NOVELTY - The apparatus comprises: a ceramic substrate having a first surface and a second surface; a cathode current collector disposed adjacent to a portion of the first surface of the substrate; a high temperature annealed cathode from a radio frequency (rf) magnetron sputtered cathode target in an argon atmosphere disposed adjacent to a portion of the gold cathode current collector; an electrolyte layer disposed adjacent to the annealed cathode; an annealed anode disposed adjacent to a portion of the electrolyte; and an anode current collector disposed adjacent to a portion of the anode.    USE - The apparatus is useful as a low-voltage, rechargeable thin film battery: in a real time clock circuit of an electronic device (all claimed) such as a cellular telephone; and in an implantable medical device, a remote sensor, a semiconductor diagnostic wafer, an automobile tire sensor, a miniature transmitter, an active radio frequency identification (RFID) tag, a smart card, a microelectromechanical system device, a non-volatile complementary metal oxide semiconductor-static RAM product such as memory chips for computers, and a passive RFID tag.    ADVANTAGE - The low-voltage, rechargeable thin film battery can be able to withstand at high processing temperatures, and has improved cycle performance and charge-discharge characteristics.    DETAILED DESCRIPTION - The apparatus comprises: a ceramic substrate having a first surface and a second surface; a cathode current collector disposed adjacent to a portion of the first surface of the substrate; a high temperature annealed cathode from a radio frequency (rf) magnetron sputtered cathode target in an argon atmosphere disposed adjacent to a portion of the gold cathode current collector; an electrolyte layer disposed adjacent to the annealed cathode; an annealed anode disposed adjacent to a portion of the electrolyte; an anode current collector disposed adjacent to a portion of the anode; and a hermetic package enclosing the apparatus. The cathode current collector has a titanium layer and a gold layer. The cathode consists of lithium cobalt oxide (LiCoO2) and lithium manganese oxide (LiMn2O4), and is annealed at a temperature of 700 degrees C. The anode is electrically insulated from the cathode and the cathode current collectors by the electrolyte. The anode is derived from a lithium intercalation compound consisting of vanadium oxide, titanium disulfide, molybdenum disulfide, molybdenum oxide sulfide (MoO2-xSx), and molybdenum trioxide, where x is 0-2. The anode current collector comprises a copper film having a thickness of 0.1-0.5 mu m, and a gold film (20) that is disposed adjacent to a portion of the copper film and has a thickness of 0.1-0.5 mu m. A portion of the cathode current collector and a portion of the anode current collector are not enclosed by the hermetic package. The anode comprises a vanadium oxide anode that is converted upon an initial charging of the apparatus to a lithium vanadium oxide ( omega LixV2O5) anode, where x is 0-4. The apparatus has an operating voltage of 1-2.2 volts. The titanium layer of the cathode current collector comprises a titanium film having a thickness of 0.01-0.10 mu m. The gold layer of the cathode current collector comprises a gold film having a thickness of 0.1-0.3 mu m. The cathode comprises a film having a thickness of 1-5 mu m. The electrolyte layer comprises an amorphous lithium phosphorus oxynitride film having a thickness of 0.5-2 mu m. The anode comprises a film having a thickness of 0.2-2 mu m. INDEPENDENT CLAIMS are included for:    (1) an electronic device comprising a real time clock circuit; and    (2) a method for making low-voltage, thin film battery.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic cross-sectional view of a low voltage thin film battery.    Substrate (12)    Gold film (20)    Cathode film (22)    Electrolyte film (24)    Anode film. (26)