When the fiber is put in a tube that is connected on each end with a copper wire and has salty fluid flowing through it, it generates power with an efficiency of over 23 percent. This is higher than previously reported fiber-shaped energy harvesting devices, the researchers say. The electrical output is higher with longer fibers, faster-flowing liquid, and more concentrated salt solution.
A 30-centimeter-long device generates 0.04 milliwatts of power. That might be enough to power very small sensors and implants. To demonstrate an application in the body, the researchers connected three 10-cm-long fibers to a frog’s sciatic nerve. When they immersed the fiber in flowing salt solution, it generated a slight muscle contraction.
The fiber could also be woven into textiles to make power-generating clothes, the researchers say.