Skin-Integrated Graphene-Embedded Lead Zirconate Titanate Rubber for Energy Harvesting and Mechanical Sensing

Thin, soft, skin-like electronics capable of transforming body mechanical motions to electrical signals have broad potential applications in biosensing and energy harvesting. Forming piezoelectric materials into flexible and stretchable formats and integrating with soft substrate would be a considerable strategy for this aspect. Here, a skin-integrated rubbery electronic device that associates with a simple low-cost fabrication method for a ternary piezoelectric rubber composite of graphene, lead zirconate tinanate (PZT), and polydimethylsiloxane (PDMS) is introduced. Comparing to the binary composite that blend with PZT and PDMS, the graphene-embedded ternary composite exhibits a significant enhancement of self-powered behavior, with a maximum power density of 972.43 µW cm⁻³ under human walking. Combined experimental and theoretical studies of the graphene-embedded PZT rubber allow the skin-integrated electronic device to exhibit excellent mechanical tolerance to bending, stretching, and twisting for thousands of cycles. Customized device geometries guided by optimized mechanical design enable a more comprehensive integration of the rubbery electronics with the human body. For instance, annulus-shape devices can perfectly mount on the joints and ensure great power output and stability under continuous and large deformations. This work demonstrates the potential of large-area, skin-integrated, self-powered electronics for energy harvesting as well as human health related mechanical sensing.