||Horst Hahn, Abhishek Sarkar, Ben Breitung, Leonardo Velasco Estrada, Qingsong Wang, Ralf Witte, Robert Kruk, Enrique Lavernia, Benjamin MacDonald, Subramshu Bhattacharya
Mechanical properties of High Entropy Alloys (HEA) exhibiting equiatomic or near-equiatomic compositions of typically more than 5 metals as single- or multi-phase structures have been studied extensively over the past 15 years. In contrast, the functional (magnetic, electric, catalytic) properties of HEA have been studied to a much lesser extent. Recently, High Entropy Oxides (HEO) and related compounds, i.e., oxyfluorides, exhibiting ionic or covalent bonding, became popular. Several groups have reported on their functional properties, such as dielectric, magnetic, catalytic, electrochemical, etc. Examples are transition metal HEO and lithiated transition metal oxyfluorides with rocksalt structure exhibiting large Li-ion conductivity, high capacities and low degradation for electrolytes and electrodes for applications in Li-ion batteries. Rare earth HEO with fluoride structure have shown interesting magnetic properties, band gap engineering and tuning of optical properties. The talk will summarize the state-of-the-art in functional properties of HE materials with metallic, ionic and covalent bonding.