A solid oxide battery electrode material and its preparation method and application

Abstract

The present invention discloses an electrode material for a solid oxide battery and its preparation method and application, belonging to the field of fuel cells and electrolytic cells. The electrode material is composed of BaZrO3 phase and La 1‑x Ba x CoO3 phase composite, 0≤x<0.6, BaZrO3 and La 1‑x Ba x The molar ratio of CoO3 is 1:5 to 1:2, wherein the particle size of BaZrO3 is 50 to 500 nanometers, and the particle size of La 1‑x Ba x The CoO3 particle size is 2 to 50 nanometers. The electrode is prepared by a reduction-oxidation precipitation method and exhibits excellent electrochemical performance when used as an oxygen electrode in solid oxide electrolyzers and fuel cells.

Description

Technical Field

[0001] The present invention belongs to the field of fuel cells and electrolytic cells, and in particular relates to an electrode material for a solid oxide battery, a preparation method thereof, and an application thereof. Background Art

[0002] Solid oxide cell (SOC) is an all-solid-state battery structure that can convert the chemical energy of fuel into electrical energy at high temperature, with a power generation efficiency of up to 60% and a combined heat and power efficiency of up to 90%. At the same time, it can also electrolyze water vapor into hydrogen and oxygen with an electrical efficiency of up to 100%, and is considered to be the most efficient electrolysis hydrogen production technology.

[0003] The membrane electrode (MEA) is the core component of a solid oxide battery (SOB). It has a "sandwich" structure, with a dense electrolyte layer in the middle and porous hydrogen and oxygen electrodes on either side. As operating temperature decreases, the sluggish oxygen reduction reaction (ORR) or oxygen evolution reaction (OER) kinetics on the oxygen electrode, compared to the rapid hydrogen oxidation or water dissociation processes on the hydrogen electrode, become the primary factor limiting MEA performance. The ORR or OER involves diffusion of oxygen molecules within the electrode pores, adsorption and desorption of oxygen molecules, surface diffusion of oxygen intermediates, charge transfer reactions, and oxygen ion-electron transfer. These reactions require the electrode material to possess high electronic conductivity, high oxygen ion conductivity, excellent catalytic oxygen surface reactivity, and a suitable pore structure. However, electrode materials with a single phase composition or structure struggle to meet these requirements, making it difficult to simultaneously achieve high performance output and stable operation. Currently, researchers are using methods such as impregnation to prepare nanoelectrodes to increase active sites and improve electrode performance. However, under operating conditions, the particles of electrodes prepared by this method are particularly prone to growth, resulting in loss of active sites and reduced battery performance. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides an electrode material for a solid oxide battery, a preparation method and application thereof, and prepares a nanocomposite electrode by a reduction-oxidation precipitation method, which exhibits excellent electrochemical properties.

[0005] The present invention provides an electrode material for a solid oxide battery, wherein the electrode material is composed of BaZrO3 phase and La 1- x Ba x CoO3 phase composition, 0≤x<0.6, among which BaZrO3 and La 1-x Ba x The molar ratio of CoO3 is 1:2 to 1:0.5, the particle size of BaZrO3 is 50 to 500 nanometers, and the La 1-x Ba x The particle size of CoO3 is 2 to 50 nanometers.

[0006] Furthermore, the particle size of BaZrO3 in the electrode material is 50 to 100 nanometers, and the La 1-x Ba x The particle size of CoO3 is 2 to 20 nanometers.

[0007] Furthermore, BaZrO3 and La in the electrode material 1-x Ba x The molar ratio of CoO3 is 1:2 to 1:1.

[0008] The present invention also provides a method for preparing an electrode material for a solid oxide battery, comprising the following steps:

[0009] (1) adding barium salt, lanthanum salt, zirconium salt, and cobalt salt according to a stoichiometric ratio (i.e., the amount of raw materials added is based on the desired electrode composition, and those skilled in the art can determine the amount of addition based on demand) to deionized water, and the concentration of metal ions in the solution is 0.5 to 2 M;

[0010] (2) Prepare a precipitant solution with a concentration of 0.2 to 2 M, with a molar ratio of precipitant to metal ion of 3:1 to 6:1.

[0011] (3) adding the metal ion mixture obtained in step (1) dropwise to the precipitant solution, allowing to stand, filtering, and drying to obtain an electrode precursor;

[0012] (4) The electrode precursor is calcined in an inert atmosphere for 1 to 5 hours at a calcination temperature of 700 to 1000°C, and then the atmosphere is switched to an oxidizing atmosphere at the same temperature and calcined for 1 to 5 hours, and then cooled to room temperature to obtain an electrode material.

[0013] Furthermore, the barium salt includes Ba(NO3)2, the lanthanum salt includes La(NO3)3·5H2O, the zirconium salt includes Zr(NO3)4·5H2O, and the cobalt salt includes Co(NO3)2·6H2O.

[0014] Furthermore, the inert atmosphere is an N2, Ar or He atmosphere with a purity of 99.99% or more; the oxidizing atmosphere is air or an oxygen atmosphere with a purity of 99.99% or more.

[0015] Furthermore, the calcination temperature in an inert atmosphere is 750-900°C.

[0016] Furthermore, the precipitant includes ammonium bicarbonate, urea or ammonia water.

[0017] Furthermore, the standing time is 1 to 50 hours, the drying temperature is 80 to 120° C., and the drying time is 10 to 30 hours.

[0018] The present invention also provides the application of the electrode material or the electrode material prepared by the preparation method. The electrode can be used as the anode of a solid oxide electrolytic cell or as the cathode of a solid oxide fuel cell, and the operating temperature of the battery can be reduced to 400-600°C.

[0019] The advantages of the present invention are:

[0020] (1) BaZrO3-La prepared by the present invention 1-x Ba x The CoO3 composite electrode has excellent activity and stability. The electrode material of the present invention is a nano-BaZrO3-La composite electrode formed by in-situ self-assembly of metal ions during the reduction-oxidation precipitation process of the corresponding La, Ba, Zr, and Co oxides. 1-x Ba x The CoO3 composite electrode system makes the entire system more thermodynamically stable. In addition, BaZrO3 and La 1-x Ba x The in-situ precipitation and riveting of CoO3 nanoparticles limit the particle size growth of nanoparticles under high temperature and electric field, thus improving the stability of the electrode. In addition, in this composite electrode, the BaZrO3 phase is responsible for proton ion conduction, and the La 1-x Ba x The CoO3 phase enhances the surface catalytic reaction, and the two-phase nanocomposite increases the active sites, thereby improving the electrochemical performance of the electrode.

[0021] (2) The present invention utilizes a reduction-oxidation precipitation method to prepare high-quality nanocomposite electrodes. The electrode formation mechanism of the present invention is as follows: by reducing the oxide precursor in an inert atmosphere of N2, Ar or He at high temperature and low oxygen partial pressure, an oxide with partial oxygen deficiency is formed. The presence of oxygen vacancies promotes the diffusion of La, Ba, Zr, and Co elements between different oxides, thereby constructing a transition system of La, Ba, Zr, and Co oxides with high surface activity. After this transition system is treated in an air or oxygen atmosphere with high oxygen partial pressure, thermodynamically stable BaZrO3 and La 1-x Ba x CoO3 two-phase complex.

[0022] (3) The electrode material preparation method of the present invention is simple. The precursor is prepared by a simple and easily scalable co-precipitation method, and the reduction-oxidation process is also easily scalable. This method has the prospect of large-scale production. DETAILED DESCRIPTION

[0023] The present invention will be further described below by way of examples.

[0024] Comparative Example 1

[0025] BaZrO3-La 0.7 Ba 0.3 CoO3 (molar ratio of 1:1) nanocomposite electrode material and its preparation. 0.035 mol Ba(NO3)2, 0.065 mol La(NO3)3·5H2O, 0.05 mol Zr(NO3)4·5H2O, and 0.05 mol Co(NO3)2·6H2O were weighed and added to 200 mL of deionized water to a 1 M metal ion concentration. A 2 M ammonium bicarbonate solution was prepared with a 3:1 molar ratio of ammonium bicarbonate to metal ions. The metal ion mixture was added dropwise to the precipitant solution, allowed to stand for 10 hours, filtered, and the precipitate was dried in an oven at 80°C for 30 hours to obtain an electrode precursor. The precursor was then calcined in a muffle furnace in a static air atmosphere at 750°C for 5 hours to obtain the electrode material powder. With the above electrode materials as anode, Ni-BZY (mass ratio 1:1) as cathode, and BZY as electrolyte, the electrolysis current density of water reached -0.26Acm at 600℃ and 1.3V. -2 .

[0026] Comparative Example 2

[0027] BaZrO3-La 0.7 Ba 0.3 CoO3 (molar ratio of 1:1) nanocomposite electrode material and its preparation. 0.035 mol Ba(NO3)2, 0.065 mol La(NO3)3·5H2O, 0.05 mol Zr(NO3)4·5H2O, and 0.05 mol Co(NO3)2·6H2O were weighed and added to 200 mL of deionized water to a 1 M metal ion concentration. A 2 M ammonium bicarbonate solution was prepared with a 3:1 molar ratio of ammonium bicarbonate to metal ions. The metal ion mixture was added dropwise to the precipitant solution, then allowed to stand for 10 hours. After filtration, the precipitate was oven-dried at 80°C for 30 hours to obtain an electrode precursor. The precursor was then calcined at 750°C in a muffle furnace in a 99.99% N2 atmosphere (at a flow rate of 100 mL / min) for 5 hours to obtain the electrode material powder. With the above electrode materials as anode, Ni-BZY (mass ratio 1:1) as cathode, and BZY as electrolyte, the electrolysis current density of water reached -0.32Acm at 600℃ and 1.3V. -2 .

[0028] Comparative Example 3

[0029] BaZrO3-La 0.7 Ba 0.3CoO3 (molar ratio of 1:1) nanocomposite electrode material and its preparation. Weigh 0.035molBa(NO3)2, 0.065molLa(NO3)3·5H2O, 0.05molZr(NO3)4·5H2O, 0.05molCo(NO3)2·6H2O and add them to 200mL deionized water with a metal ion concentration of 1M; then add 0.4mol ammonium citrate to the mixed solution and complex at 70℃ for 5h. Gradually evaporate the water to form a sol, transfer it to an evaporating dish and heat it until it burns to form an electrode precursor. The electrode precursor is calcined at 1000℃ in a 99.99% N2 atmosphere (flow rate of 100mL / min) for 5h, then switch the atmosphere to an air atmosphere (flow rate of 100mL / min) at the same temperature and calcine for 5h, then cool to room temperature to obtain electrode material powder. The particle size of BaZrO3 in the electrode powder is 100-200nm, and La 0.7 Ba 0.3 The particle size of CoO3 is 200 to 500 nanometers. Using the above electrode material as the anode, Ni-BZY (mass ratio 1:1) as the cathode, and BZY as the electrolyte, the electrolysis current density of water reached -0.72Acm at 600℃ and 1.3V. -2 .

[0030] Comparative Example 4

[0031] BaZrO3-La 0.6 Ba 0.4 CoO3 (molar ratio of 1:3) nanocomposite electrode material and its preparation. 0.045 mol Ba(NO3)2, 0.055 mol La(NO3)3·5H2O, 0.075 mol Zr(NO3)4·5H2O, and 0.025 mol Co(NO3)2·6H2O were weighed and added to 400 mL of deionized water to obtain a metal ion concentration of 0.5 M. A 2 M ammonium bicarbonate solution was prepared with a molar ratio of ammonium bicarbonate to metal ions of 6:1. The metal ion mixture was added dropwise to the precipitant solution, and then allowed to stand for 10 h. After filtering, the precipitate was dried in an oven for 30 h at a drying temperature of 80°C to obtain an electrode precursor. The electrode precursor was calcined at 800°C in a 99.99% N2 atmosphere (flow rate of 100 mL / min) for 5 h, and then the atmosphere was switched to an air atmosphere (flow rate of 100 mL / min) at the same temperature and calcined for 5 h, and then cooled to room temperature to obtain an electrode material powder. The particle size of BaZrO3 in the electrode powder is 120-200 nanometers, and La 0.6 Ba 0.4The particle size of CoO3 is 80 to 100 nanometers. Using the above electrode material as the anode, Ni-BZY (mass ratio 1:1) as the cathode, and BZY as the electrolyte, the electrolysis current density of water reached -0.73Acm at 600℃ and 1.3V. -2 .

[0032] Example 1

[0033] BaZrO3-La 0.7 Ba 0.3 CoO3 (molar ratio of 1:1) nanocomposite electrode material and its preparation. 0.035 mol Ba(NO3)2, 0.065 mol La(NO3)3·5H2O, 0.05 mol Zr(NO3)4·5H2O, and 0.05 mol Co(NO3)2·6H2O were weighed and added to 200 mL of deionized water to a 1 M metal ion concentration. A 2 M ammonium bicarbonate solution was prepared with a 3:1 molar ratio of ammonium bicarbonate to metal ions. The metal ion mixture was added dropwise to the precipitant solution, allowed to stand for 10 h, filtered, and the precipitate was dried in an oven at 80°C for 30 h to obtain an electrode precursor. The electrode precursor was calcined at 1000°C for 5 h in a 99.99% N2 atmosphere (flow rate of 100 mL / min). The atmosphere was then switched to air (flow rate of 100 mL / min) and calcined for 5 h at the same temperature. The mixture was then cooled to room temperature to obtain an electrode material powder. The particle size of BaZrO3 in the electrode powder is 80 to 150 nanometers, and La 0.7 Ba 0.3 The particle size of CoO3 is 30 to 50 nanometers. Using the above electrode material as the anode, Ni-BZY (mass ratio 1:1) as the cathode, and BZY as the electrolyte, the electrolysis current density of water reached -1.02Acm at 600℃ and 1.3V. -2 .

[0034] Example 2

[0035] BaZrO3-La 0.7 Ba 0.3CoO3 (molar ratio of 1:1) nanocomposite electrode material and its preparation. 0.035 mol Ba(NO3)2, 0.065 mol La(NO3)3·5H2O, 0.05 mol Zr(NO3)4·5H2O, and 0.05 mol Co(NO3)2·6H2O were weighed and added to 200 mL of deionized water to a 1 M metal ion concentration. A 2 M ammonium bicarbonate solution was prepared with a 3:1 molar ratio of ammonium bicarbonate to metal ions. The metal ion mixture was added dropwise to the precipitant solution, allowed to stand for 10 h, filtered, and the precipitate was dried in an oven at 80°C for 30 h to obtain an electrode precursor. The electrode precursor was calcined at 800°C for 5 h in a 99.99% N2 atmosphere (flow rate of 100 mL / min). The atmosphere was then switched to air (flow rate of 100 mL / min) and calcined for 5 h at the same temperature. The mixture was then cooled to room temperature to obtain an electrode material powder. The particle size of BaZrO3 in the electrode powder is 50 to 80 nanometers, and the particle size of La 0.7 Ba 0.3 The particle size of CoO3 is 10 to 20 nanometers. Using the above electrode material as the anode, Ni-BZY (mass ratio 1:1) as the cathode, and BZY as the electrolyte, the electrolysis current density of water reached -1.38Acm at 600℃ and 1.3V. -2 , reaching 1.21Acm in fuel cell mode -2 .

[0036] Example 3

[0037] BaZrO3-La 0.7 Ba 0.3 CoO3 (molar ratio of 1:1) nanocomposite electrode material and its preparation. Weigh 0.035 mol Ba(NO3)2, 0.065 mol La(NO3)3·5H2O, 0.05 mol Zr(NO3)4·5H2O, and 0.05 mol Co(NO3)2·6H2O and add them to 200 mL of deionized water to obtain a metal ion concentration of 1 M; prepare a 2 M ammonium bicarbonate solution with a molar ratio of ammonium bicarbonate to metal ions of 3:1; add the metal ion mixture dropwise to the precipitant solution, then let it stand for 10 hours, filter and dry the precipitate in an oven for 30 hours at a drying temperature of 80°C to obtain an electrode precursor; calcine the electrode precursor in a 99.99% N2 atmosphere (flow rate of 100 mL / min) at 1000°C for 5 hours, then switch the atmosphere to a 99.999% oxygen atmosphere (flow rate of 100 mL / min) at the same temperature and calcine for 5 hours, then cool to room temperature to obtain an electrode material powder. The particle size of BaZrO3 in the electrode powder is 50 to 80 nanometers, and the particle size of La 0.7 Ba 0.3The particle size of CoO3 is 10 to 20 nanometers. Using the above electrode material as the anode, Ni-BZY (mass ratio 1:1) as the cathode, and BZY as the electrolyte, the electrolysis current density of water reached -1.38Acm at 600℃ and 1.3V. -2 .

[0038] The above embodiments and comparative examples show that the electrodes prepared by the present invention have excellent electrochemical properties and significant technical advantages by comparing the precursor preparation method, whether the reduction-oxidation precipitation treatment is added, and the changes in key parameters of the electrode preparation process.

Claims

1. An electrode material for a solid oxide battery, characterized in that: The electrode material is composed of BaZrO3 phase and La 1- x Ba x CoO3 phase composition, 0≤x<0.6, among which BaZrO3 and La 1-x Ba x The molar ratio of CoO3 is 1:2 to 1:0.5, the particle size of BaZrO3 is 50 to 500 nanometers, and the La 1-x Ba x The particle size of CoO3 is 2 to 50 nanometers; The preparation method of the electrode material comprises the following steps: (1) adding barium salt, lanthanum salt, zirconium salt, and cobalt salt to deionized water according to a stoichiometric ratio, so that the concentration of metal ions in the solution is 0.5 to 2 M; (2) preparing a precipitant solution with a concentration of 0.2 to 2 M, and a molar ratio of precipitant to metal ion of 3:1 to 6:1; (3) adding the metal ion mixture obtained in step (1) dropwise to the precipitant solution, allowing to stand, filtering, and drying to obtain an electrode precursor; (4) calcining the electrode precursor in an inert atmosphere for 1 to 5 hours at a calcination temperature of 700 to 1000° C., then switching the atmosphere to an oxidizing atmosphere at the same temperature and calcining for 1 to 5 hours, and then cooling to room temperature to obtain an electrode material; The calcination temperature in an inert atmosphere is 750-900°C.

2. The electrode material for a solid oxide battery according to claim 1, characterized in that: The particle size of BaZrO3 in the electrode material is 50 to 100 nanometers, and La 1-x Ba x The particle size of CoO3 is 2 to 20 nanometers.

3. The electrode material for a solid oxide battery according to claim 1, wherein: BaZrO3 and La in the electrode material 1-x Ba x The molar ratio of CoO3 is 1:2 to 1:

1.

4. The electrode material for a solid oxide battery according to claim 1, wherein: The inert atmosphere is an N2, Ar or He atmosphere with a purity of more than 99.99%; the oxidizing atmosphere is air or an oxygen atmosphere with a purity of more than 99.99%.

5. The electrode material for a solid oxide battery according to claim 1, characterized in that: The precipitant includes ammonium bicarbonate, urea or ammonia water.

6. The electrode material for a solid oxide battery according to claim 4, characterized in that: The standing time is 1 to 50 hours, and the drying temperature is 80 to 120°C.

7. Use of the electrode material for a solid oxide battery according to any one of claims 1 to 6, characterized in that: The electrode serves as an anode of a solid oxide electrolysis cell or as a cathode of a solid oxide fuel cell.