Stretchable batteries and body-conformable electronics poised to advance in 2025

Stretchable, wearable gadgets took a significant stride in 2024, thanks to a flurry of breakthroughs that could make soft, body-conformable electronics and power sources a reality. Researchers worldwide have unveiled improvements in flexible, high-precision sensors and displays, while engineers in China revealed a self-healing, stretchable lithium-ion battery that could power next-generation wearables. Meanwhile, LG Display showed a stretchable screen (pictured) extending from 12 to 18 inches.

Meanwhile, other teams have demonstrated equally exciting progress with circuit designs for skin-like devices. A Stanford-led group recently created high-density stretchable sensor arrays—featuring more than 2,500 transistors per square centimeter—that can keep working even when bent, twisted, or compressed. These arrays set a new bar for sensitivity and durability, paving the way for wearable tech beyond simple fitness tracking. Imagine a health-monitoring patch that adheres like a second skin, capturing cardiovascular data, muscle signals, and even glucose levels while feeling practically invisible.

Displays that bend

On the display front, industrial labs showcased prototypes that can stretch up to 50% in size, perfect for embedding into clothing or next-generation automotive dashboards. The new manufacturing approach, built on soft transfer printing and 3D structure fabrication techniques, ensures that tiny light-emitting diodes (LEDs) remain fully functional even under significant deformation. The displays are so flexible that first-responder uniforms could one day include easily expandable visual screens for on-the-spot data or vital signs. LG’s displays are some of the most advanced around. Potential applications of the technology span clothing and conformable automotive panels. LG has explored using the technology in firefighter uniforms to display live data.

In a recently published review in npj Flexible Electronics, Ruilai Wei and colleagues detail how four key fabrication methods — printed electronics, soft transfer, 3D structure fabrication, and deformation fabrication — are accelerating progress in making electronics that conform seamlessly to our bodies. By refining techniques like roll-to-roll processing, kirigami (an origami variant in which the paper is cut as well as folded)-inspired manufacturing, and shape-memory polymer transfer, the review highlights how engineers are boosting scalability and durability for devices that bend, stretch, and self-heal. Combined with advances in materials like ultra-thin adhesives and conductive hydrogels, these developments pave the way for wearable sensors and displays that function reliably during everyday motions. As the researchers conclude:  “Body-conforming electronics, compared to traditional electronics, can better adhere to the skin surface and maintain good contact during movement. This helps to improve the signal-to-noise ratio and accuracy of the human body signals collected.”

A hydrogel that doubles as a semiconductor

In another breakthrough, scientists at the University of Chicago’s Pritzker School of Molecular Engineering have created a hydrogel that’s also a semiconductor — bridging the gap between delicate living tissue and rigid electronics. This bluish, jelly-like material, described in Science, retains a hydrogel’s water-loving, flexible qualities while enabling the semiconductive performance needed to transmit signals between body and device. Because it’s a “one plus one is greater than two” combination, the hydrogel semiconductor can reduce inflammation, boost biosensing capabilities, and open paths for implants like pacemakers, drug-delivery systems, and wearable sensors without compromising comfort or compatibility with living tissue.

Conductive nanocopper ink signals more flexible electronic progress

In addition, ACS Applied Materials & Interfaces recently published an article demonstrating further progress in fabricating flexible printed electronics. Researchers at the Harbin Institute of Technology successfully synthesized copper nanoparticles at an ultra-fine scale of 8.5 nanometers, achieving exceptional conductivity levels of 1.9 μΩ·cm through a low-temperature sintering process. The development addresses oxidation resistance and printing precision challenges using a specialized formulation of ethylene glycol, ethanol, and isopropanolamine. This method of direct ink writing (DIW) technology complements the growing field of stretchable electronics.

Soft electronic connections

Adding to the momentum around stretchable devices, Michael Bartlett led a Virginia Tech research team in developing a new method for creating soft electronic connections across multiple circuit layers without drilling holes. Their approach, recently published in Nature Electronics, taps “mask-edge abnormalities” typically seen in ultraviolet exposure to build stair-like formations of liquid metal microdroplets. These vertical channels, or vias, enable robust electrical conduction through flexible layers, even under significant bending and twisting. The technique simultaneously fabricates multiple vias in under a minute, potentially paving the way for advances in how developers integrate circuits in soft robotics, wearable health monitors, and other next-generation technologies.

The team showed that by embedding the liquid metal droplets in a photoresin and using natural stratification, they could form everything from in-plane interconnects to 3D through-plane connections. Because these printed vias are sealed in a thin, paper-like layer, they maintain high mechanical reliability while preserving softness. “This brings us closer to exciting possibilities like advanced soft robotics, wearable devices, and electronics that can stretch, bend, and twist while maintaining high functionality,” said Bartlett in a press release.