THIN-FILM RECHARGEABLE LITHIUM BATTERIES FOR IMPLANTABLE DEVICES

Thin films of LiCoO2 have been synthesized in which the strongest x-ra y reflection is either weak or missing, indicating a high degree of pr eferred orientation. Thin film solid state batteries with these textur ed cathode films can deliver practical capacities at high current dens ities. For example, for one of the cells, 70% of the maximum capacity between 4.2 and 3 V (similar to 0.2 mAh/cm(2)) was delivered at a curr ent of 2 mA/cm(2). When cycled at rates of 0.1 mA/cm(2), the capacity loss was less than or equal to 0.001%/cycle. The reliability and perfo rmance of Li-LiCoO2 thin film batteries make them attractive for appli cation in implantable devices such as neural stimulators, pacemakers, and defibrillators.