The World Needs More Efficient and High-Quality Batteries. Researchers Have Come Up With an Innovative Solution: Nuclear Batteries

Battery research is progressing rapidly, and for good reason. The growing popularity of electric vehicles necessitates that energy storage devices perform at their best. Notably, a team of engineers at Ohio State University recently studied the idea of using nuclear batteries for electronic devices.

In their study published in Optical Materials: X, researchers propose that radioactive waste generated by fission reactors can be utilized to produce electricity needed for several electronic devices. “We’re harvesting something considered as waste, and by nature, trying to turn it into treasure,” author Raymond Cao said. To demonstrate this, the team created a small prototype battery measuring about 0.24 cubic inches.

The idea is to incorporate cesium-137 or cobalt-60–two radioactive elements usually produced during nuclear fission–into the battery. The goal is to harness the gamma radiation emitted by these elements to generate a small amount of electricity. The prototype successfully generated 288 nW using cesium-137 and 1.5 μW with cobalt-60.

While this amount of electricity is relatively modest, scientists are optimistic about improving their technology enough to power low-demand electronic devices, such as small sensors or monitors that require minimal maintenance.

It’s important to note that these batteries aren’t intended for the consumer market. If they successfully refine their technology, researchers believe it could be used in devices situated near locations where radioactive waste is produced, such as nuclear power plants. They also claim that their battery can be safely handled and won’t contaminate the environment. However, they acknowledge that gamma radiation is highly penetrating, necessitating a robust protective enclosure.

Another question remains unanswered: How long will the battery last?

Gamma Rays Are a Form of Ionizing Radiation

Radioactivity is a naturally occurring process by which an unstable atomic nucleus loses energy in an attempt to reach a more stable state, emitting radiation in the process. Around the nucleus, one or more elementary particles with a negative electric charge, called electrons, orbit. The nucleus is composed of protons, which are positively charged particles. The simplest atom found in nature is protium (hydrogen-1), an isotope of hydrogen with a single proton in its nucleus and a single electron orbiting around it.

However, matter isn’t solely composed of protium. It also consists of many heavier and more complex chemical elements, which contain more protons in their nucleus and more electrons orbiting around it. This raises the question: How can there be more than one proton in the nucleus if they all have a positive electric charge? You might think they couldn’t be close together, as charges repel each other. This idea is valid, and the solution to this dilemma lies in the neutrons–particles that coexist with protons in the atomic nucleus.

Unlike protons, neutrons are unique because they possess no electric charge, meaning they don’t “experience” the electromagnetic repulsion that affects protons and electrons. Neutrons’ primary function is to stabilize the nucleus, allowing multiple protons to coexist without repelling each other. They achieve this through one of the four fundamental forces of nature: the strong nuclear interaction.

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The other three fundamental forces are electromagnetic interaction, gravity, and weak interaction. Physicists often include the Higgs field at this level of fundamental interactions because it explains how particles acquire mass. However, for clarity, theory texts typically focus on these four forces.

Nucleons remain bound despite the natural repulsion between protons. This is possible because neutrons enable the strong nuclear force to act as “glue” that counteracts the electromagnetic force. Although the strong interaction has a very short range, its intensity is enormous at close distances. As previously mentioned, neutrons play a critical role in stabilizing the atomic nucleus. The more protons an atom contains, the more neutrons its nucleus requires for the strong attractive force to overcome the repulsive electromagnetic force effectively.

Interestingly, the balance between the number of protons and neutrons is quite delicate. An atom is stable if its nucleus has a specific arrangement of nucleons, with a suitable distribution of protons and neutrons that allows the strong nuclear interaction to function properly. This delicate balance explains why only a finite number of chemical elements are found in nature. Any alternative combination of protons and neutrons would disrupt this fine balance, resulting in an unstable atom.

The key factor that differentiates a stable atom from an unstable one lies in the nucleus. The strong interaction and electromagnetic force aren’t in equilibrium in an unstable atom. This causes the atom to modify its structure to reach a state of lower energy that allows for a more stable configuration. A stable atom is “comfortable” with its current structure and doesn’t require any changes. In contrast, an unstable atom must release some of its energy to achieve the necessary lower energy state.

So, how does an atom release some of its energy? The surprising answer lies in a quantum phenomenon known as the “tunneling effect.” This phenomenon enables the atom to overcome an energy barrier that might initially seem invincible. The mechanics of this quantum effect are complex and not very intuitive, but you don’t need to understand them in depth to grasp the basics of radioactivity. What matters is that an unstable atom has four distinct mechanisms to help it transition to a more stable state: alpha, beta, inverse beta, and gamma radiation.

Alpha radiation allows the atom to shed part of its nucleus by emitting an alpha particle consisting of two protons and two neutrons. Beta radiation involves a neutron in the atomic nucleus transforming into a proton, emitting an electron and an antineutrino. Inverse beta decay operates in the opposite manner. In this case, a proton is transformed into a neutron. This results in the emission of an antielectron and a neutrino, which are the antiparticles of the electron and the antineutrino emitted during beta radiation.

Finally, gamma radiation is the most energetic and penetrating mechanism. It involves the emission of a high-energy photon, commonly referred to as a gamma ray, allowing the atomic nucleus to maintain its original structure. Some of these high-energy photons can pass through very thick concrete walls and lead sheets, making gamma radiation the most dangerous type of radiation.

Radioactivity enables unstable atoms to release some of their energy to reach a lower-energy and more stable state. However, what happens to that energy? According to the law of conservation of energy, it can’t be destroyed. Instead, it’s carried away by the particles emitted from the unstable atom through any of the four forms of radiation previously mentioned. This energy propels the emitted particles away like tiny bullets, which can interact with matter along the way.

Image | Robin Glauser

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