Stability and Safety of Cathode Materials (with Possible Al Doping) for Li-Ion Batteries: Thermodynamic and Electrochemical Studies

Carlos Ziebert, Hans J. Seifert, KIT

Electrochemical reactions and phase transformations occurring in the active materials such as LiMO₂ (M = Ni, Co and/or Mn) and LiM₂O₄ compounds with possible small addition of Al were studied using adiabatic and isothermal battery calorimeters. The thermal behaviour and the heat output were investigated during charging-discharging in self-assembled coin and commercial 18650 cylindrical cells. Current interruption technique was used to measure the irreversible heat while the reversible heat was determined by potentiometric measurements at different depths of discharge (DOD). The performance of these cells under different operating conditions (temperature, C-rate) was evaluated.