Two hydrogens can form a diatomic molecule H2, which exists in gaseous form at room temperature and is therefore referred to as hydrogen. Hydrogen molecules are composed of covalent bonds, and the modern theory of covalent bonds begins with quantum mechanical studies of hydrogen molecules. Hydrogen is a clean energy source that combines with oxygen to release a lot of heat. At the same quality, the heat released by hydrogen combustion is more than four times that of coal, and its reaction product is water, which is harmless to the environment. Hydrogen can be derived from the cracking of natural gas or directly from the electrolysis of water. How to efficiently use solar energy and catalyst to decompose water into hydrogen and oxygen is an important frontier research topic.
Hydrogen of the same quality emits more energy than coal, but hydrogen is a gas at normal temperature, and the capacity of hydrogen in the same volume to store energy is much lower than that of carbon. In addition, hydrogen may explode in the air, so how to store hydrogen safely and efficiently It is also an important issue. One of the methods of efficient storage is to use a material that can adsorb hydrogen, called a hydrogen storage material. Early hydrogen storage materials can store hydrogen to a thousand times the density of hydrogen in the atmosphere. Nowadays, there are more and more types of hydrogen storage materials, and practical storage efficiency is getting higher and higher. One of the goals of the US Department of Energy's hydrogen storage battery is to meet the needs of vehicles with a single storage capacity of more than 500 kilometers in the case of space, price, safety and other aspects of competition with existing markets.
The peaceful use of controlled nuclear power plants has been around for a long time, and the technology of controlled nuclear fusion has not been realized. Among the more prone fusion reactions, the main participants are strontium, barium, 3He, 6Li, and neutrons. Among them, strontium and neutron are difficult to store, and 3He is difficult to obtain; in contrast, hydrazine is easily available, and there is about one cesium atom per 8,000 hydrogen atoms. Hydrogen atoms are abundantly present in seawater. Therefore, there is almost no problem with raw material supply through the controllable nuclear fusion of cesium. The speed at which humans consume energy is almost inexhaustible. In contrast, human energy sources have various shortcomings: the total amount of chemical fuels such as coal and petroleum is limited, nuclear energy based on nuclear fission is also limited by the total amount of raw materials, and hydropower, wind power, and solar energy are renewable. Energy can provide limited energy per unit of time. If energy is not an issue, many living habits in human society can be easily changed. For example, a large-capacity personal aircraft will be popularized. Traffic in the city is no longer limited to the road surface, but multiple levels of three-dimensional traffic can be realized; the temperature of the entire city can be adjusted to reduce severe cold and hot weather. If energy is not a problem, from a technical perspective, a new energy technology revolution will come soon; from the physical level, humans will also be able to conduct experiments at higher energy scales and explore deeper particle physics.
From the hydrogen bomb to the use of nuclear fusion to obtain civilian energy, the bottleneck in the middle is the word "controllable". An obvious difficulty lies in the temperature at which fusion occurs
if you also realize that the sun's energy comes from fusion. The critical temperature of enthalpy fusion is on the order of 100 million Kelvin. At this temperature, there are no more solids, liquids, gases, and substances exist in the form of plasma. At this time, electrons and positive ions coexist. In other words, any conventional container cannot accommodate nuclear fusion reactions at this temperature. In addition, the plasma also needs to have a sufficiently high density that fusion will not be able to output energy if the energy produced by nuclear fusion is less than the energy present in the plasma. The reason why the sun can undergo nuclear fusion is because the gravitational force generated by its massive mass constrains the plasma. Such a constraint is called inertial confinement. Among the controllable nuclear fusion schemes, some schemes are constrained by laser inertia: the laser is used to provide energy to make the small-scale (such as 10 micrometer-scale) fusion material localized and pressurized in a small space. There are also schemes that use a strong magnetic field to constrain the plasma: charged ions can do closed-loop motion under magnetic fields, thereby realizing spatial localization. This scheme is sometimes called tokamak. People are still looking for a variety of fusion methods that do not require high temperatures. These schemes are called cold nuclear fusion. Regardless of the solution, the technical difficulty required to achieve them is extremely large. Although people have been expecting controlled nuclear fusion for many years, although many countries continue to invest heavily in related research, there is currently no nuclear fusion technology available in the world.
Hydrogen, atomic number 1, is the energy base of human society, and it carries the hope of a new energy technology revolution.