Extended Electrochemical Reliability Study of All-Solid-State Thin Film Microbatteries

The long-term reliability of all-solid-state thin film microbatteries was studied through a deepened electrical characterization of the solid interfaces. After 1,500 cycles, the cells cycled at 60°C showed few changes of the intrinsic parameters at the interfaces of the active layers from the electrochemical stack. Through the implementation of an extended experimental approach incorporating impedance spectroscopy measurements from 1 MHz to 200 mHz, coupled to an equivalent electrical model, charge transfer resistances and exchange currents densities were extracted. The study highlights the reliability performances of the EnFilm™ HiCap microbattery technology. The results were confirmed through the experimental behavior study, the electrochemical integrity of EnFilm™ HiCap technology is preserved in use. Devoid of Solid Electrolyte Interface (SEI) typical of conventional liquid electrolyte Li-ion systems, all-solid-state microbatteries therefore present physical characteristics of good reliability performances.