Strontium stannate-based mixed conductive solid electrolyte and preparation method thereof

Abstract

The invention relates to a strontium stannate-based mixed conductive solid electrolyte and a preparation method thereof, the molecular formula of the strontium stannate-based mixed conductive solid electrolyte is SrSn1-xMxO3-delta, and the doping element M is Sc < 3 + >, Zn < 2 + > and Fe < 3 + >; the method comprises the following steps: preparing to mix strontium carbonate powder, tin oxide powder and doped low-valence oxide powder according to the molar ratio of Sr: Sn: M being 1: (1-x): x; by taking water or absolute ethyl alcohol as a ball milling medium, carrying out ball milling on the mixed powder and then drying; carrying out compression molding, calcining at 800-1300 DEG C for 1-10 hours, and cooling along with a furnace; and grinding until the particle size is below 200 meshes, carrying out secondary compression molding, sintering at 1300-1600 DEG C for 1-10 hours, and cooling along with the furnace. The strontium stannate-based mixed conductive solid electrolyte has proton and electron conductivity, has the characteristics of high conductivity, hydrogen catalysis and dual carrier migration, meets the application requirements of materials in the fields of hydrogen separation membranes, anode materials of fuel cells, electrode materials for electrochemical synthesis and electrolysis and the like, and has a good application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of conductive materials, and in particular relates to a strontium stannate-based mixed conductive solid electrolyte and a preparation method thereof. Technical Background

[0002] ABO3 type perovskite oxides (such as BaZrO3, BaCeO3 and their rare earth doped systems) have three-dimensional oxygen ion transport channels, which activate the proton conduction mechanism through the hydration process and show a 10 -2 to 10 -3 S / cm-level proton conductivity advantage while maintaining electronic conductivity below 10 -4 S / cm electron conduction suppression characteristics. This selective ion transport property makes it an ideal choice for electron-blocking devices such as hydrogen sensors and solid oxide fuel cell (SOFC) electrolytes.

[0003] In scenarios where proton-electron coordinated transport is required (such as hydrogen separation membranes and SOFC anodes), the material needs to construct a dual-path conduction system: the hydrogen separation membrane relies on a mixed conductive mechanism to achieve a hydrogen permeation process without external circuit drive, while the SOFC anode improves electrochemical performance by reducing the activation energy barrier of the hydrogen dissociation reaction and accelerating the efficiency of electron extraction. The current mainstream solution uses a Ni-BaCeO3 dual-continuous phase structure, in which the metal Ni provides the electron path and the perovskite matrix assumes the proton transport function. This system has three major technical bottlenecks:

[0004] (1) Component ratio threshold limit: The volume ratio of Ni to BaCeO3 needs to be precisely controlled in the range of 40-60% to maintain a bicontinuous network, which makes it difficult to introduce a third phase functional material to expand performance;

[0005] (2) Structural stability defects: Ni particles tend to agglomerate and coarsen during high-temperature service, causing the electronic conduction network to break and fail, limiting the service life of the device.

[0006] (3) Risk of interfacial side reactions: Under a reducing atmosphere, Ni and the matrix material may generate heterogeneous phases such as BaNiO2, which significantly weakens the cyclic stability of the material. Summary of the Invention

[0007] In order to solve the above problems, the present invention provides a single-component strontium stannate-based mixed conductive solid electrolyte and its preparation method. The system uses the intrinsic electronic conductor SrSnO3 as the matrix and adopts the strategy of heterovalent element substitution to introduce Sc at the Sn position. 3+ 、Zn 2+ or Fe 3+ Low-valent cations such as cations induce the formation of oxygen vacancy lattice defects and promote the hydration protonation process to construct SrSn 1-x Mx O 3-δ Proton and electron mixed conducting solid electrolyte.

[0008] The technical solutions of the present invention are as follows:

[0009] The molecular formula of the matrix of a strontium stannate-based mixed conductive solid electrolyte is SrSnO3, wherein Sr is +2 valence and Sn is +4 valence; the molecular formula of the mixed conductive material after doping is SrSn 1-x M x O 3-δ , where the doping element M is Sc 3+ 、Zn 2+ with Fe 3+ Plasma radius and Sn 4+ Close to, and the valence is any one of +3 or +2 elements; the value of x is less than 0.4, and the value of δ is balanced with the total valence state.

[0010] The preparation method of the above-mentioned strontium stannate-based mixed conductive solid electrolyte comprises the following steps:

[0011] 1. Prepare oxides, carbonates or nitrates of Sr, Sn and M elements as raw materials, wherein M is selected from Sc, Zn and Fe, and mix the raw materials in a molar ratio of Sr:Sn:M=1:1-x:x to prepare a mixed powder;

[0012] 2. Use water or anhydrous ethanol as the ball milling medium to ball mill the mixed powder to a particle size of less than 400 mesh, then dry and remove the ball milling medium to obtain ball milled powder;

[0013] 3. Use a sample press to press the ball mill powder into a shape, and then calcine it at 800-1300°C for 1-10 hours to obtain a calcined material;

[0014] 4. Grind the calcined material to a particle size of less than 200 mesh, perform secondary pressing and molding, then heat to 1300-1600° C. and sinter for 1-10 hours, and cool to room temperature in the furnace to obtain a strontium stannate-based mixed conductive solid electrolyte.

[0015] Beneficial effects of the present invention:

[0016] The present invention uses the electronic conductor SrSnO3 as the matrix and dopes Ga into the Sn position. 3+ 、Cu 2+ With Cr 3+ Low-valent elements such as ions create oxygen vacancies to promote hydration reactions to generate proton conduction, thus constructing a single-phase proton and electron mixed conductive solid electrolyte. This single-phase proton and electron mixed conductor has multiple functions:

[0017] (1) Hydrogen activation enhancement: The oxygen defect sites generated by lattice doping significantly enhance the surface hydrogen dissociation catalytic activity;

[0018] (2) Conductive path coupling: while retaining the inherent electronic conduction network of SrSnO3, a proton migration channel is formed through hydration reaction;

[0019] (3) Conductivity enhancement: The total conductivity is synergistically improved at the level of 10S / cm;

[0020] (4) Component controllability: The single-phase system breaks through the multi-phase ratio limitation in traditional composite conductors and allows the further introduction of other functional components.

[0021] This material has demonstrated unique application value in the field of hydrogen energy technology and is compatible with scenarios such as hydrogen separation membranes, fuel cell electrodes, water electrolysis catalytic layers, and hydrogen sensor sensitive elements. Its single-phase mixed conductive properties effectively solve the problems of network breakage, side reaction inactivation, and limited functional expansion in traditional Ni-BaCeO3 systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 For SrSnO3, SrSn in Examples 1, 2, and 3 of the present invention 0.9 Fe 0.1 O 3-δ 、SrSn 0.8 Fe 0.2 O 3-δ XRD pattern of

[0023] Figure 2 is an Arrhenius curve of the electrical conductivity of the strontium stannate-based mixed conductive solid electrolyte in an embodiment of the present invention;

[0024] Figure 3 1 is a graph showing the change in hydrogen permeability of a strontium stannate-based mixed conductive solid electrolyte hydrogen permeable membrane in a hydrogen concentration cell as a function of temperature in an embodiment of the present invention;

[0025] Figure 2-3 In the table, ■ represents Example 1, ○ represents Example 2, and ▲ represents Example 3;

[0026] Figure 4 This is an IV / IP curve performance diagram of SrSnO3 as a fuel cell anode in Example 1 of the present invention;

[0027] Figure 5 is SrSn in Example 2 of the present invention 0.9 Fe 0.1 O 3-δ IV / IP curve performance diagram as a fuel cell anode;

[0028] Figure 6 is SrSn in Example 3 of the present invention 0.8 Fe 0.2 O3-δ IV / IP curve performance diagram as a fuel cell anode;

[0029] Figure 4-6 In the figure, ■ is the IP curve of the material at 550℃, □ is the IV curve of the material at 550℃, ● is the IP curve of the material at 525℃, ○ is the IV curve of the material at 525℃, ▲ is the IP curve of the material at 500℃, △ is the IV curve of the material at 500℃, ◆ is the IP curve of the material at 475℃, and ◇ is the IV curve of the material at 475℃. DETAILED DESCRIPTION

[0030] The raw materials used in the examples of the present invention are commercially available analytical grade reagents.

[0031] The raw material powder in the embodiment of the present invention is carbonate or oxide of Sr, Sn, Fe, Sc, and Zn.

[0032] In the embodiment of the present invention, the ball milling medium used is anhydrous ethanol.

[0033] The ball mill jar and grinding balls used in the embodiment of the present invention are made of zirconium oxide.

[0034] In the embodiment of the present invention, the sample is pressed into a sheet with a size of

[0035] The calcining equipment in the embodiment of the present invention is a molybdenum disilicide tube furnace.

[0036] Example 1

[0037] A strontium stannate-based mixed conductive solid electrolyte has the molecular formula SrSnO3;

[0038] The preparation method of the strontium stannate-based mixed conductive solid electrolyte comprises the following specific steps:

[0039] Strontium carbonate powder and tin dioxide powder were prepared as raw materials. Strontium carbonate powder was dried in an oven at 200°C for 5 hours, and tin dioxide powder was dried in an oven at 800°C for 1 hour.

[0040] The raw material powders are mixed in a molar ratio of Sr:Sn=1:1 to prepare a mixed powder;

[0041] The raw material mixed powder was placed in a zirconia ball mill, and zirconia balls and anhydrous ethanol were added, and the mixture was ball milled at a speed of 300 rpm / min for 10 h;

[0042] The ball-milled mixed slurry was placed in an oven and dried at 80°C for 2 h to obtain a uniformly distributed mixed powder;

[0043] The mixed powder with uniform distribution was pressed into a cylinder shape at 10 MPa using a sample press and then calcined at 1200°C for 5h to obtain a calcined material;

[0044] The calcined material was ground to a particle size of 200 mesh using an agate mortar, and the ground calcined material was pressed into a sheet shape at 200 MPa using a cold isostatic press and then sintered at 1400°C for 8h, and cooled to room temperature in the furnace to obtain a strontium stannate-based mixed conductive solid electrolyte.

[0045] XRD as shown in Figure 1 , the total conductivity in a 1% H2 / Ar atmosphere as shown in Figure 2 , the hydrogen permeation amount of a hydrogen concentration cell carried by a hydrogen source 1% H2 / Ar argon gas as a function of temperature as shown in Figure 3 , and the fuel cell performance of BaCe 0.6 Zr 0.2 Y 0.2 O 3-δ as the electrolyte and SrSnO3 as the anode at different temperatures as shown in Figure 4 .

[0046] Example 2

[0047] A strontium stannate-based mixed conductive solid electrolyte has a molecular formula of SrSn 0.9 Fe 0.1 O 3-δ .

[0048] The preparation method of the strontium stannate-based mixed conductive solid electrolyte includes the following specific operation steps:

[0049] Strontium carbonate powder, tin dioxide powder, and iron sesquioxide powder were prepared as raw materials, the strontium carbonate powder was dried and pretreated in an oven at 200°C for 5h, and the tin dioxide powder and the iron sesquioxide powder were dried and pretreated in an oven at 800°C for 1h;

[0050] The raw material powders were mixed in a molar ratio of Sr:Sn:Fe=1:0.9:0.1 to prepare a mixed powder;

[0051] The mixed powder was placed in a zirconia ball mill jar, and zirconia balls and anhydrous ethanol were added, and ball milling was performed at a speed of 300rpm / min for 10h;

[0052] The mixed slurry after ball milling was placed in an oven and dried at 80°C for 2h to obtain a mixed powder with uniform distribution;

[0053] The mixed powder with uniform distribution was pressed into a cylinder shape at 8 MPa using a sample press cylindrical shape, and then calcined at 1300 °C for 5 h to obtain a calcined material;

[0054] The calcined material was ground into a particle size of less than 200 mesh using an agate mortar, and the ground calcined material was pressed into a The product was sintered at 1500 °C for 8 h and then cooled to room temperature to obtain a strontium stannate-based mixed conductive solid electrolyte.

[0055] XRD Figure 1 The total conductivity in 1% H2 / Ar atmosphere is shown as Figure 2 As shown in ○, the hydrogen permeability of the hydrogen concentration cell carried by 1% H2 / Ar argon gas as a hydrogen source changes with temperature. Figure 3 ○ shown, with BaCe 0.6 Zr 0.2 Y 0.2 O 3-δ As electrolyte, SrSn 0.9 Fe 0.1 O 3-δ The fuel cell performance at different anode temperatures is as follows: Figure 5 shown.

[0056] Example 3

[0057] A strontium stannate-based mixed conductive solid electrolyte has the molecular formula SrSn 0.8 Fe 0.2 O 3-δ ;

[0058] The preparation method of the strontium stannate-based mixed conductive solid electrolyte is the same as that of Example 2, except that:

[0059] (1) The molar ratio of Sr:Sn:Fe in all raw materials is 1:0.8:0.2;

[0060] (2) XRD Figure 1 The total conductivity in 1% H2 / Ar atmosphere is shown as Figure 2 As shown in ▲, the hydrogen permeability of the hydrogen concentration cell carried by 1% H2 / Ar argon gas as a hydrogen source changes with temperature. Figure 3 ▲As shown, BaCe 0.6 Zr 0.2 Y 0.2 O 3-δ As electrolyte, SrSn 0.8 Fe 0.2 O 3-δ The fuel cell performance at different anode temperatures is as follows: Figure 6 shown.

[0061] Example 4

[0062] A strontium stannate-based mixed conductive solid electrolyte has the molecular formula SrSn 0.9 Sc 0.1 O 3-δ ;

[0063] The preparation method of the strontium stannate-based mixed conductive solid electrolyte is the same as that of Example 2, except that:

[0064] (1) The molar ratio of Sr:Sn:Sc in all raw materials is 1:0.9:0.1;

[0065] (2) The total conductivity at 600℃ in 1% H2 / Ar atmosphere is 10.6S / cm, and the hydrogen permeation rate at 450℃ in a hydrogen concentration cell carried by 1% H2 / Ar argon gas is 153ppm / min. 0.6 Zr 0.2 Y 0.2 O 3-δ As electrolyte, SrV 0.9 Ga 0.1 O 3-δ The peak power density of the anode at 550°C is 0.62 W·cm -2 .

[0066] Example 5

[0067] A strontium stannate-based mixed conductive solid electrolyte has the molecular formula SrSn 0.8 Sc 0.2 O 3-δ ;

[0068] The preparation method of the strontium stannate-based mixed conductive solid electrolyte is the same as that of Example 2, except that:

[0069] (1) The molar ratio of Sr:Sn:Sc in all raw materials is 1:0.8:0.2;

[0070] (2) The total conductivity at 600℃ in 1% H2 / Ar atmosphere is 9.7S / cm, and the hydrogen permeation rate at 450℃ in a hydrogen concentration cell carried by 1% H2 / Ar argon gas is 136ppm / min. 0.6 Zr 0.2 Y 0.2 O 3-δ As electrolyte, SrV 0.8 Ga 0.2 O 3-δ The peak power density of the anode at 550°C is 0.47 W·cm -2 .

[0071] Example 6

[0072] A strontium stannate-based mixed conductive solid electrolyte has the molecular formula SrSn0.9 Zn 0.1 O 3-δ ;

[0073] The preparation method of the strontium stannate-based mixed conductive solid electrolyte is the same as that of Example 2, except that:

[0074] (1) The molar ratio of Sr:Sn:Zn in all raw materials is 1:0.9:0.1;

[0075] (2) The total conductivity at 600℃ in 1% H2 / Ar atmosphere is 8.6S / cm, and the hydrogen permeation rate at 450℃ in a hydrogen concentration cell carried by 1% H2 / Ar argon gas is 128ppm / min. 0.6 Zr 0.2 Y 0.2 O 3-δ As electrolyte, SrV 0.9 Cr 0.1 O 3-δ The peak power density of the anode at 550°C is 0.44 W·cm -2 .

Claims

1. A strontium stannate-based mixed conductive solid electrolyte, characterized in that: The molecular formula of the mixed conductive material matrix is ​​SrSnO3, wherein Sr has a valence of +2 and Sn has a valence of +4.

2. The strontium stannate-based mixed conductive solid electrolyte according to claim 1, characterized in that: The molecular formula of the doped mixed conductive material is SrSn 1-x M x O 3-δ , where the doping element M is Sc 3+ 、Zn 2+ with Fe 3+ Plasmon radius and Sn 4+ Close to, and the valence is any one of +3 or +2 elements; the value of x is less than 0.4, and the value of δ is balanced with the total valence state.

3. The method for preparing the strontium stannate-based mixed conductive solid electrolyte according to claim 2, wherein: The steps include: (1) preparing oxides, carbonates or nitrates of Sr, Sn and M elements as raw materials, wherein M is selected from Sc, Zn and Fe; (2) using water or anhydrous ethanol as a ball milling medium, ball milling the mixed powder to a particle size of less than 400 mesh, and then drying to remove the ball milling medium to obtain ball milled powder; (3) using a press to press the ball mill powder into a shape, and then calcining it at 800-1300° C. for 1-10 hours to obtain a calcined material; (4) Grinding the calcined material to a particle size of less than 200 mesh, pressing it into shape for the second time, then heating it to 1300-1600° C. and sintering it for 1-10 hours, and cooling it to room temperature in the furnace to obtain a strontium stannate-based mixed conductive solid electrolyte.

4. The method for preparing a strontium stannate-based mixed conductive solid electrolyte according to claim 3, wherein: In the step (1), the raw material powders are subjected to drying pretreatment before mixing, and the drying pretreatment temperature is 100-900° C. and the time is 1-8 hours.

5. The method for preparing a strontium stannate-based mixed conductive solid electrolyte according to claim 3, wherein: In the step (3), the pressure of the pressing molding is 5 to 100 MPa.

6. The method for preparing a strontium stannate-based mixed conductive solid electrolyte according to claim 3, wherein: In the step (4), the secondary molding pressure is 50 to 300 MPa.

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