HYBRID LSCFP-BASED ELECTRODE AND MANUFACTURING METHOD THEREOF

Abstract

A hybrid LSCFP-based electrode includes an electrode having porous pores formed between a plurality of nanofibers and pulverized nanofibers positioned within the porous pores, to solve the contact problem at a solid electrolyte interface, thereby providing excellent characteristics of electrolytic performance and stability at high temperatures, and providing a method for manufacturing a hybrid LSCFP-based electrode by a simple method.

Claims

1. A hybrid LSCFP-based electrode, comprising: an electrode having porous pores defined between a plurality of nanofibers; and pulverized nanofibers positioned within the porous pores.

2. The hybrid LSCFP-based electrode of claim 1, wherein the plurality of nanofibers have nanofibers represented by chemical formula 1:
La.sub.1-xSr.sub.xCo.sub.1-y-zFe.sub.yPd.sub.zO.sub.3-[Chemical formula 1] wherein the x is a value including 0.3<x<0.5, the y is a value including 0.7<y<0.9, the z is a value including 0<z0.05, and the is a value including 0<3.

3. The hybrid LSCFP-based electrode of claim 1, wherein a length of the pulverized nanofibers ranges from 500 nm to 1 m.

4. The hybrid LSCFP-based electrode of claim 1, wherein a mass ratio of the plurality of nanofibers and the pulverized nanofibers ranges from 7:3 to 3:7.

5. The hybrid LSCFP-based electrode of claim 1, wherein the hybrid LSCFP-based electrode includes nano metal particles containing cobalt (Co) positioned on at least one surface of the nanofibers.

6. A method for manufacturing a hybrid LSCFP-based electrode, the method comprising: manufacturing a nanofiber material by calcining nanofibers; manufacturing a pulverized nanofiber material by pulverizing a portion of the nanofiber material; manufacturing a mixture by mixing the nanofiber material and the pulverized nanofiber material; and manufacturing a nanofiber electrode by applying and sintering the mixture.

7. The method of claim 6, wherein the nanofibers comprise at least one selected from a group consisting of lanthanum (La), strontium (Sr), cobalt (Co), iron (Fe), and palladium (Pd).

8. The method of claim 6, wherein the manufacturing the pulverized nanofiber material comprises using at least one of mortar or ball milling.

9. The method of claim 6, wherein a mass ratio of the nanofiber material and the pulverized nanofiber material in the mixture varies between 7:3 and 3:7.

10. The method of claim 6, wherein the manufacturing the nanofiber material includes calcining nanofibers at temperatures between 900 C. and 1100 C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0034] FIG. 1 is a flow chart showing steps of a method for manufacturing a hybrid LSCFP-based electrode according to an example of the disclosure;

[0035] FIG. 2 is a schematic diagram showing a process for manufacturing nanofibers for manufacturing an LSCFP-based electrode;

[0036] FIG. 3 is a schematic diagram showing a process for manufacturing a hybrid LSCFP-based electrode according to an example of the disclosure;

[0037] FIG. 4 is a graph showing an XRD pattern measured after calcining LSCFP nanofibers in air at 1000 C. for 2 hours;

[0038] FIG. 5 is a graph showing an XRD pattern measured after heat-treating LSCFP nanofibers in a hydrogen atmosphere at 700 C. for 2 hours;

[0039] FIGS. 6A, 6B, 6C, 6D, 6E, 6F, 6G, 6H, and 6I are each a photograph of the surface of LSCFP nanofibers after calcination in a hydrogen atmosphere;

[0040] FIG. 7 is a graph of XRD patterns of LSCFP nanofibers after calcination at 700 C. for 2 hours in hydrogen and CO2 atmospheres, respectively;

[0041] FIGS. 8A, 8B, and 8C are each a photograph of the surface of LSCFP nanofibers after continuous heat treatment in hydrogen and CO2 atmospheres;

[0042] FIG. 9 is photographs of the microstructure of an electrode (F-LSCFP) manufactured with 100% nanofibers and a hybrid LSCFP-based electrode (H-LSCFP) according to an example of the disclosure;

[0043] FIGS. 10A, 10B, and 10C are each a graph comparing the electrode resistances of half-cells using F-LSCFP and H-LSCFP in LSGM electrolyte in a 100% CO.sub.2 atmosphere;

[0044] FIGS. 11A, 11B, and 11C are each a graph measuring the performance of a unit cell applied with F-LSCFP and H-LSCFP in a CO2 electrolysis cell mode;

[0045] FIGS. 12A, 12B, and 12C are each a graph measuring the long-term stability evaluation of a unit cell applied with H-LSCFP in CO2 electrolysis cell mode; and

[0046] FIGS. 13A, 13B, 13C, and 13D are each a photograph of the long-term stability evaluation of a unit cell applied with H-LSCFP in a CO2 electrolysis cell mode followed by SEM analysis.

DETAILED DESCRIPTION

[0047] Hereinafter, the disclosure will be described with reference to the accompanying drawings. However, the disclosure may be implemented in various different forms and, therefore, is not limited to the examples described herein. In order to clearly explain the disclosure in the drawings, portions unrelated to the description are omitted, and similar portions are given similar reference numerals throughout the specification.

[0048] Throughout the specification, when a portion is said to be connected (linked, contacted, combined) with another portion, this includes not only a case of being directly connected but also a case of being indirectly connected with another member in between. In addition, when a portion is said to include a certain component, this does not mean that other components are excluded, but that other components may be added, unless specifically stated to the contrary.

[0049] The terms used herein are merely used to describe specific examples and are not intended to limit the disclosure. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, it should be understood terms such as include or have are to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not to exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0050] Hereinafter, examples of the disclosure will be described in detail with reference to the accompanying drawings.

[0051] Conventional nanofiber-based electrodes have had problems in practical applications due to insufficient interfacial contact with the solid electrolyte surface.

[0052] In order to solve this problem, the disclosure provides a hybrid LSCFP-based electrode with improved interfacial contact with the solid electrolyte surface and a method for manufacturing the same.

[0053] Hereinafter, the disclosure will be described with reference to the drawings presented in this specification. For reference, the drawings may be expressed in an exaggerated manner to explain the features of the disclosure. In this case, it is preferable to interpret them in light of the entire intent of this specification.

[0054] A hybrid LSCFP-based electrode according to an example of the disclosure will be described.

[0055] A hybrid LSCFP-based electrode according to an example of the disclosure may include: an electrode having porous pores formed between a plurality of nanofibers; and pulverized nanofiber positioned within the porous pores.

[0056] The disclosure may include an electrode having porous pores formed between a plurality of nanofibers.

[0057] At this time, the nanofibers may include nanofibers represented by chemical formula 1.

La.sub.1-xSr.sub.xCo.sub.1-y-zFe.sub.yPd.sub.zO.sub.3-[Chemical formula 1] [0058] in chemical formula 1, [0059] the x is a value including 0.3<x<0.5, [0060] the y is a value including 0.7<y<0.9, [0061] the z is a value including 0<z0.05, and [0062] the & is a value including 0<3.

[0063] At this time, if the atomic ratio of the x, y, z, and & of chemical formula 1 is out of the range, Pd may not be doped into the perovskite lattice, which is the parent, so that a secondary phase may be formed.

[0064] Meanwhile, in order to improve the catalytic activity of the CO.sub.2 reduction reaction of the hybrid LSCFP-based electrode, continuous heat treatment is performed on the nanofibers in H.sub.2 and CO.sub.2 atmospheres to manufacture the hybrid LSCFP-based electrode, and at this time, the nanofibers may maintain the perovskite structure during the continuous heat treatment process.

[0065] Specifically, during the continuous heat treatment, the structure of the nanofibers is first converted from the perovskite structure to the Ruddlesden-Popper (RP) structure, and then restored to the perovskite structure again, so that the perovskite structure may be maintained.

[0066] Meanwhile, as the continuous heat treatment process is performed, nano-metal particles including cobalt (Co) may be positioned on the surface of the nanofibers of the hybrid LSCFP-based electrode.

[0067] Specifically, through the heat treatment process in an H.sub.2 atmosphere, nano-scale CoFe nano-metal particles are formed on the surface of the nanofiber, and then, when the gas environment is changed to CO.sub.2 and the continuous heat treatment is performed, the Fe particles may re-enter the lattice and Co nano-metal particles may be positioned on the surface of the nanofibers.

[0068] The disclosure may include pulverized nanofibers positioned within the porous pores.

[0069] A surface area in contact with a solid electrolyte of the hybrid LSCFP-based electrode of the disclosure may be improved through the pulverized nanofibers, thereby solving the contact problem.

[0070] At this time, the length of the pulverized nanofibers may include 500 nm to 1 m.

[0071] If the length of the pulverized nanofibers is less than 500 nm, a problem of reduced fiber-to-fiber connectivity may occur, and if the length of the pulverized nanofibers exceeds 1 m, a problem of not expressing hybrid active characteristics may occur.

[0072] Meanwhile, the pulverized nanofibers may be positioned within the porous pores existing between the plurality of nanofibers, and at this time, the amount of the pulverized nanofibers positioned may vary depending on the size of the pores.

[0073] In addition, the efficiency of the hybrid LSCFP-based electrode according to an example of the disclosure may vary depending on the mass ratio of the nanofibers and the pulverized nanofibers.

[0074] Therefore, the mass ratio of the plurality of nanofibers and the pulverized nanofibers of the hybrid LSCFP-based electrode may include 7:3 to 3:7, and preferably 6:4 to 4:6.

[0075] At this time, if the mass ratio described above is out of range, the contact problem between the electrolyte and the electrode still exists, which may cause high interfacial resistance.

[0076] Conventional nanofiber-based electrodes could not be free from the problem of conducting actual applications due to insufficient interfacial contact with the solid electrolyte surface.

[0077] Therefore, the hybrid LSCFP-based electrode using the pulverized nanofibers according to an example of the disclosure may solve the problem of insufficient interfacial contact with the solid electrolyte surface, and hereinafter, a method for manufacturing a hybrid LSCFP-based electrode of the disclosure will be described.

[0078] A method for manufacturing a hybrid LSCFP-based electrode according to an example of the disclosure will be described.

[0079] FIG. 1 is a flow chart showing steps of a method for manufacturing a hybrid LSCFP-based electrode according to an example of the disclosure.

[0080] Referring to FIG. 1, a method for manufacturing a hybrid LSCFP-based electrode according to an example of the disclosure may include: S100 manufacturing a nanofiber material by calcining nanofibers; S200 manufacturing a pulverized nanofiber material by pulverizing a portion of the nanofiber material; S300 manufacturing a mixture by mixing the nanofiber material and the pulverized nanofiber material; and S400 manufacturing a nanofiber electrode by applying and sintering the mixture.

The First Step May Include Manufacturing a Nanofiber Material by Calcining Nanofibers. (S100)

[0081] At this time, the nanofiber may include at least one from the group consisting of lanthanum (La), strontium (Sr), cobalt (Co), iron (Fe), and palladium (Pd).

[0082] At this time, in order to manufacture the nanofibers, a lanthanum precursor, a strontium precursor, a cobalt precursor, an iron precursor, and a palladium precursor may be prepared by mixing them with a nanofiber precursor and electrospinning them.

[0083] For example, the lanthanum precursor may include La(NO.sub.3).Math.36H.sub.2O, the strontium precursor may include Sr(NO.sub.3).sub.2, the cobalt precursor may include Co(NO.sub.3).Math.26H.sub.2O, the iron precursor may include Fe(NO.sub.3).Math.39H.sub.2O, and the palladium precursor may include Pd(OCOCH.sub.3).sub.2, wherein after dissolving the stoichiometric amount of the precursors in a dimethylformamide solvent, a polyvinylpyrrolidone polymer, which is a nanofiber precursor, is added to the solution to create a uniform LSCFP (polymer precursor solution) mixture solution, and electrospinning may be performed using the mixture solution.

[0084] At this time, in order to perform electrospinning, for example, the mixed solution is loaded into a plastic syringe, and then a high voltage of 16.5 kV to 18.5 kV is applied to perform electrospinning at a rate of 0.2 ml/h to 0.3 ml/h, and through this, nanofibers may be manufactured.

[0085] Specifically, the nanofibers manufactured by performing the electrospinning may include, for example, nanofibers expressed by chemical formula 1.

La.sub.1-xSr.sub.xCo.sub.1-y-zFe.sub.yPd.sub.zO.sub.3-[Chemical formula 1] [0086] in chemical formula 1, [0087] the x is a value including 0.3<x<0.5, [0088] the y is a value including 0.7<y<0.9, [0089] the z is a value including 0<z0.05, and [0090] the is a value including 0<3.

[0091] Meanwhile, depending on the time and temperature of the calcination process, the characteristics of the manufactured nanofibers may change, which may cause changes in the properties of the manufactured electrode.

[0092] Therefore, the time and temperature of the calcination process may be important, and at this time, the preferable calcination temperature may include 900 C. to 1100 C.

[0093] At this time, if the calcination temperature is less than 900 C., the perovskite crystal structure of the nanofibers may not be properly formed, and if the calcination temperature exceeds 1100 C., there may be problems in which the thickness of the nanofibers increases and the crystal structure collapses.

[0094] In addition, the preferable time of the calcination process may include, for example, 1 hour to 3 hours.

[0095] Meanwhile, in order to improve the catalytic activity of the CO.sub.2 reduction reaction of the nanofibers, an additional heat treatment process may be performed on the nanofiber material.

[0096] For example, the nanofiber material may be first heat-treated in an H.sub.2 environment and then continuously heat-treated in a CO.sub.2 environment to position Co nanometal on the surface of the nanofiber, and the Co nanometal may act as a catalyst for the CO.sub.2 reduction reaction.

[0097] At this time, the preferable temperature of the heat treatment process in the H.sub.2 environment may be 650 C. to 750 C. for 1 hour to 5 hours.

[0098] In addition, the preferable temperature of the heat treatment process in the CO.sub.2 environment may be 650 C. to 850 C. for 30 minutes to 5 hours.

[0099] At this time, if the temperature and time range of the continuous heat treatment process described above are exceeded, there may be a problem in which a change in the crystal structure occurs however, if the catalytic activity of the CO.sub.2 reduction reaction of the nanofibers is improved, the conditions are not limited to the temperature and time range described above.

The Second Step May Include Manufacturing a Pulverized Nanofiber Material by Pulverizing a Portion of the Nanofiber Material. (S200)

[0100] The pulverizing scheme for the pulverized nanofiber material may include at least one from the group consisting of mortar and ball milling, and preferably, pulverization may be performed using mortar.

[0101] At this time, in order to mix the above nanofiber material and the above pulverized nanofiber material, for example, a paste mixer capable of simultaneously rotating and rotating using a centrifugal acceleration of 400G or more may be used for mixing; however, any method capable of pulverizing while maintaining the characteristics of the nanofibers may be used without being limited to the group of methods described above.

The Third Step May Include Manufacturing a Mixture by Mixing the Nanofiber Material and the Pulverized Nanofiber Material. (S300)

[0102] The mass ratio of the nanofiber material and the pulverized nanofiber material of the mixture may include 7:3 to 3:7.

[0103] At this time, if the mass ratio described above is out of range, the contact problem between the electrolyte and the electrode still exists, which may cause high interfacial resistance.

[0104] Therefore, the mass ratio of the nanofiber material and the pulverized nanofiber material may be 7:3 to 3:7, and a more preferable mass ratio may be 6:4 to 4:6.

The Final Step May Include Manufacturing a Nanofiber Electrode by Applying and Sintering the Mixture. (S400)

[0105] At this time, the manufactured nanofiber electrode may be a hybrid LSCFP-based electrode.

[0106] At this time, the sintering process may be performed in a temperature range capable of manufacturing the nanofiber electrode, and preferably, the temperature of the sintering process may include 900 C. to 1100 C.

[0107] At this time, if the temperature of the sintering process is less than 900 C., contact between the electrolyte and the electrode interface may not be sufficient, resulting in high interface resistance and delamination problems, and if the temperature of the sintering process exceeds 1100 C., agglomeration of the electrode structure or secondary phases or unwanted phases in the crystal structure may occur.

[0108] Meanwhile, the preferable thickness of the manufactured nanofiber electrode may be 15 m to 25 m.

[0109] At this time, if the thickness of the manufactured nanofiber electrode is less than 15 m, problems such as reduction in mechanical strength and reaction surface area may occur, and if it exceeds 25 m, problems such as restriction in smooth supply and discharge of reactants and products may occur.

[0110] The hybrid LSCFP-based electrode of the disclosure may provide a high-performance/high-stability effect for CO.sub.2 reduction at high temperatures, and to this end, has the advantage of providing an effect of solving the contact problem by improving the contact surface area at the solid electrolyte interface.

[0111] Therefore, the following will describe examples, comparative examples, and experimental examples of the disclosure having the aforementioned advantages.

[0112] Hereinafter, the disclosure will be described in more detail through examples, comparative examples, and experimental examples. These examples, comparative examples, and experimental examples are only intended to illustrate the disclosure, and the scope of the disclosure is not limited by these examples, comparative examples, and experimental examples.

Example

Manufacturing of Hybrid LSCFP-Based Electrodes

[0113] FIG. 2 is a schematic diagram showing a process for manufacturing nanofibers for manufacturing an LSCFP-based electrode.

[0114] Referring to FIG. 2, first, the stoichiometric amounts of La(NO.sub.3).Math.36H.sub.2O (Alfa Aesar), Sr(NO.sub.3).sub.2 (Sigma Aldrich), Co(NO.sub.3).Math.26H.sub.2O (Alfa Aesar), Fe(NO.sub.3).Math.3H.sub.2O (Alfa Aesar), and Pd(OCOCH.sub.3).sub.2 (Sigma Aldrich) were dissolved in a dimethylformamide (Alfa Aesar) solvent, and then a polyvinylpyrrolidone (Sigma Aldrich) polymer was added to the solution to create a uniform LSCFP (polymer precursor solution) mixture solution.

[0115] Thereafter, the mixture solution was loaded into a plastic syringe, and electrospinning was performed at a rate of 0.25 ml/h by applying a high voltage of 17.5 kV to produce nanofibers.

[0116] FIG. 3 is a schematic diagram showing a process for manufacturing a hybrid LSCFP-based electrode according to an example of the disclosure.

[0117] Referring to FIG. 3, the obtained LSCFP nanofibers were calcined at 1000 C. for 2 hours to obtain a black fiber material.

[0118] Thereafter, in order to manufacture a hybrid (H-LSCFP) electrode, some of the black fiber material was pulverized with mortar to obtain a pulverized LSCFP nanofiber material.

[0119] Next, an unpulverized LSCFP nanofiber material was dispersed by ultrasonication, and the pulverized LSCFP nanofiber material and the dispersed LSCFP nanofiber material were mixed with a binder (441 ESL, Electro Science) to obtain H-LSCFP Ink.

[0120] Finally, the H-LSCFP Ink Volume=Area 0.5 cm2 (or 5107 m2)height (18 m)=9108 m3 was applied and sintered to manufacture an electrode.

[0121] At this time, the sintering temperature was 1100 C. and the time was 3 hours.

[0122] Thus, a hybrid (H-LSCFP) electrode was manufactured.

Manufacturing of Half-Cell and Unit Cell (H-LSCFP Unit Cell)

[0123] First, to fabricate a half-cell, (Sr, Mg)-doped LaGaO3 (LSGM) powder was placed in a mold and uniaxial pressing was used.

[0124] At this time, a pressure of 50 MPa was applied and sintered at 1400 C. for 5 hours to fabricate an LSGM pellet.

[0125] Thereafter, to fabricate a unit cell, the air electrode and fuel electrode, which are hybrid LSCFP nanofiber electrodes (H-LSCFP) fabricated previously, were laminated on both sides of the previously fabricated LSGM pellet and sintered simultaneously at 1100 C. for 3 hours.

[0126] Thus, a unit cell including a hybrid LSCFP-based electrode was fabricated.

Comparative Example

100% Nanofiber Electrode (F-LSCFP) Manufacturing

[0127] The same process as in the example was performed, but to manufacture the 100% nanofiber electrode (F-LSCFP), only LSCFP nanofibers were dispersed by ultrasonication and mixed with a binder (441 ESL, Electro Science) to manufacture F-LSCFP Ink, which was then used to manufacture an electrode.

[0128] Thus, a 100% nanofiber electrode (F-LSCFP) was manufactured.

Half-Cell and Unit Cell Manufacturing (F-LSCFP Unit Cell)

[0129] The same process as in the example was performed, but the previously manufactured 100% nanofiber electrode (F-LSCFP) was used.

[0130] Thus, a unit cell including a 100% nanofiber electrode was manufactured.

Experimental Example

Crystallographic Phase Analysis

[0131] The crystallographic phase of the nanofibers manufactured according to the example was analyzed.

[0132] At this time, Cu K powder XRD measurement was performed using an X-ray diffractometer (RIGAKU, SmartLab) in the 20 range of 20 to 80 with Cu K radiation (2=1.5418 ), and nanofiber XRD measurement was performed. The crystal structure of the nanofiber was analyzed using HighScore software.

[0133] FIG. 4 is a graph showing an XRD pattern measured after calcining LSCFP nanofibers in air at 1000 C. for 2 hours.

[0134] Referring to FIG. 4, Yobs represents the actual experimental results and Ycalc represents the theoretical expected results, wherein it is possible to confirm that there is almost no difference in the peak positions and values between the two.

[0135] This may mean that when the manufactured LSCFP nanofibers are calcined at 1000 C. for 2 hours, a pure Trigonal (Hexagonal-setting) perovskite structure is formed without secondary phases or impurities.

[0136] FIG. 5 is a graph showing an XRD pattern measured after heat-treating LSCFP nanofibers in a hydrogen atmosphere at 700 C. for 2 hours.

[0137] Referring to FIG. 5, it is possible to confirm that the crystal structure of LSCFP nanofibers has changed from perovskite to Ruddlesden-Popper (RP) phase (LaSrFeO4, I4/mmm, 62.7 wt %, a=b=3.88 , c=12.72 ) and there exist metal phases of CoFe alloy (Pm-3m, 36.4 wt %, a=b=c=2.86 ) and Pd (Fm-3m, 0.97 wt %, a=b=c=3.95 ).

[0138] FIGS. 6A, 6B, 6C, 6D, 6E, 6F, 6G, 6H, and 6I are each a photograph of the surface of LSCFP nanofibers after calcination in a hydrogen atmosphere.

[0139] Referring to FIGS. 6A, 6B, 6C, 6D, 6E, 6F, 6G, 6H, and 6I, the surface of the nanofibers heat-treated in a hydrogen atmosphere is confirmed, wherein as can be seen in FIG. 6A, there are CoFe nano metal particles (CoFe alloy) on the surface of the Rudolson-Papper nanofibers (RP-LSCFP).

[0140] From the HR-TEM analysis results in FIGS. 6H and 6I, the planar spacing between the nanoparticles and the particle/support interface is 0.203 and 0.257 nm, respectively, which correspond to the (110) crystal plane (Pm-3m (221)) of the CoFe alloy and the (112) plane (I4/mmm (139)) of the RP structure.

[0141] In addition, as can be seen in FIGS. 6B to 6G, each atom is uniformly distributed.

[0142] FIG. 7 is a graph of XRD patterns of LSCFP nanofibers after calcination at 700 C. for 2 hours in hydrogen and CO.sub.2 atmospheres, respectively.

[0143] Referring to FIG. 7, the crystal structure of the nanofiber was restored to perovskite, and peaks corresponding to Co and Pd on the metal were observed. It is possible to confirm that the obtained perovskite crystal structure is different from the nanofiber perovskite crystal structure heat-treated in air.

[0144] FIGS. 8A, 8B, and 8C are each a photograph of the surface of LSCFP nanofibers after continuous heat treatment in hydrogen and CO.sub.2 atmospheres.

[0145] FIG. 8A allows to confirm that the nanofibers have a perovskite structure, and confirm that cobalt nanometal (Co NP) exists on the surface of the nanofibers.

[0146] The HR-TEM analysis results in FIGS. 8B and 8C show that the interplanar spacing between the nanoparticles and the nanofiber oxides is 0.203 nm and 0.18 nm, respectively, which correspond to the (111) plane of Co in the centered cubic (FCC) structure and the (211) plane of the perovskite structure.

Electrochemical Evaluation of Half-Cell and Unit Cell

[0147] The half-cell and unit cell including the hybrid LSCFP-based electrode (H-LSCFP) manufactured according to the example and the electrode manufactured with 100% nanofibers in the past (F-LSCFP) were evaluated.

[0148] At this time, the microstructural analysis of the unit cell was performed using scanning electron microscopy (SEM, Hitachi SU8230).

[0149] In addition, the electrochemical characteristics of the half-cell and single cell were evaluated using a potentionstat (Bio-Logic, VMP-300), wherein CO.sub.2 was injected into the fuel electrode of the half-cell and single cell, and air was injected into the air electrode.

[0150] FIG. 9 is photographs of the microstructure of an electrode (F-LSCFP) manufactured with 100% nanofibers and a hybrid LSCFP-based electrode (H-LSCFP) according to an example of the disclosure.

[0151] Referring to FIG. 9, it is possible to confirm that the microstructure of H-LSCFP is denser and the pore size is smaller than that of F-LSCFP; this is because the pulverized nanofibers according to an example of the disclosure are located within the pores.

[0152] FIGS. 10A, 10B, and 10C are each a graph comparing the electrode resistances of half-cells using F-LSCFP and H-LSCFP in LSGM electrolyte in a 100% CO.sub.2 atmosphere.

[0153] As shown in FIG. 10B, the resistance of the hybrid electrode (H-LSCFP) is lower than that of the 100% nanofiber electrode (F-LSCFP) in the temperature range of 700 C. to 850 C., and at the same time, as shown in FIG. 10C, the hybrid electrode also has lower activation energy than the 100% nanofiber electrode.

[0154] For example, as shown in FIG. 10B, the resistance of the hybrid electrode at 700 C. is 0.34 cm2, which is about 44% lower than the resistance of the 100% nanofiber electrode, 0.61 cm2.

[0155] This may mean that the catalytic activity is high.

[0156] In addition, as shown in FIG. 10C, as a result of analyzing the resistance of the two electrodes using the DRT tool, it was confirmed that the CO.sub.2 surface reaction of the hybrid electrode was superior to that of the 100% nanofiber electrode.

[0157] FIGS. 11A, 11B, and 11C are each a graph measuring the performance of a unit cell applied with F-LSCFP and H-LSCFP in a CO.sub.2 electrolysis cell mode.

[0158] As shown in FIGS. 11A, 11B, and 11C, it is possible to confirm that the electrolytic performance of H-LSCFP and F-LSCFP at 800 C. at 1.5 Vis 2.2 and 1.1 A/cm2, respectively, and this shows that the electrolytic performance of the H-LSCFP of the disclosure is about twice that of the F-LSCFP.

[0159] FIGS. 12A, 12B, and 12C are each a graph measuring the long-term stability evaluation of a unit cell applied with H-LSCFP in CO.sub.2 electrolysis cell mode.

[0160] As shown in FIG. 12A, it is possible to confirm that the H-LSCFP of the disclosure maintains stable performance while showing a constant current density for 100 hours.

[0161] As shown in FIG. 12B, Raman analysis was performed to check whether carbon was deposited on the electrode surface after 100 hours of experiment, wherein it is possible to confirm that there appears no peak value enabling to confirm the presence or absence of carbon, which means that carbon deposition did not occur on the electrode surface.

[0162] As shown in FIG. 12C, it is possible to additionally confirm that carbon intensity does not appear.

[0163] FIGS. 13A, 13B, 13C, and 13D are each a photograph of the long-term stability evaluation of a unit cell applied with H-LSCFP in a CO.sub.2 electrolysis cell mode followed by SEM analysis.

[0164] As shown FIGS. 13A, 13B, 13C, it is possible to confirm that all components of the unit cell to which H-LSCFP is applied are well combined, and that, through the enlarged hybrid electrode images, carbon is not formed on the surface of the nanofibers and the nanoparticles are maintained on the surface of the nanofibers.

[0165] Through the experimental example described above, it is possible to confirm that a battery to which the hybrid LSCFP-based electrode of the disclosure, H-LSCFP, is applied has lower electrical resistance and reduced activation energy compared to a battery to which the 100% nanofiber electrode, F-LSCFP, is applied, and that the former also has excellent electrolytic performance at high temperatures and excellent stability.

[0166] The description of the disclosure described above is for illustrative purposes, and those skilled in the art will understand that the disclosure is easily modifiable into other specific forms without changing the technical idea or essential features of the disclosure. Therefore, the examples described above should be understood in all respects as illustrative and not restrictive.

[0167] For example, each component described as single may be implemented in a distributed manner, and similarly, components described as distributed may also be implemented in a combined form. The scope of the disclosure is indicated by the claims described below, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the disclosure.