Diamond battery

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Diamond battery is the name of a nuclear battery concept proposed by the University of Bristol Cabot Institute during its annual lecture [1] held on 25 November 2016 at the Wills Memorial Building. This battery is proposed to run on the radioactivity of waste graphite blocks (previously used as neutron moderator material in graphite-moderated reactors) and would generate small amounts of electricity for thousands of years.

Contents

The battery is a betavoltaic cell using carbon-14 (14C) in the form of diamond-like carbon (DLC) as the beta radiation source, and additional normal-carbon DLC to make the necessary semiconductor junction and encapsulate the carbon-14. [2]

Prototypes

Currently, no known prototype uses 14C as its source. There are, however, some prototypes that use nickel-63 (63Ni) as their source with diamond non-electrolytes/semiconductors for energy conversion, which are seen as a stepping stone to a possible 14C diamond battery prototype.

University of Bristol prototype

In 2016, researchers from the University of Bristol claimed to have constructed one of those 63Ni prototypes. [3] [4]

From their Frequently Asked Questions (FAQ document [5] ), the estimated power of a small C-14 cell is 15 J/day for thousands of years. (For reference, a AA battery of the same size has about 10 kJ total, which is equivalent to 15 J/day for just 2 years.) They note it is not possible to directly replace an AA battery with this technology, because an AA battery can produce bursts of much higher power as well. Instead, the diamond battery is aimed at applications where a low discharge rate over a long period of time is required, such as space exploration, medical devices, seabed communications, microelectronics, etc.

Moscow Institute of Physics and Technology prototype

In 2018, researchers from the Moscow Institute of Physics and Technology (MIPT), the Technological Institute for Superhard and Novel Carbon Materials (TISNCM), and the National University of Science and Technology (MISIS) announced a prototype using 2-micron thick layers of 63Ni foil sandwiched between 200 10-micron diamond converters. It produced a power output of about 1 μW at a power density of 10 μW/cm3. At those values, its energy density would be approximately 3.3 Wh/g over its 100-year half-life, about 10 times that of conventional electrochemical batteries. [6] This research was published in April 2018 in the Diamond and Related Materials journal. [7]

Carbon-14

Researchers are trying to improve the efficiency and are focusing on use of radioactive 14C, which is a minor contributor to the radioactivity of nuclear waste. [3]

14C undergoes beta decay, in which it emits a low-energy beta particle to become Nitrogen-14, which is stable (not radioactive). [8]

14
6C
 → 14
7N
 + 0
−1β

These beta particles, having an average energy of 50 keV, undergo inelastic collisions with other carbon atoms, thus creating electron-hole pairs which then contribute to an electric current. This can be restated in terms of band theory by saying that due to the high energy of the beta particles, electrons in the carbon valence band jump to its conduction band, leaving behind holes in the valence band where electrons were earlier present. [9] [4]

Proposed manufacturing

In graphite-moderated reactors, fissile uranium rods are placed inside graphite blocks. These blocks act as a neutron moderator whose purpose is to slow down fast-moving neutrons so that nuclear chain reactions can occur with thermal neutrons. [10] During their use, some of the non-radioactive carbon-12 and carbon-13 isotopes in graphite get converted into radioactive 14C by capturing neutrons. [11] When the graphite blocks are removed during station decommissioning, their induced radioactivity qualifies them as low-level waste requiring safe disposal.

Researchers at the University of Bristol demonstrated that a large amount of the radioactive 14C was concentrated on the inner walls of the graphite blocks. Due to this, they propose that much of it can be effectively removed from the blocks. This can be done by heating them to the sublimation point of 3,915 K (3,642 °C; 6,587 °F) which will release the carbon in gaseous form. After this, blocks will be less radioactive and possibly easier to dispose of with most of the radioactive 14C having been extracted. [12]

Those researchers propose that this 14C gas could be collected and used to produce man-made diamonds by a process known as chemical vapor deposition using low pressure and elevated temperature, noting that this diamond would be a thin sheet and not of the stereotypical diamond cut. The resulting diamond made of radioactive 14C would still produce beta radiation which researchers claim would allow it to be used as a betavoltaic source. Researchers also claim this diamond would be sandwiched between non-radioactive man-made diamonds made from 12C which would block radiation from the source and would also be used for energy conversion as a diamond semiconductor instead of conventional silicon semiconductors. [12]

Proposed applications

Due to its very low power density, conversion efficiency and high cost, a 14C betavoltaic device is very similar to other existing betavoltaic devices which are suited to niche applications needing very little power (microwatts) for several years in situations where conventional batteries cannot be replaced or recharged using conventional energy harvesting techniques. [13] [14] [15] Due to its longer half-life, 14C betavoltaics may have an advantage in service life when compared to other betavoltaics using tritium or nickel. However, this will likely come at the cost of further reduced power density.

Commercialization

In September 2020, Morgan Boardman, an Industrial Fellow and Strategic Advisory Consultant with the Aspire Diamond Group at the South West Nuclear Hub of the University of Bristol, was appointed CEO of a new company called Arkenlight, which was created explicitly to commercialize their diamond battery technology and possibly other nuclear radiation devices under research or development at Bristol University. [16] In September 2024, Arkenlight announced that they had created a 14C diamond. [17]

Related Research Articles

Background radiation is a measure of the level of ionizing radiation present in the environment at a particular location which is not due to deliberate introduction of radiation sources.

A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess numbers of either neutrons or protons, giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferred to one of its electrons to release it as a conversion electron; or used to create and emit a new particle (alpha particle or beta particle) from the nucleus. During those processes, the radionuclide is said to undergo radioactive decay. These emissions are considered ionizing radiation because they are energetic enough to liberate an electron from another atom. The radioactive decay can produce a stable nuclide or will sometimes produce a new unstable radionuclide which may undergo further decay. Radioactive decay is a random process at the level of single atoms: it is impossible to predict when one particular atom will decay. However, for a collection of atoms of a single nuclide the decay rate, and thus the half-life (t1/2) for that collection, can be calculated from their measured decay constants. The range of the half-lives of radioactive atoms has no known limits and spans a time range of over 55 orders of magnitude.

<span class="mw-page-title-main">Nuclear technology</span> Technology that involves the reactions of atomic nuclei

Nuclear technology is technology that involves the nuclear reactions of atomic nuclei. Among the notable nuclear technologies are nuclear reactors, nuclear medicine and nuclear weapons. It is also used, among other things, in smoke detectors and gun sights.

<span class="mw-page-title-main">Pebble-bed reactor</span> Type of very-high-temperature reactor

The pebble-bed reactor (PBR) is a design for a graphite-moderated, gas-cooled nuclear reactor. It is a type of very-high-temperature reactor (VHTR), one of the six classes of nuclear reactors in the Generation IV initiative.

<span class="mw-page-title-main">Carbon-14</span> Radiosotope of carbon

Carbon-14, C-14, 14C or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic matter is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues (1949) to date archaeological, geological and hydrogeological samples. Carbon-14 was discovered on February 27, 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley, California. Its existence had been suggested by Franz Kurie in 1934.

Ionizing radiation, including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. Some particles can travel up to 99% of the speed of light, and the electromagnetic waves are on the high-energy portion of the electromagnetic spectrum.

<span class="mw-page-title-main">Radioisotope thermoelectric generator</span> Electrical generator that uses heat from radioactive decay

A radioisotope thermoelectric generator, sometimes referred to as a radioisotope power system (RPS), is a type of nuclear battery that uses an array of thermocouples to convert the heat released by the decay of a suitable radioactive material into electricity by the Seebeck effect. This type of generator has no moving parts and is ideal for deployment in remote and harsh environments for extended periods with no risk of parts wearing out or malfunctioning.

<span class="mw-page-title-main">Scintillation counter</span> Instrument for measuring ionizing radiation

A scintillation counter is an instrument for detecting and measuring ionizing radiation by using the excitation effect of incident radiation on a scintillating material, and detecting the resultant light pulses.

<span class="mw-page-title-main">Nuclear chemistry</span> Branch of chemistry dealing with radioactivity, transmutation and other nuclear processes

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<span class="mw-page-title-main">Neutron radiation</span> Ionizing radiation that presents as free neutrons

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<span class="mw-page-title-main">Neutron activation</span> Induction of radioactivity by neutron radiation

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A betavoltaic device is a type of nuclear battery which generates electric current from beta particles (electrons) emitted from a radioactive source, using semiconductor junctions. A common source used is the hydrogen isotope tritium. Unlike most nuclear power sources which use nuclear radiation to generate heat which then is used to generate electricity, betavoltaic devices use a non-thermal conversion process, converting the electron-hole pairs produced by the ionization trail of beta particles traversing a semiconductor.

<span class="mw-page-title-main">Radiochemistry</span> Chemistry of radioactive materials

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<span class="mw-page-title-main">Nuclear fuel</span> Material fuelling nuclear reactors

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Long-lived fission products (LLFPs) are radioactive materials with a long half-life produced by nuclear fission of uranium and plutonium. Because of their persistent radiotoxicity, it is necessary to isolate them from humans and the biosphere and to confine them in nuclear waste repositories for geological periods of time. The focus of this article is radioisotopes (radionuclides) generated by fission reactors.

Betacel is considered to be the first commercially successful betavoltaic battery. It was developed in the early 1970s by Larry C. Olsen at the American corporation McDonnell Douglas, using the radioisotope Promethium-147 as the beta-electron source coupled to silicon semiconductor cells. This power source was incorporated in the Betacel-Biotronik heart pacemaker. The device was not widely adopted because of its limited lifespan and doubts over the use of radioactive material.

References

  1. ↑ "Annual Lecture 2016: Ideas to change the world". University of Bristol. Archived from the original on 2020-10-29. Retrieved 2016-12-01.
  2. ↑ "Nuclear Waste and Diamonds Make Batteries That Last 5,000 Years". Seeker. 30 November 2016.
  3. 1 2 DiStaslo, Cat (2 December 2016). "Scientists turn nuclear waste into diamond batteries that last virtually forever". Inhabitat.
  4. 1 2 "Diamond nuclear battery could generate 100 μW for 5,000 years". Electronics Weekly. 2 December 2016.
  5. ↑ "Diamond Battery FAQs" (PDF). University of Bristol. Archived (PDF) from the original on 2022-11-20. Retrieved 2022-11-21.
  6. ↑ "Prototype nuclear battery packs 10 times more power". mipt.ru.
  7. ↑ Bormashov, V.S.; Troschiev, S.Yu.; Tarelkin, S.A.; Volkov, A.P.; Teteruk, D.V.; Golovanov, A.V.; Kuznetsov, M.S.; Kornilov, N.V.; Terentiev, S.A.; Blank, V.D. (April 2018). "High power density nuclear battery prototype based on diamond Schottky diodes". Diamond and Related Materials. 84: 41–47. Bibcode:2018DRM....84...41B. doi: 10.1016/j.diamond.2018.03.006 .
  8. ↑ "Nuclear Reactions/Beta Decay". libretexts.org. 2013-11-26.
  9. ↑ "Flash Physics: Nuclear diamond battery, M G K Menon dies, four new elements named". Physics World. 30 November 2016.
  10. ↑ "'Diamond-age' of power generation as nuclear batteries developed". Youtube. University of Bristol. 28 November 2016.
  11. ↑ "Radioactive Diamond Batteries: Making Good Use Of Nuclear Waste". Forbes. 9 December 2016.
  12. 1 2 "'Diamond-age' of power generation as nuclear batteries developed". University of Bristol. 25 November 2016.
  13. ↑ "Bristol university Press release issued: 25 November 2016". Archived from the original on 20 November 2022. Retrieved 3 December 2016.
  14. ↑ "Bristol University interdisciplinary Aspire project, 2017". Archived from the original on 2021-05-29. Retrieved 2020-10-02.
  15. ↑ "Tritium Batteries as a Source of Nuclear Power". City Labs. Retrieved 25 May 2023.
  16. ↑ "New Atlas (formerly Gizmag) interview with Dr Boardman". 30 September 2020. Archived from the original on 2022-11-20. Retrieved 2020-10-02.
  17. ↑ Arkenlight (2024-09-29). "Arkenlight – Brilliant Power for Very Useful Things". Arkenlight Latest Updates. Retrieved 2024-11-07.{{cite web}}: CS1 maint: url-status (link)
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