The development of miniaturized electronic systems such as smart cards, wireless sensors and sensor networks, and implantable devices, has stimulated the demand for miniaturized power sources. For these electronic devices, the power need ranges from several microwatts to hundreds of milliwatts, and the energy requirement is from several hundreds of microwatt-hours to several milliwatt-hours. In this project, an advanced and reliable micropower source with high energy density and high power density will be developed and investigated. The nano-enabled miniaturized electrode design is geared to take advantage of the scaling relationship between interface area and overall volume. This project will leverage and transform the PI's past and current research effort on microsupercapacitors and microbatteries into developing and investigating a novel hybrid micropower system. The fabrication method involved in this system is compatible with the semiconductor manufacturing process. The novel system could be integrated with microchips, energy harvesters, power management systems and sensing components. Through fundamental research, key insights into the physical and chemical processes that occur in the electrochemical power system can be obtained. The resulting knowledge is critically needed to achieve breakthroughs that are required for the development of on-chip level micropower. This project will engage graduate and undergraduate students in cutting-edge research, and broaden the participation of minority students and women in science and engineering. The newly developed techniques and research results will be broadly disseminated to the general public. The objective of this project is to develop a hybrid micropower source with high energy density and high power density. An asymmetric on-chip level battery type hybrid microsupercapacitor will be designed, fabricated and investigated. This device will be a combination of a high power handling double-layer electrochemical capacitor microelectrode and a Li-ion based rechargeable battery microelectrode. In this research, an interdigital high-aspect-ratio microelectrode platform will be constructed by photolithography. Electrochemical active materials will be fabricated by electrostatic spray deposition. The design rules of the micropower system will be investigated based on balancing multiple factors, such as: charge, power, cycle life, and voltage window. The performance of the hybrid on-chip micropower system will be evaluated and optimized. The project will deliver a reliable stand-alone power source, that could be used as backup power for other energy harvesting systems. The unique electrode array architecture offers exciting possibilities for the optimization of ion and electron transport and capacity. This project will effectively integrate research and education in emerging micro- and nano-fabrication for on-chip micropower applications, and broaden the participation of minority students and women in science and engineering.
