Thermoelectric generators (TEGs) are an excellent candidate for powering wearable electronics and the “Internet of Things,” due to their capability of directly converting heat to electrical energy. Here, we report a high-performance wearable TEG with superior stretchability, self-healability, recyclability, and Lego-like reconfigurability, by combining modular thermoelectric chips, dynamic covalent polyimine, and flowable liquid-metal electrical wiring in a mechanical architecture design of “soft motherboard-rigid plugin modules.” A record-high open-circuit voltage among flexible TEGs is achieved, reaching 1 V/cm² at a temperature difference of 95 K. Furthermore, this TEG is integrated with a wavelength-selective metamaterial film on the cold side, leading to greatly improved device performance under solar irradiation, which is critically important for wearable energy harvesting during outdoor activities. The optimal properties and design concepts of TEGs reported here can pave the way for delivering the next-generation high-performance, adaptable, customizable, durable, economical, and eco-friendly energy-harvesting devices with wide applications.

Advances in materials, chemistry, and mechanics enable self-healing, recycling, and reconfiguring of wearable electronics.

Paper-based electronics have attracted much attention due to their softness, degradability, and low cost. However, paper-based sensors are difficult to apply to high-humidity environments or even underwater. Here, we report a fully paper-integrated piezoresistive sensing system that exhibits flexibility, waterproofing, air permeability, and biocompatibility. This system consists of hydrophobic paper as the substrate and encapsulation layer, conductive paper with a double ‘zig-zag’ and dotted surface structure as the sensing layer, and silver paste films as the interconnects. The structural design of the sensing layer helps to increase the contact area in adjacent layers under pressure and further improves the pressure sensitivity. The piezoresistive system can be worn on human skin in the ambient environment, wet environment, and water for real-time monitoring of physiological signals with air permeability and waterproofing due to its hydrophobic fiber structure. Such a device provides a reliable, economical, and eco-friendly solution to wearable technologies.

Cutting-edge technologies of stretchable, skin-mountable, and wearable electronics have attracted tremendous attention recently due to their very wide applications and promising performances. One direction of particular interest is to investigate novel properties in stretchable electronics by exploring multifunctional materials. Here, we report an integrated strain sensing system that is highly stretchable, rehealable, fully recyclable, and reconfigurable. This system consists of dynamic covalent thermoset polyimine as the moldable substrate and encapsulation, eutectic liquid metal alloy as the strain sensing unit and interconnects, and off-the-shelf chip components for measuring and magnifying functions. The device can be attached on different parts of the human body for accurately monitoring joint motion and respiration. Such a strain sensing system provides a reliable, economical, and ecofriendly solution to wearable technologies, with wide applications in health care, prosthetics, robotics, and biomedical devices.

Cutting-edge technologies of wearable electronics have recently attracted tremendous attention. One of the key issues lies in the choice of compliant and environmental-friendly materials and cost-effective fabrication methods. We here report a rehealable and highly stretchable wearable strain sensing system enabled by advanced materials. By embedding patterned liquid metal (LM) line traces into dynamic covalent thermoset polyimine through a low-cost fabrication method, a mechanically flexible and electrically sensitive strain sensor is obtained. We proposed an analytical model based on length fractions of the strain sensor to describe the resistance change under applied strain. The results show good agreement with finite element simulation and experiment. Because of the bond exchange reactions in polyimine and the flowability of LM, the sensing system has excellent rehealability when it is damaged. These superior properties make the strain sensor quantitatively precise, economically friendly and environmentally sustainable, and thus can find wide applications in various areas.