CN110021771B - Based on SnO2Preparation method of Schottky junction fuel cell of-SDC semiconductor-ion conductor - Google Patents

Abstract

The present invention belongs to a solid oxide fuel cellIn particular based on SnO₂The preparation method of the Schottky junction fuel cell of the-SDC semiconductor-ion conductor comprises the steps of SDC and SnO₂Grinding at different ratio, coating NCA L slurry on foamed nickel with thickness of 2mm, drying at 120 deg.C for 1 hr in drying oven to obtain Ni-NCA L electrode, and mixing Ni-NCA L layer and SDC-SnO₂The composite powder and the Ni-NCA L layer are sequentially put into a die, and a hydraulic press is used for applying 9MPa pressure to press the three-layer structure into a battery blank sheet, wherein the SDC and the SnO selected in the invention₂Two materials, low price, simple preparation method and the like. And mixing SDC ion conductor and SnO₂After the semiconductor is compounded, high ionic conductivity can be obtained at a lower temperature, which is the fundamental reason that the battery can obtain better battery performance output in a low-temperature region.

Description

Based on SnO2Preparation method of Schottky junction fuel cell of-SDC semiconductor-ion conductor

Technical Field

The invention belongs to the field of solid oxide fuel cells, and particularly relates to a SnO-based fuel cell₂A preparation method of the Schottky junction fuel cell of the SDC semiconductor-ion conductor.

Background

Solid Oxide Fuel Cells (SOFC) belong to the third generation of Fuel cells, and are all-Solid-state chemical power generation devices that directly convert chemical energy stored in Fuel and oxidant into electrical energy at medium and high temperatures with high efficiency and environmental friendliness. With high energy conversion efficiency (up to 50% to 80%), conventional fuel cells are made up of three components: electrolyte, cathode, anode, wherein the electrolyte is the core of the fuel cell, and its characteristics are crucial to determine the specific field of the fuel cell, and even determine the energy conversion efficiency at a specific temperature. From the development process of the electrolyte, since Yttrium Stabilized Zirconia (YSZ) was discovered and applied for the first time, the development of the electrolyte material has been dominant, since it has high ionic conductivity and good electrode matching property, and has good chemical stability under an oxygen-hydrogen atmosphere, and thus is regarded as the most successful electrolyte material. However, in order to use YSZ as an electrolyte, the SOFC needs an operating temperature as high as 1000 ℃ to obtain sufficiently high ionic conductivity, but the battery is likely to have high requirements for materials for battery matching, difficult to seal, and prone to electrode sintering, interfacial diffusion between the electrolyte and the electrode, and thermal expansion mismatch, thereby reducing the battery life. Currently, only a very small number of electrolyte materials can be operated at low temperatures (<600 ℃) with the required conductivity, and therefore development and development of new electrolyte materials is strongly demanded in order to operate SOFCs at low temperatures.

The development of the electrolyte material with high ionic conductivity at low temperature (500-800 ℃) is an effective way for realizing the low-temperature operation of the SOFC when the electrolyte material is applied to the field of fuel cells. The ionic conductivity of the composite two-phase or three-phase material can be greatly improved, and the activation energy can be effectively reduced. Recent studies have shown that semiconductor-ion conductor composite heterostructures have high ionic conductivity in medium and low temperature regions. YSZ/SrTiO reported by Garcia-Barriocanal et al₃The ionic conductivity of the heterostructure composed of the multilayer film is improved by 8 orders of magnitude relative to pure YSZ [ J.G.Barriocane, A.R.Calzada, M.Varea, Z.Sefrioui, E.Iborra, C. L eon, S.J.Pennyook, S.Santamaria.science,2008,321,676-680 ].]L in et al report Ce_0.8Gd_0.2O_2-–CoFe₂O₄The ionic conductivity of grain boundary in the composite material is obviously improved compared with single-phase material [ Y. L in, S.M.Fang, D.Su, K.S.Brinkman, F. L, Chen.Nature communications.6(2015)6824 ].]. It is thus seen that the fact that the semiconductor-ion conductor composite heterostructure has an enhancement effect on ion conduction is indissolvable. Although the semiconductor-ion conductor is differentThe ion conductivity of the composite material is greatly improved relative to that of a pure ion conductor, but few documents report that the composite material is used as an electrolyte membrane to assemble an SOFC (solid oxide Fuel cell), mainly because the open-circuit voltage and the power output of the cell are greatly reduced as long as the intermediate electrolyte layer has the electron conductivity according to the traditional electrochemical theory, so that the conventional cell structure needs to be correspondingly improved when the composite material is applied to a fuel cell, the Schottky fuel cell is a successful case for applying the composite material to the fuel cell, Zhu reports that the ion conductor material NSDC (samarium-doped cerium oxide-sodium carbonate composite material) and the semiconductor L CN (cobalt-lithium-doped NiO) are utilized to form the Ni/L CN-NSDC/Ag single-component fuel cell, wherein L CN is in a reducing atmosphere H₂The performance of the cell of this new structure is 2 times that of the conventional three-component fuel cell [ b.zhu, p.d. L und, r.raza, y.ma, & ' lttt translation = L "& ' ttt L/t & ' gtt. d.fan, m.afzal, j.patakangas, y.j.j.zhao, w.y.tan, q.a.huang, j.zhang, h.wang.advanced Energy Materials 5(2015)1401895.]。

Disclosure of Invention

The main objective of the present invention is to develop SDC-SnO with high ionic conductivity at medium and low temperature (500-₂A novel semiconductor-ion conductor composite material and its successful use as an ion transport layer to construct a Schottky fuel cell, aiming to achieve a cell exhibiting excellent performance output even at low temperatures.

SDC-SnO of the invention₂The preparation method of the semiconductor-ion conductor composite material comprises the following steps:

based on SnO₂The preparation method of the Schottky junction fuel cell of the-SDC semiconductor-ion conductor comprises the following steps:

1) synthesis of Sm-doped Ce as ion conductor material_0.8Sm_0.2O_2-Namely SDC;

2) mixing the prepared SDC and SnO₂Fully grinding according to different proportions to obtain different SnO₂Content of SDC/SnO₂A composite material; SDC/SnO₂SnO of composite material₂The mass content is 10-60%.

3) Adding 2g of NCA L powder into 5m L of terpineol according to the following weight ratio, grinding for 10min to fully and uniformly mix the powder and the terpineol to prepare NCA L slurry, coating the NCA L slurry on foamed nickel with the thickness of 2mm, and then drying for 1h at 120 ℃ in a drying oven to prepare a Ni-NCA L electrode;

4) 0.35g of SDC-SnO is weighed₂The semiconductor-ion conductor composite material is prepared by mixing Ni-NCA L layer and SDC-SnO₂And sequentially putting the composite powder and the Ni-NCA L layer into a die, and applying 9MPa pressure by using a hydraulic press to press the three-layer structure into a battery blank sheet.

The SDC synthesis method comprises the following steps:

a) ce in the molecular formula of SDC³⁺:Sm³⁺The molar ratio of 4:1, and the corresponding mass of Ce (NO) is weighed in equal proportion₃)₃·6H₂O and Sm (NO)₃)₃·6H₂Dissolving the mixture into a proper amount of deionized water, and uniformly stirring to prepare a metal ion mixed solution of 1 mol/L;

b) according to the bicarbonate ion: the metal ion molar ratio is 3: 1 weighing appropriate amount of NH₄HCO₃The powder was dissolved in deionized water to make 1 mol/L NH₄HCO₃A solution;

c) NH is dripped by a rubber head dropper₄HCO₃Slowly dripping the solution into the metal ion mixed solution, continuously stirring the solution to form a white precipitate, filtering the precipitate, washing the precipitate with deionized water for multiple times, and then putting the white precipitate into a drying oven to dry for 12 hours at 120 ℃;

d) finally the dried product was placed in a muffle furnace at 800 ℃ and sintered for 4h to obtain SDC powder.

The SnO base provided by the invention₂The preparation method of the Schottky junction fuel cell of the SDC semiconductor-ion conductor has the technical advantages that:

(1) SDC and SnO selected in the invention₂The two materials have the advantages of low price, simple preparation method and the like. And mixing SDC ion conductor and SnO₂After the semiconductor is compounded, the product can be obtained at a lower temperatureIonic conductivity, which is the fundamental reason why such a battery can achieve better battery performance output in a low temperature region.

(2) Schottky junction fuel cells are by far the simplest fuel cell technology, with low cost materials and simple manufacturing processes, requiring only one composite material made of (P or N) semiconductor-ion materials. Schottky junction fuel cells are also a new and advanced technology where physical and electrochemical processes are combined in a synergistic manner to achieve superior device performance.

(3) The cells showed good power output when tested at 550 c and 500 c temperatures. The cell has higher power output in a medium-low temperature region, and successfully reduces the operation temperature of the SOFC to below 600 ℃.

(4) Furthermore, although schottky junctions are particularly useful herein in the context of fuel cells, other potential energy applications are also contemplated. The invention and the disclosure of the scientific principle provide a new way for the fuel cell and the innovative energy technology, and accelerate the commercialization process of the fuel cell.

Drawings

Figure 1 shows the results of performance tests at 550 c for fuel cells with different SDC contents for the examples;

FIG. 2 shows examples SDC-SnO₂The battery prepared according to the optimal proportion has the performance test result at 500 ℃;

fig. 3 is an SEM cross-sectional view of a schottky fuel cell according to an example;

FIG. 4 is a graph of the rectification resulting from applying a sweep voltage across the Schottky junction fuel cell of the example.

Detailed Description

The specific technical scheme of the invention is described by combining the embodiment.

(1) Synthesis of Sm-doped Ce as ion conductor material_0.8Sm_0.2O_2-I.e. SDC, the method used is coprecipitation:

a. according to the stoichiometric ratio of each element (Ce and Sm) in the molecular formula of SDC, namely Ce³⁺:Sm³⁺Weighing Ce (NO) with corresponding mass according to 4:1 equal proportion₃)₃·6H₂O andSm(NO₃)₃·6H₂dissolving the two samples into a proper amount of deionized water, and fully stirring to prepare a uniform mixed solution with the concentration of 1 mol/L;

b. according to the bicarbonate ion: the metal ions are 3: 1 weighing appropriate amount of NH₄HCO₃The powder is dissolved in deionized water to prepare 1 mol/L NH₄HCO₃A solution;

c. NH is dripped by a rubber head dropper₄HCO₃The solution was slowly added dropwise to the metal ion mixture solution synthesized in step 2 (with constant stirring) to form a white precipitate. After fully stirring, filtering the precipitate, washing the precipitate with deionized water for multiple times, and then putting the white precipitate into a drying oven to dry for 12 hours at 120 ℃;

d. finally the dried product was placed in a muffle furnace at 800 ℃ and sintered for 4h to obtain SDC powder.

SnO₂Purchased from chemical agents, ltd, national drug group;

(2) mixing the prepared SDC and SnO₂Fully grinding according to different proportions to obtain different SnO₂SDC-SnO with content (10%, 20%, 30%, 40%, 50%, 60%)₂A semiconductor-ion conductor composite.

(3) The manufacturing process of the fuel cell comprises the following steps:

a, preparing a battery:

(a) adding 2g of NCA L powder into 5m L of terpineol, grinding for 10min to fully and uniformly mix the powder and the terpineol to prepare NCA L slurry, coating the prepared slurry on foamed nickel with the thickness of 2mm, and then drying for 1h at 120 ℃ in a drying oven to finish the preparation of a Ni-NCA L electrode;

Ni_0.8Co_0.15Al_0.05LiO(NCA L) was purchased from high tech company, Otsunobo,

(b) weighing 0.35g of SDC-SnO₂The semiconductor-ion conductor composite material is prepared by mixing Ni-NCA L layer and SDC-SnO₂And sequentially putting the composite powder and the Ni-NCA L layer into a die, and applying 9MPa pressure by using a hydraulic press to press the three-layer structure into a battery blank sheet.

b, testing the battery:

the pressed green sheets were placed in a test furnace and pre-sintered at 550 ℃ for 35 min. After sintering, H is introduced at the test temperature of 550 DEG C₂The fuel is used as fuel, air is used as oxidant, the flow rate of hydrogen is controlled to be 120ml/min, and a cell performance test is carried out, so that the cell shows good power output and higher open-circuit voltage; varying SDC/SnO₂Obtaining composite materials with different SnO2 contents, assembling the composite materials into a battery, and testing the performance of the battery. Obtaining optimum SnO₂And (4) content.

FIG. 1 shows SDC-SnO with different SDC contents for examples₂The composite material forms a fuel cell, and the performance test result is carried out at 550 ℃. As shown in fig. 1, the cell performance began to increase gradually with increasing SnO2 content and then decreased. When the content of SnO2 is 20%, the battery performance reaches the maximum value of 1059mW/cm². With SnO₂Further increase in the content of (b), increase in the electron concentration inside the battery, SnO₂A continuous electron conduction path is formed and a short circuit occurs to some extent, and thus, the battery performance is degraded.

And reducing the test temperature to 500 ℃, and testing the performance output of the battery. And (5) verifying the low-temperature working performance of the battery.

FIG. 2 shows examples SDC-SnO₂The battery prepared in the optimal proportion still has good performance at low temperature (500 ℃) as a result of performance test at 500 ℃, and the performance can reach 500mW/cm²。

For example, figure 3 shows that the catalyst is based on SDC-SnO₂SEM cross-section of Schottky fuel cell assembled from semiconductor-ion conductor composite material, which has a very obvious three-layer structure, with symmetrical NCA L-coated nickel foam electrodes on both sides, 200 μm thick electrode layers, and SDC-SnO in the middle₂And the thickness of the composite material functional layer is 500 mu m. FIG. 4 is a schematic diagram of SnO₂-rectification diagram obtained by applying a scanning voltage across the Schottky junction fuel cell constructed from the SDC semiconductor-ionic conductor.

Claims (3)

1. Based on SnO₂Production of Schottky junction fuel cell of-SDC semiconductor-ion conductorThe preparation method is characterized by comprising the following steps:

1) synthesis of Sm-doped Ce as ion conductor material_0.8Sm_0.2O_2-Namely SDC;

2) mixing the prepared SDC and SnO₂Fully grinding according to different weight proportions to obtain different SnO₂Content of SDC/SnO₂A composite material;

3) adding 2g of NCA L powder into 5m L of terpineol according to the following proportion, grinding for 10min to fully and uniformly mix the powder and the terpineol to prepare NCA L slurry, coating the NCA L slurry on foamed nickel with the thickness of 2mm, and then drying for 1h at 120 ℃ in a drying box to prepare a Ni-NCA L electrode;

4) 0.35g of SDC-SnO is weighed₂The semiconductor-ion conductor composite material comprises Ni-NCA L electrode, SDC-SnO₂And sequentially putting the composite powder and the Ni-NCA L electrode into a die, and pressing the three-layer structure into a battery blank sheet by applying 9MPa pressure by using a hydraulic press.

2. A SnO based according to claim 1₂-method for preparing a SDC semiconductor-ion conductor schottky junction fuel cell, characterized in that SDC is synthesized comprising the steps of:

a) ce in the molecular formula of SDC³⁺:Sm³⁺The molar ratio of 4:1, and the corresponding mass of Ce (NO) is weighed in equal proportion₃)₃·6H₂O and Sm (NO)₃)₃·6H₂Dissolving the mixture into a proper amount of deionized water, and uniformly stirring to prepare a metal ion mixed solution of 1 mol/L;

b) according to the bicarbonate ion: the metal ion molar ratio is 3: 1 weighing appropriate amount of NH₄HCO₃The powder was dissolved in deionized water to make 1 mol/L NH₄HCO₃A solution;

c) NH is dripped by a rubber head dropper₄HCO₃Slowly dripping the solution into the metal ion mixed solution, continuously stirring the solution to form a white precipitate, filtering the precipitate, washing the precipitate with deionized water for multiple times, and then putting the white precipitate into a drying oven to dry for 12 hours at 120 ℃;

d) finally the dried product was placed in a muffle furnace at 800 ℃ and sintered for 4h to obtain SDC powder.

3. A SnO based according to claim 1 or 2₂The preparation method of the Schottky junction fuel cell of the-SDC semiconductor-ion conductor is characterized in that the SDC/SnO in the step (2)₂SnO in composite materials₂The mass content is 10-60%.

Images