Transcutaneous ultrasound energy harvesting using capacitive triboelectric technology

A major challenge for implantable medical systems is the inclusion or reliable delivery of electrical power. We use ultrasound to deliver mechanical energy through skin and liquids, and demonstrate a thin implantable vibrating triboelectric generator able to effectively harvest it. The ultrasound can induce the micrometer scale displacement of a polymer thin membrane to generate electrical energy through contact electrification. We recharge a Li-ion battery at a rate of 166 μC/s in water. The voltage and current generated ex-vivo by ultrasound-energy transfer reached 2.4 V and 156 µA under porcine tissue. It shows that capacitive triboelectric electret is the first technology able to compete with piezoelectricity to harvest ultrasound in-vivo and power medical implants.