Dielectric Materials and Films
Navy ships have finite space below deck. As power needs grow from being dominated by the propulsion system to including advanced radars and communication systems, there is increased need to distribute, condition and store power. Capacitors comprise a substantial portion of the volume in power conditioning systems. Increased energy storage density in wound film capacitors will help accommodate the ever increasing power demands on Navy ships. The state-of-the-art dielectric in large wound film capacitors is biaxially oriented polypropylene. It can be processed into very thin films and the oriented semicrystalline morphology provides a high dielectric breakdown strength. The non-polar chemistry yields low dielectric losses but also a low permittivity and thus low energy storage density. Prior work in this program led to a number of approaches to dramatically increase the dielectric permittivity with fairly modest increases in dielectric loss. However, the combination of increased energy storage density and increased losses can exacerbate heat removal issues leading the program to revisit the balance between dielectric permittivity and losses and thermal stability.
Backup power and other devices can have increased energy density when combined with electrochemical capacitors. A small focus in this program is enhancing electrochemical capacitor performance by adding a faradaic component such as a metal oxide or conjugated polymer to the 3D electrode structure.
Research Concentration Areas
- Polymer-based wound film dielectric capacitors are a scalable and cost effective energy storage approach that can be designed with graceful failure modes
- Current dielectric films have a limited use temperature which can threaten reliability and safety factors
- Research is needed to better understand and mitigate the decreases in the performance of polymer dielectric films under high electrical loading at higher temperatures
Research Challenges and Opportunities
- Basic studies of dielectric aging and breakdown
- Processable dielectric films that maintain performance to 150 degrees Celsius or higher
- Understanding and mitigating charge injection under high voltage
- Study of charge transport in high band gap polymers and approaches to reduce it at high temperatures
- Studies to develop accelerated testing on research films to yield predictions of long term wound capacitor behavior (dielectric again and breakdown)
- Approaches to add faradiac capacitance to electrochemical capacitors (no interest in high surface area electrode development)
Program Contact Information
How to Submit
Submit white papers, QUAD charts and full proposals for contracts to this email address: ONR Code 33 Research Submissions
Follow instructions within BAA for submission of grant proposals to grants.gov website.