WO2024150916A1 - Zirconia electrolyte for solid oxide electrolysis cell, and preparation method therefor - Google Patents

Zirconia electrolyte for solid oxide electrolysis cell, and preparation method therefor Download PDF

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WO2024150916A1
WO2024150916A1 PCT/KR2023/018461 KR2023018461W WO2024150916A1 WO 2024150916 A1 WO2024150916 A1 WO 2024150916A1 KR 2023018461 W KR2023018461 W KR 2023018461W WO 2024150916 A1 WO2024150916 A1 WO 2024150916A1
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solid oxide
electrolytic cell
zirconia electrolyte
oxygen ion
formula
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French (fr)
Korean (ko)
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임경태
이희락
신형철
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주식회사케이세라셀
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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/48—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zirconium or hafnium oxides, zirconates, zircon or hafnates
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/02—Hydrogen or oxygen
    • C25B1/04—Hydrogen or oxygen by electrolysis of water
    • C25B1/042—Hydrogen or oxygen by electrolysis of water by electrolysis of steam
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B13/00—Diaphragms; Spacing elements
    • C25B13/04—Diaphragms; Spacing elements characterised by the material
    • C25B13/05—Diaphragms; Spacing elements characterised by the material based on inorganic materials
    • C25B13/07—Diaphragms; Spacing elements characterised by the material based on inorganic materials based on ceramics

Definitions

  • the present invention relates to a zirconia electrolyte for solid oxide electrolytic cells and a method for manufacturing the same.
  • Hydrogen emits water and does not emit carbon dioxide when burned, so it is attracting attention as an alternative energy to reduce carbon dioxide emissions.
  • Such hydrogen can be produced by various production methods, and can be specifically divided into gray hydrogen produced from fossil fuels and green hydrogen produced from water.
  • green hydrogen produces hydrogen and oxygen from water using electrical energy obtained through renewable energy such as solar or wind power.
  • Gray hydrogen emits carbon dioxide during the production process of hydrogen itself, and green hydrogen does not emit carbon dioxide, so research and development on green hydrogen production methods is becoming more active.
  • Solid oxide fuel cells SOFC
  • solid oxide electrolysis cells SOEC
  • Green hydrogen can be produced by electrolyzing water or in the reverse reaction.
  • a solid oxide electrolytic cell When producing hydrogen, a solid oxide electrolytic cell electrolyzes high-temperature steam, and in this high-temperature environment, the electrodes and electrolyte are easily deteriorated, causing a problem in that the hydrogen production efficiency of the electrolytic cell quickly decreases due to repeated operation. Accordingly, there is a need to develop a solid oxide electrolyte that can minimize durability degradation in a high-temperature steam environment and is suitable for SOEC.
  • the purpose of the present invention is to provide a solid oxide electrolytic cell that has high oxygen ion conductivity when applied to a solid oxide electrolytic cell and has improved durability even in a high temperature steam environment.
  • the zirconia electrolyte for a solid oxide electrolytic cell according to the present invention contains yttrium oxide and calcium oxide simultaneously as a stabilizer and satisfies the composition of Chemical Formula 1.
  • x is 0.06 to 0.1 and y is 0.002 to 0.012.
  • the zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention may be characterized in that x in Formula 1 is 0.065 to 0.095.
  • the zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention may be characterized in that y is 0.003 to 0.01 in Chemical Formula 1.
  • the zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention may be characterized as having a face-centered cubic crystal structure.
  • the zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention may be characterized as having an initial oxygen ion conductivity of 0.052 S/cm or more at 850° C. in an air atmosphere.
  • the zirconia electrolyte for a solid oxide electrolytic cell may be characterized as having an initial oxygen ion conductivity of 0.053 S/cm or more in a reducing atmosphere at 850° C. containing hydrogen:water vapor at a volume ratio of 1:1.
  • the zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention may be characterized by a reduction rate of oxygen ion conductivity of 10% or less after 100 hours in a reducing atmosphere at 850°C.
  • the present invention also provides a method for producing a zirconia electrolyte for a solid oxide electrolytic cell.
  • the method for producing a zirconia electrolyte for a solid oxide electrolytic cell according to the present invention is to prepare a composite powder by mixing yttrium oxide, calcium oxide, and zirconium oxide to satisfy the composition of the following formula (1).
  • a second step of manufacturing a molded body by molding the composite powder
  • It includes a third step of sintering the molded body.
  • x is 0.06 to 0.1 and y is 0.002 to 0.012.
  • the first step may be characterized by using a wet ball mill.
  • the sintering may be performed at 1350 to 1500 ° C. for 3 to 10 hours.
  • the zirconia electrolyte for a solid oxide electrolysis cell according to the present invention contains yttrium oxide and calcium oxide simultaneously as a stabilizer and satisfies the composition of Formula 1, thereby providing significantly higher durability and high oxygen ion conductivity in a reducing atmosphere that drives high-temperature water electrolysis.
  • x is 0.06 to 0.1 and y is 0.002 to 0.012.
  • Figure 1 shows the results of XRD (X-ray Diffraction) analysis of electrolyte specimens according to Examples and Comparative Examples of the present invention.
  • Figure 2 shows the results of measuring oxygen ion conductivity of electrolyte specimens according to Examples and Comparative Examples of the present invention in an air atmosphere.
  • Figure 3 shows the results of measuring oxygen ion conductivity of electrolyte specimens according to Examples and Comparative Examples of the present invention in a reducing atmosphere.
  • the zirconia electrolyte for a solid oxide electrolytic cell according to the present invention contains yttrium oxide and calcium oxide simultaneously as a stabilizer and satisfies the composition of the following formula (1).
  • x is 0.06 to 0.1 and y is 0.002 to 0.012.
  • the zirconia electrolyte for solid oxide electrolytic cells according to the present invention has the advantage of exhibiting high oxygen ion conductivity and durability in a high-temperature water electrolysis environment, and thus showing high efficiency when applied to solid oxide electrolytic cells.
  • x may be 0.06 to 0.1, preferably 0.065 to 0.095, and more preferably 0.075 to 0.085.
  • Yttrium oxide has the characteristic of exhibiting high oxygen ion conductivity by satisfying this content.
  • y may be 0.002 to 0.012, preferably 0.003 to 0.01, more preferably 0.0055 to 0.01, and most preferably 0.0065 to 0.0085.
  • the zirconia electrolyte for the solid oxide electrolytic cell is characterized by having a face-centered cubic crystal structure.
  • the zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention does not change the crystal structure of the electrolyte even when calcium oxide is substituted and dissolved in solid solution, and can maintain a face-centered cubic crystal structure that is advantageous for oxygen ion conduction.
  • the zirconia electrolyte for a solid oxide electrolytic cell may exhibit an initial oxygen ion conductivity of 0.52 S/cm or more, preferably 0.55 to 0.65 S/cm, at 850° C. in an air atmosphere.
  • the initial oxygen ion conductivity refers to the oxygen ion conductivity measured immediately after exposure to the atmospheric atmosphere.
  • the zirconia electrolyte for the solid oxide electrolytic cell may have an initial oxygen ion conductivity of 0.053 S/cm or more, preferably 0.055 S/cm or more, in a reducing atmosphere at 850 ° C. containing hydrogen: water vapor at a volume ratio of 1:1, After 100 hours, the rate of decrease in oxygen ion conductivity may be 10% or less, specifically 8% or less, and more specifically 7% or less.
  • the zirconia electrolyte for a solid oxide electrolytic cell according to the present invention contains calcium oxide, so it exhibits excellent initial oxygen ion conductivity even in an environment where zirconia electrolyte is easily deteriorated, and has the characteristic of exhibiting high durability even during long-term operation.
  • the present invention also provides a zirconia electrolyte for solid oxide electrolytic cells.
  • the zirconia electrolyte for a solid oxide electrolytic cell according to the present invention includes a first step of producing a composite powder by mixing yttrium oxide, calcium oxide, and zirconium oxide to satisfy the composition of the following formula (1);
  • a second step of manufacturing a molded body by molding the composite powder
  • It includes a third step of sintering the molded body.
  • x is 0.06 to 0.1 and y is 0.002 to 0.012.
  • the zirconia electrolyte for a solid oxide electrolytic cell manufactured by the method for manufacturing a zirconia electrolyte for a solid oxide electrolytic cell according to the present invention has the advantages of high oxygen ion conductivity and excellent durability in a reducing atmosphere.
  • the first step may be performed with a wet ball mill at 100 to 200 rpm, and the solvent used in the wet ball mill may be an alcohol having 4 carbon atoms or less, preferably ethanol or isopropanol. Additionally, the first step may be performed for 12 to 36 hours. In detail, 1.5 to 3.5 L of the solvent may be added per 1 kg of the total weight of the yttrium oxide, calcium oxide, and zirconium oxide (hereinafter referred to as the total oxide weight).
  • the method for producing zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention may further include a drying step of removing the solvent used in the wet ball mill after the first step, and this drying step improves molding and sintering efficiency. High and dense zirconia electrolyte can be manufactured.
  • a molded body is manufactured by molding the composite powder, and a zirconia electrolyte with excellent oxygen ion conductivity can be manufactured by sintering the manufactured molded body.
  • the second step can be used without limitation if it is a method commonly used for molding before sintering. Specifically, uniaxial pressure press molding can be used, but the present invention is not limited thereto.
  • the second step can be performed by applying a pressure of 0.7 to 1.5 tons per 1 cm 2. If the pressure applied when manufacturing the molded body is low, the density of the produced zirconia electrolyte may be lowered, and thus the oxygen ion conductivity may be lowered. .
  • the third step is a step of sintering the molded body, and the maximum temperature in the third step may be 1350 to 1500°C, preferably 1400 to 1500°C. If the maximum temperature during sintering is low, it is difficult to form a dense zirconia electrolyte, and even if the maximum temperature during sintering is high, the density does not increase any further and a lot of energy may be consumed unnecessarily in electrolyte production.
  • the third step can increase the temperature at a rate of 3 to 8 ° C. per minute until the maximum temperature is reached. If the temperature increase rate is low, the production efficiency of the zirconia electrolyte may be lowered, and if the temperature increase rate is high, the temperature may increase rapidly. Changes may cause a decrease in the physical properties of the zirconia electrolyte.
  • a zirconia electrolyte sintered body was manufactured through a solid-phase sintering reaction using Y 2 O 3 , CaO, and ZrO 2 powders with a purity of 99.9% or more as raw materials.
  • the raw materials were weighed according to the composition in Table 1 below, and a mixed slurry was prepared by ball milling at 150 rpm for 24 hours using zirconia balls and an ethanol solvent. Specifically, the ratio of metal oxide raw material/solvent during ball milling was 0.5 kg/1L, and the balls were placed at 55% of the height of the container. The prepared mixed slurry was dried at 80°C until all ethanol was removed to prepare a dried composite powder.
  • Figure 1 shows the results of analyzing each manufactured specimen using XRD (X-ray Diffraction).
  • Each sample was processed into a bar shape measuring 2 mm in width, 2 mm in height, and 20 mm in length, and then the oxygen ion conductivity was measured at 850 °C using the direct current four-terminal method. Specifically, the oxygen ion conductivity of each electrolyte specimen was measured for 9.5 hours in an air atmosphere at 850°C, and the results are shown in Table 2 and Figure 2 below.
  • the oxygen ion conductivity of E3 is slightly higher than that of E4, which has a higher CaO content. This is because as the CaO content increases excessively, some of the oxygen vacancies form oxygen ion clusters, resulting in lower oxygen ion conductivity. It can be judged as a loss.
  • Table 4 compares the initial oxygen ion conductivity measurement results in atmospheric and reducing atmospheres.

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Abstract

A zirconia electrolyte for a solid oxide electrolysis cell, of the present invention, is doped with both yttrium oxide and calcium oxide as stabilizers and satisfies the composition of chemical formula 1, thereby solving a conventional problem of low durability in a high-temperature reductive atmosphere in which water electrolysis is performed, and thus can exhibit long-term stability, remarkably high durability and a high oxygen ion conductivity.

Description

고체산화물 전해셀용 지르코니아 전해질 및 이의 제조방법Zirconia electrolyte for solid oxide electrolytic cell and method of manufacturing the same
본 발명은 고체산화물 전해셀용 지르코니아 전해질 및 이의 제조방법에 관한 것이다. The present invention relates to a zirconia electrolyte for solid oxide electrolytic cells and a method for manufacturing the same.
최근 지구 온난화에 따른 환경 문제가 대두됨에 따라, 지구 온난화를 유발하는 온실가스의 배출을 줄이기 위한 다양한 노력들이 계속되고 있다. 특히 지구 온난화의 가장 큰 원인으로 평가되는 이산화탄소는 화석 연료의 사용으로 배출된다. 이에, 이산화탄소를 배출하는 화석연료를 중심으로 하는 에너지 시스템에서 벗어나 친환경적으로 에너지를 생산할 수 있는 친환경 에너지에 대한 수요 및 이에 따른 연구 개발이 급증하고 있다. As environmental problems due to global warming have recently emerged, various efforts are continuing to reduce the emissions of greenhouse gases that cause global warming. In particular, carbon dioxide, which is considered the biggest cause of global warming, is emitted through the use of fossil fuels. Accordingly, demand for and corresponding research and development for eco-friendly energy that can produce energy in an environmentally friendly manner, moving away from the energy system centered on fossil fuels that emit carbon dioxide, is rapidly increasing.
이러한 친환경 에너지들 중 가장 주목받는 것은 수소이다. 수소는 연소되어도 물을 배출하고 이산화탄소를 배출하지 않으므로, 이산화탄소 배출을 줄이기 위한 대체 에너지로 각광받고 있다. 이러한 수소는 다양한 생산방법으로 생산될 수 있으며, 구체적으로 화석 연료로부터 생산되는 그레이 수소 및 물로부터 수소를 얻는 그린 수소 등으로 나뉠 수 있다. 구체적으로 그린 수소는 태양광 또는 풍력 등과 같은 신재생에너지를 통해 얻은 전기에너지를 이용하여 물로부터 수소와 산소를 생산한다. 그레이 수소는 수소 자체의 생산 과정에서 이산화탄소를 배출하며, 그린수소는 이산화탄소를 배출하지 않으므로 그린수소 생산 방법에 대한 연구 개발이 더욱 활발히 이루어지고 있다. Among these eco-friendly energies, the one that attracts the most attention is hydrogen. Hydrogen emits water and does not emit carbon dioxide when burned, so it is attracting attention as an alternative energy to reduce carbon dioxide emissions. Such hydrogen can be produced by various production methods, and can be specifically divided into gray hydrogen produced from fossil fuels and green hydrogen produced from water. Specifically, green hydrogen produces hydrogen and oxygen from water using electrical energy obtained through renewable energy such as solar or wind power. Gray hydrogen emits carbon dioxide during the production process of hydrogen itself, and green hydrogen does not emit carbon dioxide, so research and development on green hydrogen production methods is becoming more active.
고체산화물 연료전지(Solid Oxide Fuel Cells, 이하 SOFC라고 한다)와 고체산화물 전해셀(Solid Oxide Electrolysis Cells, SOEC)은 전극과 함께 산소 이온 전도성을 갖는 고체 전해질을 포함하며, 전기화학반응으로 전기 에너지를 생산하거나, 역반응으로 물을 전기분해하여 그린 수소를 생산할 수 있다.Solid oxide fuel cells (SOFC) and solid oxide electrolysis cells (SOEC) contain a solid electrolyte with oxygen ion conductivity along with electrodes, and convert electrical energy through an electrochemical reaction. Green hydrogen can be produced by electrolyzing water or in the reverse reaction.
수소를 생산하는 경우 고체산화물 전해셀은 고온의 스팀을 전기분해 하며, 이러한 고온 환경에서 전극 및 전해질이 쉽게 열화되어 반복 구동에 의해 전해셀의 수소 생산 효율이 빠른 시일 내에 낮아지는 문제점이 있다. 이에, 고온의 스팀 환경에서 내구도 저하를 최소화할 수 있으며, SOEC에 적합한 고체산화물 전해질의 개발이 필요한 실정이다.When producing hydrogen, a solid oxide electrolytic cell electrolyzes high-temperature steam, and in this high-temperature environment, the electrodes and electrolyte are easily deteriorated, causing a problem in that the hydrogen production efficiency of the electrolytic cell quickly decreases due to repeated operation. Accordingly, there is a need to develop a solid oxide electrolyte that can minimize durability degradation in a high-temperature steam environment and is suitable for SOEC.
본 발명의 목적은 고체산화물 전해셀에 적용 시 높은 산소 이온 전도도를 가지며, 고온의 스팀 환경에서도 향상된 내구도를 갖는 고체산화물 전해셀을 제공하는 것이다. The purpose of the present invention is to provide a solid oxide electrolytic cell that has high oxygen ion conductivity when applied to a solid oxide electrolytic cell and has improved durability even in a high temperature steam environment.
본 발명에 의한 고체산화물 전해셀용 지르코니아 전해질은 이트륨 산화물 및 칼슘 산화물이 동시에 안정화제로 치환 고용되며, 상기 화학식 1의 조성을 만족한다. The zirconia electrolyte for a solid oxide electrolytic cell according to the present invention contains yttrium oxide and calcium oxide simultaneously as a stabilizer and satisfies the composition of Chemical Formula 1.
[화학식 1][Formula 1]
(Y2O3)x(CaO)y(ZrO2)1-x-y (Y 2 O 3 ) x (CaO) y (ZrO 2 ) 1-xy
화학식 1에서, x는 0.06 내지 0.1이며, y는 0.002 내지 0.012이다.In Formula 1, x is 0.06 to 0.1 and y is 0.002 to 0.012.
본 발명의 일 실시예에 의한 고체산화물 전해셀용 지르코니아 전해질은 상기 화학식 1에서 x가 0.065 내지 0.095인 것을 특징으로 할 수 있다. The zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention may be characterized in that x in Formula 1 is 0.065 to 0.095.
본 발명의 일 실시예에 의한 고체산화물 전해셀용 지르코니아 전해질은 상기 화학식 1에서 y가 0.003 내지 0.01인 것을 특징으로 할 수 있다. The zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention may be characterized in that y is 0.003 to 0.01 in Chemical Formula 1.
본 발명의 일 실시예에 의한 고체산화물 전해셀용 지르코니아 전해질은 면심 입방정 결정구조를 갖는 것을 특징으로 할 수 있다. The zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention may be characterized as having a face-centered cubic crystal structure.
본 발명의 일 실시예에 의한 고체산화물 전해셀용 지르코니아 전해질은 850 ℃, 대기 분위기에서 초기 산소 이온 전도도가 0.052 S/cm 이상인 것을 특징으로 할 수 있다. The zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention may be characterized as having an initial oxygen ion conductivity of 0.052 S/cm or more at 850° C. in an air atmosphere.
본 발명의 일 실시예에 의한 고체산화물 전해셀용 지르코니아 전해질은 수소 : 수증기를 1:1의 부피비로 포함하는 850 ℃의 환원 분위기에서 초기 산소 이온 전도도가 0.053 S/cm 이상인 것을 특징으로 할 수 있다. The zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention may be characterized as having an initial oxygen ion conductivity of 0.053 S/cm or more in a reducing atmosphere at 850° C. containing hydrogen:water vapor at a volume ratio of 1:1.
본 발명의 일 실시예에 의한 고체산화물 전해셀용 지르코니아 전해질은 850 ℃의 환원 분위기에서 100시간 경과한 후 산소 이온 전도도 감소율이 10% 이하인 것을 특징으로 할 수 있다. The zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention may be characterized by a reduction rate of oxygen ion conductivity of 10% or less after 100 hours in a reducing atmosphere at 850°C.
본 발명은 또한 고체산화물 전해셀용 지르코니아 전해질 제조방법을 제공하며, 본 발명에 의한 고체산화물 전해셀용 지르코니아 전해질 제조방법은 하기 화학식 1의 조성을 만족하도록 이트륨 산화물, 칼슘 산화물 및 지르코늄 산화물을 혼합하여 복합분말을 제조하는 제 1단계; The present invention also provides a method for producing a zirconia electrolyte for a solid oxide electrolytic cell. The method for producing a zirconia electrolyte for a solid oxide electrolytic cell according to the present invention is to prepare a composite powder by mixing yttrium oxide, calcium oxide, and zirconium oxide to satisfy the composition of the following formula (1). First step of manufacturing;
상기 복합분말을 성형하여 성형체를 제조하는 제 2단계; 및 A second step of manufacturing a molded body by molding the composite powder; and
상기 성형체를 소결하는 제 3단계;를 포함한다. It includes a third step of sintering the molded body.
[화학식 1][Formula 1]
(Y2O3)x(CaO)y(ZrO2)1-x-y (Y 2 O 3 ) x (CaO) y (ZrO 2 ) 1-xy
화학식 1에서, x는 0.06 내지 0.1이며, y는 0.002 내지 0.012이다.In Formula 1, x is 0.06 to 0.1 and y is 0.002 to 0.012.
본 발명의 일 실시예에 의한 고체산화물 전해셀용 지르코니아 전해질 제조방법에서 상기 제 1단계는 습식 볼밀을 이용하는 것을 특징으로 할 수 있다. In the method for manufacturing zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention, the first step may be characterized by using a wet ball mill.
본 발명의 일 실시예에 의한 고체산화물 전해셀용 지르코니아 전해질 제조방법에서 상기 소결은 1350 내지 1500 ℃에서 3 내지 10시간 동안 수행되는 것을 특징으로 할 수 있다.In the method for manufacturing a zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention, the sintering may be performed at 1350 to 1500 ° C. for 3 to 10 hours.
본 발명에 의한 고체산화물 전해셀용 지르코니아 전해질은 이트륨 산화물 및 칼슘 산화물이 동시에 안정화제로 치환 고용되며, 상기 화학식 1의 조성을 만족함으로써, 고온 수전해를 구동하는 환원 분위기에서 현저히 높은 내구성 및 높은 산소 이온 전도도를 나타내는 장점이 있다. The zirconia electrolyte for a solid oxide electrolysis cell according to the present invention contains yttrium oxide and calcium oxide simultaneously as a stabilizer and satisfies the composition of Formula 1, thereby providing significantly higher durability and high oxygen ion conductivity in a reducing atmosphere that drives high-temperature water electrolysis. There are advantages to showing.
[화학식 1][Formula 1]
(Y2O3)x(CaO)y(ZrO2)1-x-y (Y 2 O 3 ) x (CaO) y (ZrO 2 ) 1-xy
화학식 1에서, x는 0.06 내지 0.1이며, y는 0.002 내지 0.012이다.In Formula 1, x is 0.06 to 0.1 and y is 0.002 to 0.012.
도 1은 본 발명의 실시예 및 비교예에 의한 전해질 시편을 XRD(X-ray Diffraction) 분석하고 그 결과를 도시한 것이다. Figure 1 shows the results of XRD (X-ray Diffraction) analysis of electrolyte specimens according to Examples and Comparative Examples of the present invention.
도 2는 본 발명의 실시예 및 비교예에 의한 전해질 시편을 대기 분위기에서 산소 이온 전도도를 측정하고 그 결과를 도시한 것이다. Figure 2 shows the results of measuring oxygen ion conductivity of electrolyte specimens according to Examples and Comparative Examples of the present invention in an air atmosphere.
도 3은 본 발명의 실시예 및 비교예에 의한 전해질 시편을 환원 분위기에서 산소 이온 전도도를 측정하고 그 결과를 도시한 것이다. Figure 3 shows the results of measuring oxygen ion conductivity of electrolyte specimens according to Examples and Comparative Examples of the present invention in a reducing atmosphere.
본 발명의 실시예들에 대한 이점 및 특징, 그리고 그것들을 달성하는 방법은 첨부되는 도면과 함께 상세하게 후술되어 있는 실시예들을 참조하면 명확해질 것이다. 그러나 본 발명은 이하에서 개시되는 실시예들에 한정되는 것이 아니라 서로 다른 다양한 형태로 구현될 수 있으며, 단지 본 실시예들은 본 발명의 개시가 완전하도록 하고, 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자에게 발명의 범주를 완전하게 알려주기 위해 제공되는 것이며, 본 발명은 청구항의 범주에 의해 정의될 뿐이다. 명세서 전체에 걸쳐 동일 참조 부호는 동일 구성 요소를 지칭한다.Advantages and features of the embodiments of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. The present embodiments are merely provided to ensure that the disclosure of the present invention is complete and to be understood by those skilled in the art in the technical field to which the present invention pertains. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.
본 발명의 실시예들을 설명함에 있어서 공지 기능 또는 구성에 대한 구체적인 설명이 본 발명의 요지를 불필요하게 흐릴 수 있다고 판단되는 경우에는 그 상세한 설명을 생략할 것이다. 그리고 후술되는 용어들은 본 발명의 실시예에서의 기능을 고려하여 정의된 용어들로서 이는 사용자, 운용자의 의도 또는 관례 등에 따라 달라질 수 있다. 그러므로 그 정의는 본 명세서 전반에 걸친 내용을 토대로 내려져야 할 것이다.In describing embodiments of the present invention, if a detailed description of a known function or configuration is judged to unnecessarily obscure the gist of the present invention, the detailed description will be omitted. The terms described below are defined in consideration of functions in the embodiments of the present invention, and may vary depending on the intention or custom of the user or operator. Therefore, the definition should be made based on the contents throughout this specification.
본 발명에 의한 고체산화물 전해셀용 지르코니아 전해질은 이트륨 산화물 및 칼슘 산화물이 동시에 안정화제로 치환 고용되며, 하기 화학식 1의 조성을 만족한다. The zirconia electrolyte for a solid oxide electrolytic cell according to the present invention contains yttrium oxide and calcium oxide simultaneously as a stabilizer and satisfies the composition of the following formula (1).
[화학식 1][Formula 1]
(Y2O3)x(CaO)y(ZrO2)1-x-y (Y 2 O 3 ) x (CaO) y (ZrO 2 ) 1-xy
화학식 1에서, x는 0.06 내지 0.1이며, y는 0.002 내지 0.012이다.In Formula 1, x is 0.06 to 0.1 and y is 0.002 to 0.012.
본 발명에 의한 고체산화물 전해셀용 지르코니아 전해질은 고온 수전해 환경에서 높은 산소 이온 전도도 및 내구도를 나타내어, 고체산화물 전해셀에 적용 시 높은 효율을 나타낼 수 있는 장점이 있다. The zirconia electrolyte for solid oxide electrolytic cells according to the present invention has the advantage of exhibiting high oxygen ion conductivity and durability in a high-temperature water electrolysis environment, and thus showing high efficiency when applied to solid oxide electrolytic cells.
상기 화학식에서 x는 0.06 내지 0.1, 좋게는 0.065 내지 0.095, 더욱 좋게는 0.075 내지 0.085일 수 있으며, 이트륨 산화물이 이러한 함량을 만족함으로써 높은 산소 이온 전도도를 나타낼 수 있는 특징이 있다. In the above formula, x may be 0.06 to 0.1, preferably 0.065 to 0.095, and more preferably 0.075 to 0.085. Yttrium oxide has the characteristic of exhibiting high oxygen ion conductivity by satisfying this content.
상기 화학식에서 y는 0.002 내지 0.012, 좋게는 0.003 내지 0.01, 더욱 좋게는 0.0055 내지 0.01, 가장 좋게는 0.0065 내지 0.0085일 수 있다. 이러한 칼슘 산화물 함량을 만족함으로써, 환원 분위기에서 산소 이온 전도도가 저하되는 것을 예방할 수 있으며, 장기 구동시 높은 내구성을 확보할 수 있는 장점이 있다. In the above formula, y may be 0.002 to 0.012, preferably 0.003 to 0.01, more preferably 0.0055 to 0.01, and most preferably 0.0065 to 0.0085. By satisfying this calcium oxide content, it is possible to prevent oxygen ion conductivity from decreasing in a reducing atmosphere and has the advantage of ensuring high durability during long-term operation.
상기 고체산화물 전해셀용 지르코니아 전해질은 면심 입방정 결정구조를 가지는 특징이 있다. 구체적으로, 본 발명의 일 실시예에 의한 고체산화물 전해셀용 지르코니아 전해질은 칼슘 산화물을 치환 고용하여도 전해질의 결정 구조에 변화가 발생하지 않으며, 산소 이온 전도에 유리한 면심 입방정 결정구조를 유지할 수 있다. The zirconia electrolyte for the solid oxide electrolytic cell is characterized by having a face-centered cubic crystal structure. Specifically, the zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention does not change the crystal structure of the electrolyte even when calcium oxide is substituted and dissolved in solid solution, and can maintain a face-centered cubic crystal structure that is advantageous for oxygen ion conduction.
상기 고체산화물 전해셀용 지르코니아 전해질은 850 ℃, 대기 분위기에서 초기 산소 이온 전도도가 0.52 S/cm 이상, 좋게는 0.55 내지 0.65 S/cm의 산소 이온 전도도를 나타낼 수 있다. 이때, 초기 산소 이온 전도도라 함은 대기 분위기에 노출 직후 측정한 산소 이온 전도도를 의미한다. The zirconia electrolyte for a solid oxide electrolytic cell may exhibit an initial oxygen ion conductivity of 0.52 S/cm or more, preferably 0.55 to 0.65 S/cm, at 850° C. in an air atmosphere. At this time, the initial oxygen ion conductivity refers to the oxygen ion conductivity measured immediately after exposure to the atmospheric atmosphere.
아울러, 상기 고체산화물 전해셀용 지르코니아 전해질은 수소 : 수증기를 1:1의 부피비로 포함하는 850 ℃의 환원 분위기에서, 초기 산소 이온 전도도가 0.053 S/cm 이상, 좋게는 0.055 S/cm 이상일 수 있으며, 100시간이 경과한 후 산소 이온 전도도 감소율이 10% 이하, 구체적으로 8% 이하, 더욱 구체적으로 7% 이하일 수 있다. In addition, the zirconia electrolyte for the solid oxide electrolytic cell may have an initial oxygen ion conductivity of 0.053 S/cm or more, preferably 0.055 S/cm or more, in a reducing atmosphere at 850 ° C. containing hydrogen: water vapor at a volume ratio of 1:1, After 100 hours, the rate of decrease in oxygen ion conductivity may be 10% or less, specifically 8% or less, and more specifically 7% or less.
즉, 본 발명에 의한 고체산화물 전해셀용 지르코니아 전해질은 칼슘 산화물을 포함함으로써, 지르코니아 전해질이 쉽게 열화되는 환경에서도 우수한 초기 산소 이온 전도도를 나타내며, 장기 구동시에도 높은 내구성을 나타내는 특징이 있다. That is, the zirconia electrolyte for a solid oxide electrolytic cell according to the present invention contains calcium oxide, so it exhibits excellent initial oxygen ion conductivity even in an environment where zirconia electrolyte is easily deteriorated, and has the characteristic of exhibiting high durability even during long-term operation.
본 발명은 또한 고체산화물 전해셀용 지르코니아 전해질을 제공한다. The present invention also provides a zirconia electrolyte for solid oxide electrolytic cells.
본 발명에 의한 고체산화물 전해셀용 지르코니아 전해질은 하기 화학식 1의 조성을 만족하도록 이트륨 산화물, 칼슘 산화물 및 지르코늄 산화물을 혼합하여 복합분말을 제조하는 제 1단계; The zirconia electrolyte for a solid oxide electrolytic cell according to the present invention includes a first step of producing a composite powder by mixing yttrium oxide, calcium oxide, and zirconium oxide to satisfy the composition of the following formula (1);
상기 복합분말을 성형하여 성형체를 제조하는 제 2단계; 및 A second step of manufacturing a molded body by molding the composite powder; and
상기 성형체를 소결하는 제 3단계;를 포함한다. It includes a third step of sintering the molded body.
[화학식 1][Formula 1]
(Y2O3)x(CaO)y(ZrO2)1-x-y (Y 2 O 3 ) x (CaO) y (ZrO 2 ) 1-xy
화학식 1에서, x는 0.06 내지 0.1이며, y는 0.002 내지 0.012이다.In Formula 1, x is 0.06 to 0.1 and y is 0.002 to 0.012.
본 발명에 의한 고체산화물 전해셀용 지르코니아 전해질 제조방법으로 제조된 고체산화물 전해셀용 지르코니아 전해질은 높은 산소 이온 전도도 및 환원 분위기에서 우수한 내구도를 나타내는 장점이 있다. The zirconia electrolyte for a solid oxide electrolytic cell manufactured by the method for manufacturing a zirconia electrolyte for a solid oxide electrolytic cell according to the present invention has the advantages of high oxygen ion conductivity and excellent durability in a reducing atmosphere.
구체적으로, 상기 제 1단계는 습식 볼밀로 100 내지 200 rpm으로 수행될 수 있으며, 이때 습식 볼밀에 이용되는 용매는 탄소수 4 이하의 알코올을 이용할 수 있으며, 좋게는 에탄올 또는 이소프로판올을 이용할 수 있다. 또한 상기 제 1단계는 12 내지 36시간 동안 수행될 수 있다. 상세하게는 상기 용매는 상기 이트륨 산화물, 칼슘 산화물 및 지르코늄 산화물의 총 중량(이하 산화물 총중량이라 한다) 1 kg 당 1.5 내지 3.5 L 투입될 수 있다. Specifically, the first step may be performed with a wet ball mill at 100 to 200 rpm, and the solvent used in the wet ball mill may be an alcohol having 4 carbon atoms or less, preferably ethanol or isopropanol. Additionally, the first step may be performed for 12 to 36 hours. In detail, 1.5 to 3.5 L of the solvent may be added per 1 kg of the total weight of the yttrium oxide, calcium oxide, and zirconium oxide (hereinafter referred to as the total oxide weight).
본 발명의 일 실시예에 의한 고체산화물 전해셀용 지르코니아 전해질 제조방법은 상기 제 1단계 후 습식 볼밀에 이용된 용매를 제거하는 건조 단계를 더 포함할 수 있으며, 이러한 건조 단계에 의하여 성형 및 소결 효율을 높이고 치밀한 지르코니아 전해질을 제조할 수 있다. The method for producing zirconia electrolyte for a solid oxide electrolytic cell according to an embodiment of the present invention may further include a drying step of removing the solvent used in the wet ball mill after the first step, and this drying step improves molding and sintering efficiency. High and dense zirconia electrolyte can be manufactured.
상기 제 2단계는 복합분말을 성형하여 성형체를 제조하며, 제조된 성형체를 소결함으로써 산소 이온 전도도가 우수한 지르코니아 전해질을 제조할 수 있다. 이때 상기 제 2단계는 통상적으로 소결 전 성형에 이용되는 방법인 경우 제한없이 이용이 가능하며, 구체적으로 일축 가압 프레스 성형을 이용할 수 있으나 본 발명이 이에 제한되는 것은 아니다. In the second step, a molded body is manufactured by molding the composite powder, and a zirconia electrolyte with excellent oxygen ion conductivity can be manufactured by sintering the manufactured molded body. At this time, the second step can be used without limitation if it is a method commonly used for molding before sintering. Specifically, uniaxial pressure press molding can be used, but the present invention is not limited thereto.
나아가 상기 제 2단계는 1 ㎠ 당 0.7 내지 1.5 톤의 압력을 가하여 수행될 수 있으며, 성형체 제조 시 가해지는 압력이 낮은 경우 제조되는 지르코니아 전해질의 치밀도가 낮아지며, 이에 따라 산소 이온 전도도가 낮아질 수 있다. Furthermore, the second step can be performed by applying a pressure of 0.7 to 1.5 tons per 1 cm 2. If the pressure applied when manufacturing the molded body is low, the density of the produced zirconia electrolyte may be lowered, and thus the oxygen ion conductivity may be lowered. .
상기 제 3단계는 성형체를 소결하는 단계로, 상기 제 3단계에서 최고 온도는 1350 내지 1500 ℃, 좋게는 1400 내지 1500 ℃일 수 있다. 소결 시 최고온도가 낮은 경우 치밀한 지르코니아 전해질을 형성하기 어려우며, 소결 시 최고온도가 높더라도 치밀도는 더 이상 높아지지 않으며 전해질 생산에 불필요하게 많은 에너지가 소모될 수 있다. The third step is a step of sintering the molded body, and the maximum temperature in the third step may be 1350 to 1500°C, preferably 1400 to 1500°C. If the maximum temperature during sintering is low, it is difficult to form a dense zirconia electrolyte, and even if the maximum temperature during sintering is high, the density does not increase any further and a lot of energy may be consumed unnecessarily in electrolyte production.
좋게는 상기 제 3단계는 상기 최고 온도에 도달할 때 까지 분당 3 내지 8 ℃의 속도로 승온할 수 있으며, 승온 속도가 낮은 경우 지르코니아 전해질의 생산효율이 낮아질 수 있고, 승온 속도가 높은 경우 급격한 온도변화에 의하여 지르코니아 전해질의 물성 저하가 발생할 수 있다. Preferably, the third step can increase the temperature at a rate of 3 to 8 ° C. per minute until the maximum temperature is reached. If the temperature increase rate is low, the production efficiency of the zirconia electrolyte may be lowered, and if the temperature increase rate is high, the temperature may increase rapidly. Changes may cause a decrease in the physical properties of the zirconia electrolyte.
이하, 본 발명을 실시예 및 비교예에 의해 구체적으로 설명한다. 아래 실시예는 본 발명의 이해를 돕기 위한 것일 뿐이며, 본 발명의 범위가 아래 실시예에 의해 한정되는 것은 아니다.Hereinafter, the present invention will be described in detail by examples and comparative examples. The examples below are only intended to aid understanding of the present invention, and the scope of the present invention is not limited by the examples below.
[실시예 및 비교예][Examples and Comparative Examples]
99.9% 이상의 순도를 갖는 Y2O3, CaO, ZrO2 분말을 원료로 고상 소결반응을 통해 지르코니아 전해질 소결체를 제조하였다. A zirconia electrolyte sintered body was manufactured through a solid-phase sintering reaction using Y 2 O 3 , CaO, and ZrO 2 powders with a purity of 99.9% or more as raw materials.
먼저 하기 표 1의 조성에 따라 원료 소재들을 칭량하고, 지르코니아 볼과 에탄올 용매를 이용하여 150 rpm으로 24시간 동안 볼밀 하여 혼합 슬러리를 제조하였다. 구체적으로 볼밀 시 금속 산화물 원료/용매의 비율은 0.5 kg/1L이며, 볼은 용기 높이의 55%가 되도록 투입하였다. 제조된 혼합 슬러리를 80 ℃에서 에탄올이 모두 제거될 때 까지 건조하여 건조된 복합 분말을 제조하였다. First, the raw materials were weighed according to the composition in Table 1 below, and a mixed slurry was prepared by ball milling at 150 rpm for 24 hours using zirconia balls and an ethanol solvent. Specifically, the ratio of metal oxide raw material/solvent during ball milling was 0.5 kg/1L, and the balls were placed at 55% of the height of the container. The prepared mixed slurry was dried at 80°C until all ethanol was removed to prepare a dried composite powder.
건조된 복합 분말을 4 × 4 ㎝ 크기의 프레스금형에 투입한 뒤, 4 metric ton의 압력을 가하여 일축 가압프레스를 통해 성형체를 제조하였다. 제조된 성형체는 대기 중에서 분당 5℃의 승온 속도로 1450 ℃까지 승온한 뒤, 1450 ℃에서 5시간 동안 소결하였다. The dried composite powder was put into a press mold measuring 4 × 4 cm, and a pressure of 4 metric tons was applied to produce a molded body through a single-axis pressure press. The manufactured molded body was heated to 1450°C at a temperature increase rate of 5°C per minute in air and then sintered at 1450°C for 5 hours.
샘플 번호sample number 샘플명sample name 조성Furtherance
E0E0 8YSZ8YSZ (Y2O3)0.08(ZrO2)0.92 (Y 2 O 3 ) 0.08 (ZrO 2 ) 0.92
E1E1 8Y0.25CaSZ8Y0.25CaSZ (Y2O3)0.08(CaO)0.0025(ZrO2)0.9175 (Y 2 O 3 ) 0.08 (CaO) 0.0025 (ZrO 2 ) 0.9175
E2E2 8Y0.5CaSZ8Y0.5CaSZ (Y2O3)0.08(CaO)0.005(ZrO2)0.915 (Y 2 O 3 ) 0.08 (CaO) 0.005 (ZrO 2 ) 0.915
E3E3 8Y0.75CaSZ8Y0.75CaSZ (Y2O3)0.08(CaO)0.0075(ZrO2)0.9125 (Y 2 O 3 ) 0.08 (CaO) 0.0075 (ZrO 2 ) 0.9125
E4E4 8Y1CaSZ8Y1CaSZ (Y2O3)0.08(CaO)0.01(ZrO2)0.91 (Y 2 O 3 ) 0.08 (CaO) 0.01 (ZrO 2 ) 0.91
결정구조 확인Crystal structure confirmation
도 1은 제조된 각 시편을 XRD(X-ray Diffraction)로 분석한 뒤, 그 결과를 도시한 것이다. Figure 1 shows the results of analyzing each manufactured specimen using XRD (X-ray Diffraction).
도 1을 참고하면, 칼슘의 함량이 증가하더라도 X선 회절 패턴에는 차이가 나타나지 않으며, 칼슘 함량이 증가하더라도 면심 입방정 구조를 유지하는 것을 확인할 수 있다. Referring to Figure 1, even if the calcium content increases, no difference appears in the X-ray diffraction pattern, and it can be seen that the face-centered cubic structure is maintained even if the calcium content increases.
대기중에서 산소 이온 전도도 확인Check oxygen ion conductivity in the atmosphere
각 샘플을 가로 2mm, 세로 2mm 및 길이 20mm 크기의 바(bar) 형태로 가공한 후 직류 4단자법을 이용하여 850 ℃에서 산소 이온 전도도를 측정하였다. 구체적으로, 850 ℃ 대기 분위기에서 9.5시간 동안 각 전해질 시편들의 산소 이온 전도도를 측정하였으며, 그 결과를 하기 표 2 및 도 2로 나타내었다. Each sample was processed into a bar shape measuring 2 mm in width, 2 mm in height, and 20 mm in length, and then the oxygen ion conductivity was measured at 850 °C using the direct current four-terminal method. Specifically, the oxygen ion conductivity of each electrolyte specimen was measured for 9.5 hours in an air atmosphere at 850°C, and the results are shown in Table 2 and Figure 2 below.
측정시간(h)Measurement time (h) 산소 이온 전도도(S/cm)Oxygen ion conductivity (S/cm)
E0E0 E1E1 E2E2 E3E3 E4E4
초기 Early 0.05220.0522 0.05230.0523 0.05280.0528 0.05840.0584 0.05710.0571
1One 0.05180.0518 0.05220.0522 0.05290.0529 0.05840.0584 0.05720.0572
22 0.05140.0514 0.0520.052 0.0530.053 0.05820.0582 0.0570.057
33 0.05110.0511 0.05150.0515 0.0530.053 0.05840.0584 0.05690.0569
44 0.05080.0508 0.05130.0513 0.05290.0529 0.05840.0584 0.05680.0568
55 0.05050.0505 0.0510.051 0.05320.0532 0.05820.0582 0.0570.057
66 0.05020.0502 0.05080.0508 0.05310.0531 0.0580.058 0.05690.0569
77 0.050.05 0.05090.0509 0.0530.053 0.0580.058 0.05710.0571
88 0.04960.0496 0.05060.0506 0.05280.0528 0.05750.0575 0.0570.057
99 0.04930.0493 0.05050.0505 0.05260.0526 0.05740.0574 0.05710.0571
9.59.5 0.04930.0493 0.05040.0504 0.05230.0523 0.05740.0574 0.05680.0568
도 2 및 표 2를 참고하면, 전반적으로 CaO의 함량이 증가하면 초기 이온 전도도가 높아지고, 시간이 경과함에 따른 산소 이온 전도도의 하락폭이 감소하는 경향을 보이는 것을 확인할 수 있다. 이를 통하여 CaO의 함량이 높아지면 격자 내부의 산소 공공이 증가하면서 산소 이온 전도도가 높아지고 결정구조 안정화에 도움을 주어 작동 시간에 따른 산소 이온 전도도의 저하를 방지하는 것으로 볼 수 있다.Referring to Figure 2 and Table 2, it can be seen that overall, as the CaO content increases, the initial ionic conductivity increases, and the decline in oxygen ion conductivity tends to decrease over time. Through this, it can be seen that as the content of CaO increases, the oxygen vacancies inside the lattice increase, thereby increasing oxygen ion conductivity and helping to stabilize the crystal structure, preventing a decrease in oxygen ion conductivity with operating time.
다만, CaO의 함량이 더욱 높은 E4보다 E3의 산소 이온 전도도가 소폭 높은 것을 확인할 수 있는데, 이는 CaO의 함량이 과도하게 높아짐에 따라 산소 공공들의 일부가 산소 이온 클러스터를 형성하여 오히려 산소 이온 전도도가 낮아지는 것으로 판단할 수 있다. However, it can be seen that the oxygen ion conductivity of E3 is slightly higher than that of E4, which has a higher CaO content. This is because as the CaO content increases excessively, some of the oxygen vacancies form oxygen ion clusters, resulting in lower oxygen ion conductivity. It can be judged as a loss.
환원 분위기에서 산소 이온 전도도 확인Check oxygen ion conductivity in reducing atmosphere
각 전해질 시편들의 환원 분위기에서 산소 이온 전도도를 측정하고 그 결과를 도 3 및 표 3으로 나타내었다. 구체적으로 산소 이온 전도도 측정방법은 대기중에서와 동일한 방법을 이용하였으며, 다만 850 ℃ 환원 분위기(H2 : H2O = 1:1(vol%))에서 100시간 동안 산소 이온 전도도를 측정하였다. The oxygen ion conductivity of each electrolyte specimen was measured in a reducing atmosphere, and the results are shown in Figure 3 and Table 3. Specifically, the same method as in air was used to measure oxygen ion conductivity, except that oxygen ion conductivity was measured for 100 hours in a reducing atmosphere at 850°C (H 2 : H 2 O = 1:1 (vol%)).
측정시간(h)Measurement time (h) 산소 이온 전도도(S/cm)Oxygen ion conductivity (S/cm)
E0E0 E1E1 E2E2 E3E3 E4E4
초기 Early 0.02840.0284 0.04550.0455 0.05260.0526 0.05770.0577 0.0590.059
1010 0.02750.0275 0.0440.044 0.05180.0518 0.05710.0571 0.5860.586
2020 0.02670.0267 0.04410.0441 0.05180.0518 0.05690.0569 0.05770.0577
3030 0.02580.0258 0.04550.0455 0.05070.0507 0.05570.0557 0.05680.0568
4040 0.02630.0263 0.04320.0432 0.04930.0493 0.05560.0556 0.05610.0561
5050 0.02510.0251 0.04450.0445 0.04850.0485 0.05590.0559 0.05620.0562
6060 0.02470.0247 0.04170.0417 0.04990.0499 0.05440.0544 0.0560.056
7070 0.02450.0245 0.03990.0399 0.04860.0486 0.05430.0543 0.0550.055
8080 0.0240.024 0.04170.0417 0.04970.0497 0.05460.0546 0.05660.0566
9090 0.0240.024 0.04170.0417 0.04870.0487 0.05410.0541 0.05670.0567
100100 0.02360.0236 0.04050.0405 0.0470.047 0.05410.0541 0.05460.0546
도 3 및 표 3을 참고하면, E3 및 E4의 전해질이 가장 높은 초기 산소 이온 전도를 나타내는 것을 확인할 수 있으며, 시간 경과에 따른 전도도 저하 또한 가장 낮은 것을 확인할 수 있다. Referring to Figure 3 and Table 3, it can be seen that the electrolytes of E3 and E4 exhibit the highest initial oxygen ion conduction, and the decrease in conductivity over time is also the lowest.
하기 표 4는 대기 및 환원 분위기에서 초기 산소 이온 전도도 측정 결과를 비교한 것이다. Table 4 below compares the initial oxygen ion conductivity measurement results in atmospheric and reducing atmospheres.
측정 환경measurement environment 산소 이온 전도도(S/cm)Oxygen ion conductivity (S/cm)
E0E0 E1E1 E2E2 E3E3 E4E4
대기중 Waiting 0.05220.0522 0.05230.0523 0.0520.052 0.05840.0584 0.05710.0571
환원 분위기atmosphere of giving back 0.02840.0284 0.04550.0455 0.05260.0526 0.05770.0577 0.0590.059
표 4를 참고하면, 칼슘 이온을 전혀 포함하지 않는 경우 실제 수전해 환경인 환원 분위기에서 산소 이온 전도도가 급격히 낮아지는 것을 확인할 수 있으며, 칼슘을 포함하는 경우 환원 분위기에서도 대기 중과 유사한 산소 이온 전도도를 나타내는 것을 확인할 수 있다. Referring to Table 4, it can be seen that when calcium ions are not included at all, the oxygen ion conductivity is rapidly lowered in a reducing atmosphere, which is an actual water electrolysis environment, and when calcium is included, oxygen ion conductivity is similar to that in the air even in a reducing atmosphere. You can check that.
아울러, 환원 분위기에서 장기 구동 안정성을 구체적으로 확인하기 위하여 초기 및 100시간이 경과한 후 산소 이온 전도도 값을 비교하여, 산소 이온 전도도 감소율을 계산한 뒤 그 결과를 하기 표 5로 나타내었다. In addition, in order to specifically confirm long-term operation stability in a reducing atmosphere, the oxygen ion conductivity values were compared initially and after 100 hours, the oxygen ion conductivity reduction rate was calculated, and the results are shown in Table 5 below.
측정시간Measurement time 산소 이온 전도도(S/cm)Oxygen ion conductivity (S/cm)
E0E0 E1E1 E2E2 E3E3 E4E4
초기Early 0.02840.0284 0.04550.0455 0.05260.0526 0.05770.0577 0.0590.059
100시간100 hours 0.02360.0236 0.04050.0405 0.0470.047 0.05410.0541 0.0546 0.0546
감소율(%)Decrease rate (%) 16.9016.90 10.9910.99 10.6410.64 6.246.24 7.457.45
표 5를 참고하면, 칼슘 산화물을 전혀 포함하지 않는 경우 초기 산소 이온 전도도도 낮지만, 시간 경과에 따른 전도도 저하가 가장 높은 것을 확인할 수 있으며, 반면 E3의 경우 100시간이 경과한 후에도 산소 이온 전도도 감소율이 7% 이하로 나타난 것을 확인할 수 있다. Referring to Table 5, it can be seen that when no calcium oxide is included, the initial oxygen ion conductivity is low, but the decrease in conductivity over time is the highest. On the other hand, in the case of E3, the rate of decrease in oxygen ion conductivity even after 100 hours has passed. It can be confirmed that this is less than 7%.

Claims (10)

  1. 이트륨 산화물 및 칼슘 산화물이 동시에 안정화제로 치환 고용되며,Yttrium oxide and calcium oxide are simultaneously substituted and dissolved as stabilizers.
    상기 화학식 1의 조성을 만족하는 고체산화물 전해셀용 지르코니아 전해질.A zirconia electrolyte for a solid oxide electrolytic cell that satisfies the composition of Chemical Formula 1.
    [화학식 1][Formula 1]
    (Y2O3)x(CaO)y(ZrO2)1-x-y (Y 2 O 3 ) x (CaO) y (ZrO 2 ) 1-xy
    (화학식 1에서, x는 0.06 내지 0.1이며, y는 0.002 내지 0.012이다.)(In Formula 1, x is 0.06 to 0.1, and y is 0.002 to 0.012.)
  2. 제 1항에 있어서,According to clause 1,
    상기 화학식 1에서 x는 0.065 내지 0.095인 것을 특징으로 하는 고체산화물 전해셀용 지르코니아 전해질. In Formula 1, x is a zirconia electrolyte for a solid oxide electrolytic cell, characterized in that 0.065 to 0.095.
  3. 제 1항에 있어서,According to clause 1,
    상기 화학식 1에서 y는 0.003 내지 0.01인 것을 특징으로 하는 고체산화물 전해셀용 지르코니아 전해질. In Formula 1, y is a zirconia electrolyte for a solid oxide electrolytic cell, characterized in that 0.003 to 0.01.
  4. 제 1항에 있어서,According to clause 1,
    상기 고체산화물 전해셀용 지르코니아 전해질은 면심 입방정 결정구조를 갖는 것을 특징으로 하는 지르코니아 고체산화물 전해셀용 지르코니아 전해질. The zirconia electrolyte for a solid oxide electrolytic cell is a zirconia electrolyte for a zirconia solid oxide electrolytic cell, characterized in that it has a face-centered cubic crystal structure.
  5. 제 1항에 있어서,According to clause 1,
    상기 고체산화물 전해셀용 지르코니아 전해질은 850 ℃, 대기 분위기에서 초기 산소 이온 전도도가 0.052 S/cm 이상인 것을 특징으로 하는 고체산화물 전해셀용 지르코니아 전해질. The zirconia electrolyte for a solid oxide electrolytic cell is characterized in that the initial oxygen ion conductivity is 0.052 S/cm or more at 850 ° C. in an air atmosphere.
  6. 제 1항에 있어서,According to clause 1,
    상기 고체산화물 전해셀용 지르코니아 전해질은 수소 : 수증기를 1:1의 부피비로 포함하는 850 ℃의 환원 분위기에서 초기 산소 이온 전도도가 0.053 S/cm 이상인 것을 특징으로 하는 고체산화물 전해셀용 지르코니아 전해질.The zirconia electrolyte for a solid oxide electrolytic cell is characterized in that the initial oxygen ion conductivity is 0.053 S/cm or more in a reducing atmosphere at 850 ° C. containing hydrogen: water vapor at a volume ratio of 1:1.
  7. 제 6항에 있어서,According to clause 6,
    상기 고체산화물 전해셀용 지르코니아 전해질은 850 ℃의 환원 분위기에서 100시간 경과한 후 산소 이온 전도도 감소율이 10% 이하인 것을 특징으로 하는 고체산화물 전해셀용 지르코니아 전해질. The zirconia electrolyte for a solid oxide electrolytic cell is characterized in that the oxygen ion conductivity reduction rate is 10% or less after 100 hours in a reducing atmosphere at 850 ° C.
  8. 하기 화학식 1의 조성을 만족하도록 이트륨 산화물, 칼슘 산화물 및 지르코늄 산화물을 혼합하여 복합분말을 제조하는 제 1단계; A first step of preparing a composite powder by mixing yttrium oxide, calcium oxide, and zirconium oxide to satisfy the composition of Formula 1 below;
    상기 복합분말을 성형하여 성형체를 제조하는 제 2단계; 및 A second step of manufacturing a molded body by molding the composite powder; and
    상기 성형체를 소결하는 제 3단계;를 포함하는 고체산화물 전해셀용 지르코니아 전해질 제조방법. A method for producing zirconia electrolyte for a solid oxide electrolytic cell comprising a third step of sintering the molded body.
    [화학식 1][Formula 1]
    (Y2O3)x(CaO)y(ZrO2)1-x-y (Y 2 O 3 ) x (CaO) y (ZrO 2 ) 1-xy
    (화학식 1에서, x는 0.06 내지 0.1이며, y는 0.002 내지 0.012이다.)(In Formula 1, x is 0.06 to 0.1, and y is 0.002 to 0.012.)
  9. 제 8항에 있어서,According to clause 8,
    상기 제 1단계는 습식 볼밀을 이용하는 것을 특징으로 하는 고체산화물 전해셀용 지르코니아 전해질 제조방법. The first step is a method of manufacturing a zirconia electrolyte for a solid oxide electrolytic cell, characterized in that using a wet ball mill.
  10. 제 8항에 있어서,According to clause 8,
    상기 소결은 1350 내지 1500 ℃에서 3 내지 10시간 동안 수행되는 것을 특징으로 하는 고체산화물 전해셀용 지르코니아 전해질 제조방법. A method for producing zirconia electrolyte for a solid oxide electrolytic cell, characterized in that the sintering is performed at 1350 to 1500 ° C. for 3 to 10 hours.
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