Highly Stretchable Nanocomposite Piezofibers: A Step Forward into Practical Applications in Biomedical Devices

High-performance biocompatible composite materials are gaining attention for their potential in various fields such as neural tissue scaffolds, bio-implantable devices, energy harvesting, and biomechanical sensors. However, these devices currently face limitations in miniaturization, finite battery lifetimes, fabrication complexity, and rigidity. Hence, there is an urgent need for smart and self-powering soft devices that are easily deployable under physiological conditions. Herein, we present a straightforward and efficient fabrication technique for creating flexible/stretchable fiber-based piezoelectric structures using a hybrid nanocomposite of polyvinylidene fluoride (PVDF), reduced graphene oxide (rGO), and barium-titanium oxide (BT). These nanocomposite fibers are capable of converting biomechanical stimuli into electrical signals across various structural designs (knit, braid, woven, and coil). It was found that a stretchable configuration with higher output voltage (4 V) and a power density (87 μW cm