The next generation of wireless sensor networks requires the energy production and storage mechanism to be integrated on-chip. We are designing a micro-scale lithium secondary battery to be deposited on the backside of a millimeter scale wireless sensor. The battery will continuously be charged by energy scavenging devices such as MEMS piezo-benders or heat engines. The battery novelty comes from designing the cell around the duty cycle for a given application. The material novelty in the system lies in adaptation of Dunn's V 2O 5 aerogel cathode and Kostecki's pyrolyzed carbon anode for micro scale implementation. We will fabricate the entire cell on campus: the cathode from sol gel processing, the anode from standard micro fabrication photolithography, and combining them in a SiN 2 or similar enclosure. Theoretical performance is discussed based on experimental results from half cell reactions.