A bismuth vanadate-based composite oxygen-ion conductor material with strong resistance to reduction and high mechanical strength and a preparation method thereof

Abstract

The application relates to a bismuth vanadate-based composite oxygen ion conductor material with high resistance to reduction and high mechanical strength and a preparation method thereof. The conductor material comprises bismuth vanadate-based oxygen ion conductor powder particles and an oxide coating layer. The chemical composition of the bismuth vanadate-based oxygen ion conductor powder particles is Bi4(V 1‑y Me y ) x O 11+z , Me is a metal cation, and is at least one selected from copper, chromium, silver, magnesium, titanium, nickel and zinc; x is 1.7-2.2, and y is 0-0.3; the oxide coating layer is coated on the surface of the powder particles, and the oxide is at least one selected from aluminum oxide, yttrium oxide stabilized zirconium oxide, silicon oxide, magnesium oxide, zinc oxide and titanium oxide. The bismuth vanadate-based composite oxygen ion conductor material has high conductivity, the total conductivity reaches 1*10 ‑3 S / cm at 300 DEG C, and the conductor material obtained by sintering is a ceramic, and the stability and mechanical strength of the ceramic under reduction conditions are significantly improved. The preparation process is simple, the raw material cost is low, and the application requirements of a middle-low temperature oxide fuel cell and an oxygen sensor can be met.

Description

Technical Field

[0001] This invention relates to the field of conductor material preparation technology, and in particular to a bismuth vanadate-based composite oxygen ion conductor material with strong resistance to reduction and high mechanical strength, and its preparation method. Background Technology

[0002] Bismuth vanadate (Bi4V2O) 11 () is a unique Bi2O3-based electrolyte, whose structure consists of (Bi2O2) 2+ Layers and perovskite-like (VO) 3.5 □ 0.5 ) 2 Alternating layers are formed, and □ represents intrinsic oxygen vacancies. Studies have found that doping with metal ions (Me) at the V site can stabilize the high-temperature tetragonal phase to room temperature. The resulting BiMeVOx series compounds exhibit excellent ionic conductivity at medium and low temperatures, such as the Cu-doped stable tetragonal phase Bi4V. 1.8 Cu 0.2 O 10.7 It is the compound with the highest reported ionic conductivity at medium and low temperatures to date, with a grain conductivity of 1×10⁻⁶ at 300 °C. -3 S / cm is a highly promising solid electrolyte material.

[0003] However, existing bismuth vanadate-based oxygen ion conductors are easily reduced in low oxygen partial pressure environments, leading to material structure damage, decreased conductivity, and insufficient mechanical strength, making it difficult to withstand thermal cycling and assembly stress, which severely limits their practical application in solid oxide fuel cells (SOFCs).

[0004] Therefore, there is an urgent need to develop a bismuth vanadate-based composite oxygen ion conductor material that combines excellent resistance to reduction, high mechanical strength, simple processing, and low cost.

[0005] It should be noted that this section is intended to provide background or context for the technical solutions of the invention as set forth in the claims. The description herein does not imply acceptance as prior art simply because it is included in this section. Summary of the Invention

[0006] The purpose of this invention is to provide a bismuth vanadate-based composite oxygen ion conductor material with strong resistance to reduction and high mechanical strength, and a method for preparing the same, thereby at least partially solving one or more problems caused by the limitations and defects of related technologies.

[0007] This invention first provides a bismuth vanadate-based composite oxygen ion conductor material with strong resistance to reduction and high mechanical strength, wherein the bismuth vanadate-based composite oxygen ion conductor material comprises bismuth vanadate-based oxygen ion conductor powder particles and an oxide coating layer; The chemical composition of the bismuth vanadate-based oxygen ion conductor powder particles is Bi4(V 1-y Me y ) x O 11+z Me is a metal cation selected from at least one of copper, chromium, silver, magnesium, titanium, nickel and zinc; x is 1.7 to 2.2, y is 0 to 0.3, and z is determined according to the composition of Me; The oxide coating layer is applied to the surface of the powder particles, and the oxide is at least one of aluminum oxide, yttrium-stabilized zirconium oxide, silicon oxide, magnesium oxide, zinc oxide, and titanium oxide.

[0008] In this invention, the thickness of the oxide coating layer is 10–100 nm.

[0009] The present invention further provides a method for preparing a bismuth vanadate-based composite oxygen ion conductor material, the method comprising the following steps: S1, Bismuth vanadate-based oxygen ion conductor powder particles were synthesized by a high-temperature solid-state method; S2, the powder particles are mixed with oxide sol, and the oxide sol is coated on the surface of the powder particles by vacuum impregnation. S3, calcined to form a dense coating layer, yields a bismuth vanadate-based composite oxygen ion conductor material.

[0010] In this invention, S1 specifically includes the following steps: S101, a compound of bismuth oxide, vanadium pentoxide and metallic Me is mixed evenly according to stoichiometric ratio to obtain a mixture; S102, the mixture is calcined in air atmosphere to obtain bismuth vanadate-based oxygen ion conductor powder particles.

[0011] In this invention, in S102, the mixture is calcined at a temperature of 800–950°C in an air atmosphere for a time of 1–30 h.

[0012] In this invention, in S2, the mass fraction of oxides in the oxide sol is 0.5%-15%.

[0013] In this invention, in step S3, the coating is dried in air at 100-500°C for 2-10 hours. Then, the coating is pressed into shape using polyvinyl alcohol as a binder and dried in atmospheric air at 750-900°C. C, sinter for 0.5-24 h to obtain bismuth vanadate-based composite oxygen ion conductor ceramic.

[0014] The technical solution provided by this invention may include the following beneficial effects: The bismuth vanadate-based composite oxygen ion conductor material of the present invention has high conductivity, with a total conductivity of 1×10⁻⁶ at 300 °C. -3 The sintered conductor material is ceramic, exhibiting significantly improved stability and mechanical strength under reducing conditions. The preparation process is simple, with low raw material costs, and meets the application requirements of low- and medium-temperature oxide fuel cells and oxygen sensors. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0016] Figure 1 The X-ray diffraction pattern of the product of Example 1 of the present invention is shown; Figure 2 The temperature-conductivity curve of the product of Example 1 of the present invention is shown; Figure 3 The results of ion transport number of the product of Example 1 of the present invention under an argon atmosphere are shown; Figure 4 The results of ion transport number of the product of Example 1 of the present invention under an argon-hydrogen mixed atmosphere are shown. Figure 5 The hardness values ​​of the product of Example 1 of the present invention are shown; Figure 6 The image shown is a scanning electron microscope image of the product of Embodiment 2 of the present invention. Detailed Implementation

[0017] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the invention will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0018] Furthermore, the accompanying drawings are merely illustrative diagrams of embodiments of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0019] This example embodiment provides a bismuth vanadate-based composite oxygen ion conductor material with strong resistance to reduction and high mechanical strength. The bismuth vanadate-based composite oxygen ion conductor material includes bismuth vanadate-based oxygen ion conductor powder particles and an oxide coating layer. The chemical composition of the bismuth vanadate-based oxygen ion conductor powder particles is Bi4(V 1-y Me y ) x O 11+z Me is a metal cation selected from at least one of copper, chromium, silver, magnesium, titanium, nickel and zinc; x is 1.7 to 2.2, y is 0 to 0.3, and z is determined according to the composition of Me; The oxide coating layer is applied to the surface of the powder particles, and the oxide is at least one of aluminum oxide, yttrium-stabilized zirconium oxide, silicon oxide, magnesium oxide, zinc oxide, and titanium oxide.

[0020] The thickness of the oxide coating layer is 10–100 nm, such as 20 nm, 50 nm, 80 nm, etc., but not limited to this. The mass fraction of oxide in the oxide sol is 0.5%–15%, such as 1%, 5%, 8%, 10%, 12%, etc., but not limited to this.

[0021] The bismuth vanadate-based composite oxygen ion conductor material of this invention has high conductivity, reaching a total conductivity of 1×10⁻⁶ at 300 °C. -3 The S / cm ratio is high, and the sintered conductor material is ceramic, which exhibits significantly improved stability and mechanical strength under reducing conditions.

[0022] This example embodiment provides a method for preparing a bismuth vanadate-based composite oxygen ion conductor material, the method comprising the following steps: S1, Bismuth vanadate-based oxygen ion conductor powder particles were synthesized by a high-temperature solid-state method; S2, the powder particles are mixed with oxide sol, and the oxide sol is coated on the surface of the powder particles by vacuum impregnation. S3, calcination treatment to form a dense coating layer, yielding a bismuth vanadate-based composite oxygen ion conductor material. The calcination temperature is 750–900℃, for example 780℃, 800℃, 850℃, etc., and the calcination time is 0.5–24h, for example 2h, 5h, 10h, 20h, etc.

[0023] Specifically, S1 includes the following steps: S101, a compound of bismuth oxide, vanadium pentoxide and metallic Me is mixed evenly according to stoichiometric ratio to obtain a mixture; S102, the mixture is calcined in air to obtain bismuth vanadate-based oxygen ion conductor powder particles. The calcination temperature is 800-950℃, for example 820℃, 850℃, 900℃, 920℃, etc., and the calcination time is 1-30h, for example 2h, 5h, 8h, 10h, 15h, 20h, 24h, etc.

[0024] In this embodiment, the preparation process is simple, the raw material cost is low, and it can meet the application requirements of medium and low temperature oxide fuel cells and oxygen sensors.

[0025] The following specific examples illustrate the preparation of the materials of this application.

[0026] Example 1 Preparation of Bi4(V) 0.9 Cu 0.1 ) 1.95 O 10.5825 Bismuth vanadate-based composite oxygen ion ceramic material coated with 3 wt% Al2O3 sol once The preparation steps are as follows: (1) Using Bi2O3, V2O5 and CuO as raw materials, dry at 500 °C for 5 hours, according to Bi4(V 0.9 Cu 0.1 ) 1.95 O 10.5825 Weigh and mix the ingredients according to the chemical stoichiometry; mix the weighed powder evenly with a ball mill, and dry the evenly mixed slurry in an oven.

[0027] (2) The dried mixed raw materials were calcined at 870 °C for 24 hours to obtain bismuth vanadate-based oxygen ion conductor.

[0028] (3) The bismuth vanadate-based oxygen ion conductor obtained by calcination was ball-milled for 12 h. The ball-milled slurry was dried and then the powder was heat-treated at 700 ℃ for 2 h.

[0029] (4) The heat-treated powder was mixed evenly with 3 wt% Al2O3 sol, immersed in a vacuum oven for 12 h, and then centrifuged. The resulting slurry was dried at 100 ℃ for 5 h to obtain bismuth vanadate-based composite oxygen ion ceramic powder.

[0030] (5) The obtained powder is pressed into shape in a tablet press with polyvinyl alcohol (PVA) as binder and sintered in an atmospheric atmosphere at a temperature of 810 °C for 3 hours; thus, the bismuth vanadate-based composite oxygen ion conductor ceramic is obtained.

[0031] The Bi4(V) prepared in this embodiment 0.9 Cu 0.1 ) 1.95 O10.5825 The XRD pattern of a bismuth vanadate-based composite oxygen ion conductor ceramic coated with 3 wt% Al2O3 once is shown below. Figure 1 As shown, from Figure 1 It can be seen that the prepared ceramic has a single tetragonal phase structure, and no diffraction peaks of Al2O3 were found.

[0032] Figure 2 This is the Bi4(V) prepared in this embodiment. 0.9 Cu 0.1 ) 1.95 O 10.5825 Temperature-conductivity curves of bismuth vanadate-based composite oxygen ion conductor ceramics coated once with 3 wt% Al₂O₃ sol. The coated sample exhibits a total conductivity of 3 × 10⁻⁶ at 500 °C. - 2 S / cm. Figure 3 This is the Bi4(V) prepared in this embodiment. 0.9 Cu 0.1 ) 1.95 O 10.5825 Ion transference number of bismuth vanadate-based composite oxygen ion conductor ceramic coated once with 3 wt% Al2O3 sol under argon atmosphere at 300 to 450 °C. Figure 4 This is the Bi4(V) prepared in this embodiment. 0.9 Cu 0.1 ) 1.95 O 10.5825 The ion transport numbers of bismuth vanadate-based composite oxygen ion conductor ceramics coated once with 3 wt% Al2O3 sol under reducing atmospheres at 300 to 450 °C. The ion transport numbers of the ceramic samples coated once with 3 wt% Al2O3 sol were significantly increased under both argon and reducing atmospheres at 300 to 450 °C. Figure 5 This is the Bi4(V) prepared in this embodiment. 0.9 Cu 0.1 ) 1.95 O 10.5825 The hardness values ​​of bismuth vanadate-based composite oxygen ion conductor ceramics coated once with 3 wt% Al2O3 sol and uncoated ceramic samples were compared. The hardness value of the coated ceramic sample was significantly improved.

[0033] Example 2 Preparation of Bi4(V) 0.9 Ti 0.1 ) 1.9 O 10.655 Bismuth vanadate-based composite oxygen ion ceramic material coated with 10 wt% Al2O3 sol once The preparation method is as follows: (1) Using Bi2O3, V2O5 and TiO2 as raw materials, dry at 500 °C for 4 hours, according to the chemical formula Bi4(V 0.9Ti 0.1 ) 1.9 O 10.655 Weigh and mix the ingredients; mix the weighed powder evenly using a ball mill, and dry the evenly mixed slurry in an oven.

[0034] (2) The dried mixed raw materials were calcined at 900 °C for 10 hours to obtain bismuth vanadate-based oxygen ion conductor material.

[0035] (3) The bismuth vanadate-based oxygen ion conductor material obtained by calcination was ball-milled for 10 h. The ball-milled slurry was dried and then the powder was heat-treated at 700 ℃ for 2 h.

[0036] (4) The heat-treated powder was mixed evenly with 10 wt% Al2O3 sol and immersed in a vacuum oven for 10 h. The mixture was then centrifuged and the resulting slurry was dried at 100 ℃ for 3 h to obtain bismuth vanadate-based composite oxygen ion ceramic powder.

[0037] (5) The obtained powder was pressed into shape in a tablet press using polyvinyl alcohol (PVA) as a binder, and sintered in an atmospheric atmosphere at a temperature of 850 °C for 0.5 h to obtain Bi4(V 0.9 Ti 0.1 ) 1.9 O 10.655 Bismuth vanadate-based composite oxygen ion ceramic coated once with 10wt% Al2O3 sol.

[0038] The scanning electron microscope image after coating and drying in this embodiment is shown below. Figure 6 As shown, the sol coating is uniform. At 300 °C, the total conductivity is approximately 1.4 × 10⁻⁶. -3 S / cm. Exhibits good stability under reducing conditions.

[0039] Example 3 Preparation of Bi4(V) 0.9 Cu 0.1 ) 1.95 O 10.5825 Coated twice with 2 wt% Zr 0.8 Y 0.2 O 1.9 Sol-based bismuth vanadate-based composite oxygen ion ceramic materials. (1) Using Bi2O3, V2O5 and CuO as raw materials, dry at 500 °C for 5 hours, according to Bi4(V 0.9 Cu 0.1 ) 1.95 O 10.5825 Weigh and mix the ingredients according to the chemical stoichiometry; mix the weighed powder evenly with a ball mill, and dry the evenly mixed slurry in an oven.

[0040] (2) The dried mixed raw materials were calcined at 870 °C for 24 hours to obtain bismuth vanadate-based oxygen ion conductor material.

[0041] (3) The bismuth vanadate-based oxygen ion conductor material obtained by calcination was ball-milled for 12 h. The ball-milled slurry was dried and then the powder was heat-treated at 700 ℃ for 2 h.

[0042] (4) Mix the heat-treated powder with 2 wt% Zr 0.8 Y 0.2 O 1.9 The sol was mixed evenly and impregnated in a vacuum oven for 5 h. The mixture was then centrifuged and the resulting slurry was dried at 100 ℃ for 5 h to obtain bismuth vanadate-based composite oxygen ion ceramic powder.

[0043] (5) The obtained powder is pressed into shape in a tablet press with polyvinyl alcohol (PVA) as binder and sintered in an atmospheric atmosphere at a temperature of 860 °C for 2 hours; thus, the bismuth vanadate-based composite oxygen ion conductor ceramic is obtained.

[0044] The Bi4(V) prepared in this embodiment 0.9 Cu 0.1 ) 1.95 O 10.5825 Coated twice with 2 wt% Zr 0.8 Y 0.2 O 1.9 The sol-based bismuth vanadate-based composite oxygen ion ceramics achieved a total conductivity of 2.1 × 10⁻⁶ at 300 °C. -3 S / cm. It also exhibits good stability under reducing conditions.

[0045] Example 4 Preparation of Bi4(V) 0.7 Mg 0.3 ) 2.1 O 10.305 Bismuth vanadate-based composite oxygen ion ceramic material coated once with 7 wt% SiO2 sol (1) Using Bi2O3, V2O5 and MgO as raw materials, dry at 200 °C for 10 hours, according to the chemical formula Bi4(V 0.7 Mg 0.3 ) 2.1 O 10.305 Weigh and mix the ingredients; mix the weighed powder evenly using a ball mill, and dry the evenly mixed slurry in an oven.

[0046] (2) The dried mixed raw materials were calcined at 840 °C for 10 hours to obtain bismuth vanadate-based oxygen ion conductor material.

[0047] (3) The bismuth vanadate-based oxygen ion conductor material obtained by calcination was ball-milled for 10 h. The ball-milled slurry was dried and then the powder was heat-treated at 600 ℃ for 5 h.

[0048] (4) The heat-treated powder was mixed with 7 wt% SiO2 sol and immersed in a vacuum oven for 10 h. The mixture was then centrifuged and the resulting slurry was dried at 200 ℃ for 6 h to obtain bismuth vanadate-based composite oxygen ion ceramic powder.

[0049] (5) The obtained powder was pressed into shape in a tablet press using polyvinyl alcohol (PVA) as a binder, and sintered in an atmospheric atmosphere at a temperature of 840 °C for 5 hours; thus, the bismuth vanadate-based composite oxygen ion conductor ceramic was obtained. At 300 °C, the total conductivity reached 0.8 × 10⁻⁶. -3 S / cm. It also exhibits good stability under reducing conditions.

[0050] In addition to the above embodiments, the preparation of other bismuth vanadate-based composite oxygen ion conductor ceramic materials can also be achieved.

[0051] In summary, this application addresses the shortcomings of bismuth vanadate-based oxygen ion conductors and enhances their thermal stability and mechanical strength under low oxygen partial pressure. It provides a bismuth vanadate-based composite oxygen ion conductor material by coating the material surface with a stable oxide layer, effectively preventing contact between the electrolyte material and reducing gas while simultaneously improving mechanical strength. Another objective of this invention is to provide a method for preparing the aforementioned bismuth vanadate-based composite oxygen ion conductor material. First, a bismuth vanadate-based oxygen ion conductor is prepared using a high-temperature solid-state method. Then, bismuth vanadate powder is mixed with a stable oxide sol, and the bismuth vanadate-based composite oxygen ion conductor material is obtained using a vacuum impregnation method. The preparation process is simple, the raw material cost is low, and it meets the application requirements of medium- and low-temperature oxide fuel cells and oxygen sensors.

[0052] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0053] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the appended claims.

Claims

1. A bismuth vanadate-based composite oxygen ion conductor material with strong resistance to reduction and high mechanical strength, characterized in that, The bismuth vanadate-based composite oxygen ion conductor material includes bismuth vanadate-based oxygen ion conductor powder particles and an oxide coating layer. The chemical composition of the bismuth vanadate-based oxygen ion conductor powder particles is Bi4(V 1-y Me y ) x O 11+z Me is a metal cation selected from at least one of copper, chromium, silver, magnesium, titanium, nickel and zinc; x is 1.7 to 2.2, y is 0 to 0.3, and z is determined according to the composition of Me; The oxide coating layer is applied to the surface of the powder particles, and the oxide is at least one of aluminum oxide, yttrium-stabilized zirconium oxide, silicon oxide, magnesium oxide, zinc oxide, and titanium oxide.

2. The bismuth vanadate-based composite oxygen ion conductor material according to claim 1, characterized in that, The thickness of the oxide coating layer is 10–100 nm.

3. The method for preparing the bismuth vanadate-based composite oxygen ion conductor material as described in claim 1 or 2, characterized in that, The preparation method Includes the following steps: S1, Bismuth vanadate-based oxygen ion conductor powder particles were synthesized by high-temperature solid-state method; S2, the powder particles are mixed with oxide sol, and the oxide sol is coated on the surface of the powder particles by vacuum impregnation. S3, calcined to form a dense coating layer, yields a bismuth vanadate-based composite oxygen ion conductor material.

4. The preparation method according to claim 3, characterized in that, S1 specifically includes the following steps: S101, a compound of bismuth oxide, vanadium pentoxide and metallic Me is mixed evenly according to stoichiometric ratio to obtain a mixture; S102, the mixture is calcined in air atmosphere to obtain bismuth vanadate-based oxygen ion conductor powder particles.

5. The preparation method according to claim 4, characterized in that, In S102, the mixture is calcined in air at a temperature of 800–950°C for 1–30 h.

6. The preparation method according to claim 3, characterized in that, In S2, the mass fraction of oxides in the oxide sol is 0.5%-15%.

7. The preparation method according to claim 3, characterized in that, In S3, the coating is dried in air at 100-500°C for 2-10 hours. Then, the coating is pressed into shape using polyvinyl alcohol as a binder and dried in atmospheric air at 750-900°C. C, sinter for 0.5-24 h to obtain bismuth vanadate-based composite oxygen ion conductor ceramic.

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