Ultrasound Energy Could Provide Wireless Power for Underwater Sensors, In-Body Implants

A team at the Korea Institute of Science and Technology (KIST) and a number of Korean universities have unveiled a system for wirelessly powering or recharging implanted electronics and underwater systems safely and efficiently — using an ultrasonic probe.

"This study demonstrated that electronic devices can be driven by wireless power charging via ultrasonic waves," explains project lead Hyun-Cheol Song, PhD, of the work. "If the stability and efficiency of the device are further improved in the future, this technology can be applied to supply power wirelessly to implantable sensors or deep-sea sensors, in which replacing batteries is cumbersome."

Designed for use where traditional wireless charging — that relies on electromagnetic induction, which doesn't work terribly well through water or living tissue — is not possible, the team's approach relies on using ultrasound as a medium for the transmission of energy.

The model developed by the team is based on triboelectric generation, turning tiny movements into energy, and uses a ferroelectric triboelectric generator to boost the energy transfer efficiency of an ultrasound-based power transmission system from under one per cent to over four per cent — still low, admittedly, but a massive boost.

In tests, the system proved capable of delivering over 8mW of power at a distance of 6cm through water — enough to drive a matrix of 200 LEDs, or to power a Bluetooth transmitter for the collection of sensor data. Similar tests were carried out for transmission through tissue and wood.

"We anticipate," the researchers conclude, "that our approach will enable current next-level AET [Acoustic Energy Transfer] technology to be utilized in the actual field." Thus far, however, no timescale to commercialization has been provided.

The team's work has been published in the journal Energy & Environmental Science under closed-access terms.