Comparison between rf-sputtered and electron beam evaporated thin electrode and electrolyte films for application in rechargeable lithium microbateries

The electrochemical performance of ion conducting thin films depends strongly on the deposition method. This provides a possibility of tailoring thin films with new functional properties. A comparative study was made between rf-sputtering and electron beam evaporation which are the two most commonly employed methods for the preparation of thin films. For this purpose, thin films of Li_3±xPO_4±yN_z were rf-sputtered and electron beam evaporated and investigated with regard to the electrochemical properties. It was found that solid thin films of the electrolyte Li_3±xPO_4±yN_z may be sputtered, but not electron beam evaporated. Compared to rf-sputtered Li_1±xCoO_2±y and C thin films, electron beam evaporated Li_1±xCoO_2±y and C thin films show chemical diffusion coefficients which are at least one order of magnitude higher. Paper presented at the 4^th Euroconference on Solid State Ionics, Renvyle, Galway, Ireland, Sept. 13–19, 1997