Hydrogen is a chemical element that has the atomic number 1 in the periodic table. It consists of one proton and one electron.
In its normal state, hydrogen is a gaseous element that is colorless, odorless and much lighter than air. At temperatures below -250 °C, it changes its state of aggregation from gaseous to liquid and solid as the temperature drops. At a temperature of -253 °C, hydrogen liquefies and at -259 °C it becomes solid. The energy density of hydrogen is 33.3 kWh/kg.
In the future, hydrogen will be used as a fuel for motor vehicles and also in various industrial applications. For example, in steel production. In the automotive industry, the conversion into electrical energy takes place by means of fuel cells. The PEM fuel cell is favored for this purpose.