Chinese researchers have replicated the principles of hydroelectric power production on the nano-scale. A lightweight power generator based on carbon nanotube fibers was designed to convert the energy of any flowing liquid, including blood in blood vessels, into electricity.

The fluidic nanogenerator fiber is flexible and stretchable and achieved a power conversion efficiency of 23.3 percent. Source: Fudan University

Scientists from Fudan University in Shanghai, China, developed a fiber with a thickness of less than a millimeter that generates electrical power when surrounded by flowing saline solution — in a thin tube or even in a blood vessel. An ordered array of carbon nanotubes was continuously wrapped around a polymeric core to form electroactive threads. Carbon nanotube sheets coated the fiber core with a thickness of less than half a micron.

The fiber-shaped fluidic nanogenerator (FFNG) was connected to electrodes and immersed into flowing water or simply repeatedly dipped into a saline solution. The researchers explain that electricity was produced from the relative movement between the FFNG and the solution. An electrical double layer is created around the fiber, and then the flowing solution distorts the symmetrical charge distribution, generating an electricity gradient along the long axis.

Researchers documented a high power conversion efficiency — 23.3 percent — compared with other types of miniature energy-harvesting devices. The device also features elasticity, tunability and one-dimensionality, all of which offer scope for diverse applications.

The FFNG can be rendered stretchable just by spinning the sheets around an elastic fiber substrate. It might also be woven into fabrics for designing wearable electronics or be used to harvest electrical energy from the bloodstream for medical applications.