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Soft, deformable electronic devices provide the means to monitor physiological information and health conditions for disease diagnostics. However, their practical utility is limited due to the lack of intrinsical thermal switching for mechanically transformative adaptability and self-healing capability against mechanical damages. Here, the design concepts, materials and physics, manufacturing approaches, and application opportunities of self-healing, reconfigurable, thermal-switching device platforms based on hyperbranched polymers and biphasic liquid metal are reported. The former provides excellent self-healing performance and unique tunable stiffness and adhesion regulated by temperature for the on-skin switch, whereas the latter results in liquid metal circuits with extreme stretchability (>900%) and high conductivity (3.40 × 104  S cm-1 ), as well as simple recycling capability. Triggered by the increased temperature from the skin surface, a multifunctional device platform can conveniently conform and strongly adhere to the hierarchically textured skin surface for non-invasive, continuous, comfortable health monitoring. Additionally, the self-healing and adhesive characteristics allow multiple multifunctional circuit components to assemble and completely wrap on 3D curvilinear surfaces. Together, the design, manufacturing, and proof-of-concept demonstration of the self-healing, transformative, and self-assembled electronics open up new opportunities for robust soft deformable devices, smart robotics, prosthetics, and Internet-of-Things, and human-machine interfaces on irregular surfaces.

Stretchable triboelectric nanogenerators (TENGs) represent a new class of energy‐harvesting devices for powering wearable devices. However, most of them are associated with poor stretchability, low stability, and limited substrate material choices. This work presents the design and demonstration of highly stretchable and stable TENGs based on liquid metalel ectrodes with different phases. The conductive and fluidic properties of eutectic gallium‐indium (EGaIn) in the serpentine microfluidic channel ensure the robust performance of the EGaIn‐based TENG upon stretching over several hundred percent. The bi‐phasic EGaIn (bGaIn) from oxidation lowers surface tension and increases adhesion for printing on diverse substrates with high output performance parameters. The optimization of the electrode shapes in the bGaIn‐based TENGs can reduce the device footprint and weight, while enhancing stretchability. The applications of the EGaIn‐ and bGaIn‐based TENG include smart elastic bands for human movement monitoring and smart carpets with integrated data transmission/processing modules for headcount monitoring/control. Combining the concept of origami in the paper‐based bGaIn TENG can reduce the device footprint to improve output performance per unit area. The integration of bGaIn‐TENG on a self‐healing polymer substrate with corrosion resistance against acidic and alkaline solutions further facilitates its use in various challenging and extreme environments. [ABSTRACT FROM AUTHOR]

Transition metal single atoms have been considered as promising candidates for oxygen reduction reaction catalysts for developing high-performance zinc–air batteries. How to uniformly disperse metal single atoms onto an ideal porous carbon framework for full utilization of the catalyst with enriched active sites and fast mass diffusion still remains a challenge. Herein, by taking advantage of both the efficient single-atom Cu catalyst and the effective NaCl-template sacrificing method, we report the design and fabrication of a single-atom Cu catalyst decorated on a three-dimensional (3D) nitrogen–carbon (NC) framework. The developed catalyst exhibits excellent (oxygen reduction reaction) ORR catalytic activity with a high half-wave potential of 0.86 V, maximum current density of 5.53 mA cm–2, and Tafel slope of 81.52 mV dec–1, which are better than those of the commercial Pt/C catalyst. The comparison experiment with the 3D NC framework (no copper salt added) and the bulk Cu decorated NC framework (no NaCl added) verifies the synergistic effect between the Cu single atoms as the efficient ORR catalyst and the NaCl template to achieve the ideal porous structure. Aqueous zinc–air batteries assembled with the developed catalyst deliver good battery performance with a high open circuit voltage of 1.48 V, large specific discharge capacity of 760.47 mAh g–1, high peak power density of 120 mW cm–2, and stable charge–discharge cyclability for 600 h. Gel polymer electrolyte-based zinc–air batteries are also demonstrated to be workable under bending conditions for practical wearable electronic applications. [ABSTRACT FROM AUTHOR]