Three-dimensional nanostructured tritium battery

Abstract

A three-dimensional nanostructured tritium voltaic battery relates to an isotope battery. It is a sandwich structure, which includes, from top to bottom, a top electrode, a three-dimensional nanostructured semiconductor and a bottom electrode; the three-dimensional nanostructured semiconductor is a three-dimensional grid frame structure composed of semiconductor materials, and a hole gap is provided between the grid frames. The three-dimensional nanostructured semiconductor is provided between the bottom electrode and the top electrode. The three-dimensional nanostructured semiconductor is a three-dimensional nanostructured semiconductor integrated with a tritium-based isotope source, and the tritium-based isotope source is stored in a tritiated metal in the hole gap between the semiconductor grid frames, or a tritiated semiconductor formed by a composite of tritium and a three-dimensional nanostructured semiconductor material, or a coexistence structure of a tritiated metal and a tritiated semiconductor; the tritiated metal forms a Schottky contact or an Ohmic contact with the three-dimensional nanostructured semiconductor, and is also connected to the top electrode or the bottom electrode.

Description

Technical Field

[0001] The invention relates to an isotope battery, in particular to a three-dimensional nanostructured tritium voltaic battery which directly converts the beta radiation energy of isotope tritium into electrical energy by using a three-dimensional nanostructured semiconductor. Background Art

[0002] Extreme areas such as the deep sea and polar regions have problems such as harsh environment and difficulty in reaching. In these places, human activities were often less in the past. In recent years, countries around the world have vigorously carried out relevant research work in these areas due to their rich resources, important geographical location, and lack of division. For example, by establishing a deep-sea observation network, environmental parameters such as temperature, topography, and ocean currents in the deep sea can be recorded, and then deep-sea maps can be drawn. These deep-sea geographic data parameters have great scientific, economic and military value. These areas are characterized by unattended operation, inconvenient maintenance, and harsh environment. Therefore, long-term maintenance-free requirements are put forward for sensor monitoring equipment and wireless communication equipment established in these areas. Among them, the energy system is the most typical equipment in these equipment with life and maintenance-free requirements. Conventional power supply methods such as solar energy, chemical fuel energy, ocean energy, wind energy, and temperature difference energy cannot meet the power supply needs of sensor monitoring and communication equipment due to environmental influences, regular maintenance, and large volume and weight, becoming a bottleneck problem restricting the deployment of monitoring equipment. In order to solve the "maintenance-free" problem of the energy system in the equipment, researchers have thought of "nuclear energy" in recent years. Nuclear fusion and nuclear fission can generate huge amounts of energy, but the devices are very large and complex, and require high maintenance. However, batteries made from the radiation energy generated by isotope decay have the characteristics of long life, no environmental impact, and maintenance-free, making them the most rational candidate energy source for environmental monitoring systems.

[0003] Isotope batteries have several conversion mechanisms, including temperature difference, hot ions, direct charging, heat engines, and radiovoltaic effect. Considering miniaturization and energy conversion efficiency, the radiovoltaic effect conversion method is an ideal candidate. Radiovoltaic effect batteries use the kinetic energy of radiation particles to interact with semiconductor structures to directly generate electrical energy. The energy density is tens of thousands times that of lithium batteries, and the theoretical efficiency of the battery can reach 30%. From the use of isotope radiation sources, three factors are mainly considered: 1) the average energy of β particles; 2) the half-life of the isotope source; 3) the source of the isotope and the manufacturing cost. Since the radiation damage threshold of semiconductors is 250-300KeV, high radiation kinetic energy β sources, such as krypton-85, ruthenium-106, strontium-90, etc., will cause the battery performance to decay. Considering the battery life and average energy, the half-life of the isotope source must be more than 5 years, so the more suitable isotope sources are tritium (average energy = 5.7KeV, half-life 12.3 years) and 63 Ni (average energy = 17.4 KeV, half-life 100 years). 63Ni sources are limited and very expensive, while tritium resources are very abundant and widely found in nuclear reactor waste and the ocean. Therefore, tritium is the most ideal isotope for the preparation of industrialized betavoltaic batteries. Since commercial tritium raw materials usually exist in the form of tritium gas, how to integrate tritium into semiconductor energy conversion matrices is an urgent problem that needs to be solved.

[0004] Traditional betavoltaic cells mainly use single crystal semiconductors (such as silicon, diamond, silicon carbide and gallium nitride) to make planar devices, and realize the battery structure by integrating radiation sources on the device surface. The main disadvantage of this structure is the low efficiency of radiation source utilization and the limited number of effective radiation sources integrated per unit area. For example, the Moscow Institute of Physics and Technology in Russia uses diamond as the conversion material and nickel-63 ( 63 Ni) as the radiation source of betavoltaic batteries, the battery output power can reach μW level, the battery life can reach 100 years, but the efficiency is only 1.25% (Reference: Diamond & Related Materials, vol. 84, pp. 41–47, 2018). City Labs in the United States has currently commercialized tritium-based betavoltaic batteries, using gallium arsenide (GaAs) crystals as conversion materials, integrating 100 Curies of tritium on the device surface and realizing multi-cell cascade. The battery output power can reach about 100 μW, but the actual efficiency is less than 3% (https: / / citylabs.net / ). Therefore, how to improve the energy conversion efficiency of betavoltaic batteries is currently a top priority for research. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a three-dimensional nanostructured tritium voltaic battery.

[0006] The invention presents a sandwich structure, which comprises, from top to bottom, a top electrode, a three-dimensional nanostructured semiconductor and a bottom electrode; the three-dimensional nanostructured semiconductor is a three-dimensional grid frame structure composed of semiconductor materials, and a channel gap is arranged between the grid frames. The three-dimensional nanostructured semiconductor is arranged between the bottom electrode and the top electrode. The three-dimensional nanostructured semiconductor is a three-dimensional nanostructured semiconductor integrated with a tritium-based isotope source, and the tritium-based isotope source is stored in a tritiated metal in the channel gap between the semiconductor grid frames, or is a tritiated semiconductor formed by a composite of tritium and a three-dimensional nanostructured semiconductor material, or is a coexistence structure of a tritiated metal and a tritiated semiconductor; the tritiated metal forms a Schottky contact or an Ohmic contact with the three-dimensional nanostructured semiconductor, and is also connected to the top electrode or the bottom electrode.

[0007] The three-dimensional nanostructured semiconductor can be a single crystal or polycrystalline semiconductor. The semiconductor material includes two major categories: elemental semiconductors and compound semiconductors. The elemental semiconductors include germanium and silicon. The compound semiconductors include group III and group V compounds, group II and group VI compounds, oxide semiconductors, and solid solutions composed of group III-V compounds and group II-VI compounds; the group III and group V compounds can be selected from gallium arsenide, gallium phosphide, gallium nitride, etc.; the group II and group VI compounds can be selected from cadmium sulfide, zinc sulfide, etc.; the oxide semiconductor can be selected from zinc oxide, tin oxide, titanium oxide, gallium oxide, etc.; the solid solution composed of group III-V compounds and group II-VI compounds can be selected from gallium aluminum arsenic, gallium arsenic phosphide, etc.

[0008] The three-dimensional nanostructure is an ordered or disordered thin film material composed of at least one basic structural unit of zero dimension, one dimension and two dimension, and the thickness of the thin film material can be 1 to 500 μm. The basic structural units include nanodots, nanoparticles, nanowires, nanorods, nanopillars, nanotubes, nanoflowers, nanosheets, nanobelts, nanosprings, nanorings, nanocombs, nanonails, nanoneedles, nanocages, nanotetrapods, tower-shaped nanostructures, disk-shaped nanostructures, star-shaped nanostructures, branch-shaped nanostructures, hollow nanospheres, nanoarrays, etc.

[0009] In order to improve the energy conversion efficiency of the tritium voltaic cell, the three-dimensional nanostructured semiconductor improves the generation and transport efficiency of carriers through a material modification process. The material modification process may include high-temperature reduction annealing in an inert gas or hydrogen atmosphere, ion implantation doping of metal or non-metal elements, high-temperature diffusion doping, chemical reaction doping, etc.

[0010] The tritium-based isotope source includes tritiated metals and tritiated semiconductors. The tritiated metals are transition metals, alkali metals, alkaline earth metals, rare earth metals and their alloys. After high-temperature tritiation, tritium forms a stable metal-tritium bond with the metal, resulting in a large amount of tritium absorbed by the metal layer to form tritiated metals; the tritiated semiconductor is a tritiated semiconductor formed by the metal and non-metal elements in the semiconductor forming a stable chemical bond with tritium after the semiconductor material is tritiated at high temperature, resulting in tritium and semiconductor materials being compounded. The transition metals include titanium, zirconium, scandium, palladium, cobalt, etc., the alkali metals include lithium, etc., the alkaline earth metals include beryllium and magnesium, etc., the rare earth metals include lanthanum, uranium, erbium, etc., and the alloys include zirconium cobalt, zirconium vanadium, lanthanum nickel, etc. The metal-tritium bond includes titanium-tritium bond, lithium-tritium bond, magnesium-tritium bond, etc. The metal and non-metal elements in the semiconductor form stable chemical bonds with tritium including titanium-tritium bond, silicon-tritium bond, oxygen-tritium bond, sulfur-tritium bond, etc.

[0011] The integration of the tritiated metal in the three-dimensional nanostructure is achieved by the following process: first, a 5-1000 nm metal thin layer is pre-deposited on the surface of the three-dimensional nanostructure semiconductor by atomic layer deposition, chemical vapor deposition, metal sputtering, metal electroplating or metal evaporation, and then the metal thin layer is tritiated in a tritium atmosphere, the temperature range used is 100-800°C, and the pressure range is 100-1000kPa.

[0012] The tritiated semiconductor is a three-dimensional nanostructured semiconductor that is directly tritiated in a tritium atmosphere at high temperature and high pressure, with a temperature range of 100 to 800° C. and a pressure range of 100 to 1000 kPa.

[0013] The top electrode and the bottom electrode may be selected from metal electrodes, semiconductor electrodes, graphite electrodes, graphene electrodes, conductive polymer electrodes or conductive paste electrodes.

[0014] When the output power of a single battery is insufficient, the present invention can realize multi-unit multi-layer stacking integrated packaging through parallel connection, series connection or series-parallel mixed connection, so as to achieve the purpose of increasing the output voltage and output power.

[0015] The beneficial effects of the present invention are:

[0016] The energy conversion material used in the tritium battery of the present invention is a three-dimensional nanostructured semiconductor. The use of the three-dimensional nanostructure can increase the action area of ​​the isotope tritium radiation source and the energy conversion material, greatly increasing the proportion of isotope tritium enriched in the semiconductor material. In addition, the integration of the three-dimensional structure of the isotope source solves the problem of low utilization efficiency of the radiation source caused by the energy self-absorption effect, scattering effect, and low coupling efficiency of the radiation source, greatly improving the conversion efficiency and unit volume output power of the isotope battery. The tritiated metal and the three-dimensional nanostructured semiconductor form Schottky or ohmic contact, which can effectively separate and transmit the electron-hole pairs generated by the isotope radiation beta particles, reduce the carrier recombination rate, and effectively improve the energy conversion efficiency of the tritium battery. At the same time, as a component of the three-dimensional nanostructured semiconductor, the tritiated semiconductor can effectively separate the electron-hole pairs generated by the beta particles through the semiconductor heterojunction inside the structure, so that the energy conversion efficiency of the battery reaches about 30%. The three-dimensional nanostructured tritium voltaic battery of the present invention can realize multi-unit multi-layer stacking and integrated packaging in parallel or series connection, can achieve high output power per unit volume, and has the characteristics of small volume and high energy density. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structural composition of Example 1 of the present invention.

[0018] Figure 2 Schematic diagram of the preparation process of an embodiment of the present invention. Figure 2In the present invention, (a) a titanium sheet is used as an anode, a platinum sheet is used as a cathode, and a mixture of amine fluoride and ethylene glycol is used as an electrolyte; (b) the titanium sheet is anodized to prepare a titanium dioxide nanotube array film; (c) a tritiated titanium dioxide nanotube array film; (d) a titanium metal film is formed on the surface of the titanium dioxide nanotubes by atomic layer deposition technology; (e) a titanium metal film on the surface of the tritiated titanium dioxide nanotubes; (f) a gold electrode is evaporated on the surface of the titanium dioxide nanotube array film covered with tritiated titanium.

[0019] Figure 3 It is a schematic diagram of a series-parallel stacking package of multiple groups of three-dimensional nanostructured tritium voltaic battery units according to an embodiment of the present invention.

[0020] exist Figures 1 to 3 , the marks are: 1-top electrode, 2-tritiated three-dimensional nanostructure semiconductor, 3-tritiated metal, 4-bottom electrode, 5-metal packaging shell, 6-insulating substrate, 7-metal lead, 8-pin, 9-conductive connecting wire, 10-external load. DETAILED DESCRIPTION

[0021] The following embodiments will further illustrate the present invention in conjunction with the accompanying drawings.

[0022] Example 1

[0023] See also Figure 1 Embodiment 1 of the present invention includes: a top electrode 1, a tritiated three-dimensional nanostructure semiconductor 2, a tritiated metal 3, a bottom electrode 4, a metal packaging shell 5, an insulating substrate 6, a metal lead 7, and a pin 8.

[0024] The tritiated three-dimensional nanostructured semiconductor 2 of this embodiment is formed by vertically stacking a nanotube array and a bottom electrode 4. The material of the tritiated three-dimensional nanostructured semiconductor 2 is high-temperature tritiated wide bandgap semiconductor titanium dioxide, and the tritiated titanium dioxide lattice contains a large number of tritium-oxygen bonds, tritium-titanium bonds and interstitial tritium atoms; the material of the tritiated metal 3 is high-temperature tritiated metal titanium, and the tritiated titanium contains a large number of tritium-titanium bonds; the tritiated metal 3 is attached to the outer surface of the nanotube; the material of the top electrode 1 is gold, and the bottom electrode 4 is a titanium sheet; the three-dimensional nanostructured tritium voltaic cell is glued to an insulating substrate 6 in a metal packaging shell 5; the top electrode 1 and the bottom electrode 4 are connected to the pins 8 in the metal packaging shell 5 through metal leads 7, respectively.

[0025] The preparation method of the three-dimensional nanostructured tritium battery described in this embodiment is as follows Figure 2 As shown, the following steps are included:

[0026] (1) Preparation of tritiated three-dimensional nanostructured semiconductors: A titanium sheet is used as the anode (e.g. Figure 2(a)), a platinum metal sheet was used as the cathode, a mixture of amine fluoride and ethylene glycol was used as the electrolyte, and a titanium dioxide nanotube array film was prepared on a metal titanium sheet by an electrochemical anodic oxidation process (as shown in FIG. Figure 2 (b)), the nanotube diameter is 10 to 1000 nm, and the nanotube depth is 200 nm to 1000 μm. Then the sample is placed in a tritium atmosphere for high temperature and high pressure annealing and tritiation. The temperature range is 100 to 800 ° C, and the pressure range is 100 to 1000 kPa. Finally, a tritiated titanium dioxide nanotube array film (such as Figure 2 (c));

[0027] (2) Preparation of tritiated metal: The preparation of tritiated metal includes two steps: 1) using atomic layer deposition technology to deposit titanium metal film on the surface of the three-dimensional nanostructure; 2) using a high temperature and high pressure tritiation system to tritiate the titanium metal film on the surface of the three-dimensional nanostructure.

[0028] 1) Atomic layer deposition of titanium metal film: The deposition system is purged with an inert gas to remove air and moisture from the deposition system. Then the cleaned titanium dioxide nanotube array film sample and the weighed titanium metal precursor source (such as titanium tetrachloride precursor (TiCl4), [pentamethylcyclopentadienyl] titanium (trimethoxy) precursor ([Me5Cp]Ti(OCH3)3), tetrakis(dimethylamino)titanium precursor (Ti[N(CH3)2]4, etc.) are placed in a deposition system under inert gas protection. Next, the metal titanium precursor is heated to a vapor state, the sample substrate temperature is controlled at 30-600°C, and the pressure in the chamber is controlled at 0.133Pa ~133kPa. After the titanium dioxide nanotube surface is fully adsorbed by the metal titanium precursor source, the metal precursor source vapor in the deposition system is evacuated and hydrogen gas or hydrogen plasma is introduced to fully react with the metal titanium precursor source deposited on the surface of the titanium dioxide nanotube. Finally, the metal titanium precursor source adsorbed on the surface of the titanium dioxide nanotube is reduced to metal titanium, and the gas generated by the reaction (such as HCl, CH4, H2O, etc.) is evacuated. Repeat this cycle many times to form a titanium metal film (such as HCl, CH4, H2O, etc.) with a thickness of 10 to 30 nm on the surface of the titanium dioxide nanotube. Figure 2 After completion, the system is cooled to room temperature and pressure.

[0029] 2) Tritiation of titanium metal film: Place the titanium dioxide nanotube array film sample with the titanium metal film deposited in the tritiation furnace, set the furnace temperature range to 100-800°C, the pressure range to 100-1000kPa, and introduce tritium gas or deuterium-tritium mixed gas. The titanium metal film on the surface of the titanium dioxide nanotubes will absorb and react with tritium gas or deuterium-tritium mixed gas. Finally, tritium-titanium bonds or deuterium-titanium bonds are generated in the titanium metal to form tritiated titanium metal (such as Figure 2 (e)).

[0030] (3) Preparation of electrodes: Using metal thermal evaporation technology, gold is evaporated on the surface of the titanium dioxide nanotube array thin film sample covered with tritiated titanium to form the top electrode of the battery. At the same time, the titanium sheet of the titanium dioxide nanotube array structure is used as the bottom electrode (such as Figure 2 (f)).

[0031] Example 2

[0032] like Figure 3 As shown, two three-dimensional nanostructured tritium volt batteries described in Example 1 are stacked together and connected in parallel through a conductive connecting line 9 to form a battery pack unit. The total power output by the battery pack unit is the sum of the output powers of the two tritium volt batteries. In this way, two identical battery pack units can be connected in series to form a battery pack with a higher output power, and the total power output by the battery pack is the sum of the output powers of four tritium volt batteries. The battery pack unit can continue to topologically form a series-parallel hybrid structure of multiple battery pack units to form a higher output power, which can drive an external load 10.

Claims

1. A three-dimensional nanostructured tritium battery, characterized in that The structure is a sandwich structure, which includes, from top to bottom, a top electrode, a three-dimensional nanostructured semiconductor, and a bottom electrode; the three-dimensional nanostructured semiconductor is a three-dimensional grid frame structure composed of semiconductor materials, and a hole gap is provided between the grid frames. The three-dimensional nanostructured semiconductor is provided between the bottom electrode and the top electrode. The three-dimensional nanostructured semiconductor is a three-dimensional nanostructured semiconductor integrated with a tritium-based isotope source, and the tritium-based isotope source is stored in a tritiated metal in the hole gap between the semiconductor grid frames, or is a tritiated semiconductor formed by a composite of tritium and a three-dimensional nanostructured semiconductor material, or is a coexistence structure of a tritiated metal and a tritiated semiconductor; the tritiated metal forms a Schottky contact or an Ohmic contact with the three-dimensional nanostructured semiconductor, and is also connected to the top electrode or the bottom electrode; The semiconductor materials include two categories: elemental semiconductors and compound semiconductors. The elemental semiconductors include germanium and silicon. The compound semiconductors include Group III and Group V compounds, Group II and Group VI compounds, oxide semiconductors, and solid solutions composed of Group III-V compounds and Group II-VI compounds. The III and V group compounds are selected from gallium arsenide, gallium phosphide, and gallium nitride; the II and VI group compounds are selected from cadmium sulfide and zinc sulfide; the oxide semiconductor is selected from zinc oxide, tin oxide, titanium oxide, and gallium oxide; the solid solution composed of the III-V group compound and the II-VI group compound is selected from gallium aluminum arsenic and gallium arsenic phosphide; The method for integrating the tritiated metal in the three-dimensional nanostructure is as follows: firstly, a metal thin layer of 5 to 1000 nm is pre-deposited on the surface of the three-dimensional nanostructure semiconductor by atomic layer deposition, chemical vapor deposition, metal sputtering, metal electroplating or metal evaporation process, and then the metal thin layer is tritiated in a tritium atmosphere, the temperature range used is 100 to 800° C., and the pressure range is 100 to 1000 kPa; The tritiated semiconductor is a three-dimensional nanostructured semiconductor that is directly tritiated at high temperature and high pressure in a tritium atmosphere, with a temperature range of 100 to 800° C. and a pressure range of 100 to 1000 kPa.

2. The three-dimensional nanostructured tritium battery according to claim 1, characterized in that The three-dimensional nanostructured semiconductor is a single crystal or polycrystalline semiconductor.

3. The three-dimensional nanostructured tritium battery according to claim 1, characterized in that The three-dimensional nanostructure is an ordered or disordered thin film material composed of at least one basic structural unit of zero dimension, one dimension and two dimension, and the thickness of the thin film material is 1 to 500 mm; the basic structural units include nanodots, nanoparticles, nanowires, nanorods, nanocolumns, nanotubes, nanoflowers, nanosheets, nanobelts, nanosprings, nanorings, nanocombs, nanonails, nanoneedles, nanocages, nanotetrapods, tower-shaped nanostructures, disk-shaped nanostructures, star-shaped nanostructures, branched nanostructures, hollow nanomicrospheres and nanoarrays.

4. The three-dimensional nanostructured tritium battery according to claim 1, characterized in that The three-dimensional nanostructured semiconductor improves the generation and transport efficiency of carriers through a material modification process, wherein the material modification process includes high-temperature reduction annealing in an inert gas or hydrogen atmosphere, ion implantation doping of metal or non-metal elements, high-temperature diffusion doping, and chemical reaction doping.

5. The three-dimensional nanostructured tritium battery according to claim 1, characterized in that The tritium-based isotope source includes tritiated metals and tritiated semiconductors. The tritiated metals are transition metals, alkali metals, alkaline earth metals, rare earth metals and their alloys, which form stable metal-tritium bonds with metals after high-temperature tritiation. The tritiated semiconductors are tritiated semiconductor materials, which are formed by the metal and non-metal elements in the semiconductor forming stable chemical bonds with tritium after high-temperature tritiation, resulting in the complexation of tritium with the semiconductor material.

6. The three-dimensional nanostructured tritium battery according to claim 5, characterized in that The transition metals include titanium, zirconium, scandium, palladium, and cobalt; the alkali metals include lithium; the alkaline earth metals include beryllium and magnesium; the rare earth metals include lanthanum, uranium, and erbium; the alloys include zirconium cobalt, zirconium vanadium, and lanthanum nickel; the metal-tritium bond includes titanium-tritium bond, lithium-tritium bond, and magnesium-tritium bond; the metal and non-metal elements in the semiconductor form stable chemical bonds with tritium including titanium-tritium bond, silicon-tritium bond, oxygen-tritium bond, and sulfur-tritium bond.

7. The three-dimensional nanostructured tritium battery according to claim 1, characterized in that The top electrode and the bottom electrode are selected from metal electrodes, semiconductor electrodes, graphite electrodes, graphene electrodes, conductive polymer electrodes or conductive paste electrodes.

Images