Lithium
The chemical element lithium with the symbol Li has the atomic number 3 in the periodic table of elements. It belongs to the alkali metals, is the lightest metal and has a silvery-white colour in its pure form. Although it is a metal, it is very soft and can even be cut with a knife. It is also characterised by a low density (0.534 g/cm³) and a melting point of only approx. 180 °C.
Lithium is a very reactive element. It reacts strongly with water, releasing hydrogen, but also with oxygen, forming lithium oxides. Due to its reactivity, lithium is often stored in oil or in an inert atmosphere to prevent an undesired reaction with atmospheric water vapour (humidity) or other components of the air such as nitrogen and oxygen.
As a lithophilic element, lithium is mainly found in the earth’s crust with a concentration of between 20 and 60 µg/g, exclusively in the bound form of minerals such as spodumene, petalite and lepidolite or dissolved in (hydrothermal) pore or surface waters. Lithium has a wide range of applications, from accumulators to alloys and medicine. Lithium-ion batteries are widely used in many electronic devices, including mobile phones, laptops and electric cars. In human medicine, lithium is used in the form of salts such as lithium carbonate or lithium sulphate to treat bipolar disorder or as antidepressants.
In geoscientific research, the two natural lithium isotopes 6Li and 7Li can also be used for different research questions. For example, lithium isotope analysis can provide insights into the geochemical development of hydrothermal fluids, allowing conclusions to be drawn about the formation of deposits or providing insights into the evolution of the earth’s crust. Another field of application of lithium isotope analysis is, for example, in palaeoclimate reconstruction, where it enables us to determine weathering rates.
Due to the growing demand for lithium-ion batteries for electric vehicles or photovoltaic systems, for example, lithium has gained in economic importance in recent years. Countries such as Chile, Australia and Argentina have significant lithium deposits and are important producers for the global market. However, European countries such as Germany, France and the Scandinavian countries also have lithium deposits that are worth developing. One ambitious project, for example, has been extracting lithium from geothermal wells in the Upper Rhine Graben since the end of 2023.