Electrochemical cell, power generation method using electrochemical cell, and hydrogen production method using electrochemical cell

Abstract

[Task] Provide an electrochemical battery suitable for use in a temperature range of 200°C to 600°C, a power generation method using the electrochemical battery, and a hydrogen production method using the electrochemical battery. [Solution] Fuel cell 1 (electrochemical battery) includes (Li,H) 14‑ 2x Zn 1+x (GeO4)4 represents the proton conductor 5, in which Li 14‑2x Zn 1+x Partial lithium ions in (GeO4)4 are replaced by protons, where x is a number equal to or greater than 0. The proton conductor has a conductivity of 0.01 Siemens / cm or higher at 300°C. An anode 6 is disposed on one side of the proton conductor, a cathode 7 is disposed on the other side of the proton conductor, a first partition 9 is disposed on the anode side 8 of the proton conductor to define an anode chamber, and a second partition 12 is disposed on the cathode side of the proton conductor to define a cathode chamber 11.

Description

Technical Field

[0001] This invention relates to an electrochemical battery, a method for generating electricity using an electrochemical battery, and a method for producing hydrogen using an electrochemical battery. Background Technology

[0002] Polymer electrolyte fuel cells (PEFCs) for automobiles, phosphoric acid fuel cells (PAFCs) for stationary applications, molten carbonate fuel cells (MCFCs), and solid oxide fuel cells (SOFCs) are already in practical use. Polymer electrolyte fuel cells operate between room temperature and 100°C, phosphoric acid fuel cells between 180°C and 200°C, molten carbonate fuel cells between 600°C and 700°C, and solid oxide fuel cells between 600°C and 900°C. However, no fuel cell operates within the moderate temperature range of 200°C to 600°C.

[0003] Fuel cells operating in a moderate temperature range of 200°C to 600°C are suitable not only for hydrogen-oxygen fuel cells but also for direct-type fuel cells. They generate hydrogen from various fuels in the fuel electrode chamber and then use the produced hydrogen to generate electricity. Furthermore, fuel cells operating in this moderate temperature range can promote the fuel cell reaction and thus improve efficiency compared to those operating in a temperature range of 200°C or lower.

[0004] Fuel cells that operate within the moderate temperature range of 200°C to 600°C do not exist because there are no ionic conductors with sufficient ionic conductivity within this temperature range. To date, cesium dihydrogen phosphate (CsH₂PO₄), discovered in 1997, has attracted considerable attention as the proton conductor with the highest conductivity. However, cesium dihydrogen phosphate undergoes a phase transition at temperatures of 270°C or higher, therefore its operating temperature limit is set at 270°C. The typical operating temperature of cesium dihydrogen phosphate is 250°C, at which temperature its conductivity σ (Siemens / cm) is approximately 0.008. Therefore, realizing fuel cells that operate within the moderate temperature range has been an important research topic since the 1990s.

[0005] Patent document 1 discloses a direct-type fuel cell. The direct-type fuel cell supplies its cell with organohydride compounds such as methylcyclohexane and decahydronaphthalene as fuel, and induces a dehydrogenation reaction by contacting the organohydride compounds with a noble metal catalyst fixed on the fuel electrode.

[0006] The platinum alumina catalyst developed by Chiyoda Corporation (Patent Document 2) can be used as a dehydrogenation catalyst to promote the dehydrogenation of methylcyclohexane to hydrogen. Non-Patent Document 1 shows that a large-scale hydrogen supply chain system using an organic chemical hydride method with a dehydrogenation catalyst has been demonstrated internationally and is moving towards commercialization. This dehydrogenation catalyst has high yield and lifespan and can be used at an industrial level, primarily for producing hydrogen from methylcyclohexane via a dehydrogenation reaction at the point of use. However, since the dehydrogenation reaction is endothermic, a heat source is required, which may be costly. Furthermore, if the heat source is fossil fuel, the CO2 produced may reduce the life cycle assessment CO2 (LCACO2).

[0007] In Patent Document 1, hydrogen gas generated at the fuel electrode transfers electrons to the fuel electrode, thus becoming protons. These protons move within the electrolyte membrane and, together with oxygen atoms activated at the anti-air electrode, receive electrons from the electrodes to promote the fuel cell reaction. The electrolyte membrane is a mixture of cesium dihydrogen phosphate (CsH2SO4) microcrystals and polytetrafluoroethylene. The direct-type fuel cell in Patent Document 1 has an output power of 40 mW / cm² at an operating temperature of 170°C to 220°C. 2 .

[0008] However, when using solid electrolytes as organic thin films, the operating temperature is typically 100°C or lower. If the operating temperature exceeds 200°C, the heat resistance of the organic film is insufficient. Cesium dihydrogen phosphate is a solid electrolyte that can be used at temperatures of 200°C or higher. However, since the operating temperature limit of cesium dihydrogen phosphate is 270°C, a new proton conductor is needed that can be used at even higher temperatures.

[0009] To address this need, non-patent document 2 discloses Li 13.9 Sr 0.1 Zn(GeO4)4, of which Li is a solid electrolyte of LISICON. 14 Some of the lithium in Zn(GeO4)4 is converted to Sr.Li 13.9 Sr 0.1 Zn(GeO4)4 substitution exhibits a conductivity of 0.039 Siemens / cm at 600℃, which is higher than that of conventional zirconium-based or cerium-based solid electrolytes. Furthermore, the application of Li... 13.9 Sr 0.1 The Zn(GeO4)4 fuel cell outputs approximately 0.4 W / cm³ at an operating temperature of 600°C. 2 Furthermore, if Li 13.9 Sr 0.1In Zn(GeO4)4, mobile lithium ions are completely replaced by protons, increasing the conductivity to 0.048 Siemens / cm at an operating temperature of 600°C. Lithium ions exchange protons in water or dilute acetic acid. For example, by stirring Li in a 5 mmol aqueous solution of acetic acid... 13.9 Sr 0.1 Zn(GeO4) takes 424 hours to exchange lithium ions.

[0010] Non-Patent Document 3 discloses a proton conductor, wherein Li is subjected to a 5 mmol aqueous solution of acetic acid. 14-2x Zn 1+x (GeO4)4 undergoes ion exchange treatment, allowing lithium ions to exchange with protons. Non-Patent Document 3 addresses different Li... + / Zn 2+ The ratio of Li 14 Zn(GeO4)4, Li 12 Zn2(GeO4)4 and Li 10 Zn3(GeO4)4 was treated with ion exchange, each sample was identified, and weight changes were measured during temperature increases, thus confirming that the more lithium contained in the sample, the greater the amount of lithium ions exchanged with protons. Furthermore, Non-Patent Document 3 discovered the possibility of obtaining the same conductivity as the proton conductor disclosed in Non-Patent Document 2 from measurements of the electromotive force of hydrogen concentration batteries using proton conductors.

[0011] Existing technical documents

[0012] Patent documents

[0013] Patent document 1: JP2005-166486A

[0014] Patent document 2: JP5897811B2

[0015] Non-patent document 1: Journal of the Gas Turbine Society, Vol.49, No.2, Pages 1-6 (2021)

[0016] Non-Patent Document 2: Chem. Mater., 2017, 29, 1490-1495

[0017] Non-Patent Document 3: The Electrochemical Society of Japan, 2018 Autumn Meeting Proceedings, 1B02 Summary of the Invention

[0018] The task to be accomplished by this invention

[0019] However, in the temperature range of 200°C to 600°C, a novel proton conductor with higher conductivity is needed. Electrochemical cells using such a proton conductor as the solid electrolyte can operate at temperatures between 200°C and 600°C, promoting the dehydrogenation reaction of organic hydrides in the fuel electrode. Furthermore, electrolytic cells using this proton conductor as the solid electrolyte can operate at temperatures between 200°C and 600°C, improving the efficiency of the electrolysis reaction.

[0020] Therefore, the objective of this invention is to provide an electrochemical battery suitable for use in a temperature range of 200°C to 600°C, a method for generating electricity using the electrochemical battery, and a method for producing hydrogen using the electrochemical battery.

[0021] means of completing the task

[0022] To achieve this objective, one aspect of the present invention is to provide an electrochemical battery (1), comprising: (Li,

[0023] H) 14-2x Zn 1+x (GeO4)4 represents the proton conductor (5), in which Li 14-2x Zn 1+x Partial lithium ions in (GeO4)4 are replaced by protons, where x is a number equal to or greater than 0; the proton conductor has a conductivity of 0.01 Siemens / cm or higher at 300°C; an anode (6) is disposed on one side of the proton conductor; a cathode (7) is disposed on the other side of the proton conductor; a first partition (9) is disposed on the anode side of the proton conductor to define an anode chamber (8); and a second partition (12) is disposed on the cathode side of the proton conductor to define a cathode chamber (11). x may contain decimals.

[0024] Li 14-2x Zn 1+x (GeO4)4 can be used with Li 2+2y Zn 1-y GeO4 represents the structure. For these structures, the condition "x = 3 - 4y" is satisfied.

[0025] Li 14-2x Zn 1+x The structure of (GeO4)4, where some lithium ions are replaced by protons, can be represented as (Li,H). 14-2x Zn 1+x (GeO4)4 or (Li,H) 2+2y Zn 1-y GeO4.

[0026] Based on this, an electrochemical battery suitable for use in a temperature range between 200°C and 600°C can be provided. This electrochemical battery can be used as a fuel cell and an electrolyzer.

[0027] In the foregoing, preferably, the electrochemical battery further includes a temperature regulator configured to maintain the temperature of the proton conductor in a range between 200°C and 600°C.

[0028] Based on this aspect, the conductivity of the proton conductor can be maintained at a very high level.

[0029] In the above aspects, preferably, x is 0.

[0030] In the above aspects, preferably, Li 14-2x Zn 1+x The mobile lithium ions contained in (GeO4)4 are replaced by protons in the range of 40% to 70%. Furthermore, in the above aspects, preferably, Li... 14-2x Zn 1+x In (GeO4)4, the mobile lithium ions are replaced by protons in a range of 50% to 60%. Mobile lithium ions refer to those contained in Li 14-2x Zn 1+x (GeO4)4 contains all lithium ions and is able to be found in Li 14-2x Zn 1+x Lithium ions moving within (GeO4)4. Li 14-2x Zn 1+x The ratio of mobile lithium ions to all lithium ions in (GeO4)4 is (3-x) to (14-2x).

[0031] Based on these aspects, the conductivity of the proton conductor can be improved.

[0032] In the foregoing, preferably, the electrochemical battery comprises a plurality of batteries (2), each battery comprising the proton conductor, the anode, the cathode, the first separator and the second separator, wherein the first separator of one of the plurality of batteries contacts the second separator of another of the plurality of batteries for heat exchange.

[0033] Based on this aspect, the heat generated by the reaction of protons and oxygen at the cathode is transferred to the anode through the first and second separators. Therefore, it is more likely that the temperature of the proton conductor will be maintained between 200°C and 600°C.

[0034] In the above aspects, preferably, hydrogen is supplied to the anode chamber, air is supplied to the cathode chamber, and an electromotive force is generated between the anode and the cathode, and the electrochemical cell functions as a hydrogen-oxygen fuel cell.

[0035] Based on this, hydrogen-oxygen fuel cells can be provided.

[0036] In the above aspects, preferably, a hydrogen-containing compound containing hydrogen is supplied to the anode chamber, air is supplied to the cathode chamber, a catalyst layer containing a catalyst configured to generate hydrogen from the hydrogen-containing compound is disposed in the anode chamber, and an electromotive force is generated between the anode and the cathode, and the electrochemical cell functions as a hydrogen-oxygen fuel cell.

[0037] Based on this, direct-type fuel cells can be provided.

[0038] In the foregoing, preferably, the hydrogen-containing compound is an organohydride, wherein an aromatic compound having 1-3 rings is hydrogenated. Furthermore, preferably, the hydrogen-containing compound comprises at least one compound selected from the group consisting of methylcyclohexane, cyclohexane, trimethylcyclohexane, decahydronaphthalene, benzyltoluene, and dibenzotriol.

[0039] Based on this, a direct-type fuel cell can be provided in which organic hydrides are supplied to the anode. Furthermore, the heat of reaction required for the endothermic reaction to generate hydrogen from the fuel can be compensated by the heat generated by the fuel cell reaction, which is an exothermic reaction producing water.

[0040] In the dehydrogenation reaction, hydrogen produced by the dehydrogenation catalyst transfers electrons to the anode in the anode chamber, becoming protons. These protons move within the proton conductor and reach the cathode at the opposite electrode. At this point, the fuel cell reaction proceeds as protons and oxygen ions accept electrons at the cathode to form water. Correspondingly, electrons flow through the circuit, generating electricity. The dehydrogenation reaction is an equilibrium reaction regulated by chemical equilibrium. Taking the dehydrogenation of methylcyclohexane as an example, a reaction temperature of 320°C is required at the normal reaction pressure in a normal reactor to induce a near-100% dehydrogenation reaction. In an electrochemical cell, protons are migrated by the proton conductor to the opposite electrode, shifting the chemical equilibrium to a lower temperature. Therefore, almost 100% dehydrogenation can occur even at 320°C or lower. Furthermore, increasing the operating temperature can promote the dehydrogenation reaction.

[0041] In the foregoing, preferably, the hydrogen-containing compound comprises at least one compound selected from the group consisting of ammonia, formic acid, methanol and dimethyl ether.

[0042] In the foregoing, preferably, the catalyst is a dehydrogenation catalyst comprising an alumina support and platinum supported on the alumina support; and the average particle diameter of the platinum is 2 nanometers or less.

[0043] Based on this, the dehydrogenation reaction of methylcyclohexane at the anode can be promoted. The hydrogen gas formed by the dehydrogenation reaction in the anode chamber transfers electrons to the anode electrode, becoming protons, and then passes through the proton conductor. Therefore, the hydrogen gas formed by the dehydrogenation reaction is migrated, shifting the chemical equilibrium to a lower temperature and promoting the dehydrogenation reaction.

[0044] The dehydrogenation catalyst can be a platinum-supported alumina catalyst developed by Chiyoda Corporation. This is a catalyst in which platinum particles are highly dispersed on the surface of porous γ-alumina, which serves as a catalyst support. Platinum-supported alumina catalysts have been used in a variety of reactions. Conventional platinum-supported alumina catalysts have relatively large platinum particles, even the smallest of which are over 2 nanometers, resulting in an average particle diameter of over 2 nanometers. If the dehydrogenation reaction of organic hydrides is caused by such a conventional platinum catalyst, a decomposition reaction occurs on the platinum particles, and carbon deposition reaction is highly likely to occur, where carbonaceous materials detoxify the active sites on the surface of the platinum particles. Because the active sites of the platinum particles decrease rapidly, the lifespan of such catalysts is only a few days. In the catalyst developed by Chiyoda Corporation, most of the platinum particles are about 1 nanometer in diameter, with an average particle diameter of less than 2 nanometers, and the platinum particles are highly dispersed on the surface of the alumina support. Therefore, the catalyst developed by Chiyoda Corporation can be used continuously in industry for more than a year while suppressing carbon deposition reactions. This catalyst, pioneered by Chiyoda Corporation for the dehydrogenation of organic hydrides, can be used as a dehydrogenation catalyst for the dehydrogenation reaction of organic hydrides according to the present invention.

[0045] In the above aspects, preferably, water vapor is supplied to the anode chamber, a DC power supply is connected between the anode and the cathode, and the electrochemical cell functions as an electrolytic cell to form hydrogen at the cathode. In this respect, it is not necessary to supply raw materials to the cathode chamber.

[0046] Based on this, it is possible to provide an electrolytic cell suitable for use in a temperature range between 200°C and 600°C.

[0047] Another aspect of the present invention is to provide a method for generating electricity using the electrochemical cell, comprising: supplying hydrogen to the anode chamber; supplying air to the cathode chamber; and maintaining the temperature of the proton conductor within a range of 200°C to 600°C.

[0048] Based on this, by using an electrochemical battery, it is possible to generate electricity from hydrogen, which is used as fuel.

[0049] Another aspect of the present invention is to provide a method for generating electricity using the electrochemical battery, comprising: providing a catalyst layer in the anode chamber, the catalyst layer being configured to generate hydrogen from a hydrogen-containing compound; supplying the hydrogen-containing compound to the anode chamber; supplying air to the cathode chamber; and maintaining the temperature of the proton conductor within a range of 200°C to 600°C.

[0050] Based on this, by using electrochemical batteries, it is possible to generate electricity from hydrogen-containing compounds used as fuel.

[0051] In the foregoing, preferably, the hydrogen-containing compound is an organohydride, wherein an aromatic compound having 1-3 rings is hydrogenated. Furthermore, preferably, the hydrogen-containing compound comprises at least one compound selected from the group consisting of methylcyclohexane, cyclohexane, trimethylcyclohexane, decahydronaphthalene, benzyltoluene, and dibenzotriol. Furthermore, preferably, the hydrogen-containing compound comprises at least one compound selected from the group consisting of ammonia, formic acid, methanol, and dimethyl ether.

[0052] In the foregoing, preferably, the catalyst is a dehydrogenation catalyst comprising an alumina support and platinum supported on the alumina support; and the average particle diameter of the platinum is 2 nanometers or less.

[0053] Based on this, the dehydrogenation reaction of methylcyclohexane at the anode can be promoted.

[0054] Another aspect of the invention provides a method for producing hydrogen using the electrolysis of the said electrochemical cell, comprising: supplying water vapor to the anode chamber; supplying water to the cathode chamber; maintaining the temperature of the proton conductor within a range of 200°C to 600°C; and applying a DC voltage between the anode and the cathode to generate hydrogen gas at the cathode. In this respect, it is not necessary to supply raw materials to the cathode chamber.

[0055] Based on this, it is possible to use electrochemical batteries to generate hydrogen.

[0056] Another aspect of the invention provides a method for producing hydrogen using the electrolysis of the aforementioned electrochemical cell, comprising: providing a catalyst layer in the anode chamber; supplying the anode chamber with ammonia or at least one hydrocarbon selected from the group consisting of methylcyclohexane, formic acid, methanol, and dimethyl ether; maintaining the temperature of the proton conductor in a range between 200°C and 600°C; applying a direct current voltage between the anode and the cathode; and generating protons from the ammonia or the hydrocarbon through the catalyst in the anode chamber, causing the protons to move through the proton conductor to the cathode, and generating hydrogen gas at the cathode. In this respect, it is not necessary to supply feedstock to the cathode chamber.

[0057] Based on this, hydrogen can be produced by using an electrochemical battery.

[0058] Another aspect of the present invention provides a method for producing hydrogen using the electrolysis of the said electrochemical cell, comprising: performing electrolysis under pressure.

[0059] Based on this, high-pressure hydrogen can be formed.

[0060] Effects of the present invention

[0061] Based on the above aspects, it is possible to provide an electrochemical battery suitable for use in a temperature range of 200°C to 600°C, a power generation method using the electrochemical battery, and a hydrogen production method using the electrochemical battery. Attached Figure Description

[0062] Figure 1 This is a schematic diagram of the structure of a fuel cell;

[0063] Figure 2 This is a schematic diagram of the structure of a power generation battery;

[0064] Figure 3 It shows a graph illustrating the conductivity of a solid electrolyte; and

[0065] Figure 4 This is a schematic diagram of an electrolytic cell. Detailed Implementation

[0066] (First Implementation)

[0067] In the following sections, embodiments of the electrochemical battery according to the present invention will be described. A first embodiment describes an example in which the electrochemical battery according to the present invention is applied to a fuel cell. For example... Figure 1 As shown, fuel cell 1 includes fuel cell stack 3, and fuel cell stack 3 includes multiple power generating cells 2 stacked on top of each other. Figure 1 and Figure 2 As shown, each power generation cell 2 includes a proton conductor 5, an anode 6 disposed on one side of the proton conductor 5, a cathode 7 disposed on the other side, a first partition 9 disposed on the anode side (one side of the anode 6) of the proton conductor 5 to define an anode chamber 8, and a second partition 12 disposed on the cathode side (one side of the cathode 7) of the proton conductor 5 to define a cathode chamber 11.

[0068] In this embodiment, a hydrogen-containing compound is supplied to the anode chamber 8, and air is supplied to the cathode chamber 11. The hydrogen-containing compound may be an organic hydride, wherein an aromatic compound having 1-3 rings is hydrogenated. The hydrogen-containing compound may include at least one group selected from methylcyclohexane, cyclohexane, trimethylcyclohexane, decahydronaphthalene, benzyltoluene, and dibenzotriol. Furthermore, the hydrogen-containing compound may include at least one compound selected from groups composed of ammonia, formic acid, methanol, and dimethyl ether. In this embodiment, the hydrogen-containing compound used as fuel is methylcyclohexane (MCH). The anode 6 may be referred to as the fuel electrode, the cathode 7 as the air electrode, the anode chamber 8 as the fuel passage, and the cathode chamber 11 as the air passage.

[0069] The proton conductor 5 forms a thin film. The proton conductor 5 has a structure in which Li... 14-2x Zn 1+xIn (GeO4)4, some lithium is replaced by protons. In the above structural formula, "x" is a number equal to or greater than 0, and may contain decimals. Li 14- 2x Zn 1+x (GeO4)4 can be used with Li 2+2y Zn 1-y GeO4 represents this. For these structural formulas, the condition "x = 3 - 4y" holds. Li 14-2x Zn 1+x The structure of (GeO4)4, where some lithium ions are replaced by protons, can be represented as (Li,H). 14-2x Zn 1+x (GeO4)4 or (Li,H) 2+ 2y Zn 1-y GeO4. Li 14-2x Zn 1+x (GeO4)4 is a lithium superionic conductor (LISICON) belonging to solid electrolytes. For example, "x" can be 0, 1, or 2.

[0070] LISICON has a framework structure composed of tetrahedra of LiO4, GeO4, SiO4, PO4, ZnO4, and γ-Li3PO4 type VO4, as well as octahedra of LiO6. 14 Zn(GeO4)4 is a solid solution of zinc dissolved in Li4GeO4 as a matrix, and has very high electrical conductivity.

[0071] The proton conductor 5 has a conductivity of 0.01 Siemens / cm or higher at 300°C. In the proton conductor 5, Li... 14- 2x Zn 1+x In (GeO4)4, mobile lithium ions are replaced by protons in the range of 40% to 70%. Furthermore, in the proton conductor 5, Li... 14-2x Zn 1+x In (GeO4)4, 50% to 60% of the mobile lithium ions can be replaced by protons. In proton conductor 5, Li... 14 In Zn(GeO4)4, mobile lithium ions can be proton-substituted in the range of 40% to 70%. Furthermore, in proton conductor 5, Li... 14 In Zn(GeO4)4, 50% to 60% of the mobile lithium ions can be replaced by protons.

[0072] The manufacturing method of the proton conductor 5 will be described below. First, the process of manufacturing the Li before ion exchange will be described. 14-2x Zn 1+x Preparation method of (GeO4)4. Li 14-2x Zn 1+xThe preparation method of (GeO4)4 is also disclosed in the aforementioned non-patent document 3. Li can be prepared by a solid-state method. 14-2x Zn 1+x (GeO4)4. The reagent powders of "lithium source," "zinc source," and "germanium source" are mixed overnight in an organic solvent, and then pulverized. The organic solvent is then evaporated to obtain a mixture. The lithium source may contain at least one selected from the group consisting of LiOH, Li2O, and LiNO3. The zinc source may contain at least one selected from the group consisting of Zn(OH)2, ZnCO3, and Zn(NO3)2. The germanium source may contain at least one selected from the group consisting of GeO and GeCl2. A combination of lithium, zinc, and germanium sources may be Li2CO3, ZnO, and GeO2. The organic solvent may be at least one selected from the group consisting of ethanol, methanol, 1-propanol, 2-propanol, and 1-butanol. The mixture is then molded into granules using a molding machine, and the molded product is burned in air. The molded product is then pulverized into powder to obtain Li. 14-2x Zn 1+x (GeO4)4.

[0073] The firing temperature of the molded articles in air can be from 1000°C to 1200°C, preferably from 1100°C to 1150°C. If the firing temperature is below 1000°C, the solid-phase reaction may not proceed well. If the firing temperature is above 1200°C, the molded articles may melt. The firing time of the molded articles can be from 3 to 7 hours, preferably from 4 to 6 hours. The molded articles can be baked in air, for example, at 1150°C for 5 hours.

[0074] Li 14-2x Zn 1+x (GeO4)4 could be, for example, Li. 14 Zn(GeO4)4, Li 12 Zn2(GeO4)4 or Li 10 Zn3(GeO4)4. In Li 14-2x Zn 1+x In (GeO4)4, the ratio of lithium to zinc can vary depending on the mixing ratio of lithium source, zinc source and germanium source.

[0075] Next, we will describe a method of replacing Li with protons. 14-2x Zn 1+x A method involving a portion of lithium ions from (GeO4)4. By using Li 14-2x Zn 1+x A powder sample of (GeO4)4 was immersed in an acidic non-aqueous solvent, and the powder sample and the non-aqueous solvent were stirred to allow Li to react. 14-2x Zn 1+xA portion of the mobile lithium ions contained in (GeO4)4 are replaced by protons. The non-aqueous solvent can be an aprotic solvent. The non-aqueous solvent may contain a solvent selected from the group consisting of toluene, dimethyl sulfoxide, tetrahydrofuran, and N,N-dimethylformamide. The acid may contain at least one selected from the group consisting of benzoic acid, m-nitrophenol, acetic acid, p-toluenesulfonic acid, oxalic acid, and methanesulfonic acid. For example, toluene dehydrated by a dehydrating agent can be used as a non-aqueous solvent to allow Li to... 14-2x Zn 1+x (GeO4)4 was stirred in 100 mL of a non-aqueous organic solution for 24 hours, with benzoic acid dissolved in it at a concentration of 5 mmol as a proton source, thereby ion exchange.

[0076] By changing Li 14-2x Zn 1+x The concentration of (GeO4)4 in the solvent and the type of acid can adjust the Li 14-2x Zn 1+x The ion exchange rate between mobile lithium ions and protons contained in (GeO4)4. If the solvent is water and the acid is acetic acid, then determine the Li... 14-2x Zn 1+x The ion exchange rate between mobile lithium ions and protons in (GeO4)4 reaches 100%.

[0077] The proton conductor powder after ion exchange is obtained by removing the solvent. The drying temperature can be between the boiling point of the solvent used and 300°C. If the drying temperature is below the boiling point, solvent residue may remain. If the drying temperature is above 300°C, protons in the sample may be desorbed. Based on the above range, powdered proton conductors can be obtained. The powdered proton conductors can be formed into thin film shapes, for example, using a molding machine. Furthermore, the powdered proton conductors can be shaped using wet or dry methods (such as vapor deposition).

[0078] like Figure 2 As shown, the anode 6 includes an anode catalyst layer 6A stacked on a first surface 5A of the proton conductor 5, and an anode gas diffusion layer 6B stacked on the side of the anode catalyst layer 6A opposite to the proton conductor 5. The cathode 7 includes a cathode catalyst layer 7A stacked on a second surface 5B of the proton conductor 5 opposite to the first surface 5A, and a cathode gas diffusion layer 7B stacked on the side of the cathode catalyst layer 7A opposite to the proton conductor 5.

[0079] The anode catalyst layer 6A and the cathode catalyst layer 7A each comprise a conductive porous support and an electrode catalyst supported by the support, respectively. The support is, for example, an ionomer. As the electrode catalyst described above, electrode catalysts known to be used in PEFCs can be used. The electrode catalyst can be, for example, a noble metal catalyst such as platinum, palladium, iridium, or ruthenium. Alternatively, the electrode catalyst can be an inexpensive metal catalyst.

[0080] The anode gas diffusion layer 6B and the cathode gas diffusion layer 7B are made of porous materials in which reactive gases diffuse. The anode gas diffusion layer 6B and the cathode gas diffusion layer 7B can be made of, for example, a porous metallic material or a carbon fiber nonwoven fabric. In this embodiment, the anode gas diffusion layer 6B and the cathode gas diffusion layer 7B have electrical conductivity.

[0081] The dehydrogenation catalyst is coupled to at least one of the anode gas diffusion layer 6B and the anode catalyst layer 6A. The dehydrogenation catalyst is preferably a platinum-supported alumina catalyst used in organic chemical hydrogenation methods. The platinum-supported alumina catalyst comprises an alumina support and platinum as the active metal supported on the alumina support. The platinum is formed in particulate form and dispersed on the alumina support. The platinum-supported alumina catalyst is active for the dehydrogenation reaction of aromatic compounds such as methylcyclohexane.

[0082] The average particle diameter of the platinum particles can be 2 nanometers or smaller, preferably between 0.5 nanometers and 2.0 nanometers, more preferably between 0.8 nanometers and 1.5 nanometers. Furthermore, 70% or more of the platinum particles can be 2 nanometers or smaller, preferably between 0.5 nanometers and 2.0 nanometers, more preferably between 0.8 nanometers and 1.5 nanometers. The average particle size and size of the platinum particles can be measured using transmission electron microscopy. The platinum particles can be supported on an alumina carrier as platinum element (Pt) in a range from 0.1 wt% to 1.5 wt%.

[0083] Alumina supports can include γ-alumina supports. The surface area of ​​γ-alumina supports can reach 200 m². 2 / g or more, the pore volume of the r-alumina carrier can reach 0.50 m. 2 / g or more, the average pore size of the r-alumina carrier can be... to Within the range, the diameter is in the average aperture range The ratio of the pore volume within the range to the total pore volume can reach 60% or more.

[0084] Platinum-supported alumina catalysts, used as dehydrogenation catalysts, may contain a second component along with platinum particles. The second component may be selected from at least one of the group consisting of alkali metals such as sodium and potassium, vanadium, molybdenum, chromium, sulfur, and phosphorus. The second component may be supported on an alumina support in the range of 0.5 wt% to 1.5 wt%. For example, the alumina support may contain sulfur or sulfur compounds in an amount of elemental sulfur (S) ranging from 0.5 wt% to 1.2 wt%. Furthermore, the alumina support may carry an alkali metal in the range of 0.5 wt% to 1.5 wt%. The second component increases the selectivity of the platinum-supported alumina catalyst, thereby extending the catalyst lifetime.

[0085] The dehydrogenation catalyst can be disposed in the anode gas diffusion layer 6B in various known forms. For example, the dehydrogenation catalyst can be formed into a powder, and the powdered dehydrogenation catalyst can be fixed onto the structure forming the anode gas diffusion layer 6B. Alternatively, the anode gas diffusion layer 6B can be formed by pulverizing the dehydrogenation catalyst and shaping the powdered dehydrogenation catalyst. The dehydrogenation catalyst can be disposed in the anode catalyst layer 6A.

[0086] The first partition 9 defines the anode chamber 8 between the first partition 9 and the anode gas diffusion layer 6B. A plurality of grooves forming the anode chamber 8 may be provided on the anode gas diffusion layer side (one side of the anode gas diffusion layer 6B) of the first partition 9. A gasket 15 may be provided between the first partition 9 and the anode gas diffusion layer 6B to expand the anode chamber 8. In another embodiment, the gasket 15 may be omitted, and the first partition 9 and the anode gas diffusion layer 6B may be in direct contact with each other.

[0087] The second partition 12 defines a cathode chamber 11 between the second partition 12 and the cathode gas diffusion layer 7B. A plurality of slots forming the cathode chamber 11 are provided on the cathode gas diffusion layer side of the second partition 12 (one side of the cathode gas diffusion layer 7B). A gasket 16 can be provided between the second partition 12 and the cathode gas diffusion layer 7B to expand the cathode chamber 11. In another embodiment, the gasket 16 can be omitted, and the second partition 12 and the cathode gas diffusion layer 7B can be in direct contact with each other.

[0088] The first separator 9 and the second separator 12 are made of thermal conductors. Alternatively, in this embodiment, the first separator 9 and the second separator 12 are made of conductive materials. The first separator 9 and the second separator 12 may be made of metals such as stainless steel, carbon, or carbon resin composites. The first separator 9 is electrically connected to the anode 6, while the second separator 12 is electrically connected to the cathode 7.

[0089] The inlet of the anode chamber 8 of each power generation cell 2 is connected to the common fuel inlet 21. The outlet of the anode chamber 8 of each power generation cell 2 is connected to the common fuel outlet 22. The inlet of the cathode chamber 11 of each power generation cell 2 is connected to the common air inlet 23. The outlet of the cathode chamber 11 of each power generation cell 2 is connected to the common air outlet 24.

[0090] The power generation cells 2 are stacked on top of each other. A first separator 9 of one power generation cell 2 contacts a second separator 12 of another power generation cell 2 to exchange heat. The first separator 9 and second separator 12 of adjacent power generation cells 2 can be integrally formed. Because the first separator 9 and second separator 12 are in contact with each other, adjacent power generation cells 2 are electrically connected in series. A first separator 9 located at one end of the stacked power generation cells 2 is connected to the negative electrode 25 of the fuel cell stack 3. A second separator 12 located at the other end of the stacked power generation cells 2 is connected to the positive electrode 26 of the fuel cell stack 3. An external load is connected to the negative electrode 25 and the positive electrode 26.

[0091] Fuel inlet 21 is connected to fuel tank 31 via heater 32. Heater 32 heats and vaporizes liquid methylcyclohexane supplied from fuel tank 31. Heater 32 can be an electric heater with a power line that generates heat through electricity, or it can be a heater that uses the heat of fossil fuel combustion as a heat source. The vaporized methylcyclohexane by heater 32 is supplied to fuel inlet 21.

[0092] Fuel outlet 22 is connected to used fuel tank 35 via cooler 33 and gas-liquid separator 34. Cooler 33 cools the exhaust gas discharged from fuel outlet 22. The exhaust gas mainly contains methylcyclohexane and toluene and hydrogen formed from unreacted methylcyclohexane. Cooler 33 liquefies the toluene and methylcyclohexane in the exhaust gas. Cooler 33 cools the exhaust gas to the boiling point of toluene, 110.6°C or lower. Cooler 33 and heater 32 may include a heat exchanger that exchanges heat between fuel and exhaust gas. Cooler 33 may include an air-cooled heat exchanger or a water-cooled heat exchanger.

[0093] The gas-liquid separator 34 separates liquid toluene and methylcyclohexane from the exhaust gas. The separated toluene and methylcyclohexane are stored in the used fuel tank 35. The gaseous component of the exhaust gas separated from the liquid toluene and methylcyclohexane is mainly hydrogen. This gaseous component of the exhaust gas can be piped from the gas-liquid separator 34 to the fuel inlet 21 of the fuel cell stack 3.

[0094] The inlet of cathode chamber 11 is connected to an air intake pipe for drawing in air. The outlet of cathode chamber 11 is connected to an exhaust pipe for discharging water and air.

[0095] The fuel cell 1 may include a temperature regulator configured to maintain the temperature of the proton conductor 5 within a range of 200°C to 600°C. The temperature regulator may maintain the temperature of the proton conductor 5 within a range of 250°C to 600°C. The temperature regulator may be a heater 32 that regulates the temperature of the methylcyclohexane supplied to the anode chamber 8. Alternatively, the temperature regulator may be a temperature regulating device 41 that includes an air-cooling device that cools the fuel cell stack 3 with external air or a water-cooling device that cools the fuel cell stack 3 with cooling water. Alternatively, the temperature regulator may be a flow control valve that regulates the flow rate of the methylcyclohexane supplied to the anode chamber 8. A method of generating electricity using the fuel cell 1 includes the process of maintaining the temperature of the proton conductor 5 within a range of 200°C to 600°C. The temperature of the fuel cell 1 can be maintained within a range of 200°C to 600°C by means of the temperature regulator.

[0096] Next, the operation of the fuel cell 1 with the above configuration will be described. Methylcyclohexane is supplied from the fuel tank 31 to the anode chamber 8 of each power generation cell 2 of the fuel cell 1 via the fuel inlet 21. The methylcyclohexane is heated and vaporized by the heater 32 and then supplied to the anode chamber 8. Oxygen-containing air is supplied as an oxidant to the cathode chamber 11 of each power generation cell 2 of the fuel cell 1 via the air inlet 23.

[0097] The methylcyclohexane supplied to the anode chamber 8 diffuses into the anode gas diffusion layer 6B. In the anode gas diffusion layer 6B, which is equipped with a dehydrogenation catalyst, the methylcyclohexane decomposes into hydrogen and toluene through a dehydrogenation reaction, as shown in the following reaction formula (1).

[0098]

[0099] This reaction is endothermic. By using the heat of reaction of the cathode reaction (reaction formula (3)), the temperature of the anode chamber 8 is maintained between 200°C and 600°C.

[0100] In the presence of an electrode catalyst, the hydrogen gas formed by the dehydrogenation reaction releases electrons and forms protons in the anode catalyst layer 6A through the anode reaction, as shown in the following reaction formula (2).

[0101] H2→2H + +2e - ···(2)

[0102] Protons formed in the anode catalyst layer 6A pass through the interior of the proton conductor 5 and reach the cathode catalyst layer 7A. In the cathode catalyst layer 7A, in the presence of the electrode catalyst, protons and oxygen accept electrons and form water through the cathode reaction shown in the following reaction formula (3). The cathode reaction is an exothermic reaction. Therefore, an electromotive force is generated between the anode 6 and the cathode 7.

[0103] O2+4H+ +4e - →2H2O···(3)

[0104] The heat generated in the cathode catalyst layer 7A is transferred to the anode catalyst layer 6A via the proton conductor 5 and to the anode gas diffusion layer 6B via the cathode gas diffusion layer 7B, the second separator 12, and the first separator 9. Therefore, the anode catalyst layer 6A and the anode gas diffusion layer 6B are maintained between 200°C and 600°C, thereby promoting the dehydrogenation reaction.

[0105] The effects of the fuel cell 1 (electrochemical cell) according to this embodiment will be described below. Figure 3 The conductivity of various solid electrolytes is shown. Figure 3 The asterisk indicates the conductivity σ (0.008 Siemens / cm) of cesium dihydrogen phosphate (CsH2PO4) at 250°C (logσ = -2.1). The conductivity marked with a circle indicates the proton conductor 5 ((Li, H) according to this embodiment). 14 The conductivity of Zn(GeO4)4. The proton conductor 5 according to this embodiment has a higher conductivity at 300°C than that of cesium dihydrogen phosphate (CsH2PO4) at 250°C. Furthermore, the proton conductor 5 according to this embodiment has a higher conductivity at 600°C than that of various solid electrolytes used in SOFCs.

[0106] also, Figure 3 The top right corner shows Nafion, an organic polymer ion exchange membrane used in automotive fuel cells. TM (Nafion TM The conductivity of the proton conductor 5 according to this embodiment is equivalent to that of Nafion at temperatures between 500°C and 600°C. TM Conductivity of the ion exchange membrane at an operating temperature of approximately 90°C. Using Nafion. TM The PEFC with ion exchange membrane consists of a fuel cell of approximately 100 kW and is very small in size. SOFC is much larger than PEFC. When using the proton conductor 5 of this embodiment as a solid electrolyte, the operating temperature of the current SOFC can be reduced and its size can be decreased.

[0107] The proton conductor 5 according to this embodiment has a higher conductivity than cesium dihydrogen phosphate, which operates as a solid electrolyte in a temperature range between 200°C and 250°C. Furthermore, the proton conductor 5 according to this embodiment exhibits high conductivity even in a temperature range between 300°C and 600°C. The proton conductor 5 according to this embodiment has conductivity equivalent to that of Nafion used in automotive fuel cells in a temperature range of 500°C or higher. TMThe conductivity of the ion exchange membrane. Furthermore, the proton conductor 5 according to this embodiment can be used at temperatures of 600°C or higher, and the conductivity of the proton conductor 5 according to this embodiment at 600°C is equivalent to the conductivity of the solid electrolyte used in conventional SOFCs at operating temperatures of 600°C or higher. The proton conductor 5 according to this embodiment moves protons rather than oxide ions, thereby achieving high conductivity and lowering its operating temperature to approximately 600°C. Therefore, the proton conductor 5 according to this embodiment can provide a more efficient and convenient fuel cell than conventional SOFCs.

[0108] In the method for manufacturing a proton conductor according to this embodiment, Li 14-2x Zn 1+x (GeO4)4 was soaked and stirred in an acidic non-aqueous organic solution to allow Li to... 14-2x Zn 1+x The ion exchange rate between mobile lithium ions and protons in (GeO4)4 can be between 40% and 70%. When the ion exchange rate between mobile lithium ions and protons is between 40% and 70%, the structural stability of the proton conductor 5 is improved, and the conductivity is higher. In contrast, when Li... 14-2x Zn 1+x When (GeO4)4 is soaked and stirred in an aqueous acetic acid solution, it is confirmed that Li 14-2x Zn 1+x In (GeO4)4, the ion exchange rate between mobile lithium ions and the contained protons is 100%. However, the proton conductor in this case exhibits lower structural stability, with byproduct phases generated during powder forming, and a corresponding decrease in conductivity has been confirmed. When a non-aqueous solvent is used in the manufacture of the proton conductor, structural stability is improved; therefore, even though the ion exchange rate may decrease compared to the case using an aqueous solvent, conductivity increases.

[0109] Because fuel cell 1 uses a proton conductor 5 with high conductivity between 200°C and 600°C, it can generate electricity efficiently. Furthermore, since the dehydrogenation reaction is initiated using the heat generated by the cathode reaction on cathode 7, energy efficiency can be improved.

[0110] In fuel cell 1, protons are migrated by the proton conductor to the opposite electrode, thus shifting the chemical equilibrium to a lower temperature. Therefore, almost 100% of the dehydrogenation reaction can occur at 320°C or lower. Furthermore, increasing the operating temperature can promote the dehydrogenation reaction.

[0111] The inventors of this application discovered that protons can be moved by ion exchange from lithium ions to hydrogen ions (protons) in LISICON. Furthermore, the inventors of this application discovered that using a non-aqueous solution instead of an aqueous solution for ion exchange results in very high electrical conductivity. Therefore, the inventors of this application completed a fuel cell 1 (electrochemical cell) according to an embodiment. The proton conductor 5 of the fuel cell 1 according to this embodiment improves electrical conductivity compared to conventional proton conductors. As described above, the proton conductor 5 of the fuel cell 1 according to this embodiment has a very high electrical conductivity compared to the conductivity σ0.008 (Siemens / cm, S / cm) of CsH2PO4 at an operating temperature of 250°C. CsH2PO4 has been attracting attention as the material with the highest electrical conductivity. The proton conductor 5 of the fuel cell 1 according to this embodiment makes it possible to form an electrochemical cell operating at a medium temperature between 200°C and 600°C, which has not yet been put into practical use. Accordingly, the proton conductor 5 can be used for various applications besides the fuel cell 1, such as electrolytic cells.

[0112] The fuel cell 1 (electrochemical cell) according to this embodiment is expected to improve battery performance by nearly 10 times compared to conventional fuel cells using CsH2PO4 operating between 200°C and 600°C. Electrode materials containing noble metals used in conventional solid electrolyte fuel cells and electrolyzers can be used in a temperature range between 200°C and 600°C, and their reaction rates increase with increasing temperature. When the above-mentioned electrode materials are applied to direct-type fuel cells, depending on the type of fuel, a decomposition catalyst for generating hydrogen from the fuel may be required. Existing industrial thermochemical catalysts can serve as such decomposition catalysts, with sufficiently fast reaction rates. Correspondingly, the performance of the electrochemical cell using CsH2PO4 is limited by the proton conduction velocity and is considered to be proportional to the conductivity of the proton conductor. By applying the proton conductor of this embodiment, it is highly likely that the battery performance can be improved by approximately 10 times.

[0113] (Second Implementation)

[0114] In the fuel cell, according to the first embodiment, instead of methylcyclohexane, the fuel may contain at least one selected from the group consisting of ammonia, formic acid, methanol, and dimethyl ether. If ammonia is used as fuel in the fuel cell according to the first embodiment, the dehydrogenation catalyst may be replaced by a known ammonia decomposition catalyst. An ammonia decomposition catalyst is a catalyst that promotes the decomposition reaction from ammonia to hydrogen and nitrogen, and may be, for example, a ruthenium-based catalyst, a cobalt-based catalyst, or a nickel-based catalyst. When formic acid is used as fuel in the fuel cell according to the first embodiment, the dehydrogenation catalyst may be replaced by a known formic acid reforming catalyst. A formic acid reforming catalyst is a catalyst that promotes the production of hydrogen and carbon dioxide by the formic acid reforming reaction, and may be, for example, an iridium complex catalyst. When methanol is used as fuel in the fuel cell according to the first embodiment, the dehydrogenation catalyst may be replaced by a known methanol reforming catalyst. A methanol reforming catalyst is a catalyst that promotes the reforming reaction to produce hydrogen and carbon dioxide from methanol and water, and may be, for example, an iridium complex catalyst. When dimethyl ether is used as fuel in the fuel cell according to the first embodiment, the dehydrogenation catalyst may be replaced by a known dimethyl ether reforming catalyst. Any reaction that produces hydrogen from ammonia, formic acid, methanol, or dimethyl ether is endothermic. Therefore, the heat generated by the cathode reaction can be used to accelerate the reaction.

[0115] In another embodiment, hydrogen can be supplied as fuel to the anode chamber 8. In this case, the dehydrogenation catalyst in the anode chamber 8 can be omitted.

[0116] (Third Implementation)

[0117] like Figure 4 As shown, each power generation cell 2 of the fuel cell according to the first embodiment can be used as an electrolyzer 50. In this case, the proton conductor 5 acts as an ion exchange membrane, while the first separator 9 and the second separator 12 act as a container 52. The anode 55 is connected to the positive terminal of the DC power supply 53, and the cathode 56 is connected to the negative terminal of the DC power supply 53. Accordingly, a DC voltage is applied between the anode 55 and the cathode 56. The anode 55 and the cathode 56 are electrically insulated from the container 52. The anode chamber 58 and the cathode chamber 59 are separated from each other by the proton conductor 5. A first substance to be oxidized can be supplied to the anode chamber 58, and a second substance to be reduced can be supplied to the cathode chamber 59.

[0118] Electrolytic cell 50 can be used for electrolysis in a temperature range of 200°C to 600°C. For example, electrolytic cell 50 can be used for high-temperature steam electrolysis. Water vapor can be supplied to the anode chamber 58 as the first substance. No substance may be supplied to the cathode chamber 59, or a purge gas such as water vapor or nitrogen may be supplied to the cathode chamber 59 as the second substance. In electrolytic cell 50, water molecules transfer electrons to the anode 55, thus forming oxygen and protons at the anode 55 (2H₂O → O₂ + 4H₂O). + +4e - The protons formed at the anode 55 pass through the proton conductor 5 and move to the cathode 56. The protons then accept electrons at the cathode 56, thereby forming hydrogen molecules (2H₂O). + +2e - →H2). Accordingly, oxygen is formed in the anode chamber 58 and hydrogen is formed in the cathode chamber 59.

[0119] Electrolyzer 50 can be used to electrolyze hydrocarbons or ammonia in a temperature range between 200°C and 600°C. For example, electrolyzer 50 can be used to generate hydrogen from hydrocarbons. In this case, instead of a dehydrogenation catalyst, a reforming catalyst is provided in the anode 55 of electrolyzer 50. Hydrocarbon gas and water vapor can be supplied as first substances to the anode chamber 58. The hydrocarbons may include at least one selected from the group consisting of methylcyclohexane, formic acid, methanol, and dimethyl ether. The hydrocarbons may include smaller hydrocarbons such as methane, ethane, propane, and butane. In electrolyzer 50, hydrocarbons and water transfer electrons to the anode 55, thus forming protons and carbon monoxide in the anode 55. The protons move through the proton conductor 5 to the cathode 56. The protons then accept electrons at the cathode, thereby becoming hydrogen molecules. Accordingly, carbon monoxide is formed in the anode chamber 58 and hydrogen molecules are formed in the cathode chamber 59, thereby forming syngas by electrolyzing hydrocarbon gas. Since only hydrogen gas is formed in the cathode chamber 59, high-purity hydrogen can be produced. Electrolysis can also be carried out under pressure. In this case, the pressure of the gas supplied to the anode chamber 58 and cathode chamber 59 of the electrolytic cell 50 can be increased.

[0120] Furthermore, the electrolytic cell 50 can be used to electrolyze and reduce carbon dioxide gas within a temperature range between 200°C and 600°C. For example, the electrolytic cell 50 can be used to generate synthesis gases such as ethylene from carbon dioxide by electrolysis. In this case, instead of a dehydrogenation catalyst, a carbon dioxide reduction catalyst is provided at the anode 55 of the electrolytic cell 50. For example, the carbon dioxide reduction catalyst contains at least one Group 11 element such as copper, a Group 12 element such as zinc, a Group 13 element such as gallium, a Group 14 element such as germanium, or a metal compound thereof. Water, as the first substance, can be supplied to the anode chamber 58, and carbon dioxide gas, as the second substance, can be supplied to the cathode chamber 59. In the electrolytic cell 50, carbon dioxide is reduced, and thus ethylene and water (2CO2 + 12H2O) are formed in the cathode 56. + +12e - →C2H4+4H2O). Water is oxidized, thus oxygen is formed at the anode (2H2O→O2+4H). + +4e - Accordingly, oxygen is formed in the anode chamber 58 and ethylene is formed in the cathode chamber 59.

[0121] One method uses a solid oxide electrolytic cell (SOEC), which electrolyzes water into water vapor at temperatures above 600°C using oxides as a solid electrolyte. Since the theoretical voltage required for water electrolysis decreases with increasing temperature, and a portion of the energy required for electrolysis is given as heat, this method reduces the energy supplied in the form of electricity. However, due to the high operating temperature above 600°C, it is difficult to start and stop as quickly as a SOFC, leading to operational issues. Furthermore, like a SOFC, maintaining a tight seal at 600°C or higher temperatures, and potentially requiring materials that are stable at 600°C or higher for extended periods, can result in high costs. The electrolytic cell 50 according to this embodiment utilizes a proton conductor 5 as an ion exchange membrane, which exhibits high conductivity in a moderate temperature range of 200°C to 600°C. Therefore, electrolysis at equivalent current densities can be performed at temperatures below 600°C.

[0122] The electrolytic cell 50 according to this embodiment can also be applied to methods for the electrochemical production of light hydrocarbons such as ethylene and formic acid from carbon dioxide and hydrogen. Typically, this method may slow down the reaction rate because a polymer membrane is used as an ion exchange membrane. The electrolytic cell 50 according to this embodiment operates between 200°C and 600°C, thereby increasing the current density. Therefore, a compact electrolytic cell can be achieved.

[0123] The electrolytic cell 50 according to this embodiment can be applied to a method for selectively separating, compressing, and pressurizing hydrogen in a hydrogen-containing gas. The electrolytic cell 50 according to this embodiment operates between 200°C and 600°C, thereby effectively purifying and compressing hydrogen.

[0124] [Example]

[0125] (Li 14 Preparation method of Zn(GeO4)4

[0126] The lithium source was lithium carbonate, the zinc source was zinc oxide, and the germanium source was germanium oxide. Lithium carbonate, zinc oxide, and germanium oxide were added in a weight ratio of 25:4:21. These sources were then pulverized and mixed with ethanol and zirconium oxide balls for 24 hours to form a slurry in a sealed container. The slurry was dried at 130°C to obtain a powder, which was then granulated using a press. These granules were calcined in air at 1150°C for 5 hours in an alumina crucible. Subsequently, the calcined granules were ground in magnetic slurry for 2 hours, and the ground product was again granulated. The granules were then calcined in air at 1150°C in an alumina crucible for 5 hours. The calcined granules were again ground in magnetic slurry for 2 hours to obtain untreated Li₂O₃. 14 Zn(GeO4)4 powder.

[0127] (Example 1)

[0128] Toluene, dehydrated using a dehydrating agent, was used as a non-aqueous solvent. Benzoic acid, with a concentration of 5 mmol, was dissolved in toluene as a proton source to form a non-aqueous organic solution. 2.5 g of Li before ion exchange was... 14 Zn(GeO4)4 powder sample was stirred with 100 mL of non-aqueous organic solution for 24 hours for ion exchange. After ion exchange, the sample was filtered and the powder was collected. The powder was washed with toluene and then dried overnight under vacuum at 130°C to obtain the ion-exchanged powder of Example 1. According to Example 1, the ion exchange rate between mobile lithium ions and protons in the proton conductor was 52%.

[0129] (Comparative Example 1)

[0130] Li before ion exchange 14 Zn(GeO4)4 powder was added to a 5 mmol aqueous solution of acetic acid, which was 40 times its weight in volume, and stirred at room temperature for 24 hours to perform ion exchange. After ion exchange, the mixture was filtered and washed, and then dried in a vacuum dryer at 130°C. This yielded the ion-exchange product of Comparative Example 1. According to Comparative Example 1, the ion exchange rate between mobile lithium ions and protons in the proton conductor was 100%.

[0131] (Comparison of Example 1 and Comparative Example 1)

[0132] The conductivity of the ion exchangers in Example 1 and Comparative Example 1 was measured. The measurements were performed using an electrochemical evaluation apparatus (Solartron Analytical's ModuLab) with both DC four-terminal and AC two-terminal methods in a 10% humidified nitrogen atmosphere. The results are shown in Table 1 below.

[0133] [Table 1]

[0134]

[0135] As shown in Table 1, it was confirmed that the conductivity of Example 1 was higher than that of Comparative Example 1.

[0136] (Example 2)

[0137] Dimethyl sulfoxide was used as the non-aqueous solvent, and m-nitrophenol, acetic acid, benzoic acid, p-toluenesulfonic acid, oxalic acid, and methanesulfonic acid were used as proton sources. Ion exchange was performed using the same method as in Example 1, while varying the concentration from 5 mmol to 100 mmol. Then, the Li undergoing ion exchange was... 14 Thermogravimetric analysis was performed on Zn(GeO4)4 powder to measure its ion exchange capacity. The results showed that the ion exchange capacity per proton source ranged from 45% to 65%.

[0138] [Industrial Applicability]

[0139] The fuel cell according to this embodiment, in addition to conventional fuel cells using hydrogen as fuel, can also be used as a direct-type fuel cell using various fuels. Furthermore, the fuel cell according to this embodiment can be converted into an electrolyzer, which utilizes a reaction opposite to that of a fuel cell. The fuel cell according to this embodiment can operate between 200°C and 600°C, thereby increasing the rate of the electrochemical reaction compared to fuel cells using polymer membranes and operating at 100°C or lower. Furthermore, the fuel cell according to this embodiment can operate between 200°C and 600°C, thereby relaxing material limitations compared to SOFCs operating at 600°C or higher. Moreover, in this embodiment, proton movement occurs in the fuel cell, thereby increasing the reaction rate compared to SOFCs where oxygen ions move. As described above, the fuel cell and electrolyzer according to this embodiment have extremely high industrial applicability.

[0140] Specific embodiments of the present invention have been described above, but the present invention should not be limited to the foregoing embodiments. Various modifications and changes can be made within the scope of the present invention.

[0141] Figure Labels

[0142] 1: Fuel Cell (Electrochemical Battery)

[0143] 2: Power generation battery (electrochemical battery)

[0144] 3: Fuel cell stack

[0145] 5: Proton conductor

[0146] 6: Anode

[0147] 6A: Anode catalyst layer

[0148] 6B: Anode gas diffusion layer

[0149] 7: Cathode

[0150] 7A: Cathode Catalyst Layer

[0151] 7B: Cathode gas diffusion layer

[0152] 8: Anode Chamber

[0153] 9: First separator

[0154] 11: Cathode Chamber

[0155] 12: Second separator

[0156] 25: Negative electrode

[0157] 26: Positive electrode

[0158] 41: Temperature Regulator

[0159] 50: Electrolytic cell (electrochemical battery)

[0160] 52: Container

[0161] 53: DC power supply

[0162] 54: Container

[0163] 55: Anode

[0164] 56: Cathode

[0165] 58: Anode Chamber

[0166] 59: Cathode Chamber

Claims

1. An electrochemical battery, comprising: With (Li, H) 14-2x Zn 1+x (GeO4)4 represents a proton conductor, in which Li 14-2x Zn 1+x Part of the lithium ions in (GeO4)4 are replaced by protons, where x is a number equal to or greater than 0, and the proton conductor has a conductivity of 0.01 Siemens / cm or higher at 300°C. The anode is disposed on one side of the proton conductor; A cathode is disposed on the other side of the proton conductor; A first partition is disposed on the anode side of the proton conductor to define the anode chamber; as well as A second partition is disposed on the cathode side of the proton conductor to define a cathode chamber; Among them, Li 14-2x Zn 1+x The mobile lithium ions contained in (GeO4)4 are replaced by protons in the range of 40% to 70%.

2. The electrochemical battery of claim 1 further includes a temperature regulator configured to maintain the temperature of the proton conductor in a range between 200°C and 600°C.

3. The electrochemical battery according to claim 1, wherein, The x is 0.

4. The electrochemical battery according to claim 1, wherein, Li 14-2x Zn 1+x The mobile lithium ions contained in (GeO4)4 are replaced by protons in the range of 50% to 60%.

5. The electrochemical battery according to claim 1, further comprising a plurality of batteries, each battery comprising the proton conductor, the anode, the cathode, the first separator, and the second separator. in, The first separator of one of the plurality of batteries comes into contact with the second separator of another of the plurality of batteries to exchange heat.

6. The electrochemical battery according to any one of claims 1 to 5, wherein, Hydrogen is supplied to the anode chamber. Air is supplied to the cathode chamber, and An electromotive force is generated between the anode and the cathode, and the electrochemical cell functions as a hydrogen-oxygen fuel cell.

7. The electrochemical battery according to any one of claims 1 to 5, wherein, A hydrogen-containing compound is supplied to the anode chamber. Air is supplied to the cathode chamber. A catalyst layer comprising a catalyst configured to generate hydrogen from the hydrogen-containing compound is disposed in the anode chamber, and An electromotive force is generated between the anode and the cathode, and the electrochemical cell functions as a hydrogen-oxygen fuel cell.

8. The electrochemical battery according to claim 7, wherein, The hydrogen-containing compound is an organic hydride, wherein an aromatic compound having 1-3 rings is hydrogenated.

9. The electrochemical battery according to claim 7, wherein, The hydrogen-containing compound includes at least one compound selected from the group consisting of methylcyclohexane, cyclohexane, trimethylcyclohexane, decahydronaphthalene, benzyltoluene, and dibenzotriol.

10. The electrochemical battery according to claim 7, wherein, The hydrogen-containing compound includes at least one compound selected from the group consisting of ammonia, formic acid, methanol, and dimethyl ether.

11. The electrochemical battery according to claim 7, wherein, The catalyst is a dehydrogenation catalyst, comprising an alumina support and platinum supported on the alumina support; and The average particle diameter of the platinum is 2 nanometers or smaller.

12. The electrochemical battery according to any one of claims 1 to 5, wherein, Water vapor is supplied to the anode chamber. A DC power supply is connected between the anode and the cathode, and The electrochemical cell functions as an electrolytic cell to generate hydrogen gas at the cathode.

13. A method for generating electricity using an electrochemical battery according to any one of claims 1 to 5, comprising: Hydrogen gas is supplied to the anode chamber; Air is supplied to the cathode chamber; as well as The temperature of the proton conductor is maintained in the range of 200°C to 600°C.

14. A method for generating electricity using an electrochemical battery according to any one of claims 1 to 5, comprising: A catalyst layer is provided in the anode chamber, the catalyst layer being configured to generate hydrogen from hydrogen-containing compounds; The hydrogen-containing compound is supplied to the anode chamber; Air is supplied to the cathode chamber; as well as The temperature of the proton conductor is maintained in the range of 200°C to 600°C.

15. The power generation method according to claim 14, wherein, The hydrogen-containing compound is an organic hydride, wherein an aromatic compound having 1-3 rings is hydrogenated.

16. The power generation method according to claim 14, wherein, The hydrogen-containing compound includes at least one compound selected from the group consisting of methylcyclohexane, cyclohexane, trimethylcyclohexane, decahydronaphthalene, benzyltoluene, and dibenzotriol.

17. The power generation method according to claim 14, wherein, The hydrogen-containing compound includes at least one compound selected from the group consisting of ammonia, formic acid, methanol, and dimethyl ether.

18. The power generation method according to claim 14, wherein, The catalyst in the catalyst layer is a dehydrogenation catalyst, comprising an alumina support and platinum supported on the alumina support; and The average particle diameter of the platinum is 2 nanometers or smaller.

19. A method for producing hydrogen using electrolytic cell electrolysis according to any one of claims 1 to 5, comprising: Water vapor is supplied to the anode chamber; The temperature of the proton conductor is maintained within the range of 200°C to 600°C; as well as A DC voltage is applied between the anode and the cathode, and hydrogen gas is generated at the cathode.

20. A method for producing hydrogen using electrolytic cell electrolysis according to any one of claims 1 to 5, comprising: A catalyst layer is provided in the anode chamber; Ammonia or at least one hydrocarbon selected from the group consisting of methylcyclohexane, formic acid, methanol and dimethyl ether is supplied to the anode chamber; The temperature of the proton conductor is maintained within the range of 200°C to 600°C; A DC voltage is applied between the anode and the cathode; as well as The protons are generated from the ammonia or hydrocarbon by the catalyst in the catalyst layer in the anode chamber, and the protons move through the proton conductor to the cathode, where hydrogen is generated.

21. A method for producing hydrogen using electrolytic cell electrolysis according to any one of claims 1 to 5, comprising: Electrolysis is carried out under pressure.

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