阅读说明：本技术 一种CeO2基复合固体电解质材料及其制备方法 (CeO (CeO)2Base composite solid electrolyte material and preparation method thereof ) 是由 阳杰 尹奇异 朱德伦 王明 李少波 孟俊杰 徐建华 曹龙 于 2020-04-24 设计创作，主要内容包括：本发明公开了一种CeO<Sub>2</Sub>基复合固体电解质材料及其制备方法,该CeO<Sub>2</Sub>基复合固体电解质材料的结构通式如下：Ce<Sub>0.8</Sub>Pr<Sub>0.1</Sub>La<Sub>0.1</Sub>O<Sub>2–δ</Sub>·x(Li<Sub>0.5</Sub>K<Sub>0.5</Sub>Cl),式中δ为缺氧量。本发明通过微波助燃法在Ce<Sub>0.8</Sub>Pr<Sub>0.1</Sub>La<Sub>0.1</Sub>O<Sub>2–δ</Sub>材料中掺杂特定的低熔点盐Li<Sub>0.5</Sub>K<Sub>0.5</Sub>Cl,形成了CeO<Sub>2</Sub>基固体复合电解质材料,能够大大提高材料在中低温阶段的电导率,改善材料的电化学性能,而且制备工艺简单、成本低、快速节能环保。(The invention discloses CeO 2 Composite solid electrolyte material, its preparation method and CeO 2 The structural general formula of the base composite solid electrolyte material is as follows: ce 0.8 Pr 0.1 La 0.1 O 2– ·x(Li 0.5 K 0.5 Cl), where the oxygen deficiency is present. The invention adopts a microwave combustion-supporting method to prepare Ce 0.8 Pr 0.1 La 0.1 O 2– Doping the material with a specific low-melting-point salt Li 0.5 K 0.5 Cl, formation of CeO 2 The base solid composite electrolyte material can greatly improve the conductivity of the material at a medium-low temperature stage, improve the electrochemical performance of the material, and has the advantages of simple preparation process, low cost, rapidness, energy conservation and environmental protection.)

1. CeO (CeO)₂The composite solid electrolyte material is characterized in that the structural general formula is as follows: ce_0.8Pr_0.1La_0.1O_2–·x(Li_0.5K_0.5Cl), where the oxygen deficiency is present.

2. The CeO of claim 1₂The matrix composite solid electrolyte material is characterized in that x is not less than 1/3 and not more than 3.

3. CeO according to claim 1 or 2₂A matrix composite solid electrolyte material characterized in that x is 1/2.

4. CeO according to any one of claims 1 to 3₂The preparation method of the matrix composite solid electrolyte material is characterized by comprising the following steps:

s1 according to the structural formula Ce_0.8Pr_0.1La_0.1O_2–·x(Li_0.5K_0.5Cl), weighing praseodymium salt, cerium salt, lanthanum salt, potassium chloride and lithium chloride, uniformly mixing with a proper amount of organic acid, and then adding water to dissolve to obtain a mixed solution;

s2, adjusting the pH value of the mixed solution to be neutral to obtain a precursor;

s3, carrying out microwave combustion reaction on the precursor, drying and ball milling to obtain CeO₂A base composite solid electrolyte material.

5. The CeO of claim 4₂The preparation method of the base composite solid electrolyte material is characterized in that in the step S3, the power of the microwave combustion reaction is 800-; preferably, the power of the microwave combustion reaction is 1000W, and the reaction time is 15 min.

6. CeO according to claim 4 or 5₂A method for producing a base composite solid electrolyte material, characterized in thatWherein the organic acid is (1-1.5) × (nCe + nPr + nLa + nLi + nK), preferably 1.2 × (nCe + nPr + nLa + nLi + nK).

7. CeO according to any one of claims 4 to 6₂A method for producing a base composite solid electrolyte material, characterized in that the praseodymium salt is praseodymium nitrate, the cerium salt is cerium nitrate, and the lanthanum salt is lanthanum nitrate; the organic acid is at least one of tartaric acid, citric acid, oxalic acid and lactic acid.

8. CeO according to any one of claims 4 to 7₂The preparation method of the matrix composite solid electrolyte material is characterized in that in the step S3, the drying temperature is 120-150 ℃, and the drying time is 0.5-2 h; preferably, the drying temperature is 140 ℃ and the drying time is 1 h.

9. CeO (CeO)₂The composite solid electrolyte comprising the CeO according to any one of claims 1 to 3₂The base composite solid electrolyte material is prepared by drying, granulating, pressing and sintering.

10. The CeO of claim 9₂The composite solid electrolyte is characterized by comprising the following preparation methods:

(1) subjecting the CeO to₂After drying the base composite solid electrolyte material, adding a PVA binder solution with the solid content of 4-6%, grinding and granulating, and pressing into a blank;

(2) heating the blank body to 350 ℃ at the speed of 0.5-2 ℃/min, heating to 750 ℃ at the speed of 1-3 ℃/min, sintering at the temperature of 650-₂A composite solid electrolyte.

Technical Field

The invention relates to the technical field of solid electrolytes, in particular to CeO₂A composite solid electrolyte material and a preparation method thereof.

Background

A solid electrolyte fuel cell (SOFC) belongs to a third-generation fuel cell and has the advantages of high conversion efficiency, environmental friendliness and high system safety. The electrolyte is the core component of the SOFC, and the performance of the electrolyte directly determines the operating temperature and the performance of the fuel cell. The electrolyte functions to separate the fuel gas and the oxidizing gas while allowing only ions to pass through, but not electrons to pass through. Thus, ions can pass through the electrolyte and electrons can only move from one pole to the other through an external circuit. Currently, CeO₂Base-doped materials are one of the hot spots in the study of solid electrolyte materials. CeO (CeO)₂Has higher ionic conductivity and lower conductive activation energy than YSZ, and low price, so that CeO₂The base solid electrolyte becomes one of the most promising electrolytes for achieving the warm-up in SOFC. However, CeO₂The conductivity of the base solid electrolyte material at the medium and low temperature stage still needs to be improved, and the method becomes an important research direction at present.

Disclosure of Invention

Based on the technical problems in the prior art, the invention provides CeO₂A composite solid electrolyte material and a preparation method thereof.

The invention provides CeO₂The structural general formula of the composite solid electrolyte material is as follows: ce_0.8Pr_0.1La_0.1O_2–·x(Li_0.5K_0.5Cl), where the oxygen deficiency is present.

Preferably, wherein 1/3 ≦ x ≦ 3.

More preferably, x is 1/2.

The CeO₂The preparation method of the matrix composite solid electrolyte material comprises the following steps:

s1 according to the structural formula Ce_0.8Pr_0.1La_0.1O_2–·x(Li_0.5K_0.5Cl), weighing praseodymium salt, cerium salt, lanthanum salt, potassium chloride and lithium chloride, uniformly mixing with a proper amount of organic acid, and then adding water to dissolve to obtain a mixed solution;

s2, adjusting the pH value of the mixed solution to be neutral to obtain a precursor;

s3, carrying out microwave combustion reaction on the precursor, drying and ball milling to obtain CeO₂A base composite solid electrolyte material.

Preferably, in the step S3, the power of the microwave combustion reaction is 800-; preferably, the power of the microwave combustion reaction is 1000W, and the reaction time is 15 min.

Preferably, the organic acid is present in a molar amount of (1-1.5) × (nCe + nPr + nLa + nLi + nK), i.e.: the molar weight of the organic acid is 1 to 1.5 times of the total molar weight of Ce, Pr, La, Li and K; preferably, the organic acid is present in a molar amount of 1.2 × (nCe + nPr + nLa + nLi + nK).

Preferably, the praseodymium salt is praseodymium nitrate, the cerium salt is cerium nitrate, and the lanthanum salt is lanthanum nitrate.

Preferably, the organic acid is at least one of tartaric acid, citric acid, oxalic acid and lactic acid.

Preferably, in the step S3, the drying temperature is 120-150 ℃, and the drying time is 0.5-2 h; preferably, the drying temperature is 140 ℃ and the drying time is 1 h.

CeO (CeO)₂Based on a composite solid electrolyte of the above-mentioned CeO₂The base composite solid electrolyte material is prepared by drying, granulating, pressing and sintering.

Preferably, the CeO₂The preparation method of the base composite solid electrolyte comprises the following steps:

(1) subjecting the CeO to₂After drying the base composite solid electrolyte material, adding a PVA binder solution with the solid content of 4-6%, grinding and granulating, and pressing into a blank;

(2) heating the blank body to 350 ℃ at the speed of 0.5-2 ℃/min, heating to 750 ℃ at the speed of 1-3 ℃/min, sintering at the temperature of 650-₂A composite solid electrolyte.

The invention has the following beneficial effects:

(1) the invention is realized by adding Ce_0.8Pr_0.1La_0.1O_2–Doping the material with a specific low-melting-point salt Li_0.5K_0.5Cl, formation of CeO₂A base solid composite electrolyte material, wherein Ce_0.8Pr_0.1La_0.1O_2–The material has oxygen ion conductivity and electronic conductivity, wherein the oxygen ion conductivity is dominant; and Li_0.5K_0.5Cl improves the ion transmission efficiency to a certain extent, accelerates the ion movement and reduces Ce_0.8Pr_0.1La_0.1O_2–The grain boundary of the material promotes the increase of the conductivity of the material, can greatly improve the conductivity of the material at a medium-low temperature stage, and improves the electrochemical performance of the material.

(2) The method takes praseodymium salt, cerium salt, lanthanum salt, potassium chloride and lithium chloride as raw materials, organic acid has the combustion supporting effect, and CeO is prepared by a microwave combustion supporting method₂Compared with the traditional solid phase method and the sol-gel method, the sintering effect is better, the chloride is fused between crystal grains or crystal boundaries, the prepared material particles are relatively compact, the air holes are fewer, the product density is relatively better, and the relative density can reach more than 94 percent, so that the conductivity of the material is further improved, and the preparation method is simple, low in cost, rapid, energy-saving and environment-friendly.

Drawings

FIG. 1 shows CeO according to the present invention₂XRD pattern of the base composite solid electrolyte.

FIG. 2 shows CeO according to the present invention₂SEM image of the base composite solid electrolyte.

FIG. 3 shows CeO according to the present invention₂The conductivity of the composite solid electrolyte at different working test temperatures.

FIG. 4 shows CeO according to the present invention₂Arrhenius curve of the electrical conductivity of the base composite solid electrolyte.

Detailed Description

The technical solution of the present invention will be described in detail below with reference to specific examples.