Session 4: Energy Generation and Storage
Gary Rubloff (University of Maryland) started his presentation noting that there were three areas in particular that he wanted to address: power generation, integration of nanocomponents, and hierarchical systems. Rubloff provided many detailed comments regarding “random” and “regular” heterogeneous 3D nanostructures, exposed and embedded nanostructures (e.g., applications and differences between the two approaches), engineering aspects of 3D structures (e.g., keeping impurities from impacting performance), process and device integration (e.g., integration at the nano-level to improve volume/weight), and multifunctional nanosystems (e.g., nano-integrated photovoltaic and energy storage systems). Rubloff also discussed what he refers to as the “three self’s”— self-assembly, self-alignment, and self-limiting reactions—and how these can be used to keep costs down. In terms of the NASA roadmap, Rubloff indicated that for the top technical challenges, he saw mechanisms for identifying defects to be lacking the most. He also identified some technology gaps, including using modeling and simulation to guide systems design and prioritization, as well as system level strategies for managing defects and reliability. Correspondingly, Rubloff noted that the high-priority areas that NASA should focus on are defect and reliability mechanisms, integrated systems, and model-based system design. Finally, relative to the time horizon of the NASA roadmap, Rubloff commented that the manufacturing equipment for these materials/systems will need to be there in time.
Public Comment and Discussion Session
The following are views expressed during the public comment and discussion session by either presenters, members of the panel, or others in attendance.
• Technology investment process. One presenter suggested forming a working group across NASA centers that meets regularly and generates consensus on areas with the largest payoffs with some external review. He mentioned that, out of a $1 billion program, spending $100 million on two or three specific areas to demonstrate significant advancement/commitment might make sense.
• Areas for NASA to lead. It was suggested that crosscutting areas like nanotech will be a challenge, and that there is work going in other groups, so it is not clear what NASA should be doing. One response suggested that NASA should take the lead in nanotechnology research related to extreme environments and multifunctional systems. It was raised that on the sensors side, NASA could be a real user/customer but not necessarily a development leader. Another area of suggested emphasis are opportunities in propulsion (e.g., microthrusters). Energy storage was mentioned as another area to look at, but that this might be led by the Department of Energy.
• Nanotechnology research at other agencies. There was a discussion on the substantial research in nano-technology going on at other groups, and it was suggested NASA should look to collaborate and benefit from the large amount invested by nine different agencies. Other agencies were said to be looking at the use of nanotechnology in radiation-hardened electronics, carbon nanotube memory, and ASICs, but no specific agency is coordinating the research. It was noted that the USAF perspective is to compromise between short/high-quality versus long/low-quality carbon nanotubes.
• Timeframe incorporation of nanotubes into structures. Clay nanocomposites have been incorporated into structures in the automotive industry for more than 10 years, whereas nanofiber structures have not been used much in commercial applications yet (ceramics for ballistic protection may be coming online in the next 1 to 2 years). There are examples of layers being used, but that they are not there yet for structural applications. This was seen as similar to the history with carbon fiber—initially it appeared in low-complexity sports equipment, and eventually made its way to more complex systems (e.g., aerospace). It was estimated that high-performance structural applications are likely to happen in the next 10 to 15 years.