Smart power system of biocompatible and flexible micro-supercapacitor

Abstract

Flexible micro-supercapacitor (MSC) is an ideal energy storage device for flexible and small-scale electronics, specifically some human health sensors, because of its flexibility, long working life, high power density, and high charge and discharge rate. In this work, a smart power system of MSC is developed. First, utilizing ink-jet printing and electrochemical deposition, flexible MSC is fabricated on the biocompatible substrate of a modified silk protein film, making the power system suitable for implantable devices. Second, aiming at the common drawbacks of small energy density and large voltage variation of MSC, a wireless charging component and a wireless inductor–capacitor (LC) voltage sensor are integrated with the MSC unit. Using pulse charging mode, charging and voltage detection can be performed at the same time. The LC voltage sensor, using varactor diodes to realize voltage capacitance mapping, does not need extra ICs or consume any energy. Such a system has great application potential as the energy supply part of small devices implanted in the human body.