Patterning and annealing of nanocrystalline LiCoO2 thin films

For the development of new high power density cathode materials for lithium ion batteries (LIB) the combination of thin film technology and laser technology is investigated. For this purpose thin films of lithium cobalt oxide (LiCoO 2 ) synthesized by r.f. magnetron sputtering were structured with laser radiation to significantly increase the active surface area. Subsequent heat treatment using laser annealing was performed in order to synthesize the required high temperature phase of LiCoO 2 . The cathode material was studied by Raman spectroscopy to determine the structure before and after laser treatment. X-ray photoelectron spectroscopy was applied to determine the chemical composition of the films. The battery performance of laser treated cathode material was investigated by means of electrochemical cycling. A significant improvement of capacity retention by laser structuring was detected.