Nuclear battery, also known as isotope battery, is a device that uses radioactive isotope decay to release high-energy particles (such as alpha particles, beta particles and gamma rays) and convert their energy into electrical energy. According to the supplied voltage, nuclear batteries can be divided into two types: high-voltage type (hundreds to thousands of volts) and low-voltage type (about tens of MV- 1V). According to the energy conversion mechanism, they can be divided into direct conversion type and indirect conversion type. More specifically, it includes direct charging nuclear battery, gas ionization nuclear battery, radiation volt effect energy conversion nuclear battery, phosphorescent photoelectric nuclear battery, thermoelectric nuclear battery, thermoelectric nuclear battery, thermionic emission nuclear battery, electromagnetic radiation energy conversion nuclear battery and thermomechanical conversion nuclear battery. Among them, direct charging nuclear battery and gas ionization nuclear battery belong to direct conversion type and are rarely used. At present, the most widely used are thermonuclear battery and thermomechanical conversion nuclear battery. The substantial progress of nuclear batteries began in the 1950s. Because of its small size, light weight, long service life, and its energy and speed are not affected by the temperature, chemical reaction, pressure and electromagnetic field of the external environment, it can work in a wide temperature range and harsh environment.

It is understood that when radioactive substances decay, charged particles can be released, and if used correctly, current can be generated. Usually unstable (radioactive) nuclei will decay and become more stable after emitting particles and energy. Nuclear batteries are made by using the principle that radioactive materials will release energy when they decay. Nuclear batteries have been used in military or aerospace fields before, but they are often large. In the past, a major difficulty in battery research and development was that in order to improve performance, the size of the battery was often larger than the product itself. The research team led by Quan Zaiwan, a professor of computer engineering at the University of Missouri, successfully slimmed down the "nuclear battery" and developed a small but powerful "nuclear battery". The nuclear battery developed by Professor Quan Zaiwan is only slightly larger than 1 cent coin (diameter 1 .95cm, thickness1.55mm), but its power is ten thousand times that of ordinary chemical batteries. The research team of the University of Missouri said that the purpose of developing small nuclear batteries is to find suitable energy for micro-electromechanical systems or nano-electromechanical systems. How to find a small enough energy source device for micro-nano electromechanical system is a hot spot in the field of micro-device research.

Another attraction of nuclear batteries is that isotopes that provide electric energy work for a very long time, which may even reach 5000 years.

Imagine that in the near future, you only need a battery the size of a coin, and your mobile phone can be used without charging for 5000 years.

General nuclear batteries are similar in appearance to ordinary dry batteries, and they are all cylindrical. The radioisotope source is sealed in the center of the cylinder, and the thermionic transducer or thermocouple transducer is arranged outside. The outer layer of the transducer is a radiation shielding layer, and the outermost layer is a metal cylindrical shell.