A modified bismuth vanadate-based oxygen ion conductor material and preparation method thereof
By doping bismuth vanadate-based oxygen ion conductor materials modified by metal cations, the high temperature problem of YSZ electrolyte and the difficult problem of large ceramic grain boundary resistance are solved, and the application of high conductivity and low-cost medium and low-temperature solid oxide fuel cells is realized, which is suitable for medium and low-temperature oxide fuel cells and oxygen sensors.
Patent Information
- Application Number
- CN202211395394.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-11-09
- Publication Date
- 2025-09-09
- Estimated Expiration
- 2042-11-09
AI Technical Summary
In existing medium- and low-temperature solid oxide fuel cells, the high operating temperature of YSZ electrolyte leads to electrode sintering, high sealing costs, interface diffusion, and thermal instability problems, which limit its application. In addition, the ceramic grain boundary resistance of existing modified materials is large, and the electrical conductivity needs to be further improved.
A modified bismuth vanadate-based oxygen ion conductor material Bi4(V1-yMy)xO11+z is used. By selecting appropriate metal cations M (such as copper, chromium, silver, magnesium, titanium, zinc, etc.) for doping and through a specific preparation process including mixing, drying, ball milling, calcination and sintering, a modified bismuth vanadate-based oxygen ion conductor with high oxygen ion conductivity is formed.
At 300°C, the grain conductivity of the modified bismuth vanadate-based oxygen ion conductor material reaches 10-2S/cm, and the total conductivity reaches 1.2×10-3S/cm, which significantly improves the conductivity of oxygen ion conductors at medium and low temperatures, reduces material costs, and simplifies the preparation process.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of novel solid-state oxygen ion conductors and solid-state electrolytes, and relates to solid-state ion conductor materials and preparation methods for medium- and low-temperature solid-state oxide fuel cell electrolytes and oxygen sensors, and specifically relates to a modified bismuth vanadate-based oxygen ion conductor material and a preparation method thereof. Background Art
[0002] Solid oxide fuel cells (SOFCs), a novel, clean energy conversion device, have attracted considerable attention due to their robust all-solid-state structure, high conversion efficiency (60-80%), wide range of fuel types, no need for precious metals in electrodes, and no threat of carbon monoxide poisoning. They hold broad application prospects in power generation, transportation, aerospace, and other fields, and are being hailed as the green energy of the 21st century. The dense electrolyte layer sandwiched between the two electrodes is a key material in SOFCs, responsible for carrier transport and isolating the reactant gases between the electrodes. Yttria-stabilized zirconia (YSZ) electrolytes, with ionic conductivity reaching 0.1 S / cm at 800-1000°C, are currently a widely used oxygen ion conductor. However, their high operating temperature, resulting in electrode sintering, high sealing costs, interfacial diffusion between the electrolyte and electrode materials, and thermal instability limit the application of SOFCs using YSZ as the electrolyte. Lowering the operating temperature of SOFCs, maintaining phase and thermal stability, and achieving the desired conductivity levels are the primary goals of SOFC electrolyte research and development. Designing and developing new solid oxygen ion conductors at medium and low temperatures (300-750°C) is the key to realizing the application of medium and low temperature solid oxide fuel cells.
[0003] Compound Bi4V2O 11 It is made of (Bi2O2) 2+ Layer and perovskite-like (VO 3.5 □ 0.5 ) 2- The layers are formed alternately, and □ represents intrinsic oxygen vacancies. The oxygen vacancies in the crystal structure make this type of material have good ionic conductivity at medium and low temperatures. The tetragonal phase Bi4V 1.8 Cu 0.2 O 10.7 It is the compound with the highest ionic conductivity at low temperature reported so far, and the grain conductivity reaches 1×10 -3 S / cm, but due to the large resistance of ceramic grain boundaries, the overall conductivity of the material is about 10 -4 S / cm level, in practical applications, still needs to be further improved to achieve better electrical performance. In addition, oxygen ion conductor materials are also widely used in oxygen sensors. Oxygen ion conductor materials with high conductivity at medium and low temperatures are also of great value in improving sensor performance. Summary of the Invention
[0004] In order to avoid the shortcomings of the prior art, the present invention provides a modified bismuth vanadate-based oxygen ion conductor material and a preparation method thereof. The modified bismuth vanadate-based oxygen ion conductor material of the present invention has high oxygen ion conductivity at temperatures of 300°C and above.
[0005] According to one aspect of the present invention, a modified bismuth vanadate-based oxygen ion conductor material is provided, wherein the chemical composition of the modified bismuth vanadate-based oxygen ion conductor material is expressed as follows: Bi4(V 1-y M y ) x O 11+z , wherein M is a metal cation selected from one or more of copper, chromium, silver, magnesium, titanium, nickel, zinc, etc., wherein 1.7≤x≤2.2 and x≠2, 0<y≤0.3, and z depends on the electrical neutrality balance of the M cation composition.
[0006] Preferably, M is copper, and x=1.9, y=0.1.
[0007] According to another aspect of the present invention, a method for preparing the modified bismuth vanadate-based oxygen ion conductor material is provided, comprising the following steps:
[0008] (1) using a bismuth-containing compound, a vanadium-containing compound, and a metal M-containing compound as raw materials, preparing the ingredients according to the proportions of bismuth, vanadium, and metal M elements in the above chemical composition formula, and then mixing them uniformly to obtain a mixture;
[0009] (2) drying the mixture and then calcining it;
[0010] (3) The calcined powder is pressed into shape using a polyvinyl alcohol (PVA) solution as a binder and then sintered to obtain the modified bismuth vanadate-based oxygen ion conductor material.
[0011] The method may further include drying the bismuth-containing compound, the vanadium-containing compound and the metal M-containing compound raw materials at 100-500° C. for 2-12 hours before mixing.
[0012] The mixing is carried out in a planetary ball mill with a ball-to-material ratio of 2:1, anhydrous ethanol as the ball milling medium, a rotation speed of 300 r / min, and a ball milling time of 2 to 12 hours.
[0013] The calcination temperature is 500-800° C., and the calcination time is 12-96 hours.
[0014] Wherein, the sintering temperature is 750-900° C., and the sintering time is 0.5-6 hours.
[0015] Preferably, in step (1), the bismuth-containing compound is bismuth oxide, the vanadium-containing compound is vanadium pentoxide, and the metal M-containing compound is an oxide or carbonate of metal M.
[0016] The modified bismuth vanadate-based oxygen ion conductor material Bi4 (V 1-y M y ) x O 11+z The structure is stable and the conductivity is high, among which Bi4(V 0.9 Cu 0.1 ) 1.9 O 10.465 At 300℃, the grain conductivity is 10 -2 S / cm level, the total ionic conductivity of ceramics reaches 1.2×10 -3 S / cm, which is about 1 order of magnitude higher than the current highest value reported in the literature. Its raw material cost is low and the preparation process is simple, which can meet the application requirements of medium and low temperature oxide fuel cells and oxygen sensors. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 is an X-ray diffraction pattern of the modified bismuth vanadate-based oxygen ion conductor material according to Example 1 of the present invention;
[0018] Figure 2 is a scanning electron microscope image of the modified bismuth vanadate-based oxygen ion conductor material according to Example 1 of the present invention;
[0019] Figure 3 The temperature-conductivity data of the modified bismuth vanadate-based oxygen ion conductor material according to Example 1 of the present invention are shown. DETAILED DESCRIPTION
[0020] In order to more clearly understand the purpose, technical solutions and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.
[0021] The chemical formula of the modified bismuth vanadate-based oxygen ion conductor material provided by the present invention is Bi4(V 1-y M y ) x O 11+z , where M is a metal cation, selected from one or more metal elements such as copper, chromium, silver, magnesium, titanium, nickel, zinc, etc., where the value of x is between 1.7 and 2.2 and x≠2, the value of y is greater than 0 and less than or equal to 0.3, and z is determined by the composition of the M cation.
[0022] The preparation method of the modified bismuth vanadate-based oxygen ion conductor material comprises the following steps:
[0023] (1) Drying the raw materials of the bismuth-containing compound, the vanadium-containing compound and the metal M-containing compound at 100-500° C. for 2-12 hours.
[0024] (2) The raw material powder in step (1) is prepared according to the chemical formula Bi4(V 1-y M y ) x O 11+z Weigh the ingredients.
[0025] (3) The powders weighed in step (2) are mixed in a ball mill with a ball-to-material ratio of 2:1, anhydrous ethanol as the ball milling medium, a rotation speed of 300 r / min, and ball milling for 2 to 12 hours.
[0026] (4) Drying the slurry obtained in step (3) in an oven.
[0027] (5) calcining the mixture obtained in step (4) at 500-800° C. for 12-96 hours.
[0028] (6) Adding polyvinyl alcohol (PVA) solution as a binder to the powder calcined in step (5) and pressing it into shape, and sintering it at 750-900° C. for 0.5-6 hours to obtain the modified bismuth vanadate-based oxygen ion conductor material with high oxygen ion conductivity of the present invention.
[0029] Example 1:
[0030] Preparation of Bi4(V 0.9 Cu 0.1 ) 1.9 O 10.465 Oxygen ion conductor materials
[0031] Here are the steps:
[0032] (1) Bi2O3, V2O5 and CuO were used as raw materials and dried at 500℃ for 12 hours. 0.9 Cu 0.1 ) 1.9 O 10.465 The proportion of each metal element in the mixture is weighed and mixed; the weighed powder is mixed evenly using a ball mill, the ball milling medium is anhydrous ethanol, the rotation speed is 300r / min, and the ball milling time is 12 hours; the evenly mixed slurry is dried in an oven.
[0033] (2) The dried mixed raw materials were calcined at 650°C for 48 hours; the processed powder was ground and then calcined at 650°C for another 48 hours.
[0034] (3) The calcined powder is pressed into a tablet press using a polyvinyl alcohol (PVA) solution as a binder, and sintered in an atmospheric atmosphere at a sintering temperature of 830° C. for 2 hours to obtain the tetragonal oxygen ion conductor ceramic with high oxygen ion conductivity.
[0035] The Bi4(V 0.9 Cu 0.1 ) 1.9 O 10.465 XRD spectrum of oxygen ion conductor ceramics Figure 1 As shown, phase identification and crystal structure refinement show that the prepared ceramics have a single tetragonal phase structure. Figure 2 Example Bi4 (V 0.9 Cu 0.1 ) 1.9 O 10.465 The scanning electron microscope image shows that the prepared ceramic sample has a high density. The electrical conductivity of the ceramic is evaluated using an AC impedance analyzer. Figure 3 As shown in Figure 2, at 300°C, the grain conductivity reaches 1.1×10 -2 S / cm, and the total conductivity is 1.2×10 -3 S / cm.
[0036] Example 2:
[0037] Preparation of Bi4(V 0.9 Cr 0.1 ) 1.75 O 10.2 Oxygen ion conductor materials
[0038] (1) Bi2O3, V2O5 and Cr2O3 were used as raw materials and dried at 500℃ for 4 hours. 0.9 Cr 0.1 ) 1.75 O 10.2 The proportion of each metal element in the mixture is weighed and mixed; the weighed powder is mixed evenly using a ball mill, the ball milling medium is anhydrous ethanol, the speed is 300r / min, and the ball milling time is 10 hours; the evenly mixed slurry is dried in an oven.
[0039] (2) The dried mixed raw materials were calcined at 660°C for 48 hours; the processed powder was ground and then calcined at 660°C for another 48 hours.
[0040] (3) The calcined powder is pressed into a tablet press using a polyvinyl alcohol (PVA) solution as a binder and sintered in an atmosphere at a temperature of 870°C for 4 hours to obtain the oxygen ion conductor ceramic with high oxygen ion conductivity. At 300°C, the grain conductivity is 0.8×10 -2S / cm, and the total conductivity is 1.1×10 -3 S / cm.
[0041] Example 3:
[0042] Preparation of Bi4(V 0.9 Zn 0.1 ) 1.8 O 10.23 Oxygen ion conductor materials
[0043] (1) Bi2O3, V2O5 and ZnCO3 were used as raw materials and dried at 400℃ for 6 hours. 0.9 Zn 0.1 ) 1.8 O 10.23 The proportion of each metal element in the mixture is weighed and mixed; the weighed powder is mixed evenly using a ball mill, the ball milling medium is anhydrous ethanol, the speed is 300r / min, and the ball milling time is 5 hours; the evenly mixed slurry is dried in an oven.
[0044] (2) The dried mixed raw materials were calcined at 630°C for 20 hours; the processed powder was ground and then calcined at 630°C for another 20 hours.
[0045] (3) The calcined powder is pressed into a tablet press using a polyvinyl alcohol (PVA) solution as a binder and sintered in an atmosphere at a temperature of 850°C for 3 hours to obtain the oxygen ion conductor material ceramic with high oxygen ion conductivity. At 300°C, the grain conductivity is 0.9×10 -2 S / cm, and the total conductivity is 1.1×10 -3 S / cm.
[0046] Example 4:
[0047] Preparation of Bi4(V 0.7 Cu 0.3 ) 2.2 O 10.51 Oxygen ion conductor materials
[0048] (1) Bi2O3, V2O5 and CuCO3 were used as raw materials and dried at 100℃ for 12 hours. 0.9 Cr 0.1 ) 1.75 O 10.2 The proportion of each metal element in the mixture is weighed and mixed; the weighed powder is mixed evenly using a ball mill, the ball milling medium is anhydrous ethanol, the speed is 300r / min, and the ball milling time is 2 hours; the evenly mixed slurry is dried in an oven.
[0049] (2) The dried mixed raw materials were calcined at 800°C for 6 hours; the processed powder was ground and then calcined at 800°C for another 6 hours.
[0050] (3) The calcined powder is pressed into a tablet press using a polyvinyl alcohol (PVA) solution as a binder and sintered in an atmosphere at a temperature of 900°C for 0.5 hours to obtain the oxygen ion conductor ceramic with high oxygen ion conductivity. At 300°C, the grain conductivity is 0.4×10 -2 S / cm, and the total conductivity is 0.9×10 -3 S / cm.
[0051] Example 5:
[0052] Preparation of Bi4(V 0.95 Mg 0.025 Cu 0.025 ) 2.1 O 10.23 Oxygen ion conductor materials
[0053] (1) Bi2O3, V2O5 and Cr2O3 were used as raw materials and dried at 400℃ for 12 hours. 0.9 Cr 0.1 ) 1.75 O 10.2 The proportion of each metal element in the mixture is weighed and mixed; the weighed powder is mixed evenly using a ball mill, the ball milling medium is anhydrous ethanol, the speed is 300r / min, and the ball milling time is 10 hours; the evenly mixed slurry is dried in an oven.
[0054] (2) The dried mixed raw materials were calcined at 550°C for 48 hours; the processed powder was ground and then calcined at 550°C for another 48 hours.
[0055] (3) The calcined powder is pressed into a tablet press using a polyvinyl alcohol (PVA) solution as a binder and sintered in an atmosphere at a temperature of 800°C for 6 hours to obtain the oxygen ion conductor ceramic with high oxygen ion conductivity. At 300°C, the grain conductivity is 0.2×10 -2 S / cm, and the total conductivity is 0.8×10 -3 S / cm.
[0056] In addition to the above embodiments, the preparation of modified bismuth vanadate-based oxygen ion conductor materials with other components can also be achieved.
Claims
1. A modified bismuth vanadate-based oxygen ion conductor material, wherein the chemical composition of the modified bismuth vanadate-based oxygen ion conductor material is expressed as follows: Bi4(V 1-y M y ) x O 11+z , wherein M is a metal cation selected from one or more of copper, chromium, silver, magnesium, titanium, nickel, and zinc, wherein 1.7≤x≤2.2 and x≠2, 0<y≤0.3, and z depends on the neutral balance of the metal cation composition.
2. The modified bismuth vanadate-based oxygen ion conductor material according to claim 1, wherein M is copper, and x=1.9, y=0.
1.
3. A method for preparing the modified bismuth vanadate-based oxygen ion conductor material according to claim 1, comprising the following steps: (1) using a bismuth-containing compound, a vanadium-containing compound, and a metal M-containing compound as raw materials, preparing the ingredients according to the proportions of bismuth, vanadium, and metal M elements in the chemical composition expression, and then mixing them uniformly to obtain a mixture; (2) drying the mixture and then calcining it; (3) The calcined powder is pressed into shape using a polyvinyl alcohol solution as a binder and then sintered to obtain the modified bismuth vanadate-based oxygen ion conductor material.
4. The method according to claim 3, wherein the method further comprises drying the bismuth-containing compound, the vanadium-containing compound and the metal M-containing compound raw materials at 100-500°C for 2-12 hours before mixing.
5. The method according to claim 3, wherein the mixing is carried out in a planetary ball mill with a ball-to-material ratio of 2:1, anhydrous ethanol as the ball milling medium, a rotation speed of 300 r / min, and a ball milling time of 2 to 12 hours.
6. The method according to claim 3, wherein the calcination temperature is 500-800°C and the calcination time is 12-96 hours.
7. The method according to claim 3, wherein the sintering temperature is 750-900°C and the sintering time is 0.5-6 hours.
8. The method according to claim 3, wherein the bismuth-containing compound is bismuth oxide, the vanadium-containing compound is vanadium pentoxide, and the metal M-containing compound is an oxide or carbonate of metal M.