Institute for Applied Materials – Materials Science and Engineering

Development of electrolyte systems

Our main research focus is the electrolyte development of lithium- and sodium ion batteries (LIB/SIB). The research is aimed to increase the battery safety while maintaining or increasing power and energy density. Established electrolyte systems in LIB and/or SIB usually contain highly volatile and flammable organic solvents as well as components that cause burns when in contact with water. To increase the energy density, higher cell voltages are desired. However, the electrochemical stability of standard electrolyte systems is not sufficient for cell voltages above 4.5 V.

Our approaches in detail:

 
  • Replacement of volatile organic solvents by Ionic Liquids (IL)
 
  • Influence of active inorganic fillers on safety and electrolyte performance.
 
  • Comprehensive knowledge of physical and (electro-)chemical behaviour and its modelling.
  • Use of ion-conducting polymers as electrolyte matrix.
 
  • Targeted selection of additives regarding electrolyte and cell chemistry.

 

The main focus of our research is the development of suitable electrolytes for high-energy lithium-ion batteries. Key material properties, taking into account water content and temperature, are being systematically researched.

  • Rheological properties using rotational viscometry
  • Electrochemical impedance spectroscopy (EIS, frequency range between 1 mHz and 5 MHz)
  • Electrochemical stability via cyclovoltammetry
  • Interface analysis
  • Thermal decomposition behaviour via differential scanning calorimetry (DSC)
  • Wetting behaviour on electrode materials via drop shape analysis
  • Density and density change of electrolyte mixtures (flexural resonator method)
 
  • Gas chromatography of liquid and gaseous electrolyte products

 

For any further questions on this topic please contanct Mr. Dr. Andreas Hofmann.