Minerals as basis for functional materials

Mineralogy deals with the structure and related physical and chemical properties of materials in the geo- and biosphere. The knowledge about these minerals and their specific properties is increasingly used in various technical, medical and environmental fields [1]. One of the most impressive examples is garnet, a mineral which usually occurs in magmatic and metamorphic rocks. On the one hand, its chemistry is closely related to the chemistry of the host rock and, more importantly, its crystal structure reflects the pressure and temperature conditions during its formation. On the other hand, garnet is an important material for technical issues, e.g. the well-known Yttrium Aluminum Garnet (YAG)-Laser, and it finds now new applications, e.g. in the field of energy storage. Even though the chemical composition varies considerably all garnets have in common the same crystal structure. Li-oxide garnet with the composition Li₇La₃Zr₂O₁₂ (LLZO) is an excellent example to demonstrate the application of mineralogical knowledge in material science. Recently, these garnets have been identified as a promising material in the field of energy storage, as they can be used as solid state electrolyte in Li-based all solid state battery concepts. In Li-ion batteries, solid electrolytes are considered to replace polymer based electrolytes, which have disadvantages e.g. they are highly inflammable.

The presentation of garnet stands as an example for numerous other mineral groups which build the basis for their application in material science, such as spinel, perovskite, zeolite, sphalerite, chalcopyrite, kesterite, argyrodite, etc. In our contribution some of these mineral groups and their importance as basis for functional materials will be presented.

[1] S.-Heuss-Aßbichler, G. Amthauer, M. John (Eds.). Highlights in Applied Mineralogy. Dr Gruyter Berlin/Boston 2017, 344 pp.