy and stability. Among them, a series of perovskite energetic materials with perchlorate ions at the X position have attracted much attention due to their high detonation performance and excellent heat resistance. Summary of the Invention

[0004] The present application aims to provide a B-site controllably doped perovskite energetic material and a preparation method thereof. The energetic material can improve the performance of the perovskite energetic material by regulating the composition and crystal microstructure. Moreover, the preparation method thereof is simple, the conditions are mild, the reaction yield is high, and the safety is high.

[0005] In order to achieve the technical objectives of this application, the following technical solutions are adopted:

[0006] In one aspect of the present application, a perovskite energetic material with controllable doping at the B-site is provided. The energetic material includes a compound composed of at least A cations, B cations, B' cations, and perchlorate ions. The general structural formula of the compound is AB (1-x) B ’ x (ClO4)3, where 0 < x < 1. The A cations are selected from nitrogen-containing organic cations, and the B cations and B' cations are monovalent cations with different elemental species.

[0007] In one embodiment, the B cations are selected from NH4 + , Li + , Na + , K + , Rb + , Ag + or one or more of them.

[0008] Furthermore, the B cations are selected from NH4 + .

[0009] In one embodiment, the B' cations are selected from NH4 + , Li + , Na + , K + , Rb + , Ag + or one or more of them.

[0010] Furthermore, the B' cations are selected from Na + , K + , Rb + , Ag + or one or more of them.

[0011] In one embodiment, the A cations are selected from protonated triethylenediamine and / or hexamethylenetetramine.

[0012] Furthermore, the A cations are selected from diprotonated triethylenediamine cation [H2dabco] 2+ .

[0013] In another aspect of the present application, a preparation method of a perovskite energetic material with controllable doping at the B-site is provided, including:

[0014] Prepare a solid-liquid mixed phase containing AB(ClO4)3 and B' salt, heat up to dissolve;

[0015] Cool down to precipitate solids to obtain an energetic material doped with B' ions.

[0016] In one embodiment, the energetic material includes a compound with the general structural formula AB(1-x) B ’ x A compound of (ClO4)3, where 0 < x < 1, the A cation is selected from nitrogen-containing organic cations, and both the B cation and the B' cation are monovalent cations.

[0017] In one embodiment, the B' salt is selected from one or more of chlorides, perchlorates, and nitrates.

[0018] In one embodiment, the solvent of the solution containing the B' salt is selected from one or more of water, ethanol, and methanol.

[0019] In one embodiment, the heating and dissolution are carried out at 65 - 75 °C.

[0020] In one embodiment, the molar ratio of AB(ClO4)3 to the B' salt in the solid-liquid mixture phase is 1:0.1 - 40.

[0021] The beneficial effects of this application are as follows:

[0022] 1) This application first provides an AB perovskite energetic material with adjustable B-site ion ratio and species, where 0 < x < ...... (1-x) B ’ x type perovskite energetic material and its preparation method, where 0 < x < 1.

[0023] 2) The perovskite energetic material prepared in this application, such as (H2dabco)(NH4) 0.483 Na 0.517 (ClO4)3, can have a higher thermal decomposition temperature. Compared with DAP-4, the initial thermal decomposition temperature is increased by about 20 °C.

[0024] 3) The crystal theoretical density of the doped sample prepared in this application is greater than that of the original AB(ClO4)3 energetic material, and the energy level is improved accordingly.

[0025] 4) The preparation method of this application is simple and environmentally friendly. Water can be used as the solvent, and the heating temperature is generally about 70 °C. The operation is simple, the conditions are mild, and the safety is high. Description of the Drawings

[0026] Figure 1 Powder X-ray diffraction (PXRD) pattern of the product (H2dabco)NH 4(1-x) Na x (ClO4)3 in Example 1;

[0027] Figure 2The DSC curves of the product of Example 1, DAP-1, and DAP-4 are shown in Figure 1; Figure a is a comparison of the products of Example 1, DAP-1, and DAP-4; and Figure b is a comparison of the products at different feed ratios.

[0028] Figure 3 (H2dabco)(NH4) of Example 1 0.715 Na 0.285 Crystal structure diagram of (ClO4)3;

[0029] Figure 4 (H2dabco)NH 4(1-x) Ag x Powder X-ray diffraction (PXRD) pattern of (ClO4)3 product;

[0030] Figure 5 (H2dabco)(NH4) of Example 2 0.91 Ag 0.09 Crystal structure diagram of (ClO4)3;

[0031] Figure 6 (H2dabco)(NH4) of Example 3 0.079 K 0.921 Crystal structure diagram of (ClO4)3;

[0032] Figure 7 (H2dabco)Rb of Example 4 0.472 K 0.528 Crystal structure diagram of (ClO4)3. DETAILED DESCRIPTION

[0033] The technical scheme of the present application will be clearly and completely described below in conjunction with specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are some embodiments of the present application, rather than all embodiments, and are only used to illustrate the present application, and should not be considered as limiting the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present application. Those who do not specify specific conditions in the embodiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Those whose reagents or instruments are not specified as manufacturers are conventional products that can be purchased commercially.

[0034] The purpose of this application is to provide a perovskite energetic material with controllable doping at the B-site. This material system uses an AB(ClO4)3-type perovskite framework as the matrix, and by introducing different types and ratios of monovalent cations at the B-site, a doped perovskite structure with adjustable B-site ion composition is constructed. Specifically, by controlling the stoichiometric ratio and ion type of the doped ions, precise regulation of the B-site ion species and occupancy is achieved. The experimental results show that doping at the B-site can significantly improve the thermal stability of the material and reduce the mechanical sensitivity, while maintaining or enhancing its energy density characteristics, providing a new molecular engineering approach for the safety design and performance optimization of energetic materials.

[0035] In this application, a perovskite energetic material with controllable doping at the B-site is provided. The energetic material includes a compound composed of at least A cations, B cations, B' cations, and perchlorate ions, and the structural general formula of this compound is AB (1-x) B ’ x (ClO4)3, where 0 < x < 1. The A cations are selected from nitrogen-containing organic cations, and the B cations and B' cations are monovalent cations with different element species.

[0036] In some embodiments, both the B cations and the B' cations are selected from NH4 + 、Li + 、Na + 、K + 、Rb + 、Ag + or one or more of them. For example, the structural general formula of this compound can be A(NH4) (1-x) Li x (ClO4)3, A(NH4) (1-x) Na x (ClO4)3, A(NH4) (1-x) K x (ClO4)3, A(NH4) (1-x) Rb x (ClO4)3, A(NH4) (1-x) Ag x (ClO4)3, ALi (1-x) Ag x (ClO4)3, ANa (1-x) K x (ClO4)3, AK (1-x) Li x (ClO4)3, ARb (1-x) K x (ClO4)3, AAg (1-x) Na x (ClO4)3, etc.

[0037] In some embodiments, the B cation is selected from NH4 + , and the B' cation is selected from Na + , K + , Rb + , Ag + or one or more of them. For example, the general structural formula of an energetic material can be A(NH4) (1-x) Na x (ClO4)3, A(NH4) (1-x) K x (ClO4)3, A(NH4) (1-x) Rb x (ClO4)3, A(NH4) (1-x) Ag x (ClO4)3.

[0038] In some embodiments, the A cation is selected from protonated triethylenediamine and / or hexamethylenetetramine. For example, when the A cation is selected from bis-protonated triethylenediamine, the general structural formula of an energetic material can be (H2dabco)B (1-x) B ’ x (ClO4)3.

[0039] In another embodiment of the present application, a preparation method of a perovskite energetic material with controllable B-site doping is provided. The preparation method includes: preparing a solid-liquid mixed phase containing AB(ClO4)3 and B' salt, heating to dissolve, cooling to precipitate solids, and obtaining an energetic material doped with B' ions. Among them, the energetic material includes a compound composed of at least A cations, B cations, B' cations, and perchlorate ions, and the structural formula of the compound is AB (1-x) B ’ x (ClO4)3, where 0 < x < 1, the A cation is selected from nitrogen-containing organic cations, and both the B cation and the B' cation are monovalent cations.

[0040] After further dissolving the solid-liquid mixed phase containing AB(ClO4)3 and B' salt under heating conditions, heating is stopped, and the reaction system is cooled naturally or by means of programmed cooling. During the cooling process, the solubility of AB(ClO4)3 and B' salt decreases with the decrease in temperature, the solution gradually reaches a supersaturated state, solute molecules or ions begin to aggregate to form crystal nuclei, and gradually grow into crystals, and the solid target perovskite energetic material is precipitated from the solution. <0000​In certain embodiments, in the solid-liquid mixture containing AB(ClO4)3 and B' salt, the B' salt is completely dissolved, the AB(ClO4)3 is partially dissolved, or both the B' salt and AB(ClO4)3 are partially dissolved. Generally speaking, the B' salt is completely soluble in a solvent at room temperature and pressure, while a certain amount of AB(ClO4)3 is not completely soluble under the same conditions.

[0042] In certain embodiments, the B' salt is selected from one or more of chloride, perchlorate, and nitrate salts, and the solvent of the solution containing the B' salt is selected from one or more of water, ethanol, and methanol. For example, a certain amount of B' salt is dissolved in a certain amount of water, and a certain amount of AB(ClO4)3 is added to the aqueous solution to form a solid-liquid mixed phase.

[0043] In certain embodiments, the solid-liquid mixture is dissolved at a temperature of 65-75°C. For example, the temperature can be raised to 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C, or 75°C for dissolution. The temperature can be raised to an oil bath, a water bath, or microwave-assisted dissolution. Generally, AB(ClO4)3 and B' salts can be completely dissolved at a temperature of 65-75°C.

[0044] In certain embodiments, in order to ensure uniformity during the dissolution process and to improve the dissolution efficiency, a stirring operation is performed during the temperature rise dissolution process. A uniform solution system helps to form a product with high crystallinity and uniform particle size distribution when the solid is precipitated by cooling. Stirring can be performed using a magnetic stirrer or a mechanical stirrer. The stirring speed is not limited in this application. In actual operation, the appropriate stirring speed can be determined based on factors such as the properties of the solution, the size and shape of the reaction vessel, and the solubility characteristics of the raw materials.

[0045] In certain embodiments, stirring is performed during the cooling and solid precipitation process, and the stirring time is continued until the mass of the precipitated solid no longer increases. Stirring during the precipitation process can effectively control the uniformity of the product particle size distribution.

[0046] In certain embodiments, the molar ratio of AB(ClO4)3 and B' salt added to the solid-liquid mixed phase is 1:0.1 to 40. Specifically, the molar ratio of AB(ClO4)3 and B' salt can be 1:0.1, 1:0.3, 1:0.5, 1:1, 1:5, 1:10, 1:20, or 1:40.

[0047] The technical solution of the present application is further described below with reference to specific exemplary embodiments.

[0048] Example 1

[0049] A perovskite energetic material with the structural formula (H2dabco)(NH4) 0.593 Na 0.407 (ClO4)3, the preparation method is as follows:

[0050] 1) Dissolve 203.62 mg of sodium chloride in 5 mL of deionized water.

[0051] 2) Dissolve 300 mg of DAP-4 in the sodium chloride solution from step 1), heat to 65°C, and stir until the solute is completely dissolved;

[0052] 3) Stop temperature control, cool naturally to room temperature, and keep stirring for about 24 hours;

[0053] 4) Stop stirring, filter and dry to obtain (H2dabco)(NH4) 0.593 Na 0.407 (ClO4)3 crystal product.

[0054] Under the same conditions, the amount of DAP-4 remains unchanged, and the amount of sodium chloride is changed to obtain products with different sodium doping amounts. The specific content and calculated powder density are shown in Table 1 below. Each batch of products is subjected to powder X-ray diffraction (PXRD) testing, and each batch is a single phase without impurities. Figure 1 , where the sodium content was measured by ICP-MS.

[0055] Table 1 Doped products with adjustable sodium and ammonium ratios at position B

[0056]

[0057] a) The sample density was calculated by PXRD.

[0058] DSC tests have shown that, under the condition of similar crystallinity of crystal powder (about 92%), the sodium-doped perovskite energetic material can have a higher decomposition temperature: compared with DAP-4, the initial decomposition temperature can be increased by 20°C, and compared with DAP-1, it can be increased by about 10°C. Figure 2 In a. Moreover, (H2dabco)(NH4) 0.593 Na 0.407 The thermal decomposition temperature of (ClO4)3 energetic materials varies with the sodium content within a range of 10°C. Figure 2 Middle b.

[0059] The powder sample obtained by mixing DAP-4 and NaCl in a ratio of 1:1 was dissolved, and single crystals were grown by slow volatilization. The crystal structure was obtained by single crystal X-ray diffraction. Figure 3 , the single crystal data are shown in Table 2.

[0060] Table 2 Sodium-ammonium doped single crystal structure determination data

[0061]

[0062] Example 2

[0063] A perovskite energetic material with the structural formula (H2dabco)(NH4) 0.797 Ag 0.203 (ClO4)3, the preparation method is as follows:

[0064] 1) Dissolve 722.54 mg of silver perchlorate in 5 mL of deionized water.

[0065] 2) Dissolve 300 mg of DAP-4 in the solution of step (1), heat to about 70°C, and stir until the solute is completely dissolved;

[0066] 3) Stop temperature control, cool naturally to room temperature, and keep stirring for about 24 hours;

[0067] 4) Stop stirring, filter and dry to obtain (H2dabco)(NH4) 0.797 Ag 0.203 (ClO4)3 crystal product.

[0068] Under the same conditions, the amount of DAP-4 remains unchanged, and the amount of silver perchlorate added is changed to obtain products with different silver doping amounts. The specific content and calculated powder density are shown in Table 3 below. Each batch of products is subjected to powder X-ray diffraction (PXRD) testing, and each batch is a single phase without impurities. Figure 4 ; The silver content was determined by ICP-MS.

[0069] Table 3. Doped products with adjustable silver-ammonium ratio at position B

[0070]

[0071] a) The density of the samples was calculated by PXRD.

[0072] As shown in Table 3, compared with the theoretical density of DAP-4 (223K, 1.905 g / cm 3 ), calculated by room temperature PXRD test of silver-doped (H2dabco)(NH4) (1-x) Ag x (ClO4)3 powder has a higher density (greater than 2g / cm 3 At the same time, the energy level of an energetic material is closely related to its crystal density. Generally, the higher the energetic crystal density, the higher the energetic level of the energetic material. Silver-doped perovskite energetic materials can have even higher energy levels.

[0073] The powder sample obtained by mixing DAP-4 and silver perchlorate in a ratio of 1:1 was dissolved, and single crystals were grown by slow volatilization. The crystal structure was obtained by single crystal X-ray diffraction. Figure 5 , the single crystal data are shown in Table 4.

[0074] Table 4 Single crystal structure determination data of silver ammonium doped

[0075]

[0076] Example 3

[0077] A perovskite energetic material with the structural formula (H2dabco)(NH4) 0.079 K 0.921 (ClO4)3, the preparation method is as follows:

[0078] 1) Dissolve 51.95 mg of potassium chloride in 10 mL of deionized water.

[0079] 2) Dissolve 300 mg of DAP-4 in the solution of step (1), heat to about 70°C, and stir until the solute is completely dissolved;

[0080] 3) Stop temperature control and cool naturally to room temperature to obtain (H2dabco)(NH4) 0.079 K 0.921 (ClO4)3 crystal product.

[0081] To obtain (H2dabco)(NH4) 0.079 K 0.921 (ClO4)3 crystal product was subjected to single crystal X-ray testing, and the crystal structure was obtained. Figure 6 , the single crystal data are shown in Table 5.

[0082] Table 5 Single crystal structure determination data of potassium ammonium doping

[0083]

[0084] Example 4

[0085] A perovskite energetic material with the structural formula (H2dabco)Rb 0.472 K 0.528 (ClO4)3, the preparation method is as follows:

[0086] 1) Dissolve 51.95 mg of potassium chloride and 84.26 mg of rubidium chloride in 10 mL of deionized water.

[0087] 2) Dissolve 300 mg of DAP-4 in the solution from step (1), heat to about 75°C, and stir until the solute is completely dissolved;

[0088] 3) Stop temperature control and cool naturally to room temperature to obtain the product and perform single crystal X-ray testing to obtain (H2dabco)Rb 0.472 K 0.528 (ClO4)3 crystal structure, see Figure 7 , the single crystal data are shown in Table 6.

[0089] Table 6 Data of single crystal structure determination of rubidium potassium doped

[0090]

[0091] Although the embodiments of the present application are described above in conjunction with the accompanying drawings, the present application is not limited to the above-mentioned specific embodiments and application fields. The above-mentioned specific embodiments are merely illustrative and instructive, and not restrictive. A person of ordinary skill in the art, guided by this specification and without departing from the scope of protection of the claims of this application, may also devise various forms, all of which fall within the scope of protection of this application.

Claims

1. A B-site controllably doped perovskite energetic material, characterized in that: The general structural formula of the perovskite energetic material compound is AB (1-x) B ’ x (ClO4)3, where 0 < x < 1, the A cation is selected from nitrogen-containing organic cations, and the B cation and the B' cation are monovalent cations with different element species.

2. The perovskite energetic material according to claim 1, characterized in that The B cation is selected from NH4 + 、Li + 、Na + , K + , Rb + 、Ag + One or more of the following: the B' cation is selected from NH4 + 、Li + 、Na + , K + , Rb + 、Ag + One or more of the following.

3. The perovskite energetic material according to claim 2, characterized in that The B cation is selected from NH4 + .

4. The perovskite energetic material according to claim 2, characterized in that The B' cation is selected from Na + , K + , Rb + 、Ag + One or more of the following.

5. The perovskite energetic material according to claim 1, characterized in that The A cation is selected from protonated triethylenediamine and / or hexamethylenetetramine.

6. The method for preparing the perovskite energetic material according to any one of claims 1 to 5, characterized in that: include: Prepare a solid-liquid mixture containing AB(ClO4)3 and B' salt, and heat to dissolve; The solid is precipitated by cooling to obtain the B' ion-doped energetic material.

7. The preparation method according to claim 6, characterized in that The B' salt is selected from one or more of chloride, perchlorate and nitrate.

8. The preparation method according to claim 6, characterized in that The solvent of the solid-liquid mixed phase is selected from one or more of water, ethanol and methanol.

9. The preparation method according to claim 6, characterized in that The molar ratio of AB(ClO4)3 and B' salt in the solid-liquid mixed phase is 1:0.1-40.

10. The preparation method according to claim 6, characterized in that The stirring until dissolving is carried out at 65-75°C.

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