DEVELOPMENT AND PERFORMANCE OF A RECHARGEABLE THIN-FILM SOLID-STATE MICROBATTERY

A thin-film solid-state Li/TiS2 microbattery has been developed at Eveready Battery Company (EBC). It is fabricated using sputtering for deposition of the metal contacts, TiS2 cathode, and oxide/sulfide glassy electrolyte. High vacuum evaporation is used to deposit a Lil layer and Li anode. EBC Microbatteries range from 8 to 12 mu m in thickness and have a capacity between 35 and 100 mu Ah/cm(2), depending on the amount of anode and cathode deposited. The microbattery open-circuit voltage is approximately 2.5 V. EBC Microbatteries routinely go more than 1000 cycles between 1.4 and 2.8 V, with greater than 90% cathode utilization, at current densities as high as 300 mu A/cm(2). Several EBC Microbatteries have gone over 10 000 cycles at 100 mu A/cm(2) with greater than 90% cathode utilization on each cycle. The microbatteries will cycle at temperatures as low as -10 degrees C at a current density of 100 mu A/cm(2), are capable of supplying pulse currents of several mA/cm(2), and have excellent long-term stability both on shelf and while cycling. Sets of five microbatteries have been assembled in either a series or parallel configuration and cycled more than 1000 times. EBC Microbatteries as large as 10 cm(2) have been fabricated and cycled over 1000 times at close to 100% cathode efficiency.