Research Area: Mixed Conductors

Mixed ionic/electronic conducting materials (MIECs) are a class of electrical conductors in which electric transport occurs by both ion and electron motion. MIECs play an eminent role in many devices, in particular, for energy storage, energy transformation, energy efficiency and catalysis. The number of MIEC materials known to date is, however, rather small compared to the cardinal numbers of insulators, electronic conductors or solid electrolytes.

Despite their large technological importance, only bulk properties of MIECs are nowadays fairly well understood – but only few attempts have been made to systematically explore size effects in MIEC. Reducing the spatial dimensions brings transport and storage in nonstoichiometric mixed-conducting thin films, layers and near-interface regions in general into focus – phenomena, which are of great importance in solid-state chemistry and physics, electrochemistry, and numerous advanced solid-state technologies. Moreover, thin MIEC layers form naturally through interface reactions in reactive systems, e.g., at electrodes where at least one electronic and one ionic conducting phase meet. Here, ion and electron transport across these MIEC layers control both the function and the stability of the electrode.

Lithium-ion-batteries (LiBs) as key technology for today’s society are one of the most prominent examples for the application of MIEC materials. LiBs are not only based on MIEC electrode materials, but also their safe and reliable function is guaranteed by a thin MIEC layer – the so-called solid-electrolyte interphase. The development of new MIEC materials will result in better batteries, e. g. for electric vehicles or electronic devices, which in turn will have a great impact on tomorrow’s society.

Fundamental and application related research on MIEC materials (bulk and at reduced spatial dimensions) is conducted in many of the research groups at JLU Giessen and U Marburg (Chemistry, Physics, Materials Science).


  • Scientific exchange and discussion
  • Initiating research cooperations in the field of MIECs
  • Networking

Contact information

Dr. Thomas Leichtweiß

Research Coordinator


Center for Materials Research (ZfM)
Justus-Liebig-University Giessen