Power with a twist: Twisted ropes made from single-walled carbon nanotubes could store enough energy to power sensors within the human body while avoiding the chemical hazards associated with batteries. (Courtesy: Shigenori UTSUMI)
Topics: Applied Physics, Battery, Carbon Nanotubes, Chemistry, Materials Science, Nanoengineering
Mechanical watches and clockwork toys might seem like relics of a bygone age, but scientists in the US and Japan are bringing this old-fashioned form of energy storage into the modern era. By making single-walled carbon nanotubes (SWCNTs) into ropes and twisting them like the string on an overworked yo-yo, Katsumi Kaneko, Sanjeev Kumar Ujjain , and colleagues showed that they can store twice as much energy per unit mass as the best commercial lithium-ion batteries. The nanotube ropes are also stable at a wide range of temperatures, and the team says they could be safer than batteries for powering devices such as medical sensors.
SWCNTs are made from sheets of pure carbon just one atom thick that have been rolled into a straw-like tube. They are impressively tough – five times stiffer and 100 times stronger than steel – and earlier theoretical studies by team member David Tománek and others suggested that twisting them could be a viable means of storing large amounts of energy in a compact, lightweight system.
Twisted carbon nanotubes store more energy than lithium-ion batteries, Margaret Harris, Physics World.
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