RU2625460C2 - Tube element of electrochemical device with thin-layer solid-oxide electrolyte (versions) and method of its manufacture - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: proposed tubular fuel cell with a thin-layer solid oxide electrolyte, gas diffusion electrodes, interface and collector layers is made with monolithic end bosses that have a smooth transition to the electrolyte. Reducing the thickness of the carrier solid electrolyte is achieved due to end thickenings and/or of carcass in the working area, as well as by increasing the thickness of one or both current electrode collectors. The cylindrical or weakly cone tube of the carrier electrolyte is made of ceramics with an average crystallite size of less than 500 nm, has a wall thickness of less than 0.3 mm With end thickenings up to 0.5 mm and thin-layered 15-20 mcm electrodes located on the lateral surface of the electrolyte in the interval between the end thickenings. The method for manufacturing a tubular element includes the use of nanoscale solid electrolyte powders, micro-sized and nanoscale powders of electrode materials and interface layers prepared in the form of films with a polymeric binder, from which a multilayer preform of the element is formed by winding the films onto a rod, laminating layers of the preform, for example, by magnetic pulse method and at least two-stage sintered together at temperatures below 1300°C.

EFFECT: improvement of manufacturability of production of solid oxide element, reduction of mass and dimensions characteristics and increase of electrical and resource characteristics of fuel cell.

8 cl, 7 dwg

Description

Area of use

The invention relates to high-temperature electrochemical devices (ECUs), such as electrochemical current generators on fuel cells, oxygen pumps, electrolyzers, converters, etc., based on solid oxide cells (TOE) - cells with solid oxide electrolyte. More precisely, to the design of the solid oxide element of these devices and the method of its manufacture.

State of the art

The high operating temperature of ECC on solid oxide elements, up to 1000 ° C, necessary to ensure high electrical and electrochemical characteristics of the device, determines a number of requirements and restrictions on the design and materials of its component components: solid electrolyte, electrodes, current collectors, current passages, current leads, as well as others structural parts, which are all in an elevated temperature zone. Known ECUs contain TOE - analogues, for example, fuel cells, with a solid electrolyte most often based on zirconium dioxide, having a tubular, planar or block (monolithic) electrolyte structure with a gas diffusion anode and cathode deposited. Analogues of the element and the method of its manufacture are described in detail in the monograph [Perfilyev M.V. High-temperature electrolysis of gases / M.V. Perfiliev, A.K. Demin, B.L. Kuzin, A.S. Lipilin. - M .: Nauka, 1988. - 232 p.].

In constructions with a supporting electrolyte, it is advisable to consider it as the main component. The solid electrolyte itself, often used and the most durable, based on zirconia stabilized with yttrium oxide (YSZ) or scandium (ScSZ), and alternative ones based on cerium, gallium or bismuth oxides, is a ceramic that by its nature temperatures has a fairly low strength. Moreover, in devices with separated gas spaces, whether it is a fuel and an oxidizing chamber in a fuel cell or an air and oxygen chamber of an oxygen pump, a solid oxide cell in the temperature range of 800-1000 ° C must ensure inter-cavity tightness: in a solid electrolyte, the presence of through porosity and cracks. Until now, in structures with a supporting electrolyte in the form of a pipe (test tube), it has been used with a wall thickness of at least 0.5 mm, which is primarily due to the capabilities of existing technologies (extrusion, slip casting, etc.), as well as the need to ensure its gas tightness and mechanical strength. Moreover, the large thickness of the solid electrolyte causes, firstly, an increased consumption of material of the solid electrolyte, and secondly, losses on the ohmic resistance of the element, which reduce its electrical efficiency and increase in direct proportion to its thickness. Reducing the thickness of a solid electrolyte is an important technical task, especially in structures where it is a supporting component of the system.

Description of analogues

The authors consider, for example, RF patent No. 2178560 [Cell of a high-temperature element of an electrochemical device with a solid electrolyte, G01N 27/406, Vostrotin VA, Grechko MV, Zakutnev AD, as analogues of an element of an electrochemical device with a supporting solid electrolyte, Krylova O.E., Kulaev V.V., Lukashenko I.G., Ustyugov A.V., Chukharev V.F., application filing date: 09/17/1998, publication date. formulas: 06/27/2000]. The analogue used an element of an electrochemical device in the form of a test tube made of a solid electrolyte with uniformly applied gas diffusion electrodes and organized current collection and current transport through granular filling (for example, from electrode material) along the element with the internal and external tubes leading to the end part (s) of the tube metal down conductors. In this case, the internal down conductor performs the function of a gas outlet. In this sense, one should understand an element of an electrochemical device that does not have a current passage along the generatrix of the pipe. The disadvantage of this element should be considered increased internal losses on the element (thick-walled tube), an inefficient current collection scheme using the charge collector (s) and the length (working area) of the element, which is large for the charge current collector, and, therefore, low electrical efficiency.

To the analogues of the method of manufacturing an element of an electrochemical device, more precisely its electrochemical part - structure "current collector - electrode - electrolyte - electrode - current collector", the authors attribute the known technologies [Minh N.Q. Science and technology of ceramic fuel cells / N.Q. Minh, T. Takahasi. - Amsterdam: Elsevier Science BV, 1995. - 366 p.], Which consist in the preliminary manufacture of the supporting base in the form of an electrolyte pipe or one of the internal electrodes most often by extrusion of a (thermo) plastic mass from a ceramic coarse powder and a polymer binder, or other methods: injection under pressure into the mold, slip casting the suspension from the powder into the mold, followed by drying, spraying or “freezing” on the core, pressing, etc. Then, the base is sintered completely or partially at high temperature temperature and subsequent application of the following layers by methods known from the prior art.

The disadvantages of analogues include a large number of operations of applying functional layers and heat treatment at high temperature, up to 1600 ° C. The high temperature necessary to ensure, for example, the gas-tight state of the solid electrolyte layer or high conductivity and strength of one of the supporting electrodes, causes high production costs, complicates or makes it impossible to sinter the functional layers of the cell together, and also leads to a decrease in the electrochemical activity of the electrodes. In addition, these methods are unsuitable for the manufacture of tubular elements with a thin-layer solid electrolyte as a supporting component. Note that reducing the number of operations in the manufacture of an element and the temperature of technological annealing will help reduce the cost of products.

The authors consider patent [US 6974516 B2, C03B 29/00, H01M 8/00, "Method of making laminate thin-wall ceramic tubes and said tubes with electrodes, particulary for solid oxide, the closest analogue to the prototype of the element, as well as the method for its manufacture. fuel cells ”, Alan Devoe, Mary Trinh, application filing date: 02/23/2004, publ. formulas: January 6, 2005], which describes an element of an electrochemical device of a tubular structure with a thin-walled carrier, several hundred microns, a solid oxide electrolyte and gas diffusion electrodes, having thickened end parts with respect to the middle part of the element to ensure mechanical strength.

The disadvantages of the element of the electrochemical device of the prototype include the large length (working area) of the tubular element of the electrochemical device, which, according to the description, is 20-100 cm with a diameter of less than 6 mm, which is an irrational technical condition for transporting current from a single element through its end (s) a solution that reduces its electrical efficiency. The thickened end parts of the element most likely fulfill the function of hardening for mechanical fixation to a gas or current collector, for example, by a clamp. In addition, thickenings at the ends made of electrolyte material are located on top of the structure of the element itself, i.e. on top of the outer one of the porous electrodes, and, thus, there is no integrated integrity of the thickening and the supporting pipe of the electrolyte. In this case, the electrode layers exit to the end face of the element, and there is the possibility of their closure.

A method of manufacturing an element of an electrochemical device (prototype), proposed in patent US 6974516 B2, consists in forming part or all of the structure of this element (in layers) by sequentially winding films of SOFC components with a polymer binder onto the rod, laminating the workpiece in an aqueous hydrostat at a pressure of 20- 35 MPa, removing the rod and subsequent sintering. Coarse powders are supposed to be used in films, which becomes clear from the indicated values of lamination pressure, as well as linear shrinkage during sintering of the material. Films based on polyvinyl butyral (PVB) from coarse powders, although they are sufficiently plastic, nevertheless, they require the use of higher pressure to obtain monolithic preforms free of layer defects and microporosity. In addition, when using coarse-grained electrolyte powder, the content of which in the film does not exceed 55-60% in volume, at the temperatures of joint sintering of the components of the solid oxide element without significant solid-phase interaction, i.e. no more than 1250-1300 ° C, it is almost impossible to get a dense thin layer of solid electrolyte without open porosity. The prototype authors use, presumably, partially stabilized zirconia (about 3 mol.% Yttrium oxide) in tetragonal modification. Only this allows us to talk about the possibility of implementing their proposed element design in this way. The use, for example, of the most preferred zirconia in cubic modification or other materials having many times the ionic conductivity, but less strength and processability compared to zirconia in tetragonal modification is a more complex and urgent task.

Disclosure of invention

The aim of the present invention is to provide a tubular element of an electrochemical device with a thin-layer solid oxide electrolyte, devoid of most of the disadvantages of the prototype.

The technical challenge is the design and method of manufacturing SOE, namely: to propose the design of a tubular element of an electrochemical device based on a thin-layer, less than 0.3 mm, supporting solid electrolyte with gas diffusion electrodes, interface and collector layers, structurally possessing the necessary strength and regularity of the end parts, improved electrochemical characteristics, as well as the method of its manufacture.

This goal is achieved due to the design of the tubular element of the electrochemical device with a thin-layer solid oxide electrolyte, gas diffusion electrodes, interface and collector layers, having thickenings at the ends, in which the necessary mechanical strength is ensured by all its components, and an additional decrease in the thickness of the solid electrolyte in the working part is achieved due to thickening at the ends and / or frame in the working area with a smooth transition to a thin electrolyte.

It is advisable to produce a cylindrical or slightly conical carrier electrolyte pipe from ceramics with an average crystallite size of less than 500 nm with a wall thickness of the working part of the solid electrolyte of 0.03-0.3 mm and thickenings at the ends of the pipe about 0.2-0.4 mm with thin layers, 15 -20 μm, with electrodes located on the lateral inner and outer surfaces of the solid electrolyte in the interval between the end thickenings, which additionally include interface and collector layers. It is advisable to have a cell length of small, not more than 100 mm, to form a battery by a series connection of the end-to-end elements. The end parts of the element of the electrochemical device are free of electrodes whose length is less than the length of the element by the total width of the end thickenings. This completely eliminates the possibility of their closure and increases the manufacturability of the assembly when using high-temperature adhesives (for example, glass sealants). Additionally, at the interface of each electrode with the electrolyte, thin, no more than 5 microns, interface layers for various purposes can be located: catalytic, barrier, etc. The use of a solid electrolyte with a fine crystalline structure (in the submicron range) provides it with stable improved electrical and mechanical characteristics compared to traditional coarse-grained material of the same composition [see, for example, A. Spirin, V. Ivanov, A. Nikonov, et al . Scandia-stabilized zirconia doped with yttria: synthesis, properties, and aging behavior, Solid State Ionics, 225 (2012), P. 448-452], and also to a greater extent guarantees the absence of open porosity of a layer of solid electrolyte of small thickness, which should not be less than 0.03 mm for reasons of lack of through porosity and ensuring strength. Moreover, the upper limit of the wall thickness of the electrolyte pipe is due to the existing level of technology. The thickenings at the ends of the solid electrolyte pipe serve to ensure stable cylindrical geometry of the end parts of the element of the electrochemical device during its manufacture, i.e. minimize their deformation (the formation of ellipse), which is realized for various reasons during sintering of thin-walled products. In addition, end thickenings provide the necessary mechanical strength to the already sintered thin-walled ceramic element and, therefore, manufacturability when assembling the elements into the battery, and also increase the resistance of the ends under conditions of sealing with high-temperature sealants. The thickness and width of the end thickenings are selected in such a way as to satisfy the specified requirements for specific geometric dimensions of the element of the electrochemical device, the ratio of length and diameter, as well as the material used. In this case, the end thickenings can be formed from a material having increased strength in comparison with the solid electrolyte material, provided that they have chemical affinity and the thermal expansion coefficients are close. Such materials may be, for example, partially stabilized zirconia or a composite based on solid electrolyte material. To minimize stresses that usually occur during sintering of ceramic parts with ledges, the transition from structural end thickenings to the working thin-walled part of the electrolyte pipe is made smooth, in contrast to the prototype electrochemical device. The diameters of the opposite ends of the tubular element may differ by the size of the technological cone, due to the manufacturing method. In this case, the weak taper of the solid oxide element provides a more snug fit of the mating parts of the current switching.

The design options for the TOE are illustrated by the drawings in FIG. 1-5, where longitudinal sections of tubular SOE (10) with a thin-layer solid electrolyte (11), hardened cylindrical ends (12) and thin-layer electrodes (13, 14) are schematically presented. A TOE can be implemented both with a carrier electrolyte (11) with a thickness of 0.03-0.3 mm (Fig. 1), and with a carrier one of the electrodes (13) or (14) (Fig. 2, 3), more precisely , their current collector (15) or (16), or supporting both electrodes, more precisely, their current collectors (15 and 16) (Fig. 4). Between layers (11) and (13), (11) and (14), additional interface layers for various purposes (not shown in the drawings) may be located. The design options of the latter differ from the initial one by a reduced thickness of the electrolyte (11) in the middle working part of the cell due to an increase in the thickness of one or both electrodes, more precisely, of their current collectors. The use of a current collector instead of an electrode as a supporting component is a more rational technical solution, since electrode layers of materials with a mixed type of conductivity are necessary for the implementation of an electrochemical reaction that proceeds at the phase boundary — the three-phase electrolyte-electrode-gas interface. Therefore, the thickness of this reaction region is not advisable to make more than 50 microns, preferably 10-20 microns. In addition, the materials of current collectors have higher electronic conductivity compared to electrode ones, and, therefore, can be made more porous to reduce difficulties in the delivery of reagents to the corresponding three-phase boundary.

In variants of the design of a SOFC with one of the current collectors as a carrier, it is more preferable to use one that makes a greater contribution to the total resistance of the element, for example, a ceramic SOFC based on manganites, cobaltites and chromites instead of a cermet anode, for example, based on Ni with the addition of material solid electrolyte based on stabilized ΖrO ₂ (Y ₂ O ₃ —ZrO ₂ , Sc ₂ O ₃ ), doped with CeO ₂ (Gd ₂ O ₃ —CeO ₂ , Sm ₂ O ₃ —CeO ₂ , etc.).

It is also possible to design a TOE (Fig. 5) with a supporting solid electrolyte and thin-layer electrodes, which differs from the initial one in that in the middle working part the electrolyte pipe is made with recesses - cells having up to several times smaller wall thickness relative to the wall thickness of the main electrolyte pipe , which can now be considered as a frame (17). At the same time, the bearing capacity of the electrolyte pipe is preserved and the internal losses on the cells and element of the electrochemical device as a whole are reduced. The cells of the tubular frame of the electrolyte may have a symmetrical shape, i.e. be rectangular, triangular, round, hexagonal, etc. or have any shape under the condition of a high fill factor of the pipe surface.

The essence of the invention is illustrated by drawings in FIG. 1-7.

In FIG. 1 shows a schematic illustration of a tubular element of an electrochemical device 10 (option 1) with a supporting thin-layer solid electrolyte, which has: 11 - a working layer of solid electrolyte, 12 - structural thickening of the electrolyte pipe, 13 - gas diffusion internal electrode, 14 - gas diffusion external electrode (between layers 11-13, 11-14 are interface layers, not shown in the drawings).

In FIG. 2 shows a schematic illustration of a tubular element of an electrochemical device 10 (option 2) with a thin layer solid electrolyte and a supporting current collector of the internal electrode, which has: 11 - a working layer of solid electrolyte, 12 - structural thickening of the electrolyte pipe, 13 - gas diffusion internal electrode, 14 - gas diffusion external electrode, 15 - gas diffusion current collector of the internal electrode (between layers 11-13, 11-14 there are interface layers not shown in the drawings).

In FIG. 3 shows a schematic illustration of a tubular element of an electrochemical device 10 (option 3) with a thin layer solid electrolyte and a supporting current collector of the external electrode, which has: 11 - a working layer of solid electrolyte, 12 - structural thickening of the electrolyte pipe, 13 - gas diffusion internal electrode, 14 - gas diffusion external electrode, 16 - gas diffusion current collector of the external electrode (between layers 11-13, 11-14 there are interface layers not shown in the drawings).

In FIG. 4 shows a schematic illustration of a tubular element of an electrochemical device 10 (option 4) with a thin layer solid electrolyte and supporting both current collectors, which has: 11 - a working layer of solid electrolyte, 12 - structural thickening of the electrolyte pipe, 13 - gas diffusion internal electrode, 14 - gas diffusion external electrode, 15 - gas diffusion current collector of the internal electrode, 16 - gas diffusion current collector of the external electrode (between layers 11-13, 11-14 are interface layers, not shown in the drawings).

In FIG. 5 shows a schematic illustration of a tubular element of an electrochemical device 10 (option 5) with a supporting thin-layer solid electrolyte in the form of a frame, which has: 11 - a working layer of solid electrolyte, 12 - structural thickening of the electrolyte pipe, 13 - gas diffusion internal electrode, 14 - gas diffusion external electrode 15 - gas diffusion current collector of the internal electrode, 16 - gas diffusion current collector of the external electrode, 17 - mesh frame of a solid electrolyte pipe with cells 11; FIG. 5 also contains an isometric image of a solid electrolyte tube without electrodes.

In FIG. 6 shows a diagram of radial magnetic pulse pressing in an inductor, in which: 1 - a spiral single-layer inductor, 2 - a metal sheath (for example, copper), 3 - a forming core, 4 - a multilayer blank from a film, 5 - a buffer layer of powder, 6 - sealed plug (elements 2-6 make up the mold).

In FIG. Figure 7 shows the appearance of tubular solid oxide elements of an electrochemical device with a three-layer structure, an electrode-electrolyte-electrode, based on a YSZ supporting solid electrolyte with a thickness of about 150-200 μm.

In the general case, the solid electrolyte material for the proposed TOE options can be a finely structured ceramic based on stabilized ΖrO ₂ , with the general formula (A _y B _1-y ) _x Zr _1-x O _2-δ (A, B-Nd, Gd, Dy, But, Y, Er, Tm, Yb, Lu, Se, Ca, Mg, etc.), where 0.05≤x≤0.20, 0≤y≤1; based on cerium dioxide with a fluorite-type structure, Ln _x Ce _1-x O _2-δ or (Ln _0.95-y Sr _y Ba _0.05 ) _x Ce _1-x O _2-δ (Ln-Sm, Gd, La), where 0.15≤x, y≤0.20; based on lanthanum gallate with a perovskite-like structure, (La _1-x Sr _x ) (Ga _1-y Mg _y ) O _3-δ , where 0.12≤x≤0.20, 0.10≤y≤0, 20 and others, with the choice of the wall thickness of the pipe in the working part in the range of 0.03-0.3 mm, based on the provision for the selected material of the carrying capacity of the electrolyte pipe.

Depending on the type of electrode materials used, the proposed TOE variants according to the present invention can have various applications: a fuel cell (electrolysis cell), an oxygen pump, a converter, etc. In this case, the electrodes are usually made of composite materials with mixed ion-electron conductivity, one of which is stable in an oxidizing atmosphere, e.g., a composite La _1-x Sr _x MnO _3-δ (LSM) -YSZ, other - in a reducing atmosphere, e.g., cermet Ni-YSZ, wherein the first applications for the anode or cathode of yshenazvannyh materials located on the inner or on the outer surface of the element. In the case of an oxygen pump, the element has both electrodes stable in an oxidizing atmosphere, and in the case of a converter, the element has both electrodes stable in a reducing atmosphere.

The task of the technical performance of the TOE options is solved by forming a heterostructure of the entire element or its majority (for example, a semi-element) with functional layers and structural parts that differ both in composition (components of the ECM element) and in morphology (dense, porous), from ultrafine and nanoscale powders in one molding operation and subsequent joint sintering of layers of a ceramic element at a temperature lowered to 1100-1250 ° C.

According to the present invention, the method involves the use of weakly aggregated solid electrolyte nanopowders, for example, based on ZrO ₂ (8.5-10 mol.% Y ₂ O ₃ , Sc ₂ O ₃ ), with a particle size of 10-20 nm and a specific surface area of at least 55 m ² / g, which at a temperature of about 1100-1250 ° C and an initial relative density of the powder of about 50-55% allows you to get thin gas-tight (hydrogen) ceramic layers with a relative density of at least 97% while maintaining a small crystallite size in the range of 100 -500 nm. The remaining fraction in the ceramic volume (~ 3%) is occupied by closed pores with a characteristic size of tens of nanometers. As you know, the fine structure of ceramics, which is realized during low-temperature sintering in the range of 1050–1300 ° C, determines the improved ceramic performance: electrical, mechanical, and thermophysical. In addition, the reduced sintering temperature significantly expands the possibilities for joint sintering of electrolyte layers with electrode layers, for example, based on manganites, cobaltites and lanthanum-strontium chromites. The use of ultrafine powders of electrode materials allows one to obtain electrodes with high electrochemical activity, not inferior to the activity of electrodes from Pt. The use of films for the manufacture of a tubular electrochemical cell, for example, by winding (winding) functional layers on a rod in the required sequence, allows reproducibly forming layers of a given geometry and thickness, up to 5-10 microns. Due to the presence of an organic binder in the film, for example, PVB, and their small thickness, the films are sufficiently plastic. A more plastic state is realized when heated to a temperature of 70-120 ° C, which can be advantageously used when laminating layers. The shrinkage characteristics of the components of the cell, electrolyte, electrodes, etc., which is one of the main tasks for joint sintering, are controlled by varying the content of active powder in the film, varying the dispersion of powder particles, and also introducing into films, for example, from electrode materials , various passive components, for example, carbon powder as a blowing agent. The use of magnetic-pulse technology for laminating a multilayer billet of films is considered a very promising way. Lamination of the blanks is carried out by radial compression of a thin-walled metal pipe, inside which a multilayer blank of films on a rod (collectively a mold) is concentrically placed, under the influence of an external pulsed pressure on the shell. The pressure on the shell is exerted by the pulsed magnetic field of the inductor, for example, a spiral single-layer solenoid, along the turns of which a pulsed current flows when it is discharged onto the solenoid of a capacitor bank. The duration of the current pulse (field) varies in the range of 50-200 μs, the amplitude of the magnetic field pressure is up to 300 MPa [see, for example, S. Paranin, V. Ivanov, A. Nikonov, et al. Densification of Nano-Sized Alumina Powders under Radial Magnetic Pulsed Compaction, Advances in Science and Technology, 45 (2006), pp. 899-904]. The mold is placed in the cylindrical channel of the inductor (Fig. 6), while the impact on the metal pipe is non-contact, which greatly simplifies the automation of the process. Lamination can be done with a vacuum inside the mold (or without it), as well as with preheating (or without it). In the mold, the gap between the metal pipe and the rod on which the multilayer preform is formed, it is advisable to fill the buffer powder, for example, coarse powder YSZ. This ensures the uniformity of the compression pressure of the workpiece, the multiplication of pressure due to the inertial effects inherent in dynamic methods, and simplifies the extraction of the compacted compact workpiece from the film, for example, mechanically. In addition, the use of coarse powder makes it possible to create additional macro roughness on the surface of the pressed workpiece, which develops the contact area of the electrode with the electrolyte and increases the adhesion adhesion of the electrode layers to the electrolyte layer in a compact blank of an element of an electrochemical device. To simplify the extraction of the inner forming core it is made with a small cone.

Sintering of the obtained billet is carried out in an atmosphere of air in a resistive furnace, for example, in several stages that differ in heating speed and aging, providing optimal conditions for the removal of organic fillers and subsequent joint shrinkage of the components of the element.

According to the present invention, the method includes:

- Formation of thin films of solid electrolyte, for example, based on zirconia or an alternative material, 5-30 μm thick, with a thermoplastic binder, for example, polyvinyl butyral, according to the technology, for example, casting films on a lavsan substrate or extrusion followed by calendaring, using for slip weakly aggregated nanosized powders (particle size no more than 20 nm);

- Formation of thin films from composite electrode materials, for example, from LSM-YSZ, Ni-YSZ or alternative materials, with a thickness of 5-30 μm, with a thermoplastic binder, for example, polyvinyl butyral, using the indicated technologies, using active powders of various dispersion (nanoscale for preparing slips) and micro-sized) and, if necessary, passive components - blowing agents, in an amount of 10-50 vol. % in relation to the active material;

- Formation (if necessary) of thin films of interface, transition layers, for example, of (Gd ₂ O ₃ ) _x (CeO ₂ ) _1-x or an alternative material, about 5 μm thick, with a thermoplastic binder, for example, polyvinyl butyral, using the specified technologies, using nano-sized powders for slip;

- Production of film patterns in the form of stripes. Moreover, the width of the strips (equivalent to the length of the element of the electrochemical device) from electrode materials and interface layers is made less by the value of the total width of the end thickenings of the element. The length of the patterns is chosen in such a way as to provide the necessary thickness of the functional layer and approximately equals the product π⋅D⋅Δ / δ, where D is the diameter of the forming core on which the element is formed, Δ is the required wall thickness of the pipe blank, δ is the film thickness, and their Δ / δ ratio determines the required number of film layers. In this case, for a more precise control of the thickness, a correction should be introduced for the diameter D increasing with the winding of the layers;

- Formation of a multilayer element blank by winding (winding) the films of the necessary components onto a rigid rod, for example, of structural steel, including winding the first electrode layer (s) by winding, forming the first interface layer (if necessary) over the first electrode, forming the required electrolyte pipe by winding the number of layers (revolutions) so that the winding of the electrolyte symmetrically overlaps the first electrode layer, leaving sections free of electrodes at the ends of the pipe, mation second interface layer (if necessary), the formation of the outer electrode, disposed symmetrically with the first (inner) electrode and the formation of narrow bands, e.g., the electrolyte film of the end bosses, with providing the required thickness. To fabricate the design of a cell with a supporting electrolyte in the form of a frame with cells, the stage of formation of the electrolyte pipe can be divided into two, the first of which consists in winding whole stripes of film to a thickness corresponding to the thickness of the cells of the frame, and the second in laying, for example, in one thickened layer patterns with manufactured cells, for example, by cutting down;

- Lamination of all components of the tubular element of the required design with all-round pressure, for example, realized by compressing a metal pipe with a magnetic pulse method, under conditions that ensure the monolithic layers of the films and remove microporosity from the electrolyte film: when heated to a temperature, for example, for PVB - 70- 120 ° C (or without it), when discharged in a pressing tube (or without it), and a magnetic field pressure of 150-250 MPa, followed by extraction of a compact workpiece, for example, by mechanical means;

- Joint sintering of the multilayer structure of the element, which is carried out under conditions providing a gas-tight layer of solid electrolyte and porous gas diffusion electrodes, for example, by two-stage heating of a workpiece in an atmosphere of air to a temperature of 400-600 ° C at a rate of 0.05-1 ° C / min and holding 0-30 min, necessary to remove organic fillers, and final sintering when heated at a speed of 5-10 ° C / min to a temperature of 1100-1250 ° C with a holding time of 1-10 hours and cooling at a speed of 5-10 ° C / min .

Element execution example

A polyvinyl butyral-based slip (10-14 wt.%) Of slips based on polyvinyl butyral (10-14 wt.%) Was cast by casting a film about 15 microns thick from a weakly aggregated nanopowder of YSZ solid electrolyte (8.5 mol.% Y ₂ O ₃ ) with a specific surface area of about 55-60 m ² / g. From a composite powder of electrode material LSM-YSZ with a volume ratio of LSM: YSZ = 50: 50, selected by the particle size distribution of the LSM material and the addition of a pore former - carbon black (30 vol.% To the active material), a film with a thickness of about 25 μm was cast (12-16 % wt. PVB). Patterns (strips) of all components of the element of the required width and length were cut from powder films separated from the mylar ribbon to form single electrodes, while the strips of these components had a strip width less than the strip of electrolyte material by the width of two end thickenings. The length of the strips from the electrolyte film was chosen such that a 6, 12, and 18-layer carrier electrolyte pipe with an electrolyte layer thickness of about 90, 180, and 270 μm, respectively, was formed on the mold core. The bands were wound around the rod in the required sequence. At the final stage, on the end parts of the billet, free of electrodes, were laid (wound) with narrow strips of a film of electrolyte material with a width of about 2-3 mm thickening. Then, after installing the rod with the winding in a copper pipe, backfilling the buffer powder, evacuating and heating to 100 ° C, magnetic pulse pressing (monolithic thermoplastic layers) was performed at a pressure of a pulsed magnetic field of about 200 MPa, and the amplitude of the pressure of the powder on the workpiece was at least 2 times higher than magnetic. The compact was removed from the pipe and removed from the rod mechanically. The compact billet was sintered in an atmosphere of air in two stages: heating at a speed of 0.5 ° / min to 600 ° C, followed by heating to 1150 ° C at a speed of 5 ° / min with exposure at a maximum temperature of 4 hours.

As a result, a SOE with a three-layer electrode-electrolyte-electrode structure (elements of an oxygen pump) with a diameter of about 12 mm and a gas-tight layer of solid electrolyte 8.5YSZ with a relative density of at least 97%, and a grain size of solid electrolyte ceramics of about 300 nm were obtained and the thickness of the electrolyte layer, respectively 70, 140 and 215 μm in the middle part and the thickness of the end thickenings of 300-400 μm, with an ellipse of the ends of the element not more than 5% (defined as the difference between the larger and smaller diameters of the thickened end of the element, referred to their average th value), with lamella, 15-20 microns, the electrodes characterized by an open porosity of 25-30 vol. % (Fig. 7). Tests of the obtained elements of the oxygen pump at a temperature of 800 ° C did not reveal the presence of diffusion difficulties in the delivery of gases up to current densities of about 2 A / cm ² . Moreover, according to estimates, at a current density of 1.5 A / cm ^{2, the} overvoltage of composite LSM-YSZ electrodes (their polarization) did not exceed 30% of the voltage applied to the cell.

The technical result of the proposed TOE options and the method of their manufacture should be considered as the increase in specific characteristics (reduction of internal losses), improvement of the operational stability of the TOE, reduction of material consumption, improvement of manufacturability in the manufacture and connection of the TOE into the battery, as well as a reduction in energy costs for manufacturing.

Claims (11)

1. A tubular element of an electrochemical device with a thin-layer solid oxide electrolyte, gas diffusion electrodes, interface and collector layers, having end thickenings, characterized in that the end thickenings are made integrally with a smooth transition to the electrolyte, and the decrease in the thickness of the supporting solid electrolyte is achieved due to the end thickenings and or frame in the working area. 2. A tubular element of an electrochemical device with a thin-layer solid oxide electrolyte, gas diffusion electrodes, interface and collector layers, having end thickenings, characterized in that the end thickenings are made in one piece with a smooth transition to the electrolyte, and the cylindrical or slightly conical supporting electrolyte is made of ceramic with medium size crystallites less than 500 nm, has a wall thickness of less than 0.3 mm with end thickenings of up to 0.5 mm and thin-layer electrodes of 15-20 microns located on the side the surface of the electrolyte in the interval between the end thickenings, including additional interface and collector layers. 3. A tubular element of an electrochemical device with a thin-layer solid oxide electrolyte, gas diffusion electrodes, interface and collector layers, having end thickenings, characterized in that the end thickenings are made in one piece with a smooth transition to the electrolyte, and the cylindrical or slightly conical solid electrolyte pipe is made of medium-sized ceramic. crystallites less than 500 nm, has a wall thickness of less than 0.3 mm with end thickenings of up to 0.5 mm and thin-layer electrodes of 15-20 microns located on the side the surface of the electrolyte in the interval between the end thickenings, including additional interface and collector layers, and the thickness of the pipe of the solid electrolyte in the working part of the cell is reduced by increasing the thickness of one or both of the current electrode collectors. 4. A tubular element of an electrochemical device with a thin-layer solid oxide electrolyte, gas diffusion electrodes, interface and collector layers, having end thickenings, characterized in that the end thickenings are made in one piece with a smooth transition to the electrolyte, and the cylindrical or slightly conical electrolyte pipe is made of ceramic with an average crystalline size less than 500 nm and has a frame in the working part of the element with cells having the shape of an N-gon (for example, a triangle, a rectangle, etc.), a circle and others, in which the thickness of the electrolyte is several times less than the thickness of the wall of the frame, and contains functional thickness gas diffusion electrodes located along the entire side surface of the cell in the interval between the end thickenings. 5. A tubular element of an electrochemical device with a thin-layer solid oxide electrolyte, gas diffusion electrodes, interface and collector layers, having end thickenings, characterized in that the end thickenings are made in one piece with a smooth transition to the electrolyte, and a cylindrical or slightly conical solid electrolyte pipe is made of thin-structured crystallites of less than 500 nm ceramics: based on zirconium dioxide with the general formula (A _y B _1-y ) _x Zr _1-x O _2-δ (A, B-Nd, Gd, Dy, But, Y, Er, Tm, Yb, Lu, Sc, Ca , Mg, etc.), where 0.05≤x≤0.20, 0≤y≤1; based on cerium dioxide with the general formula Ln _x Ce _1-x O _2-δ or (Ln _0.95-y Sr _y Ba _0.05 ) _x Ce _1-x O _2-δ (Ln-Sm, Gd, La) where 0.15 x x, y 0 0.20, with a crystal structure such as fluorite; based on lanthanum gallate with the general formula (La _1-x Sr _x ) (Ga _1-y Mg _y ) O _3-δ , where 0.12≤x≤0.20, 0.10≤y≤0.20, s perovskite-like crystalline structure, has a wall thickness of less than 0.3 mm with end thickenings up to 0.5 mm and thin-layer electrodes of 15-20 μm located on the side surface of the electrolyte in the interval between the end thickenings and made of composite materials with mixed ion-electron conductivity, one of which is stable in an oxidizing atmosphere, for example, LSM-YSZ composite, the other in a reducing atmosphere, for example, Ni-YSZ, and a tubular cell with electrodes, anode and cathode of the above materials, one of which is located on the inner or outer surface of the cell, the other on the opposite, allows it to be used in an electrochemical device such as a fuel cell (electrolysis cell), and a tubular element with both electrodes stable in an oxidizing medium - in an electrochemical device such as an oxygen pump, and a tubular element with both electrodes stable in a reducing environment - in electrodes nical device type converter. 6. A tubular element of an electrochemical device with a thin-layer solid oxide electrolyte, gas diffusion electrodes, interface and collector layers, having end thickenings, characterized in that the end thickenings are made integrally with a smooth transition to the electrolyte, and the decrease in the thickness of the solid electrolyte in the working area is achieved due to the end thickenings and / or frame, which is made of a dispersion hardened solid electrolyte material, or of a material compatible with a solid electrolyte, o possessing greater mechanical strength. 7. A method of manufacturing a tubular element of an electrochemical device with a thin-layer solid oxide electrolyte, gas diffusion electrodes, interface and collector layers, having end thickenings of the solid electrolyte pipe, including winding stripes of films from component components formed by casting an alcohol or aqueous suspension based on a polymer, followed by compacting and sintering characterized in that the films of solid electrolyte and end thickenings are made of weakly aggregated nanopowders s having a particle size of 15-20 nm and a surface area of at least 50 m ² / g, the electrode films and interface layers - of a mixture of micro and nanoscale powders comprising the components that are in the form of strips required width and length is wound in a desired sequence a conical (0.3-0.5 °) rod to obtain the required number of layers and the relative positions of the components, place the blank of the element on the rod in a metal pipe, and in the gap between the tube and the workpiece, an intermediate buffer layer of powder is filled, for example, from an electrolyte material with a particle size of 1-30 μm, the pipe’s internal space is degassed with simultaneous heating to 70-120 ° С, the layers are laminated (monolithic) in a magnetically pulsed manner in an inductor at a pulsed magnetic field pressure with an amplitude of 150-250 MPa and a duration of 50- 200 μs, the compact blank of the element is removed from the mold, at least two-stage joint sintering of the multilayer blank of the polymer-ceramic element in air is carried out with heating to a temperature of 400-600 ° C at a rate of 0.05-1 ° / min 0-30 min exposure and continued heating at a speed of 5-10 ° / min to a temperature of 1100-1250 ° C with 1-10 hours delay. 8. A method of manufacturing a tubular element of an electrochemical device with a thin-layer solid oxide electrolyte, gas diffusion electrodes, interface and collector layers according to claim 4, comprising winding strip of films from the components of the element formed by casting an alcohol or aqueous suspension based on a polymer with subsequent compacting and sintering, characterized in that that films of solid electrolyte and end thickenings are made of weakly aggregated nanopowders with a particle size of 15-20 nm and a specific surface not less than 50 m ² / g, film of electrodes and interface layers - from a mixture of micro-sized and nanosized powders that are part of the components, which are wound in the desired sequence in the form of strips of the necessary width and length on a conical (0.3-0.5 °) a rod to obtain the required number of layers and the relative positions of the components, and for the manufacture of the frame of the electrolyte pipe on a thin continuous layer (s) of the electrolyte film, the required number of layers of the supporting frame with the cells of the selected shape made an example, by cutting down a method, place the element’s billet on a rod in a metal pipe, and put an intermediate buffer layer of powder, for example, from an electrolyte material with a particle size of 1-30 μm, into the gap between the pipe and the workpiece, degenerate the inner space of the pipe while heating to 70- 120 ° С, lamination (homologation) of the layers is carried out by the magnetic pulse method in the inductor at a pressure of a pulsed magnetic field with an amplitude of 150-250 MPa and a duration of 50-200 μs, a compact element blank is removed from the mold, joint at least two-stage sintering of a multilayer billet of a polymer-ceramic element in air is heated with heating to a temperature of 400-600 ° C at a speed of 0.05-1 ° / min with a shutter speed of 0-30 min and continued heating at a speed of 5- 10 ° / min to a temperature of 1100-1250 ° C with an exposure of 1-10 hours.

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