An ultrasound-driven implantable wireless energy harvesting system using a triboelectric transducer

Wireless power transfer can significantly extend the application range and service life of implantable medical devices, such as pacemakers, neurostimulators, and vascular applicators. However, existing transmission schemes are faced with shortcomings such as weak power, discontinuity, or impact on human health. Here, we design a subcutaneously implantable flexible ultrasound energy harvesting system that integrates a triboelectric nanogenerator (TENG) transducer and a power management circuit into a single flexible printed circuit board. We maximize the TENG transducer performance by choosing an attached-electrode TENG with optimized structural parameters, which offers 66% higher output power and lower impedance than the existing work. Such a flexible system shows broad applications in various environments. It can successfully provide a stable direct current voltage of 1.8 V with >1 mW continuous DC output power and >10 mW instantaneous power, which is sufficient to continuously drive various sensor systems, operate micromotors, and apply nerve stimulation.