NOVELTY - Improvement of life of a thin film rechargeable battery (32), comprises applying a planarization material over an anode (24) layer and thin film battery to provide a relatively smooth, pinhole free planarization layer; and applying barrier layer(s) to the planarization layer, the barrier layers consisting of metal materials, ceramic materials, or polymeric materials.    USE - The method is for improvement of life of a thin film rechargeable battery (claimed) for microelectronic devices and circuits, implantable medical devices, remote sensors, miniature transmitters, smart cards, and micro electro mechanical systems devices. The thin film rechargeable battery is used for e.g. PCMCIA (sic) cards and other types of complementary MOS-static RAM devices.    ADVANTAGE - The method provides a thin film battery having an extended life or a life approaching 20 years.    DETAILED DESCRIPTION - Improvement of life of a thin film rechargeable battery having a solid electrolyte (22), comprises providing a thin film battery having an anode layer reactive with oxygen and water vapor; applying a planarization material over the anode layer and thin film battery to provide a relatively smooth, pinhole free planarization layer, where surface roughness of the planarization layer is not greater than 1.0 nm root mean square, and the planarization material in the planarization layer is non-reactive with the anode layer; and applying barrier layer(s) to the planarization layer, the barrier layers consisting of metal materials, ceramic materials, or polymeric materials, where planarization layer and barrier layer(s) provide a thin film battery having an extended life.    An INDEPENDENT CLAIM is also included for a long-life, thin film rechargeable battery, comprising a support substrate having a support surface; a cathode current collector (16) spaced-apart from an anode current collector (18) deposited on the support surface of the substrate; a cathode (20) layer deposited on a portion of the cathode current collector; a solid electrolyte layer deposited on the cathode material, substrate, and a first portion of the anode current collector; an anode layer deposited on the electrolyte layer, and a second portion of the anode current collector to provide a thin film battery stack; a planarization material applied over the thin film battery stack, to provide a relatively smooth planarization layer having a surface roughness of not greater than 1.0 nm root mean square, and the planarization material in the planarization layer is nonreactive with the anode layer; and barrier layer(s) applied over the planarization layer, and consisting of metal materials, ceramic materials, or polymeric materials, where planarization layer and barrier layer(s) provide a thin film battery having an extended life.    DESCRIPTION OF DRAWING(S) - The figure is a cross-sectional view, not to scale, of a thin-film battery containing a planarization/barrier layer.    Cathode current collector (16)    Anode current collector (18)    Cathode (20)    Solid electrolyte (22)    Anode (24)    Thin film battery (32)