Liquid metal modified all-nanofiber triboelectric nanogenerator for energy harvesting and multi-functional self-powered sensing

All-nanofiber triboelectric nanogenerators (TENGs) have emerged as promising candidates for wearable electronics and IoT systems due to their intrinsic flexibility, breathability, and skin-conformable designs. Yet, the trade-off between dielectric enhancement and mechanical reliability persists in current commonly-used composite strategies. In this study, we present a novel liquid metal (LM) inner-encapsulated all-nanofiber TENG (TM-TENG) to improve both mechanical energy harvesting and self-powered sensing capabilities. By embedding LM nanoparticles into a hierarchically structured nanofiber network, a dual optimization of interfacial polarization and charge trapping capabilities is achieved. The resulting LM-TENG demonstrates excellent electrical outputs, with open-circuit voltage of 162 V, short-circuit current of 3.3 μA, and power density of 176 mW∙m⁻² as well as ultralong-term stability (>10,000 cycles). Its pressure-sensitive triboelectric response (6.11 V∙kPa⁻¹) enables multimodal sensing, including real-time physiological signal monitoring, gait analysis, information transmission, and encrypted human-machine communication. Remarkably, the LM-TENG device can also serve as an impedance-matched and sustainable power source for wireless humidity sensors. When integrated with a convolutional neural network, the integrated system achieves 96.97 % accuracy in sleep apnea severity classification. This work establishes a universal strategy for designing high-performance, fully fiber-based TENGs, which is promising for next-generation smart healthcare systems and human-machine interfaces.