The device described in the Nano Energy journal under the title "High output voltage generation of over 5V from liquid motion on single-layer MoS 2" is made of molybdenum disulfide (MoS 2) flexible thin films, it generates electricity when drops of salted water slide down on its upper surface.
Previously, it has been shown that a graphene sheet could generate electricity from the liquid movement across its surface, but output voltage was limited to about 0.1V, making it impractical for energy harvesting. To make use of MoS 2 for the generator, the researchers had to figure out a way to fabricate a large-area single-layer MoS 2 film on a plastic film, something unachievable with conventional methods.
"In our study, we succeeded in fabricating this form of MoS 2 film by means of chemical vapor deposition using a sapphire substrate with molybdenum oxide (MoO 3) and sulphur powders. We also used a polystyrene film as a bearing material for the MoS 2 film, so that we were able to transfer the synthesized MoS 2 film to the surface of the plastic film quite easily", explained Professor Ohno of the Institute of Materials and Systems for Sustainability at Nagoya University.
The newly developed generator is flexible enough to be installed on the curved inner surface of plumbing, and is thus expected to be used to power IoT devices used in liquids, such as self-powered rain gauges and acid rain monitors, as well as water quality sensors that can generate power from industrial wastewater while monitoring it.
"Our MoS 2 nanogenerator is able to harvest energy from multiple forms of liquid motion, including droplets, spraying, and sea waves. From a broader perspective, this device could also be used in applications involving hydrodynamics, such as generating electricity from rainwater and waterfalls", added Professor Ohno.
Nagoya University – https://en.nagoya-u.ac.jp
Kyushu University - www.kyushu-u.ac.jp