Self-powered self-healing piezoelectric hydrogel nanogenerator-based electronic skin for real-time handwriting recognition and Morse code communication

Abstract

Skin-conformal human–machine interfaces that operate reliably under mechanical deformation and harsh environments are essential for next-generation wearable electronics, defense systems, and Internet of Things (IoT) platforms. Here, a resilient and stretchable flexible piezoelectric nanogenerator (RS‑FPENG) is reported that seamlessly integrates self-powered sensing and energy harvesting within a dual-hydrogel architecture. The device combines a highly conductive, self-healing ElectraGel electrode with a bio-derived BioWeave‑LS@BaTiO₃ piezoelectric core featuring a dynamically reversible multibond network, enabling exceptional mechanical compliance, environmental tolerance, and interfacial stability. The RS‑FPENG delivers a peak output voltage of ~1.15 V, representing a ~ 4.6-fold improvement over conventional PDMS-based FPENGs, with a maximum power density of 8.48 µW m⁻², fast response (~120 ms), high linearity (R² = 0.9738), and a sensitivity of 4.15 × 10⁻³ V g⁻¹ across an ultrawide force range (0.01–883 N). Stable electromechanical performance is retained under broad humidity, temperature, and chemical conditions. Beyond energy harvesting, the RS‑FPENG enables self-powered detection of complex biomechanical motions and supports multilingual handwriting recognition and Morse code communication with real-time decoding. This work establishes a robust materials platform for environmentally resilient, battery-free wearable interfaces and intelligent assistive IoT systems.