Synthesis of thin-film electrodes based on LiPON and LiPON-LLTO-LiPON

Thin lithium-conducting amorphous films of lithium phosphorus oxynitride (LiPON) are synthesized by high-frequency (HF) magnetron sputtering. The effect of sputtering conditions (HF power, support temperature, working gas pressure, and deposition time) on the microstructure of LiPON films is studied. The optimal conditions of HF magnetron sputtering that allow dense, uniform, crack-free, air-stable, amorphous thin LIPON films to be formed are studied. The composite solid electrolyte LiPON-LLTO-LiPON is synthesized based on LiPON films and the La2/3 - x Li-3x TiO3 (LLTO) ceramics characterized by the high conductivity with respect to lithium ions but unstable in contact with metal lithium. Its microstructure and electrophysical properties are studied. It is found that the LiPON film prevents the chemical reaction of metal lithium with the LLTO solid electrolyte. Due to the high chemical stability and the enhanced conductivity, the composite solid electrolyte based on LiPON-LLTO-LiPON can be used in electrochemical devices.