Scientific and commercial advances have set high requirements for wearable electronics. However, the power supply, breathability, and mass production of wearable electronics still have many challenges that need to be overcome. In this study, a self-powered nanofiber-based triboelectric sensor (SNTS) was fabricated by batch-scale fabrication technologies using electrospinning and screen-printing for health monitoring via respiratory monitoring. Typically, an arch structural SNTS is assembled by a nanofiber membrane and a Ag nanoparticle electrode. The pile of nanofibers and the conductive network of Ag nanoparticles ensure a gas channel across the whole device. The gas permeability of the SNTS was as high as 6.16 mm/s, which has overwhelming advantages when compared with commonly used wearable devices composed of air-tight cast films. Due to the softness of the nanofiber membrane, the SNTS showed excellent electronic output performance irrespective of whether it was bent, twisted, or folded. The superior properties, such as breathability, skin-friendliness, self-power, and batch fabrication of SNTS offer huge potential for their application in healthcare monitoring and multifunctional intelligent systems.

Triboelectric nanogenerators (TENGs) for harvesting rotary mechanical energy are mostly based on in-plane sliding or free-standing mode. However, the relative displacement between two contacting triboelectric layers causes abrasion, which lowers the output power and reduces service life. Therefore, it is important to develop a method to minimize abrasion when harvesting rotary mechanical energy. Here, we report a scale-like structured TENG (SL-TENG), in which two triboelectric layers work under a contact-separation mode to avoid in-plane relative sliding in order to minimize abrasion. As a result, the SL-TENG exhibits outstanding robustness. For example, the output voltage of the SL-TENG does not exhibit any measurable decay although this output has been continuously generated through more than a million cycles. Moreover, at a very low rotation rate of 120 rpm, the SL-TENG can generate a maximum short-circuit current of 78 μA, delivering an instantaneous power density of 2.54 W/m² to an external load. In relation to this, a Li-ion battery was charged using the SL-TENG. After a 30-min charging time, the battery achieved a discharge capacity of 0.1 mAh. Through a power management circuit integrated into the SL-TENG, a continuous direct current (DC) of 5 V is outputted, providing sufficient DC power for driving a radio-frequency wireless sensor and other conventional electronics.