Clever Carbon Fiber Composite Can Curve, Flatten Under the Control of Electrical Current

Created by layering carbon fiber doped with lithium ions, the new material could lead to more efficient wind turbines and aircraft.

Gareth Halfacree
20 days ago β€’ Robotics
Applying a current curves the material; reversing it curves it back again. (πŸ“·: Johannisson et al)

A team from the KTH Royal Institute of Technology in Sweden has demonstrated a carbon fiber composite which can change shape under the influence of electrical impulses β€” and it's hoping to use the material to improve aircraft and wind turbine efficiency.

"We have developed an entirely new concept," claims Daniel Zenkert, co-author of the paper detailing the novel material and its capabilities. "It's lightweight, stiffer than aluminium and the material changes shape using electric current.

"We have for some time worked with structural batteries, such as carbon fiber composites that also store energy like a lithium-ion battery. Now we have further developed the work. We expect it lead to completely new concepts for materials that change shape only by electrical control, materials that are also light and rigid."

The new composite is built in three layers. Two of these are off-the-shelf commercial carbon fiber which has been doped with lithium ions, while the centre layer acts as a separator. Without the application of electrical current, the material is straight and lies flat; apply a current, though, and the lithium ions migrate from one side to the other and the material curves. Reverse the current, and the composite flattens out again.

Zenkert and colleagues have suggested the material could be used to build wind turbine blades capable of dynamically changing their shape to match prevailing wind conditions, or aircraft wings which can steer without the need for mechanical rudders and ailerons. No timeline for commercialisation has yet been provided, however.

The team's work has been published in the journal PNAS under open-access terms.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire: freelance@halfacree.co.uk.
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