Structuring self-powering refers to the structural material serving as an energy source in the absence of device incorporation. An electret is a permanent electric dipole. A true electret is one that does not need poling. In case that the material is a conductor, the electret provides a voltage and allows current to pass through. It is akin to a battery, but there is no electrolyte. A true electret discharges upon short-circuiting (which supplies energy by electrically disturbing the electret) and self-charges upon open-circuiting. Self-charge occurs because the charged state is thermodynamically stable. In contrast to a battery, no current is needed for self-charge (no need to stop to recharge, thus increasing the non-stop mileage) and no self-discharge occurs. Due to the conductivity, the current density is substantial, thus allowing the energy generation to be substantial, in spite of the low electric field. The electrets presence is due to the interaction of a small fraction of the mobile charge carriers with the atoms. This interaction mainly occurs at crystallite boundaries, so a finer microstructure helps. Carbon materials are true electrets, as discovered by Chung (U.S. patent application filed, peer-reviewed paper published in Carbon, journal, Impact Factor 8.821). This Phase I project is aimed at showing the feasibility of structural self-powering in carbon fiber polymer-matrix composites without device incorporation. The application is focused on electric vertical take-off and landing aircraft (eVTOL, dual use, for last-mile delivery, air metro, and air taxi) propelled electrically. Batteries of current eVTOL take up as much as half of the aircraft weight. The structural self-powering will reduce the need for batteries, which suffer from the limited service life, safety concern, weight/volume addition, self-discharge, and need for electricity to charge. In addition, this project is aimed at increasing the energy performance of structural self-powering by energy-based selection of the carbon fiber, without compromising on the mechanical behavior. The work will include the design, fabrication, and testing of carbon fiber composites. The electrodes and their configuration and packaging will be developed and their durability evaluated. The eVTOL dual-use applicability will be assessed, with linkage with Air Force customers and end-users. KAI, LLC (Small Business, Koo, PI) will work with Research Foundation of SUNY (U. Buffalo, RI, Chung, PI). Chung invented and owns the background technology. Due to the uniqueness, there is no competitor. In Phase I, SUNY will provide material development, electrical testing expertise, and science-based guidance, whereas KAI will provide eVTOL-application-oriented evaluation, linkage with Air Force customers/end-users, eVTOL companies, and expertise in technology commercialization. The products will be services to render the structural self-powering function to existing and new eVTOL, and a control unit.
