Fabrication and testing of all solid-state microscale lithium batteries for microspacecraft applications

Abstract

A microfabrication process has been developed to prepare thin film solid-state lithium batteries as small as 50 μm × 50 μm. Individual cells operate nominally at 3.9 V with 10 μA h cm⁻² for a 0.25 μm thick cathode film. The cells are easily fabricated in series and parallel arrangement to yield batteries with higher voltage and/or capacity. Multiple charge/ discharge cycles are possible, though an apparent reaction of the in situ plated Li film with water or oxygen decreases cycle life several orders of magnitude from expected results. Further optimization of an encapsulating film will likely extend the cell cyclability. These microbattery arrays will be useful for providing on-chip power for low current, high voltage applications for microspacecraft and other miniaturized systems.