An ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel, its preparation method and application
By preparing an all-inorganic perovskite cesium bismuth iodine aerogel, the problems of high brittleness and high thermal conductivity of aerogel materials were solved, achieving high efficiency and low thermal conductivity, making it suitable for medium and low temperature insulation applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NORTHWESTERN POLYTECHNICAL UNIV
- Filing Date
- 2023-10-12
- Publication Date
- 2026-05-26
AI Technical Summary
Existing aerogel materials suffer from high brittleness and intrinsic thermal conductivity, which limits their development in the field of thermal insulation materials. Furthermore, existing perovskite aerogel preparation technologies are mostly composite materials, which do not fully utilize their low thermal conductivity properties.
An all-inorganic perovskite cesium bismuth iodide aerogel was prepared by reacting cesium iodide and bismuth triiodide in a specific solvent to form cesium bismuth iodide nanocrystal colloids, and then preparing ultra-low thermal conductivity cesium bismuth iodide aerogel by filtration and drying.
A cesium bismuth iodine aerogel with high quality, low density, good uniformity, and low thermal conductivity was prepared. It has good thermal insulation properties, can replace common thermal insulation aerogels, and is suitable for mass production.
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Figure CN117504747B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aerogel technology, specifically to an ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel, its preparation method, and its applications. Background Technology
[0002] Aerogels are solid materials with nanoscale porous network structures. Due to their excellent properties such as ultra-low density, ultra-low thermal conductivity, and good thermal stability, they have become a research focus in thermal insulation materials in recent years and are widely used in aerospace, construction engineering, and biomedicine. However, traditional aerogel materials are still characterized by high brittleness and high intrinsic thermal conductivity, which limits their development potential. For example, SiO2 aerogel has a thermal conductivity of 0.021 W / (m·K) or even lower, while its intrinsic thermal conductivity is as high as 0.8-1.2 W / (m·K). Although the development of nanowire aerogel materials in recent years has greatly improved the mechanical properties of aerogel materials, there is still considerable room for development in reducing their intrinsic thermal conductivity to improve their thermal insulation and cold preservation properties.
[0003] Perovskite materials, with their excellent optoelectronic properties, occupy an important research position in areas such as solar power generation and radiation detection, and their thermal properties are also gradually attracting researchers' attention. Studies have found that most perovskite materials have extremely low thermal conductivity, with single-crystal thermal conductivity reaching 0.5-0.01 W / (m·K) or even lower. These materials with extremely low intrinsic thermal conductivity can have their thermal conductivity further reduced by fabricating them into porous aerogels.
[0004] Existing perovskite-related preparation and application technologies are mostly concentrated on the preparation of perovskite single crystals, polycrystalline perovskites, nanowires, and their optoelectronic applications. Technologies for preparing perovskite aerogels are relatively scarce. Similar perovskite aerogel preparations are primarily used in photocatalysis and chemical catalysis, without focusing on or utilizing their low thermal conductivity. Furthermore, existing low thermal conductivity perovskite aerogel preparation technologies are mostly based on composite materials such as SiO2 aerogel, failing to fully leverage the low intrinsic thermal conductivity. Technology for preparing perovskite aerogels with ultra-low thermal conductivity represents a current gap in the field of perovskite aerogel preparation. Summary of the Invention
[0005] To address the shortcomings of the aforementioned background technologies, this invention primarily solves the problem of preparing perovskite aerogels using cesium bismuth iodide without relying on other aerogel materials as the matrix framework; specifically, it provides an ultra-low thermal conductivity cesium bismuth iodide aerogel lower than that of traditional insulating aerogel materials. This invention offers an ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodide aerogel, its preparation method, and its applications. The method involves dissolving cesium iodide and bismuth triiodide in a mixed solvent of acid (OA), oleylamine (OM), and octadecene (ODE), reacting at elevated temperatures to obtain cesium bismuth iodide nanocrystalline colloids. The solution, nanocrystalline colloids, and precipitated phase are then separated by filtration. Finally, the purified cesium bismuth iodide nanocrystalline colloids are aged and dried to obtain the cesium bismuth iodide aerogel. The ultra-low intrinsic thermal conductivity of the all-inorganic perovskite cesium bismuth iodide, along with its low-temperature thermal stability, improves the aerogel's performance in medium- and low-temperature insulation applications.
[0006] The first objective of this invention is to provide a method for preparing ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel, comprising the following steps:
[0007] Cesium iodide and bismuth triiodide were dissolved in a mixed solvent of oleic acid, oleylamine and octadecene to obtain a cesium bismuth iodide mixed solution;
[0008] After incubating the cesium bismuth iodine mixed solution at 120-260℃ for 1-48 hours, it was purified by filtration to obtain cesium bismuth iodine colloid.
[0009] Cesium bismuth iodine colloid was aged and then dried to form an ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel.
[0010] Preferably, the molar concentration of cesium bismuth iodine in the cesium bismuth iodine mixed solution is 0.01 to 0.1 mol / ml.
[0011] Preferably, the aging treatment temperature is 120–280°C and the aging time is 24–48 h.
[0012] Preferably, the volume ratio of oleic acid, oleylamine and octadecene is (3-5):(3-5):(40-60).
[0013] Preferably, the filtration is performed using filter paper to remove undissolved cesium iodide and bismuth triiodide powders, as well as the precipitation of tiny crystals.
[0014] Preferably, the purification is performed by using a filter membrane to aggregate the particles in the colloid, wherein the filter membrane is one of a polyethersulfone membrane, a polytetrafluoroethylene membrane, a polyvinylidene fluoride membrane, or a polyvinylidene fluoride membrane.
[0015] Preferably, the purity of cesium iodide and bismuth triiodide is 99.99%.
[0016] Preferably, the drying process involves drying the wet sol at 60-100°C for 36-48 hours to form a perovskite cesium bismuth iodine aerogel.
[0017] Alternatively, cesium bismuth iodine aerogel can be formed by drying in supercritical conditions for 24 hours using one of methanol, ethanol, isopropanol, or CO2 as the drying medium.
[0018] The second objective of this invention is to provide an ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel.
[0019] The third objective of this invention is to provide an application of ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel in the field of low-temperature insulation.
[0020] Compared with the prior art, the beneficial effects of the present invention are:
[0021] This invention utilizes CsI and BiI3 to form Cs, Bi, and I ions in oleic acid, oleylamine, and octadecene solutions. Temperature control induces the spontaneous combination of these ionic atoms to form cesium bismuth iodide nanocrystalline colloids. The colloid is then purified by filtration to separate it from the solvent, and subsequently converted into an aerogel through drying. This invention features a simple preparation process suitable for mass production. The prepared cesium bismuth iodide aerogel exhibits high quality, low density, good uniformity, and low thermal conductivity, demonstrating excellent thermal insulation properties. As a novel low thermal conductivity material, it can effectively replace existing common thermal insulation aerogels. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the cesium bismuth iodine aerogel preparation process provided in the example.
[0023] Figure 2 The XRD pattern of the cesium bismuth iodine aerogel powder provided in Example 1.
[0024] Figure 3 The heat capacity comparison curves of the cesium bismuth iodine aerogel provided in Example 1 and the traditional silica aerogel are shown. Detailed Implementation
[0025] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.
[0026] The purpose of this invention is to prepare a novel ultra-low thermal conductivity aerogel by utilizing the ultra-low intrinsic thermal conductivity of the all-inorganic perovskite cesium bismuth iodine. The ultra-low intrinsic thermal conductivity of cesium bismuth iodine, along with its low-temperature thermal stability, further improves the aerogel's performance in medium- and low-temperature insulation applications.
[0027] To achieve the above objectives, this invention involves dissolving cesium iodide and bismuth triiodide in a mixed solvent of acid (OA), oleylamine (OM), and octadecene (ODE), reacting the solutions at elevated temperatures to obtain cesium bismuth iodide nanocrystalline colloids. The solution, nanocrystalline colloids, and precipitated phase are then separated by filtration. Finally, the purified cesium bismuth iodide nanocrystalline colloids are aged and dried to obtain cesium bismuth iodide aerogel. Details are as follows:
[0028] A method for preparing an ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel includes the following steps:
[0029] (1) Cesium iodide with a purity of 99.99% and bismuth triiodide with a purity of 99.99% are dissolved in a mixed solvent of oleic acid (OA), oleylamine (OM) and octadecene (ODE) with a volume ratio of (3-5):(3-5):(40-60), and stirred to obtain a mixed solution with a molar mass concentration of cesium bismuth iodide of 0.1-0.01 mol / ml. The three solvents selected in this invention can fully dissolve cesium iodide and bismuth triiodide while also enabling them to form colloidal particles at a certain solubility.
[0030] (2) Place the solution in an oven and heat it to 120-260℃, then keep it at that temperature for 1-48 hours to allow the solution to react fully. Heating to 120-260℃ can increase solubility and accelerate particle movement to ensure a full reaction.
[0031] (3) Use filter paper to filter out undissolved cesium iodide and bismuth triiodide powders as well as the precipitation of tiny crystals.
[0032] (4) Use one of the following membranes—polyethersulfone (PES), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), or polyvinylidene fluoride—to filter out particle aggregation in the colloid, forming a high-purity cesium bismuth iodine colloid. Excess solution is filtered through the membrane to obtain colloidal particles. The purification effect is achieved because the colloidal particle molecules are larger than solvent molecules and cannot pass through the filter membrane.
[0033] (5) Transfer the colloid to an oven and heat it at 120-280℃ for 24-48 hours to form a cesium bismuth iodine wet sol. Aging can strengthen the connection between colloids and increase the stability of the pore structure. This helps to improve the mechanical strength and thermal stability of the aerogel.
[0034] (6) The wet sol is dried at room temperature and then dried in an oven at 60-100℃ for 36-48 hours to form perovskite cesium bismuth iodine aerogel.
[0035] (7) Alternatively, CO2 can be used as the drying medium to dry the cesium bismuth iodine aerogel for 24 hours under its supercritical state; both drying methods can cause the wet sol to expand during drying, and either one can be chosen.
[0036] This invention provides an ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel.
[0037] This invention also provides an application of ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel in the field of low-temperature insulation.
[0038] It should be noted that, unless otherwise specified, the experimental methods used in this invention are all conventional methods; and the reagents and materials used, unless otherwise specified, are all commercially available.
[0039] Example 1
[0040] A method for preparing an ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel, see [link to relevant documentation]. Figure 1 As shown, it includes the following steps:
[0041] Step 1: Add 3ml of oleic acid (OA), 3ml of oleylamine (OM) and 40ml of octadecene (ODE) to a 50ml beaker. Add 1.039g of CsI with a purity of 99.99% and 1.573g of BiI3 with a purity of 99.99%, with a molar ratio of 3:2.
[0042] Step 2: Seal the mouth of the beaker with sealing film, place it in a constant temperature oven, set the temperature to 190℃, and keep it at that temperature for 1 hour.
[0043] Step 3: Remove the beaker and filter the remaining raw materials and precipitated impurities using filter paper and a funnel;
[0044] Step 4: Filter with a polytetrafluoroethylene (PTFE) membrane for 3 hours to remove excess solvent and obtain cesium bismuth iodine nanocrystal colloid;
[0045] Step 5: Place the filtered nanocrystalline colloid in a beaker, transfer it to an oven, and keep it at 100℃ for 48 hours.
[0046] Step 6: Adjust the oven temperature to 60 degrees Celsius, keep it warm for 72 hours, and then remove it to obtain cesium bismuth iodine aerogel.
[0047] Example 2
[0048] A method for preparing an ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel, see [link to relevant documentation]. Figure 1 As shown, it includes the following steps:
[0049] Step 1: In a 50ml beaker, add 6ml of oleic acid (OA), 6ml of oleylamine (OM), and 38ml of octadecene (ODE). Add 1.039g of CsI and 1.573g of BiI3 with a purity of 99.99%, respectively, in a molar ratio of 3:2.
[0050] Step 2: Place the product in a constant temperature oven, set the temperature to 190℃, and keep it at that temperature for 8 hours.
[0051] Step 3: Remove the beaker and filter the remaining raw materials and precipitated impurities using filter paper and a funnel;
[0052] Step 4: Filter with a (PES) polyethersulfone membrane for 3 hours to remove excess solvent and obtain cesium bismuth iodine nanocrystal colloid;
[0053] Step 5: Place the filtered nanocrystalline colloid in a beaker, transfer it to an oven, and keep it at 120℃ for 48 hours.
[0054] Step 6: Adjust the oven temperature to 100 degrees Celsius, keep it warm for 72 hours, and then remove it to obtain cesium bismuth iodine aerogel.
[0055] Example 3
[0056] A method for preparing an ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel, see [link to relevant documentation]. Figure 1 As shown, it includes the following steps:
[0057] Step 1: In a 50ml beaker, add 3ml oleic acid (OA), 3ml oleylamine (OM), and 40ml octadecene (ODE). Add 1.039g of 99.99% pure CsI and 1.573g of 99.99% pure BiI3, with a molar ratio of 3:2.
[0058] Step 2: Place the product in a constant temperature oven, set the temperature to 220℃, and keep it at that temperature for 8 hours.
[0059] Step 3: Remove the beaker and filter the remaining raw materials and precipitated impurities using filter paper and a funnel;
[0060] Step 4: Filter with a polyvinylidene fluoride (PVDF) membrane for 3 hours to remove excess solvent and obtain cesium bismuth iodine nanocrystal colloid;
[0061] Step 5: Place the filtered nanocrystalline colloid in a beaker, transfer it to an oven, and keep it at 280℃ for 48 hours.
[0062] Step 6: Adjust the oven temperature to 100 degrees Celsius, keep it warm for 72 hours, and then remove it to obtain cesium bismuth iodine aerogel.
[0063] Example 4
[0064] A method for preparing an ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel, see [link to relevant documentation]. Figure 1 As shown, it includes the following steps:
[0065] Step 1: In a 50ml beaker, add 3ml oleic acid (OA), 3ml oleylamine (OM), and 40ml octadecene (ODE). Add 1.039g of 99.99% pure CsI and 1.573g of 99.99% pure BiI3, with a molar ratio of 3:2.
[0066] Step 2: Place the product in a constant temperature oven, set the temperature to 220℃, and keep it at that temperature for 8 hours.
[0067] Step 3: Remove the beaker and filter the remaining raw materials and precipitated impurities using filter paper and a funnel;
[0068] Step 4: Filter with a polyvinylidene fluoride membrane for 3 hours to remove excess solvent and obtain cesium bismuth iodine nanocrystal colloid;
[0069] Step 5: Place the filtered nanocrystalline colloid in a beaker, transfer it to an oven, and keep it at 280℃ for 48 hours.
[0070] Step 6: Remove the beaker and place the cesium bismuth iodine gel in the beaker into a CO2 supercritical drying device and dry it at 100°C for 24 hours to obtain cesium bismuth iodine aerogel.
[0071] To illustrate the relevant properties of the cesium bismuth iodine aerogel prepared by the method provided in this invention, the accompanying drawings are provided.
[0072] Figure 2 The XRD pattern of the cesium bismuth iodine aerogel powder provided in Example 1 is shown. The cesium bismuth iodine powder was obtained by grinding the cesium bismuth iodine aerogel, and the XRD diffraction pattern of the powder sample is shown at 15°–55°. The black line represents the obtained X-ray diffraction pattern, and the red line represents the standard diffraction peaks. Figure 2 In the standard card, the main intensity peaks of the diffraction spectrum are basically consistent with the standard card. Each high diffraction intensity diffraction crystal plane appears in the black diffraction spectrum. A small number of low intensity diffraction crystal planes have very close diffraction angles, such as 32.5°, 34°, and 39°, which causes the corresponding diffraction peak intensity to increase and the full width at half maximum (FWHM) to widen. Figure 2 This indicates that the main component of the sample aerogel is cesium bismuth iodine.
[0073] Figure 3 The graph shows a comparison of the heat capacity of cesium bismuth iodine aerogel and traditional silica aerogel provided in Example 1. Silica aerogel has been widely used as an insulation material in building insulation, production insulation, and other fields. As can be seen from the graph, at low and room temperatures, the heat capacity of cesium bismuth iodine is much higher than that of silica. According to experimental data from existing technologies, the heat capacity of silica aerogel can reach 60 J·(mol·K) at room temperature. -1 According to the test results of this patent, the heat capacity of cesium bismuth iodine aerogel at room temperature can reach 300 J·(mol·K). -1This indicates that at low and normal temperatures, when the ambient temperature changes, cesium bismuth iodine aerogel needs to absorb more energy to change its own temperature compared to silica aerogel, resulting in lower thermal conductivity and better heat preservation.
[0074] This invention describes preferred embodiments and their effects. However, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to include both the preferred embodiments and all changes and modifications falling within the scope of this invention.
[0075] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for preparing an ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel, characterized in that, Includes the following steps: Cesium iodide and bismuth triiodide were dissolved in a mixed solvent of oleic acid, oleylamine and octadecene to obtain a cesium bismuth iodide mixed solution; After incubating the cesium bismuth iodine mixed solution at 120-260℃ for 1-48 hours, it was purified by filtration to obtain cesium bismuth iodine colloid. After aging treatment, cesium bismuth iodine colloid is dried to form an ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel. The aging treatment temperature is 120~280℃, and the aging time is 24-48h; The volume ratio of oleic acid, oleylamine and octadecene is (3-5):(3-5):(40-60).
2. The preparation method of ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel according to claim 1, characterized in that, The cesium bismuth iodine mixed solution has a molar mass concentration of 0.01~0.1 mol / ml.
3. The method for preparing ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel according to claim 1, characterized in that, The filtration process involves using filter paper to remove undissolved cesium iodide and bismuth triiodide powders, as well as the precipitation of tiny crystals.
4. The method for preparing ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel according to claim 1, characterized in that, The purification process involves using a filter membrane to aggregate the particles in the colloid. The filter membrane is one of the following: polyethersulfone membrane, polytetrafluoroethylene membrane, polyvinylidene fluoride membrane, or polyvinylidene fluoride membrane.
5. The method for preparing ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel according to claim 1, characterized in that, The purity of cesium iodide and bismuth triiodide is 99.99%.
6. The method for preparing ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel according to claim 1, characterized in that, The drying process involves drying the wet sol at 60-100℃ for 36-48 hours to form a perovskite cesium bismuth iodine aerogel. Alternatively, cesium bismuth iodine aerogel can be formed by drying in supercritical conditions for 24 hours using one of methanol, ethanol, isopropanol, or CO2 as the drying medium.
7. An ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel prepared by the method according to any one of claims 1 to 6.
8. The application of the ultra-low thermal conductivity all-inorganic perovskite cesium bismuth iodine aerogel as described in claim 7 in the field of low-temperature thermal insulation.