Flexible fibrous isotope battery and preparation method thereof

Abstract

The invention provides a fibrous isotope battery, which has a coaxial core-shell structure and sequentially comprises an inner electrode, a transduction unit, an isotope source layer and an outer electrode from inside to outside, and the fibrous isotope battery takes micron-scale fibers as a basic unit, has a natural linear structure and can be woven and processed according to actual application scenes. The isotope battery provided by the invention has the advantages of light weight, flexibility and knittability, and the application range of the isotope battery is greatly widened.

Description

Technical Field

[0001] The present invention relates to the field of isotope batteries, in particular to a flexible fiber-shaped isotope battery and a preparation method thereof. Background Art

[0002] With the development of smart manufacturing technology, there is an increasing demand for low-power, self-powered power supplies for IoT devices, electronic devices, micro-smart appliances, and wearable devices that require continuous power. Radiovoltaic isotope batteries, due to their strong environmental adaptability, long operating life, and compact size, are an ideal choice for micro-autonomous power supplies. However, current isotope batteries often use a traditional flat-plate "sandwich" configuration as a conversion structure, which has limited application suitability and cannot meet the needs of rapidly expanding smart electronic devices for miniaturized, flexible, and autonomous power supplies.

[0003] Therefore, there is a need for isotope batteries that can adapt to a wider range of usage scenarios. Summary of the Invention

[0004] In view of this, the main purpose of this application is to provide a flexible fiber-shaped isotope battery with greater design flexibility, capable of effective integration with objects of different sizes and shapes, and lighter and thinner, with a wider range of applications. In addition, this application also provides a method for preparing the flexible fiber-shaped isotope battery.

[0005] To achieve the above-mentioned objectives, the first aspect of the present invention provides a flexible fibrous isotope battery, comprising an inner electrode, a transducer unit, an isotope source layer, and an outer electrode. The fibrous isotope battery uses micron-scale fibers as basic units, has a natural linear structure, and can be woven or processed according to actual application scenarios.

[0006] In some embodiments, the isotope source layer includes a radioactive nuclide and an organic polymer, and the radioactive nuclide and the organic polymer are connected by covalent, coordination, complexation or non-covalent interaction.

[0007] In some embodiments, the radionuclide is selected from one or more of tritium, Ni-63, and Pm-147.

[0008] In some embodiments, the organic polymer is selected from one or more of polyethylene, polybutylene, polymethyl methacrylate, polyurethane, and epoxy resin.

[0009] In some embodiments, the inner electrode comprises one or more of silver nanowires, titanium wires, and carbon nanotube fibers.

[0010] In some embodiments, the inner electrode has a diameter of 0.01 mm to 0.5 mm.

[0011] In some embodiments, the inner electrode has a length of 0.5 cm to 1 m.

[0012] In some embodiments, the transducer unit includes one or more of an amorphous silicon-based transducer unit, a CuInSe2 transducer unit, a perovskite transducer unit, and an organic polymer transducer unit.

[0013] In some embodiments, the outer electrode comprises one or more of gold, silver, copper, platinum, and aluminum.

[0014] A second aspect of the present invention provides a method for preparing a flexible fiber-shaped isotope battery, comprising the following operations:

[0015] Preparation and cleaning of filamentous fiber inner electrodes as cores for isotope batteries;

[0016] With the inner electrode as the core, a transducer unit is prepared on the periphery of the fiber;

[0017] Loading an isotope source layer on the periphery of the transducer unit;

[0018] An external electrode is prepared outside the isotope source layer, wherein the energy conversion unit, the isotope source layer and the external electrode constitute the shell of the isotope battery;

[0019] and assembling isotope batteries.

[0020] In some embodiments, loading the isotope source layer includes: 1) preparing a polymer solution containing radioactive nuclides, wherein the radioactive nuclides and the polymer are mixed by covalent, coordination, complexation or non-covalent interactions to form a radioactive solution; and 2) dipping or dripping the radioactive solution.

[0021] In some embodiments, the flexible fiber-shaped isotope battery is assembled by wrapping an external wire around the inner electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic structural diagram of the flexible fiber-shaped isotope battery of this application.

[0023] Figure 2 This is a cross-sectional view of the structure of the flexible fiber-shaped isotope battery of this application.

[0024] Figure 3 Schematic diagram of the weavable structure of the flexible fiber-shaped isotope battery of this application.

[0025] Figure 4 This is the IV test curve of the tritium-perovskite fiber isotope battery, an example of the flexible fiber-shaped isotope battery of the present application.

[0026] Reference numerals

[0027] 1-Inner electrode, 2-Transducer unit, 3-Isotope source layer, 4-Outer electrode DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of this application and the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this disclosure, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this disclosure.

[0029] In the following description, numerous specific details are provided to provide a more thorough understanding of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced without one or more of these details. In other examples, certain technical features known in the art are not described to avoid confusion with the present disclosure; that is, all features of actual embodiments are not described herein, nor are well-known functions and structures described in detail.

[0030] In order to provide a clear and consistent understanding of the terms used in the specification of the present invention, some definitions are provided below. In addition, unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs.

[0031] Throughout the specification, unless otherwise specified, the terms used herein should be understood as meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention belongs.

[0032] It should be noted that, in the embodiments of the present invention, the terms "comprise," "include," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a method or apparatus comprising a series of elements includes not only the elements explicitly stated, but also other elements not explicitly listed, or elements inherent to the implementation of the method or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of other related elements in the method or apparatus comprising the element.

[0033] Radiovoltaic isotope batteries utilize beta particles produced by the decay of radioactive isotopes as an energy source, converting the energy of the beta particles into electricity through semiconductor materials. Most publicly available radiovoltaic isotope batteries use a traditional planar design, resulting in a monolithic structure that is difficult to adapt to applications requiring complex shapes.

[0034] The present application provides a flexible fiber-shaped isotope battery with a coaxial core-shell structure, wherein the battery unit is in an elongated linear form, can be flexibly bent and wound, and can be woven into a fabric shape (such as Figure 3 As shown). This flexible fiber-shaped isotope battery has the long-lasting energy output characteristics of traditional isotope batteries and the bendability and wearability of flexible batteries. On the one hand, it can provide long-term energy output, and on the other hand, it can be bent and folded, and can adapt to different shapes and sizes, thereby providing a stable and reliable power source for wearable devices, implantable medical devices, and flexible electronics. For example, Figure 1 shows a schematic diagram of its structure, Figure 2 A cross-sectional view thereof is shown.

[0035] Flexible fiber-shaped isotope battery

[0036] like Figure 1 As shown, the flexible fiber-shaped isotope battery of the present application has a coaxial core-shell structure, which includes an inner electrode 1, a transducer unit 2, an isotope source layer 3 and an outer electrode 4 from the inside to the outside. Figure 2 The inner electrode 1 shown constitutes the "axis" and "core" of the coaxial core-shell structure, and the transducer unit 2, isotope source layer 3 and outer electrode 4 constitute the "shell" of the coaxial core-shell structure.

[0037] [Inner electrode]

[0038] The inner electrode acts as the negative terminal of the battery, accepting electrons so that the electrons can then flow through the wires to the load, thereby generating an electric current.

[0039] In this application, the inner electrode 1 serves as the "axis" and "core" of the coaxial core-shell structure. Therefore, while playing the role of accepting electrons, silver nanowires, titanium wires, and carbon nanotube fibers are selected as the inner electrode. Since the current density of the radioisotope battery is relatively low, generally less than 1μA / cm 2 Therefore, when selecting electrodes, materials with high conductivity must be selected to effectively collect the current generated by beta particles. The conductivity of silver nanowires, titanium wires, and carbon nanotube fibers can reach 1×10 4 S / m or above, its excellent conductivity can effectively reduce the loss of charge transfer. By selecting the above materials, it is beneficial to improve the efficiency of charge transfer.

[0040] Furthermore, the inner electrode 1 may have a diameter of 0.01 mm to 0.5 mm. The inner electrode diameter within the above range is conducive to making the battery have better flexibility and better applicability. At the same time, it is suitable for processing and operation, which helps to reduce processing costs. Exemplarily, the diameter of the inner electrode is 0.01 mm, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm or a value between the ranges consisting of any two of them. Optionally, the diameter of the inner electrode is 0.2 mm.

[0041] Furthermore, the inner electrode 1 may have an effective length of 0.5 cm to 1 m, where the effective length is defined as the functional length for actual energy conversion, excluding the portion leading to the external circuit. The effective length of the inner electrode is within the above range, which is conducive to making the battery have better flexibility and better applicability. In addition, it can also avoid stress concentration, especially if it is fixed or restricted, which may cause material fatigue or damage. Exemplarily, the effective length of the inner electrode is 0.5 cm, 1 cm, 2 cm, 5 cm, 10 cm, 20 cm, 40 cm, 60 cm, 80 cm, 100 cm or a value between the ranges consisting of any two of them. Optionally, the effective length of the inner electrode is 5 cm.

[0042] [Transducer unit]

[0043] The energy conversion unit is a key component of the isotope battery, which is used to convert the decay heat energy of the isotope into electrical energy. In this application, the energy conversion unit can have a common structure in the art, such as a semiconductor diode structure.

[0044] Furthermore, the transducer unit 2 of the present application is coated on the surface of the inner electrode 1, forming the "first layer" of the coaxial core-shell structure. Therefore, the transducer unit of the present application needs to be able to achieve high conversion efficiency under low energy density input conditions, so as to form a structure that covers the inner electrode.

[0045] For example, the energy conversion unit 2 of the present application can be one or more of an amorphous silicon-based energy conversion unit, a CuInSe2 energy conversion unit, a perovskite energy conversion unit, and an organic polymer energy conversion unit. Furthermore, the energy conversion unit 2 can be a perovskite energy conversion unit. The input energy of a conventional solar cell is solar energy, and its energy density is 100mW / cm 2 , and the input energy of the isotope battery is 0.1~100μW / cm 2The energy source density of isotope batteries is far lower than that of standard sunlight. Under weak energy source input conditions, amorphous silicon, CuInSe2, perovskite, and organic polymer transducers offer higher conversion efficiencies than crystalline silicon, due to their more closely matched band gaps. Therefore, amorphous silicon, CuInSe2, perovskite, and organic polymer materials were selected as transducer units. These materials exhibit high energy conversion efficiencies, contributing to the excellent overall performance of the isotope battery.

[0046] [Isotope source layer]

[0047] The isotope source layer is the core of the isotope battery and contains radioactive isotopes. These isotopes release heat during the decay process and provide a source of energy.

[0048] Furthermore, the isotope source layer 3 of the present application is coated on the surface of the transducer unit, forming the "second layer" of the coaxial core-shell structure. Therefore, the isotope source layer of the present application needs to be able to form a highly processable, lightweight, and flexible polymer film to form a structure that covers the transducer unit.

[0049] For example, the isotope source layer includes a radionuclide and an organic polymer, which are linked by covalent bonding, coordination, complexation, or non-covalent interactions. This flexible organic isotope source layer, formed by linking the radionuclide and the organic polymer, facilitates the effective integration of the fabricated battery with objects of varying sizes and shapes, allowing it to fit into spaces of specialized shapes and accommodate a wider range of applications.

[0050] In this application, there is no particular limitation on radioactive nuclides, and those commonly used in the art may be used. For example, the radioactive nuclides are selected from one or more of tritium, Ni-63, and Pm-147. These nuclides are all beta nuclides. Compared to alpha nuclides, the beta particles produced by their decay have lower energies (the average energies of H-3, Ni-63, and Pm-147 are 5.6 keV, 17.4 keV, and 62 keV, respectively), which are lower than the damage threshold of conventional semiconductor devices (approximately 250 keV), and thus cause less irradiation damage to semiconductors. The selection of the above-mentioned radioactive nuclides is beneficial for extending the service life of the battery.

[0051] For example, the organic polymer is selected from one or more of polyethylene, polybutene, polymethyl methacrylate, polyurethane, and epoxy resin. The selected polymer is required to react chemically with the radionuclide or form a blend through non-covalent interactions. For example, polyethylene and polybutene can form polymers with tritium, while polymethyl methacrylate, polyurethane, and epoxy resin can form blends with coordination compounds of nickel-63 and promethium-147. The selection of these organic polymers facilitates uniform loading of the outer layer of the fibrous transducer unit.

[0052] [External electrode]

[0053] The outer electrode serves as the positive electrode of the battery, receiving electrons flowing in from the external circuit, thereby generating electric current.

[0054] Furthermore, the outer electrode 4 of the present application is coated on the surface of the isotope source layer to form the "third layer" in the coaxial core-shell structure.

[0055] The material of the external electrode 4 of the present application is not particularly limited, and those commonly used in the art can be used. For example, the external electrode 4 can include one or more of gold, silver, copper, platinum, and aluminum.

[0056] In addition to the above structure, a heat dissipation housing (not shown) can be further arranged on the outer electrode 4 as the "fourth layer" of the coaxial core-shell structure, which is used to protect the battery and prevent radiation leakage. For example, the housing can be made of special materials, such as polyimide and polybenzoxazole films, which can both block radiation and release unused heat energy. It is also flexible enough to be arranged on the surface of the outer electrode.

[0057] Furthermore, outside the heat dissipation shell, a radiation shielding layer (not shown), such as a polyethylene film, may be further included as the "fifth layer" in the coaxial core-shell structure, which is used to prevent radiation leakage and ensure safety in use.

[0058] Preparation method

[0059] The present application also provides a method for preparing a flexible fiber-shaped isotope battery, comprising the following operations: preparing and cleaning an inner electrode; preparing a transducer unit; loading an isotope source layer; preparing an outer electrode; and assembling the isotope battery.

[0060] Furthermore, loading the isotope source layer includes: 1) preparing a polymer solution containing radioactive nuclides, wherein the radioactive nuclides and the polymer are mixed by covalent, coordination, complexation or non-covalent interaction to form a radioactive solution; and 2) loading radioactive nuclide particles.

[0061] Furthermore, the assembly of the flexible fiber-shaped isotope battery is completed by winding the external wire around the inner electrode.

[0062] In addition, the preparation methods of the above-mentioned functional layers, such as the inner electrode, the transducer unit, the isotope source layer and the outer electrode, are not particularly limited and may include the preparation methods conventionally used in the art, for example, a chemical bath deposition method, an electrochemical deposition method, a chemical vapor deposition method, a physical epitaxial growth method, a vacuum thermal evaporation method, an atomic layer deposition method, a magnetron sputtering method, a spin coating method, a slit coating method, a scraping method, etc.

[0063] Example

[0064] The present invention is described in more detail below by way of examples. It should be understood that the examples described below are illustrative and intended only to explain the present invention, and are not to be construed as limiting the present invention. Where specific techniques or conditions are not specified in the examples, the methods described in the literature in the art or in the product specifications were followed. Reagents or instruments used without manufacturer designation are commercially available conventional products. The chemical reagents and pharmaceuticals used in the examples were all of premium grade purity.

[0065] Example 1

[0066] S1: Preparation and cleaning of inner electrode fibers

[0067] A 5 cm titanium wire (fiber diameter of 0.2 mm) was cut as the inner electrode material and placed in a beaker containing polishing liquid (a mixture of HF, HNO3 and deionized water in a volume ratio of 1:9:90) and allowed to stand for 2 minutes. After being taken out, it was rinsed with clean water and then ultrasonically cleaned with deionized water, acetone and alcohol for 20 minutes in sequence to remove surface oxides and impurities.

[0068] S2: Preparation of transducer unit

[0069] a) Preparation of electron transport layer

[0070] Weigh 2.01 g of titanium sulfate solid into a round-bottom flask and add 120 mL of deionized water with stirring to dissolve. Once the solution is clarified, add 2.97 g of EDTA-2Na solution. Once a white powder precipitates, add 1.10 g of urea. Seal the flask with a stopper and stir at room temperature for 2 hours to obtain a TiO2 precursor solution.

[0071] The titanium wire cleaned in S1 was placed in the TiO2 precursor solution, and then the precursor solution containing the titanium wire was placed in a reactor, and the reactor was placed in an oven at 180°C for 2 hours.

[0072] After the reaction, the titanium wire was removed from the reactor, rinsed with deionized water to remove impurities, and then calcined in a tube furnace at 400°C for 1 hour to form a 100nm thick TiO2 film on the titanium wire. The electron transport layer provides a channel for electron transport with a thickness ranging from 50 to 300nm. This thickness is controlled by the concentration of the precursor and the reaction conditions (reaction temperature and reaction time). Too thin a thickness (<50nm) will result in direct contact between the perovskite layer and the titanium wire, causing severe electron-hole recombination. Too thick a thickness (>300nm) will increase the series resistance and reduce the electron transport efficiency.

[0073] b) Preparation of perovskite layer

[0074] 11.064 g of PbI2 powder was placed in a round-bottom flask, and 20 mL of a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) (v / v = 19:1) was added. The mixture was stirred at 60°C for 30 minutes to obtain a PbI2 solution. 0.020 g of MAI was dissolved in 20 mL of isopropanol to a concentration of 1 mg / mL and magnetically stirred at room temperature for 30 minutes to obtain an MAI solution.

[0075] 100 μL of PbI₂ solution was evenly applied to the titanium wire obtained in step a) by drop coating. After drying and cooling, a 400 nm thick PbI₂ thin film was deposited. The titanium wire with the PbI₂ film was then immersed in 1 mL of MAI solution for 2 hours. After immersion, the solution was annealed at 80°C for 20 minutes to obtain a 600 nm thick MAPbI₃ perovskite light-absorbing layer, also known as the active layer.

[0076] c) Preparation of hole transport layer

[0077] 100 mg of Spiro-OMeTAD powder was dissolved in 1 mL of chlorobenzene to obtain a Spiro-OMeTAD solution.

[0078] 0.2 mL of the Spiro-OMeTAD solution was then evenly dropped onto the titanium wire obtained in step b), followed by spin coating at a controlled speed of 3000 rpm for 30 seconds. After spin coating, the wire was annealed at 80°C for 20 minutes to form a hole transport layer with a thickness of 15 nm.

[0079] S3: Preparation of tritium isotope source layer

[0080] 0.5 mL of tritiated polyethylene-chloroform solution (1 mg / mL) was evenly dropped on the titanium wire obtained in S2 and annealed at 40°C for 30 min to prepare an isotope source layer with a thickness of 500 nm as an energy input source.

[0081] S4: Preparation of external electrodes

[0082] An external electrode silver film with a thickness of 100 nm was obtained by vacuum high-temperature evaporation on the titanium wire obtained in S3.

[0083] Finally, the copper wire is wrapped around the titanium wire to conduct the current, completing the assembly of the flexible fiber-shaped tritium radioisotope battery. It weighs 7.1 mg.

[0084] Battery parameter test

[0085] The prepared battery was subjected to an IV characteristic test. The test method was to perform a linear voltage IV characteristic scan using a digital source meter, record the open circuit voltage and short circuit current of the battery, and calculate its output power and energy density.

[0086] The test results are as follows:

[0087]

[0088]

[0089] The above results show that the output power of the 5cm-long fiber-shaped isotope battery is 1.9nW, with an energy density of 267Wh / kg, while the energy density of conventional perovskite solar cells is between 10-20Wh / kg. In addition, since the half-life of tritium is 12.3 years, the battery has a service life of at least 10 years without maintenance.

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.

Claims

1. A flexible fibrous isotope battery having a coaxial core-shell structure, comprising, from the inside out, an inner electrode, a transducer unit, an isotope source layer, and an outer electrode. The flexible fibrous isotope battery uses micron-scale fibers as basic units and has a natural linear structure, which can be woven or processed according to actual application scenarios.

2. The flexible fiber-shaped isotope battery according to claim 1, wherein: The isotope source layer includes radioactive nuclides and organic polymers, and the radioactive nuclides and the organic polymers are connected by covalent, coordination, complex or non-covalent interaction mixing.

3. The flexible fiber-shaped isotope battery according to claim 2, wherein: The radioactive nuclide is selected from one or more of tritium, Ni-63, and Pm-147; and The organic polymer is selected from one or more of polyethylene, polybutene, polymethyl methacrylate, polyurethane, and epoxy resin.

4. The flexible fiber-shaped isotope battery according to any one of claims 1 to 3, wherein: The inner electrode includes one or more of silver nanowires, titanium wires, and carbon nanotube fibers.

5. The flexible fiber-shaped isotope battery according to any one of claims 1 to 4, wherein: The inner electrode has a diameter of 0.01 mm to 0.5 mm and a length of 0.5 cm to 1 m.

6. The flexible fiber-shaped isotope battery according to any one of claims 1 to 5, wherein: The transducer unit includes one or more of an amorphous silicon-based transducer unit, a CuInSe2 transducer unit, a perovskite transducer unit, and an organic polymer transducer unit.

7. The flexible fiber-shaped isotope battery according to any one of claims 1 to 6, wherein: The external electrode includes one or more of gold, silver, copper, platinum, and aluminum.

8. A method for preparing a flexible fiber-shaped isotope battery, comprising the following steps: preparing and cleaning a filamentous fiber inner electrode as the core of the isotope battery; Using the inner electrode as the core, a transducer unit is prepared on the periphery of the fiber; Loading an isotope source layer on the periphery of the transducer unit; preparing an external electrode outside the isotope source layer, wherein the energy conversion unit, the isotope source layer and the external electrode constitute the shell of the isotope battery; and assembling isotope batteries.

9. The method according to claim 8, wherein The isotope source layer loading includes: 1) preparing a polymer solution containing radioactive nuclides, wherein the radioactive nuclides and the polymer are mixed by covalent, coordination, complexation or non-covalent interaction to form a radioactive solution; and 2) dip coating or drop coating of the radioactive solution.

10. The method according to claim 8 or 9, wherein: The flexible fiber-shaped isotope battery is assembled by winding an external wire around the inner electrode.

Images