Fundamental Aspects of Electrochemical, Chemical and Electrostatic Potentials in Lithium Batteries

Abstract

The development of high energy and power density rechargeable lithium batteries belongs to the most challenging technologies in the field of Ionics. A large number of requirements with regard to chemical stability under extreme oxidizing and reducing conditions as well as appropriate kinetic parameters for the ionic and electronic species of the electrolytes and electrodes have to be fulfilled. Suitable materials for the individual electrolyte, anode and cathode components of lithium batteries have been disclosed in recent years, but the materials by themselves are meaningless. Similar to solid state Electronics, only combinations of materials are important. These are in the case of Ionics mixed electronic-ionic conductors, one type of materials with predominant ionic conductivity and other ones with predominant electronic conductivity. The need of partial ionic conductivity in the electrodes is more obvious than that of the need of electrons in the electrolyte, which are also necessary, however, because of the equilibration of the Fermi potential across the interfaces.