A facile route to thin-film solid state lithium microelectronic batteries

We describe the synthesis and characterization of a thin-film solid state l ithium rechargeable battery, This battery was designed for integration into a multi-chip module (MCM). The battery consists of a spin-on Ag2WO4 - poly mer cathode, a lithium hexaflurophosphate - polymer-impregnated microporous nylon membrane electrolytic separator, and a lithium foil anode. Kapton(TM ) was used as the substrate and encapsulating top layer of the battery. The battery had a total area of approximately 4.0 cm(2) thickness of 0.6 mm, a nd weighed 0.4 g. The battery had an open circuit voltage of 3.5 V and was able to deliver a current density of 0.05 mA/cm(2) for 1.5 h while maintain ing a voltage above 2.0 V. The battery was cycled over 12,000 times between 3.5 and 2.0 V using a constant discharging current density of 0.1 mA/cm(2) and charging current density of 0.05 mA/cm(2). The battery was designed fo r integration into a standard 96 pin Kovar/Glass Bead quad-flatpack program mable MCM (1.42 x 1.42 x 0.16 in.). The charging and discharging characteri stics of this battery are presented and discussed in terms of its intended application. (C) 2000 Elsevier Science S.A. All rights reserved.