Rechargeable solid state lithium microbatteries

A rechargeable thin-film lithium battery that can be used as a miniature power supply for small devices has been developed. The battery consists of an amorphous vanadium pentoxide (aV/sub 2/O/sub 5/) cathode, an amorphous lithium phosphorus oxynitride (Lipon) electrolyte, and a lithium anode. A thin-film cover layer protects the battery from exposure to air and water vapor. The battery can deliver up to 60 mu A/cm/sup 2/ of current between 3.6 V and 1.5 V. Higher voltages can be achieved by fabricating two or more cells in series. A 1-cm/sup 2/ cell with a 1-1.5- mu m-thick cathode discharged from 3.6 to 1.5 V at 12 mu A typically yields about 440 mC and delivers about 1 J. Using the combined mass of the cathode, electrolyte, and the anode (3* over capacity), the specific energy of the cell is 1.4*10/sup 6/ J/kg and the energy density is 2.1*10/sup 6/ J/L.<
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