Despite the popularity and widespread demand for miniaturized electronic devices, limited advances have been made to design energy storage mechanisms that can satisfy their power and size requirements. We have developed a fabrication process to produce miniature Li-ion batteries by combining the stencil printing process to deposit thick high capacity electrodes and an adhesive based sealing method for battery packaging, with active areas as small as 1 mm2. The battery consists of printed anode and cathode layers based on graphite and lithium cobalt oxide (LCO) respectively. These batteries have roughly 9.5 times the areal capacity of commercial micro-batteries, and demonstrate a significantly higher discharge capacity (7.2 mAh/cm2) and energy density (26.7 mWh/cm2) than previously reported thin-film and thick-film, and 3D micro-batteries. Further, the larger batteries (area: 25 mm2) possess sufficient capacity to support the power requirements of SCµM-3C, a wireless sensor node on-chip.