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 (aV₂O₅) 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 μA/cm² 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-cm² cell with a 1-1.5-μm-thick cathode discharged from 3.6 to 1.5 V at 12 μA 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 1.4×10⁶ J/kg and the energy density is 2.1×10⁶ J/L