“The idea that solid ceramic electrolytes could be a highly promising alternative to traditional liquid electrolytes in batteries and accumulators is not something new in material science”, explains Dr. Daniel Mutter, a scientist from the Materials Modeling group at the Fraunhofer Institute for Mechanics of Materials (IWM) in Freiburg. Compared to traditional liquid electrolytes, solid electrolytes are safer during ongoing operation: they pose a much lower risk of explosion and, in the event of damage – e.g. due to a crash – there is no release of acid, which may otherwise cause burns and poisoning.

Suitable chemical compounds for solid electrolytes discovered

In general, the ionic conductivity of ceramic materials is lower than that of liquid electrolytes. However, the class of so-called NZP ceramics promises a high degree of ionic conductivity: their structural organization enables the existence of “migration paths” along which lithium ions can easily travel. This makes them an interesting candidate for high-performance solid electrolytes in lithium-ion batteries.

However, what remained unclear until now was why certain compounds are more efficient than others and what compounds actually perform particularly well. The requirements for the material properties of battery electrolytes are stringent: their ionic conductivity must be high and the chemical elements used must be both non-toxic and abundantly available in the earth’s crust.

Dr. Mutter used atomistic simulations to identify several combinations of chemical elements for NZP ceramics that are particularly promising in view of these requirements. “This computer-based research enables us to make definitive statements on the properties and stability of various chemical compounds without actually having to synthesize these compounds in a lab”, explains the researcher. The benefit: the actual synthesis is expensive and requires resources. He performed the simulations at the mainframe of the Steinbuch Supercomputer Center of the Karlsruhe Institute of Technology.