Highly Robust and Conductive Polymer Electrodes for Droplet Energy Harvesting and Printable On-Skin Electronics

Solution-processable conductive polymers have exhibited promising electrical properties. However, their brittleness and unsatisfactory mechanical characteristics have hindered their creation of flexible electrodes. Here, a robust bi-continuous polymer electrode (BC-PE) is reported that features a stable and high electrical conductivity (>60 S cm^-1), remarkable stretchability (>600%), high fracture strength (>57 MPa), excellent toughness (>230 MJ m^-3), recyclability, and biocompatibility. The BC-PE is fabricated by facilely blending a high-conducting polymer poly(benzodifurandione)(PBFDO) with thermoplastic polyurethane (TPU). Serving as a flexible electrode for a droplet electricity generator, a record high current density of 29.2 A m^-2 and a power density of 1124.2 W m^-2 have been attained. Moreover, the versatility of the BC-PE is validated by the direct ink writing technique, and a soft, thin, BC-PE-based self-powered electronic skin is demonstrated for touch-track recognition. This work presents a straightforward strategy for the development of advanced conductive polymer electrodes that well address the tradeoffs between conductivity and mechanical properties, showcasing their promising applications in energy harvesting and on-skin human-machine interfaces.