US-12626921-B2 - Carbon electrode for dye-sensitized betavoltaic batteries, betavoltaic battery including the same, and method of manufacturing the same

Abstract

The present invention relates to a betavoltaic battery and a method of manufacturing the same. More specifically, the present invention relates to a betavoltaic battery characterized in that 14 C, a radioisotope, is formed in the form of quantum dots and 14 C is used as the cathode and the beta-ray source of the betavoltaic battery and a method of manufacturing the betavoltaic battery.

Inventors

• Su Il IN
• Yun Ju HWANG
• Dae Hee Kim
• Young Ho Park
• Hong Soo Kim

Assignees

• DAEGU GYEONGBUK INSTITUTE OF SCIENCE AND TECHNOLOGY

Dates

Publication Date

20260512

Application Date

20201117

Priority Date

20191227

Claims (8)

1. 1 . A carbon electrode for betavoltaic batteries, comprising: a support layer comprising a conductive substrate; and a beta-ray source emission layer comprising organic carbon quantum dots comprising 14 C formed on the support layer, wherein the organic carbon quantum dots comprising 14 C comprise a fired product obtained by firing a polymer of a compound represented by Chemical Formula 2 below and quaternary ammonium ions: wherein 14 C represents a radioisotope of carbon.
2. 2 . The carbon electrode for betavoltaic batteries according to claim 1 , wherein the conductive substrate comprises one or more selected from fluorine tin oxide (FTO) glass, indium tin oxide (ITO) glass, indium zinc oxide (IZO) glass, aluminum zinc oxide (AZO) glass, and gallium zinc oxide (GZO) glass.
3. 3 . The carbon electrode for betavoltaic batteries according to claim 1 , wherein the organic carbon quantum dots have a particle diameter of 4 nm to 20 nm.
4. 4 . A betavoltaic battery, comprising the carbon electrode for betavoltaic batteries according to claim 1 as a cathode.
5. 5 . A betavoltaic battery, comprising: an anode; a cathode disposed opposite the anode; and an electrolyte, wherein the anode and the cathode are bonded via an encapsulant, a space filled with the electrolyte is formed between the anode and the cathode, the space is filled with the electrolyte, and the cathode comprises the carbon electrode for betavoltaic batteries according to claim 1 .
6. 6 . The betavoltaic battery according to claim 5 , wherein the anode comprises the support layer comprising the conductive substrate; and a TiO 2 layer onto which a ruthenium-based dye is adsorbed formed on one surface of the support layer.
7. 7 . The betavoltaic battery according to claim 6 , wherein the TiO 2 layer onto which a ruthenium-based dye is adsorbed has an average thickness of 2 μm to 25 μm.
8. 8 . The betavoltaic battery according to claim 6 , wherein the ruthenium-based dye is represented by Chemical Formula 3 or Chemical Formula 4: wherein COOTBA is a carboxylic acid group substituted with a tert-buty-alcohol group.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/KR2020/016165 which has an International filing date of Nov. 17, 2020, which claims priority to Korean Patent Application No. 10-2019-0176784, filed Dec. 27, 2019, the entire contents of each of which are hereby incorporated by reference. TECHNICAL FIELD The present invention relates to a carbon electrode (or cathode) for betavoltaic batteries including 14C quantum dots, which are radioisotopes, a betavoltaic battery using the carbon electrode as a beta-ray source, and a method of manufacturing the carbon electrode. BACKGROUND ART A betavoltaic battery is an isotope battery that absorbs, through the surface of a PN junction semiconductor, beta rays from radioisotopes that emit beta particles (electrons) and converts the beta rays into electrical energy. According to the operating principle of the betavoltaic battery, beta rays emitted from a beta-ray source generate electron-hole pairs in a space charge region in a PN junction semiconductor, and the generated carriers have the voltage and current characteristics of the betavoltaic battery (see FIG. 1). Table 1 below shows the half-life and average energy of each type of isotope emitting pure beta rays. Depending on nuclides, radioisotopes emitting beta particles have energy spectra ranging from a few eV to hundreds of keV and intrinsic maximum and average energy values. When a nuclide having a long half-life is used, the output life of a betavoltaic battery is increased. However, due to the long half-life, decay rate may be reduced, which may reduce output power. Accordingly, it is necessary to implement a betavoltaic battery suitable for intended use by appropriately selecting half-life and energy. Using the characteristics of isotope batteries with a long half-life and high energy density, betavoltaic batteries may be used as micro-power sources for sensors used in the polar regions, a remote area, or a space that are out of reach of humans for a long time or micro-power sources for military sensors. TABLE 1Beta-ray emitting nuclidesHalf-lifeAverage energy (keV)Ni-63100.2y17.4H-312.3y5.7Pm-1472.6y62.0Sr-9028.8y195.8Ca-45162y256.0 In a betavoltaic battery, the efficiency of kinetic energy of beta particles may vary depending on the structure thereof. For example, in the case of a planar structure PN junction, since a radiation source is located on the top of the PN junction, beta particles emitted in four directions from the side and beta particles emitted upwards are dissipated without being converted into electric power. As another example, when a radiation source is placed between a p-type semiconductor and an n-type semiconductor, excitons by beta particles are effectively separated. However, as the thickness of a material containing the radiation source increases, the number of recombination electrons and holes increases. In addition, as the thickness of the material decreases, the amount of the radiation source contained in the material decreases. The above two examples have a disadvantage in that the amount of current per unit area is small due to a small surface area. In such a conventional PN semiconductor-type betavoltaic battery, a beta-ray source and an energy absorber are in direct contact with each other, and emitted beta electrons collide with the absorber. Accordingly, when used for a long period of time, the absorber is damaged, which causes current loss, making it difficult to continuously generate current. In addition, in the conventional betavoltaic battery, a radioisotope in the initial form thereof is used without changing the form of the radioisotope. In addition, since the structure of a battery (or cell) is limited depending on the type of radioisotope source, there is a problem in that the amount of energy that can be used is limited. DISCLOSURE Technical Problem Therefore, the present invention has been made in view of the above problems, and it is one object of the present invention to provide a structure of a novel betavoltaic battery characterized in that the density of radiation energy within the same surface area is improved by forming a radioisotope in the form of quantum dots as a beta-ray source and introducing the radioisotope as an electrode and a beta-ray source, and a dye, not a semiconductor, is used as the energy absorber of the beta-ray source. Technical Solution In accordance with one aspect of the present invention, provided is a carbon electrode for betavoltaic batteries including a support layer including a conductive substrate; and a beta-ray source emission layer including organic carbon quantum dots including 14C formed on the support layer. As a preferred example of the present invention, the conductive substrate constituting the support layer may include one or more selected from fluorine tin oxide (FTO) glass, indium tin oxide (ITO) glass, indium zinc oxide (IZO) glas