Ocean protection increasingly relies on the internet of things (IoT) to gather essential data with the help of a variety of marine distributed sensors underwater. Most of these devices, however, have always been highly dependent on batteries, which need to be regularly changed or recharged. Inspired by nature, researchers at China’s Dalian Maritime University have developed an underwater energy-harvesting device that mimics the swaying motion of seaweed.

As reported by New Atlas, the seaweed-inspired tool is a triboelectric nanogenerator (TENG). TENG takes advantage of the triboelectric effect—a phenomenon in which certain materials become electrically charged after coming in contact and then getting separated from another material. It’s what causes the static cling in clothes when pieces of fabric rub against each other.

The recently developed device features a layer of porous sponge material sandwiched between a couple of 1.5 by 3-inch (38 by 76-mm) strips made of two different polymers. The strips are covered in a thin layer of conductive ink, with the sponge creating an air gap between them. The scientists then sealed the whole thing with waterproof tape.

Even when subjected to a relatively weak underwater current, the TENG’s polymer strips squeeze through the sponge to intermittently come in and out of contact with each other, generating an electric current in the process. In experiments, the team demonstrated that multiple TENGs could be used to power different devices, including marine environmental sensors, eliminating the need for batteries.

Source study: ACS Nano—Flexible Seaweed-Like Triboelectric Nanogenerator as a Wave Energy Harvester Powering Marine Internet of Things