The secret of never-ending power outages: Exploring the principles of nuclear batteries

　　Mobile phones are developing at a speed that exceeds Moore's Law, from single-core to 8-core, screens to 1080p, and memory from dozens of MB to 2 GB. Everything in the phone is being updated, but the battery is the only thing that is standing still. The fuel cell that has been talked about before has not been launched due to various technical problems. In order to solve the problem of battery life, many manufacturers can only increase the thickness of the phone in order to have more space to place the battery. Recently, nuclear batteries have been hotly circulated on the Internet, and it is said that they can provide power for 20 years.

　　The name of nuclear battery sounds awesome enough, but what exactly is it and can it become the ultimate weapon to solve the battery life problem of mobile phones?

　　Some people may doubt that nuclear power is such a mysterious thing, how can it be made into a battery size? However, in fact, there is such a thing, and it can be bought on Taobao. The battery rumored on the Internet is called NanoTritium, which is a nuclear battery made of tritium and is only a few centimeters in size. However, this battery is not cheap, and the price on Taobao is 6980 yuan, and it is a second-hand one.

　　However, this kind of nuclear battery is different from the nuclear battery we usually talk about and the nuclear battery carried by the Curiosity Mars Rover. At present, all nuclear power plants use the fission reaction of heavy elements to release heat, and then convert the heat into electrical energy. The NanoTritium battery on the Internet is different from the principle of nuclear power plants. It is a radioactive isotope battery. This type of battery can be roughly divided into two types, namely thermal conversion nuclear batteries and non-thermal conversion batteries. Among them, the one mentioned on Taobao belongs to the non-thermal conversion battery. This battery uses the beta particles released when the isotope decays, that is, it directly uses electrons to generate electricity, and does not involve the use of heat to generate electricity in the middle. The NanoTritium nuclear battery uses the hydrogen isotope tritium, whose atomic nucleus consists of one proton and two neutrons. This is an element that will undergo beta decay, emitting high-speed moving electrons (i.e. beta rays), and at the same time transforming into helium 3. These high-speed electrons will generate electric current when they are shot into the semiconductor.

　　Since the half-life of tritium is as long as 12.43 years, this battery can provide power continuously for a long time. However, the current it generates is not large. If you really want to use nuclear batteries to power mobile phones, the size of the battery must be larger than the mobile phone itself. Therefore, nuclear batteries are currently only suitable for those occasions where power consumption is low but uninterrupted power supply is required for a very long time, such as powering built-in medical equipment, as well as military or space purposes.

　　In addition, everyone is worried about whether this nuclear battery will cause harm to the human body. In fact, this type of nuclear battery is quite safe, because the decay of tritium will only produce high-speed electrons, and such electrons are unable to penetrate the human body. Low-Z materials such as aluminum can provide good shielding. Therefore, it is quite safe for the human body, unless you take a large amount of tritium orally or inject it into the body.

　　However, with the development of technology, perhaps in the near future, we will really only need a coin-sized battery to allow your mobile phone to be used for 5,000 years without charging.