Electrical Energy from Stretching Yarn

by Emil Morhardt

Well, yarn, sort of. This yarn is made by twisting carbon nanotubes until they become so twisted that the coil up into a helical spring-like configuration. You can do the same thing with cotton yarn or string. When the South Korean researchers (Kim et al., 2017) put the coil into an electrolyte then stretched it what they got was electrical current. Not a lot, but these are small laboratory-scale experiments and what the researchers had in mind was generating small amounts of energy to power sensors, for example, sewn into a shirt or gloves that are stretched and released under normal activities, but that wouldn’t work very well if the subject had to be immersed in an electrolyte. Or would it? They tried immersing the device, which they call a twistron, into the Gyeonpo Sea off South Korea where the temperature was 13ºC (a chilly 55ºF) and the sodium chloride content was 0.31 M, a nice electrolyte solution. But instead of sewing the yarn into a diver’s wetsuit, they attached it between a floating balloon and a sinker on the seabed to see if they could harvest ocean wave energy. Yes! They got it to light up a green LED whenever a wave came by. Continue reading

Material Architecture: Graphene and Carbon Nanotube Applications for Energy

by Alison Kibe

With the availability of cost effective and easily scalable synthesis methods, researchers have begun working with porous and 3D graphene and carbon nanotube (CNT) structures. Wang, Sun, and Chen (2014) wrote a review article outline uses for foam-like structures of CNTs, graphene, and hybrids of the two. Using a process called chemical vapor deposition, it is possible to construct defect free 3D architectures. This type of method is currently used in thin film production, i.e. production of semiconductor wafers in photovoltaic cells. Continue reading