High-conductivity perovskite-type BaZrO with controllable grain size3Preparation method of proton conductor material
阅读说明：本技术 晶粒尺寸可控的高电导率钙钛矿型BaZrO3基质子导体材料的制备方法 (High-conductivity perovskite-type BaZrO with controllable grain size3Preparation method of proton conductor material ) 是由 葛林 孙克强 徐冬 于 2021-06-22 设计创作，主要内容包括：本发明公开了一种晶粒尺寸可控的高电导率钙钛矿型BaZrO-(3)基质子导体材料制备方法。采用(ZrO-(2))-(1-x)(Y-(2)O3)-(x)(0.05≤x≤0.08)粉体作为初始原料,并在较低的温度下合成晶粒尺寸可控的BaZrO-(3)基质子导体粉体材料。本发明解决了传统固相法合成工艺中晶粒尺寸分布宽、化学组成不均匀以及湿化学法合成工艺中步骤繁琐且晶粒难以长大等问题。本发明制备的钙钛矿型BaZrO-(3)基质子导体材料形状规则,结晶度高,分散均匀。经致密化处理后拥有良好的质子导电性,晶界阻抗大大减小,在600℃时的电导率可达4.92×10～(-3)S cm～(-1)。(The invention discloses a grain size controllable high-conductivity perovskite type BaZrO 3 A method for preparing a proton conductor material. Using (ZrO) 2 ) 1‑x (Y 2 O3) x (x is more than or equal to 0.05 and less than or equal to 0.08) powder is used as an initial raw material and is synthesized into BaZrO with controllable grain size at lower temperature 3 Based on proton conductor powder material. The invention solves the problems of wide grain size distribution, uneven chemical composition, complex steps, difficult grain growth and the like in the traditional solid-phase synthesis process and the wet chemical synthesis process. Perovskite type BaZrO prepared by the invention 3 The basic proton conductor material has regular shape, high crystallinity and uniform dispersion. The densification product has good proton conductivity, greatly reduced grain boundary resistance, and conductivity of 4.92 × 10 at 600 deg.C ‑3 S cm ‑1 。)
1. High-conductivity perovskite type BaZrO with controllable grain size3The preparation method of the proton conductor material comprises the following specific steps:
(1) weighing Ba (NO)3)2Dissolving in deionized water, and adding (ZrO)2)1-x(Y2O3)x(x is more than or equal to 0.05 and less than or equal to 0.08) adding the powder, continuously heating, stirring and uniformly mixing; wherein Ba (NO)3)2And (ZrO)2)1-x(Y2O3)xThe molar ratio of (A) to (B) is 1 (0.9-1);
(2) continuously heating and stirring at 60-80 ℃ to obtain dry mixed powder;
(3) putting the dried mixed powder into a tubular muffle furnace, introducing protective atmosphere for roasting, heating to 800-850 ℃, preserving heat for 2-3 hours, and cooling after roasting to obtain the high-conductivity perovskite BaZrO with controllable grain size3A base proton conductor material.
2. The method according to claim 1, wherein the (ZrO) in the step (1)2)1-x(Y2O3)xThe particle size of (A) is 0.15 to 5 μm.
3. The method according to claim 1, wherein the temperature increase rate in the step (3) is 1 to 7 ℃/min.
4. The method according to claim 1, wherein the protective atmosphere introduced in the step (3) is N2，N2The flow rate of (A) is 20-60 mL/min.
5. The method according to claim 1, wherein the particle size of the cooled powder is 0.5 to 3 μm.
6. The production method according to claim 1, characterized in that the high-conductivity perovskite-type BaZrO produced is3The base proton conductor material has a conductivity of 3.06-4.92 x 10-3S cm-1。
Technical Field
The invention belongs to the technical field of fuel cells, and relates to a high-conductivity perovskite type BaZrO with controllable grain size3A method for preparing a proton-based conductor material, in particular to an improved solid phase method for preparing high-conductivity perovskite BaZrO3A method of producing a proton conductor material.
Background
The high-temperature proton conductor refers to a substance having proton conductivity in a high-temperature hydrogen-or hydrogen-containing atmosphere. The high-temperature proton conductor has wide application prospect in the aspects of electrolytic cells, hydrogen sensors, hydrogen separation membranes, medium and low temperature solid oxide fuel cells and the like. Among the high temperature proton conductor materials currently available, ABO3The perovskite-type oxide has the best proton conductivity. Wherein, BaCeO3Has higher proton conductivity, but contains CO2And H2The chemical stability in an atmosphere of O is poor. In contrast, BaZrO3In the presence of CO2And H2O has been widely noticed because of its excellent chemical stability and high volume conductivity in an atmosphere.
The most common BaZrO3The powder synthesis method is a solid phase method, the preparation method is simple, but the synthesis temperature is high, and the prepared powder generally has wide particle size distribution and uneven chemical composition. In addition, during sintering, the grains are difficult to grow. BaZrO due to poor sintering properties and high grain boundary resistance3The material has a low overall conductivity. Improvement of BaZrO3The main approaches to the overall conductivity of a material are: 1) preparing nano powder; 2) doping low-valence elements; 3) and adding a sintering aid. These approaches primarily increase BaZrO by promoting grain growth and reducing high resistivity grain boundary content3The overall conductivity of the material. In which BaZrO is prepared3The base nanopowder has significant limitations for promoting grain growth. Firstly, most methods for preparing nano-powder are wet chemical methods, such as sol-gel method and combustion method, and the method has complicated steps and small yield. Second, even BaZrO3The nano powder has better sintering performance, the crystal grain can only grow to 1 mu m at a very high sintering temperature (more than 1600 ℃), and the content of high-resistance grain boundary is very high. The difficulty of grain growth has great limitation on the application of proton conductor electrolytes. Hitherto, BaZrO3A fuel cell in which the base material is an electrolyte and the crystal grain size of the electrolyte reaches 1 μm has not been reported.
Existing BaZrO3Powder obtained by synthetic methodThe grain size of the body is not controllable, and the grains are difficult to grow up in the sintering process and can not meet the BaZrO3In various aspects. Therefore, the BaZrO with controllable grain size and better performance is prepared by adopting a simple process3Base powders remain an important problem to be solved urgently in this field.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a high-conductivity perovskite type BaZrO with controllable grain size3The preparation method of the base high-temperature proton conductor material improves the performance of the proton conductor. The preparation method is simple, and the prepared perovskite type BaZrO3The base high-temperature proton conductor material has smaller grain boundary resistance and higher proton conductivity.
In order to achieve the purpose, the invention adopts the technical scheme that: high-conductivity perovskite type BaZrO with controllable grain size3The preparation method of the proton conductor material comprises the following specific steps:
(1) weighing appropriate amount of Ba (NO)3)2Dissolving in deionized water, and adding (ZrO)2)1-x(Y2O3)x(x is more than or equal to 0.05 and less than or equal to 0.08) adding the powder, continuously heating, stirring and uniformly mixing; wherein Ba (NO)3)2And (ZrO)2)1-x(Y2O3)xThe molar ratio of (A) to (B) is 1 (1-0.9);
(2) continuously heating and stirring at 60-80 ℃ to obtain dry mixed powder;
(3) putting the dried mixed powder into a tubular muffle furnace, introducing protective atmosphere for roasting, heating to 800-850 ℃, preserving heat for 2-3 hours, and cooling after roasting to obtain the high-conductivity perovskite BaZrO with controllable grain size3A base proton conductor material.
(ZrO) described in the step (1) is preferable2)1-x(Y2O3)xThe particle size of (A) is 0.15 to 5 μm.
Preferably, the heating rate in the step (3) is 1-7 ℃/min.
Preferably, the protective atmosphere introduced in the step (3) is N2，N2The flow rate of (A) is 20-60 mL/min.
The cooled powder is uniformly distributed and has a regular cubic shape, and the particle size of the powder is 0.5-3 mu m.
The high-conductivity perovskite type BaZrO prepared by the invention3The powder of the proton conductor material is densified and put in a nitrogen atmosphere (3% H) of water2O) is subjected to electrochemical test, and the conductivity is 3.06-4.92 multiplied by 10-3S cm-1。
The invention can obtain the cubic perovskite powder with the grain size of 0.5-3 mu m at a lower temperature by using a simple method. Compared with the powder synthesized by the traditional solid phase method, the BZY15 powder synthesized by the method has the advantages of regular shape, uniform size distribution and controllable grain size, and the performance of the powder is improved. Compared with wet chemical methods such as a sol-gel method, a combustion method and the like, the method has simple steps and can be used for mass production. The BZY15 electrolyte with larger grain size can be obtained at lower temperature by adding effective sintering aid to densify in the subsequent sintering process. In addition, the powder synthesized by the invention can also be applied to the preparation of anode-supported fuel cells or composite cathodes.
Has the advantages that:
1. the BZY15 powder prepared by the invention is in a regular cubic crystal form, and is uniformly dispersed;
2. the invention can realize the controllability of the grain size of the powder from 0.5 to 3 mu m by adjusting the powder sintering system and the ventilation flow.
3. The powder synthesis temperature in the invention is low, and the powder with regular shape and high purity can be synthesized at 700-800 ℃.
4. After the BZY15 powder prepared by the invention is sintered and densified, the grain boundary impedance is greatly reduced, and the total conductivity is improved.
5. The preparation method is simple, only two procedures of raw material mixing and calcining are needed, large-scale production can be realized, and the method has universality.
Drawings
FIG. 1 is an XRD spectrum of BZY15 powder in example 1;
FIG. 2 is an SEM photograph of BZY15 powder of examples 1-6;
FIG. 3 is an SEM image of BZY15 powder in comparative example 1;
FIG. 4 is a bar graph of the electrical conductivity at 600 ℃ for the samples of examples 1-6 and comparative example 1.
Detailed Description
The present invention will be described in further detail with reference to examples. It should be noted that the following examples are only for illustrating the technical solutions of the present invention, but do not limit the scope of the present invention. Modifications and equivalents of the present invention may be made by those skilled in the art without departing from the spirit and scope of the present invention, and are intended to be included within the scope of the appended claims.
Example 1
Weighing 1 mol of barium nitrate, adding the barium nitrate into a proper amount of deionized water, and adding 1 mol of (ZrO) after the barium nitrate is completely dissolved2)0.92(Y2O3)0.08(particle size of 0.15-5 μm), placing on a magnetic stirrer, heating at 80 deg.C and continuously stirring to volatilize water to obtain dry mixed powder. The mixed powder was then placed in an alumina crucible and placed in a tubular muffle furnace for calcination. The heating rate is 1.33 ℃/min in the heating process, and finally the temperature is kept for 2h at 800 ℃. And introducing nitrogen into the tubular muffle furnace during the reaction process, wherein the flow rate of the nitrogen is 60 mL/min. After cooling, the XRD pattern of the synthesized BZY15 powder is shown in fig. 1. As can be seen from the figure, the characteristic diffraction peaks of the samples are all equal to BaZrO3The standard cards correspond to each other, which shows that BZY15 powder is successfully synthesized. The grain size of the synthesized powder is about 3 μm. The powder is calcined for 10 hours at 1400 ℃ after being ground, sieved, added with a sintering aid NiO, granulated and pressed into tablets. Silver paste was applied to both sides of the obtained sample, and after curing treatment, the sample was placed in a nitrogen atmosphere (3% H) of water2O) and the conductivity reaches 4.92 multiplied by 10 at 600 DEG C-3S cm-1。
Example 2
Weighing 1 mol of barium nitrate, adding the barium nitrate into a proper amount of deionized water, after the barium nitrate is completely dissolved,adding 1 mol of (ZrO)2)0.92(Y2O3)0.08(particle size of 0.15-5 μm), placing on a magnetic stirrer, heating at 80 deg.C and continuously stirring to volatilize water to obtain dry mixed powder. Then placing the mixed powder in an alumina crucible and placing the alumina crucible in a tubular muffle furnace for calcining, wherein the heating rate is 2.22 ℃/min, and finally, preserving heat for 3h at 800 ℃. And introducing nitrogen into the tubular muffle furnace during the reaction process, wherein the flow rate of the nitrogen is 60 mL/min. After cooling, the grain size of the synthesized powder is about 1.428 μm. The electrochemical testing procedure was the same as in example 1. The conductivity of the product reaches 4.44 x 10 at 600 DEG C-3S cm-1。
Example 3
Weighing 1 mol of barium nitrate, adding the barium nitrate into a proper amount of deionized water, and adding 1 mol of (ZrO) after the barium nitrate is completely dissolved2)0.92(Y2O3)0.08(particle size of 0.15-5 μm), placing on a magnetic stirrer, heating at 80 deg.C and continuously stirring to volatilize water to obtain dry mixed powder. Then placing the mixed powder in an alumina crucible and placing the alumina crucible in a tubular muffle furnace for calcining, wherein the heating rate is 3.33 ℃/min in the heating process, and finally, preserving heat for 2h at 850 ℃. Nitrogen was passed through the reaction at a flow rate of 20 mL/min. After cooling, the grain size of the synthesized powder is about 1.337 μm. The electrochemical testing procedure was the same as in example 1. The conductivity of the product reaches 4.32 x 10 at 600 DEG C-3S cm-1。
Example 4
Weighing 1 mol of barium nitrate, adding the barium nitrate into a proper amount of deionized water, and adding 1 mol of (ZrO) after the barium nitrate is completely dissolved2)0.92(Y2O3)0.08(particle size of 0.15-5 μm), placing on a magnetic stirrer, heating at 60 deg.C and continuously stirring to volatilize water to obtain dry mixed powder. Then placing the mixed powder in an alumina crucible and placing the alumina crucible in a tubular muffle furnace for calcining, wherein the heating rate is 2.22 ℃/min in the heating process, and finally, preserving the heat for 2h at 830 ℃. And introducing nitrogen into the tubular muffle furnace during the reaction process, wherein the flow rate of the nitrogen is 20 mL/min. After cooling, synthesizingThe grain size of the powder of (2) is about 1.049 μm. The electrochemical testing procedure was the same as in example 1. The conductivity of the product reaches 4.16 x 10 at 600 DEG C-3S cm-1。
Example 5
Weighing 1 mol of barium nitrate, adding the barium nitrate into a proper amount of deionized water, and adding 1 mol of (ZrO) after the barium nitrate is completely dissolved2)0.92(Y2O3)0.08(particle size of 0.15-5 μm), placing on a magnetic stirrer, heating at 70 deg.C and continuously stirring to volatilize water to obtain dry mixed powder. Then placing the mixed powder in an alumina crucible and placing the alumina crucible in a tubular muffle furnace for calcining, wherein the heating rate is 3.33 ℃/min in the heating process, and finally, preserving heat for 2.5h at 800 ℃. And introducing nitrogen into the tubular muffle furnace during the reaction process, wherein the flow rate of the nitrogen is 60 mL/min. After cooling, the grain size of the synthesized powder was about 0.667 μm. The electrochemical testing procedure was the same as in example 1. The conductivity of the product reaches 3.79 multiplied by 10 at 600 DEG C-3S cm-1。
Example 6
Weighing 1 mol of barium nitrate, adding the barium nitrate into a proper amount of deionized water, and adding 1 mol of (ZrO) after the barium nitrate is completely dissolved2)0.92(Y2O3)0.08(particle size of 0.15-5 μm), placing on a magnetic stirrer, heating at 80 deg.C and continuously stirring to volatilize water to obtain dry mixed powder. Then placing the mixed powder in an alumina crucible and placing the alumina crucible in a tubular muffle furnace for calcining, wherein the heating rate is 6.66 ℃/min in the heating process, and finally, keeping the temperature at 800 ℃ for 2 h. And introducing nitrogen into the tubular muffle furnace during the reaction process, wherein the flow rate of the nitrogen is 20 mL/min. After cooling, the grain size of the synthesized powder is about 0.517 μm. The electrochemical testing procedure was the same as in example 1. The conductivity of the product reaches 3.5 multiplied by 10 at 600 DEG C-3S cm-1。
Example 7
Weighing 1 mol of barium nitrate, adding the barium nitrate into a proper amount of deionized water, and adding 0.9 mol of (ZrO) after the barium nitrate is completely dissolved2)0.92(Y2O3)0.08(particle size of 0.15 to 5 μm),placing on a magnetic stirrer, heating at 80 deg.C and stirring continuously to volatilize water to obtain dry mixed powder. Then placing the mixed powder in an alumina crucible and placing the alumina crucible in a tubular muffle furnace for calcining, wherein the heating rate is 2.22 ℃/min in the heating process, and finally, preserving heat for 3h at 800 ℃. And introducing nitrogen into the tubular muffle furnace during the reaction process, wherein the flow rate of the nitrogen is 60 mL/min. After cooling, BaZrO3A base proton conductor material. The grain size of the synthesized powder is close to that of the example 2. The electrochemical testing procedure was the same as in example 1. The conductivity of the product reaches 3.16 x 10 at 600 DEG C-3S cm-1。
Example 8
Weighing 1 mol of barium nitrate, adding the barium nitrate into a proper amount of deionized water, and adding 1 mol of (ZrO) after the barium nitrate is completely dissolved2)0.97(Y2O3)0.05(particle size of 0.15-5 μm), placing on a magnetic stirrer, heating at 80 deg.C and continuously stirring to volatilize water to obtain dry mixed powder. Then placing the mixed powder in an alumina crucible and placing the alumina crucible in a tubular muffle furnace for calcining, wherein the heating rate is 3.33 ℃/min in the heating process, and finally, keeping the temperature at 800 ℃ for 2 h. And introducing nitrogen into the tubular muffle furnace during the reaction process, wherein the flow rate of the nitrogen is 60 mL/min. After cooling, BaZrO3A base proton conductor material. The grain size of the synthesized powder is close to that of the example 5. The electrochemical testing procedure was the same as in example 1. The conductivity of the product reaches 3.06X 10 at 600 DEG C-3 S cm-1。
SEM of the powder described in examples 1-6 above is shown in FIG. 2. As can be seen from the figure, the grain size of the powder can be adjusted within the range of 0.5-3 mu m by controlling the heating rate and the gas flux at 500-800 ℃.
Comparative example 1
Weighing 1 mol of barium carbonate and 1 mol of (ZrO)2)0.92(Y2O3)0.08Ball milling is carried out for 12 h by taking water as a ball milling medium, and mixed powder is obtained by drying, grinding and sieving. Then placing the mixed powder into an alumina crucible and placing the alumina crucible into a muffle furnace for calcining, wherein the heating rate is 3 ℃ in the heating processMin, and finally keeping the temperature at 1200 ℃ for 2 h. The SEM image of the synthesized powder is shown in FIG. 3, and the grain size is about 0.3 μm. The electrochemical testing procedure was the same as in example 1. The conductivity at 600 ℃ is 7.2X 10-4S cm-1。
FIG. 4 is a graph of the electrical conductivity at 600 ℃ for examples 1-6 and comparative example 1. It can be seen from the figure that the conductivity of the sample prepared in example 1 is the maximum, which can reach 4.92X 10-3S cm-1. Whereas the conductivity of the sample synthesized by the conventional solid phase method (comparative example 1) was only 7.2X 10 at 600 deg.C-4S cm-1. This is because the grain size of example 1 was as high as 3 μm, and the content of high-resistance grain boundaries was greatly reduced.