Liquid-metal-microdroplets-incorporated ultrasoft dielectric gel toward stretchable and healable waste-energy-harvesting devices

Abstract

In this work, an ultrasoft, healable, and portable device is designed, which is capable of harnessing lost energy from AC-powered gadgets. This soft device consisting of an ultrasoft dielectric silicone gel as a matrix and liquid metal alloy (EGaIn, eutectic gallium indium) microdroplet fillers can reduce the dielectric loss of the targeted system through the polarization of the liquid metal droplets, which allows the transfer of electricity to an attached electrode electrostatically. Although this concept has been previously introduced; the device developed in this work is remarkably capable of harnessing energy after multiple catastrophic failures owing to its healability enabled by the strong cohesive property of the gel matrix. In addition, the polymeric gel is initially too soft and moist for utilization; however, it becomes easier to handle after adding liquid metal fillers that increase its modulus of elasticity owing to the oxide layer of the liquid metal, resulting in creating portable and adhesive soft devices. The practical utility of this harnessed energy is ultimately demonstrated by powering small electrical appliances. Therefore, our research sheds light on the potential of liquid metal composites in harnessing free energy from dielectric loss of electronically powered gadgets, which can prove to be a powerful energy-harvesting system in the future.