This Nov. 25, 2013 news item on phys.org was a bit of a walk down memory lane for me,
A mobile telephone display for your jacket sleeve, ECG probes for your workout clothes—wearable electronics are in demand. In order for textiles with built-in electronics to function over longer periods of time, all of the components need to be flexible and stretchable. In the journal Angewandte Chemie, Chinese researchers have now introduced a new type of supercapacitor that fulfills this requirement. Its components are fiber-shaped and based on carbon nanotubes.
The reference to a mobile telephone display on a jacket sleeve brought back memories of Nokia’s proposed Morph device,, from my Aug. 3, 2011 posting,
For anyone who’s not familiar with the Morph, it’s an idea that Nokia and the University of Cambridge’s Nanoscience Centre have been working on for the last few years. Originally announced as a type of flexible phone that you could wrap around your wrist, the Morph is now called a concept. …
At the time I was writing about exploring the use of graphene to enable the morph (flexible phone). This latest work from China is focused on carbon nanotubes,. The Angewandte Chemie Nov. 25, 2013 press release, which originated the news item on phys.org, provides more details,
For electronic devices to be incorporated into textiles or plastic films, their components must be stretchable. This is true for LEDS, solar cells, transistors, circuits, and batteries—as well as for the supercapacitors often used for static random access memory (SRAM). SRAM is often used as a cache in processors or for local storage on chips, as well as in devices that must maintain their data over several years with no source of power.
Previous stretchable electronic components have generally been produced in a conventional planar format, which has been an obstacle to their further development for use in small, lightweight, wearable electronics. Initial attempts to produce supercapacitors in the form of wires or fibers produced flexible—but not stretchable—components. However, stretchability is a required feature for a number of applications. For example, electronic textiles would easily tear if they were not stretchable.
A team led by Huisheng Peng at Fudan University has now developed a new family of highly stretchable, fiber-shaped, high-performance supercapacitors. The devices are made by a winding process with an elastic fiber at the core. The fiber is coated with an electrolyte gel and a thin layer of carbon nanotubes is wound around it like a sheet of paper. This is followed by a second layer of electrolyte gel, another layer of carbon nanotube wrap, and a final layer of electrolyte gel.
The delicate “sheets” of carbon nanotubes are produced by chemical vapor deposition and a spinning process. In the sheets this method produces, the tiny tubes are aligned in parallel. These types of layers display a remarkable combination of properties: They are highly flexible, tear-resistant, conductive, and thermally and mechanically stable. In the wound fibers, the two layers of carbon nanotubes act as electrodes. The electrolyte gel separates the electrodes from each other while stabilizing the nanotubes during stretching so that their alignment is maintained. This results in supercapacitor fibers with a high capacity that is maintained after many stretching cycles.
For the curious, here’s a link to and a citation for the paper,
A Highly Stretchable, Fiber-Shaped Supercapacitor by Zhibin Yang, Jue Deng, Xuli Chen, Jing Ren, and Prof. Huisheng Peng. Angewandte Chemie International Edition
Early View (Online Version of Record published before inclusion in an issue)Article first published online: 8 NOV 2013 DOI: 10.1002/anie.201307619Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
This article is behind a paywall.