Developing multifunctional triboelectric nanogenerators (TENGs) with special intelligence is of great significance for next-generation self-powered electronic devices. However, the relevant work on the intelligent TENGs, especially those spontaneously responsive to external stimuli, is rarely reported. Herein, an intelligent TENG with thermal-triggered switchable functionality and high triboelectric outputs is developed by designing a movable triboelectric layer, which is driven by a two-way shape memory polyurethane. The resultant TENG device can be spontaneously switched on/off in response to the environmental temperature change, i.e., switching on at 0 °C and off at 60 °C. At the "on" state, the developed TENG exhibits excellent triboelectric performance with a maximum output power density of 5.15 W m −2 at a pressure of 30 kPa due to the unique advantages of micro-/nanofiber triboelectric surfaces. Furthermore, the great potential of the switchable TENG in intelligent wearable electronic applications is demonstrated, which can serve as not only the sensing element for monitoring human movement and physical condition in a cold environment but also the thermal-driven switch for turning on/off the heating function on demand. The intelligent "on-off" switchable TENG combined with excellent triboelectric performance may provide new opportunities for future self-powered wearable electronics.

High performance is always the research objective in developing triboelectric nanogenerators (TENGs) for future versatile applications. In this study, a flexible ethyl cellulose/thermoplastic polyurethane (EC/TPU) nanofiber triboelectric layer with barium titanate (BTO) nanoparticles is proposed for high-performance TENGs, in which electrospun EC/TPU nanofiber membranes supply the high-roughness friction surfaces and piezoelectric BTO nanoparticles are further incorporated to boost the electric outputs by the synergistic effect of piezoelectricity and triboelectricity. Consequently, when the content of the BTO nanoparticle is 8 wt % in the EC/TPU (1:4 in weight ratio) nanofibers, the composite membrane displayed a stress of 9.25 MPa and a strain of 275.2%. The corresponding TENG achieves electric outputs of 125.8 V, 34.1 μA, and 1.68 W/m2, much higher than those of an individual piezoelectric nanogenerator or TENG. The TENGs are potentially used to supply energy for commercial LEDs and microelectronics and as self-powered sensors to monitor human physical training conditions. This research provides a guideline for developing TENGs with high performance, which is crucial for their long-term use.