Intrinsically stretchable electronics represent an attractive platform for next-generation implantable devices by reducing the mechanical mismatch and the immune responses with biological tissues. Despite extensive efforts, soft implantable electronic devices often exhibit an obvious trade-off between electronic performances and mechanical deformability because of limitations of commonly used compliant electronic materials. Here, we introduce a scalable approach to create intrinsically stretchable and implantable electronic devices featuring the deployment of liquid metal components for ultrahigh stretchability up to 400% tensile strain and excellent durability against repetitive deformations. The device architecture further shows long-term stability under physiological conditions, conformal attachments to internal organs, and low interfacial impedance. Successful electrophysiological mapping on rapidly beating hearts demonstrates the potential of intrinsically stretchable electronics for widespread applications in health monitoring, disease diagnosis, and medical therapies.

Stretchable and wearable sensors allow intimate integration with the human body for health and fitness monitoring. In addition to the acquisition of various physical parameters, quantitative analysis of chemical biomarkers present in sweat may provide vital insights into the physiological state of an individual. A widely investigated system utilizes electrochemical techniques for continuous monitoring of these biomarkers. The required supporting electronics and batteries are often challenging to form a deformable system. In this study, an intrinsically stretchable sensing patch is developed with compliant mechanical properties for conformal attachment to the skin and reliable collection of sweat. In these patches, superhydrophilic colorimetric assays consisting of thermoplastic polyurethane nanofiber textiles decorated with silica nanoparticles are assembled over a styrene− ethylene−butylene−styrene-based superhydrophobic substrate, thereby generating a large wettability contrast to efficiently concentrate the sweat. The system supports multiplexed colorimetric analysis of sweat to quantify pH and ion concentrations with images acquired using smartphones, in which the influence of ambient lighting conditions is largely compensated with a set of reference color markers. Successful demonstrations of in situ analysis of sweat after physical exercises effectively illustrate the practical suitability of the sensing patch, which is attractive for advanced health monitoring, clinical diagnostics, and competitive sports.

Liquid metal confined in the elastomer represents an ideal platform for stretchable electronics with ultimate deformability. To enable facile and scalable patterning of conductive features, bulk liquid metal is typically dispersed into fine particles to formulate printable inks. The presence of native oxide or organic ligands stabilizing these liquid metal particles unfortunately inhibits their direct coalescence to recover the metallic conductivity and liquid-state deformability. Here, we report a chemical sintering process that converts printed liquid metal microparticles into a highly deformable conductor. The process involves the removal of surface passivating oxide by a short exposure to acid fume and subsequent selective wetting of liquid metal microparticles onto copper nanoplates present in the ink formulation. The chemical reaction provides the basis for a facile and scalable procedure to print conductive features over a large area with exceptional conductivity (>104 S cm–1) and ultrahigh stretchability (∼1000% strain). Their practical suitability is demonstrated by the fabrication of an ultrastretchable ribbon cable and an epidermal heater.

Electronic textiles offer exciting opportunities for an emerging class of electronic technology featuring intimate interaction with the human body. Among various functional components, a stretchable conductive textile represents a key building material to support the development of sensors, interconnects, and electrical contacts. In this study, a conductive textile is synthesized by bottom-up coassembly of silver nanowires and TPU microfibers. The conformal coverage of AgNW network over individual TPU microfibers gives rise to coherent deformations to mitigate the actual strain for enhanced stretchability and durability. The as-prepared conductive microtextile exhibits a series of desirable properties including excellent conductivity (>5000 S cm–1), exceptional stretchability (∼600% strain), soft mechanical properties, breathability, and washability. The practical implementation is demonstrated by fabricating an integrated epidermal sensing sleeve for multichannel EMG signal recordings, which supports real-time hand gesture recognitions powered by machine learning algorithm as a smart human–machine interface. The conductive textile reported in this study is well suited for garment integrated electronics with potential applications in health monitoring, robotic prosthetics, and competitive sports.

Lithium–sulfur batteries are recognized as one of the most promising next‐generation energy‐storage technologies owing to their high energy density and low cost. Nevertheless, the shuttle effect of polysulfide intermediates and the formation of lithium dendrites are the principal reasons that restrict the practical adoption of current Li–S batteries. Adjustable frameworks, structural variety, and functional adaptability of covalent organic frameworks (COFs) have the potential to overcome the issues associated with Li–S battery technology. Herein, a summary is presented of emerging COF materials in addressing the challenging problems in terms of sulfur hosts, modified separators, artificial solid electrolyte interphase layers, and solid‐state electrolytes. This comprehensive overview focuses on the design and chemistry of COFs used to upgrade Li–S batteries. Furthermore, existing difficulties, prospective remedies, and prospective research directions for COFs for Li–S batteries are discussed, laying the groundwork for future advancements in this class of fascinating materials.

Stretchable optoelectronics represent an emerging technology featuring soft mechanical properties. The advancements in this active area rely on the development of compliant electronic materials. Currently, the deformable forms of light-emitting devices often exhibit double-side emissions due to the lack of stretchable reflective electrodes. This study reports a facile procedure to deposit smooth and uniform liquid metal films over large-area elastomeric substrates as stretchable reflective electrodes. The as-prepared electrodes exhibit low sheet resistance (0.15 Ω sq −1 ), high optical reflectance (95% at 550 nm), and ultrahigh deformability (500% strain). The electrode shows sufficient durability to survive repetitive tensile deformations. Successful implementation of a liquid metal electrode in a stretchable light-emitting device achieves single-side emission with enhanced light extraction. The stretchable reflective electrode reported here represents a key building component to enable a broad range of applications such as deformable lighting, wearable displays, and soft robotics.

Stretchable electronics represents an emerging technology for next-generation smart wearables toward intimate integration with the human body. In contrast with functional devices constructed over elastomer films with limited moisture permeability, a soft electronic textile may represent the ideal skin-attachable platform to achieve long-term wearing comfort. The advancements in this active area largely hinge on a new generation of permeable conductor. Despite its intrinsic mechanical deformability, gallium-based liquid metal typically represents an impenetrable barrier for gases and liquids. In this study, we introduce a liquid metal micromesh on electrospun microfiber textile as a highly permeable and ultrastretchable conductor. The fabrication process involves dropcasting liquid metal onto an elastomeric microfiber textile followed by high-speed rotation to remove the excessive coating. The liquid metal micromesh exhibits low sheet resistance (0.38 Ω/sq), ultrahigh stretchability (>1000% strain), and mechanical durability. The porous morphology enables a high steam permeability and perception of comfort comparable to those of standard textiles. The conformal interface with the skin gives rise to low contact impedance better than that of state-of-the-art Ag/AgCl gel electrodes. The successful implementation of the liquid micromesh conductor in a multifunctional electronic system demonstrates its practical suitability for a broad range of applications in stretchable and wearable electronics.

Stretchable electronics allow functional devices to integrate with human skin seamlessly in an emerging wearable platform termed epidermal electronics. Compliant conductors represent key building components for functional devices. Among the various candidates, gallium-based liquid metals stand out with metallic conductivity and inherent deformability. Currently, the widespread applications of liquid metals in epidermal electronics are hindered by the low steam permeability and hence unpleasant wearing perceptions. In this study, a facile physical deposition approach is established to create a liquid metal micromesh over an elastomer sponge, which exhibits low sheet resistance (∼0.5 Ω sq–1), high stretchability (400% strain), and excellent durability. The porous micromesh shows textile-level permeability to achieve long-term wearing comfort. The conformal interaction of the liquid metal micromesh with the skin gives rise to a low contact impedance. An integrated epidermal sensing sleeve is demonstrated as a human–machine interface to distinguish different hand gestures by recording muscle contractions. The reported stretchable and permeable liquid metal conductor shows promising potentials in next-generation epidermal electronics.