Carbon nanotube springs have potential to compete with batteries
5 Oct, 2009 02:46 pm
MIT scientists find that carbon nanotubes springs have potential to store as much energy as lithium-ion batteries. They are also more reliable and more durable. Carol Livermore, lead author of the study, answers Scitizen's questions.
What are the advantages of storing energy in carbon nanotube springs (CNT) rather than in batteries?
CNT springs have the potential to reach comparable energy densities to those of Li-ion batteries, though they aren't there yet. The springs have the potential to release their energy very quickly, and hence are appealing for high power applications. They also have the potential for long term reversibility (that is, springs don't usually have memory effects), and they are predicted to have good long term storability (negligible or low leakage).Â Finally, they have high potential for driving mechanical loads directly, without having to go through the electrical domain.
Considering the specific characteristics of carbon nanotubes (like their resistance to extreme temperatures), is your research also concerned with engineering for extreme environnements?
Engineering for extreme environments is not a central feature of my research per se. However, we do research on small-scale systems that manipulate large amounts of power and/or energy for their size, so engineering extremes do come up quite often. Sometimes these systems wind up having good robustness in extreme environments as a natural extension of the engineering extremes that we are considering. This is one such case.
What is the potential niche of application of CNT?
The most promising applications for CNT springs are those that require the strengths that I described above. One would be regenerative braking for lightweight vehicles like bicycles, in which you could capture the energy from and release it back to the mechanical domain. They are also a promising technology for power supplies for sensors used in oil drilling because of their insensitivity to large swings in temperature. Their low leakage potential offers a path to long term back up power supplies, while their high power density (ability to release energy quickly) offers potential for portable yard tools like leaf blowers without a fuel burning engine.
What is the next step?
So far, we have tested small-scale (several millimeter long) springs in the lab. We continue to work on improving the properties of these small springs, testing new approaches to structuring fibers, and starting to connect them up to test loads.
Interview by : Clementine Fullias
Carol Livermore is an Associate Professor in the Department of Mechanical Engineering at MIT.