Soft and Stretchable Electromagnetic Energy-Harvesting Devices with Topographically Wrinkled Liquid-Metal Electrodes

Electromagnetic (EM) energy harvesting is a promising mechanism because of its eco-friendliness and sustainability. Most electronic appliances undergo EM energy dissipation as dielectric losses from adjacent dielectrics (casting, coating, and supports) during operation. Previously, liquid-metal-patterned elastomeric devices have been utilized to harvest EM energy. Attaching devices to electronic appliances can effectively scavenge wasted EM energy and convert it into useful electrical energy. In this work, we also utilized liquid-metal-electrode-patterned silicone substrates to harvest the EM energy dissipated from electronic appliances; however, the electrodes used here have topographically wrinkled geometries formed on macroscopically large areas, resulting in improved performance. Liquid-metal electrodes were homogeneously spray-coated on a topographically wrinkled silicone substrate prepared by utilizing the interfacial instability between the mechanically heterogeneous silicone elastomer bilayer. These wrinkled electrodes demonstrate improved energy-harvesting performance owing to the larger surface area, and the densities of electric charges focused on topographic wrinkles increased as a function of the aspect ratio of the wrinkles. The practical usability of energy harvested using a liquid-metal energy-harvesting device (LEHD) is ultimately demonstrated by powering small external devices. The LEHD developed in this study can be implemented in wearable energy storage devices, artificial skins, and soft robotics by integration into soft and stretchable electronics.