Intrinsically soft electronics using conducting nanomaterials and liquid metals

Flexible electronics have significantly influenced modern daily life, particularly in personalized, human-centric applications, due to their ability to conform to curved surfaces. Building on this adaptability, researchers are now focusing on developing stretchable electronic devices that promise next-generation form factors, offering unprecedented user experience and functionalities. Current approaches employ rigid electronic materials configured in strain-accommodating geometries, achieving a high level of technological maturity by leveraging well-established technologies. However, these strategies face limitations, particularly in terms of long-term durability under repeated deformation, primarily due to their reliance on non-stretchable components. To overcome these limitations and facilitate durable deformation, intrinsically stretchable electronic materials have emerged as a promising solution. This review highlights recent advancements in intrinsically soft electronics, with a particular focus on stretchable conductors based on metallic components. Key elements of intrinsically stretchable conductors are discussed, including elastomers used as stretchable substrates, and metallic ingredients such as low-dimensional metallic nanomaterials and liquid metals. Additionally, we explore various assembly and patterning techniques for these materials. Practical applications of metal-based intrinsically soft conductors are highlighted, and this review concludes with an outlook on the prospects and potential challenges for these emerging technologies. Recent advances in electronics have significantly influenced our daily lives by enabling smaller, more powerful devices. However, traditional materials such as metals and silicon remain inherently rigid, limiting their applicability in emerging technologies that demand softness and deformability. This review explores recent progress in soft and stretchable materials, which can be bent and stretched without compromising their electrical performance. These materials are particularly promising for wearable and medical devices. It highlights strategies for rendering rigid materials stretchable through structural engineering, as well as the emergence of intrinscially soft metallic materials that overcome longstanding mechanical limitations. It also covers fabrication techniques maximizing the performance of integrated devices using these materials. These innovative material and device strategies can expand the scope of soft electronics toward various applications, including wearable circuits, stretchable displays, and deformable energy storage devices. This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author. Intrinsically soft electronics marry high-conductivity metallic nanomaterials and liquid metals with elastomeric/hydrogel matrices to deliver stretchable, durable, and biocompatible devices. This review synthesizes design principles from percolation-guided nanocomposites (0D/1D/2D fillers), liquid-metal patterning, and unconventional fabrication (printing, soft/photolithography, laser) to overcome fatigue and resolution limits of geometry-engineered rigid systems. We highlight applications spanning low-impedance electrodes and sensors, strain-invariant interconnects and circuits, optoelectronics, wireless components, energy storage/harvesting, and stretchable memory. Remaining challenges—long-term stability, scalable manufacturing, and safe biointegration—are outlined with prospects for closed-loop, AI-enabled systems and fully integrated soft platforms.