Developing lightweight, green, and flexible wearable electronics with high sensitivity and multifunctional sensing capabilities is of important significance in the field of outdoor sports, such as mountaineering, animal tracking and protection. This work proposes a silk fibroin fibers-based triboelectric nanogenerator (SF-TENG) to harvest tiny energy from human fingertip tapping and act as a self-powered tactile sensor. The SF-TENG adopts a green, efficient, and low-cost fabrication strategy, in which a breathable and electropositive silk fibroin fiber membrane and a silver conductive layer are prepared by electrostatic spinning and magnetron sputtering, and combined with a conductive cloth and a breathable tape to form a flexible sensor that can be attached to a human skin. The thin and soft portable TENG device, having a thickness of only 0.3 mm and a mass of 354 mg at the dimension of 4.5 cm × 4.5 cm, can generate a maximum power density of 1.0 mW·m^–2. Furthermore, the SF-TENG has excellent sensitivity of 1.767 mV·Pa^–1 with good cyclic stability. The superior sensing characteristics provide new avenues for Morse code applications toward outdoor wearable autonomous communication. The proposed SF-TENG offers promising solutions in multi-scenario outdoor sport, human-machine interface interaction, and security systems.

Ocean is full of low-frequency, irregular, and widely distributed wave energy, which is suitable as the energy source for maritime Internet of Things (IoTs). Utilizing triboelectric nanogenerators (TENGs) to harvest ocean wave energy and power sensors is proven to be an effective scheme. However, in random ocean waves, the irregular electrical energy output by general TENGs restricts the applications. At present, achieving regularized water wave energy harvesting relies on rather complex mechanical structure designs, which is not conducive to industrialization. In this work, we proposed a novel mechanical controlled TENG (MC-TENG) with a simple controlled switch to realize the regularization function. The structural parameters of the MC-TENG are optimized, and the optimal output voltage, output current, and transferred charge respectively reach 1684.2 V, 85.4 μA, and 389.9 nC, generating a peak power density of 38.46 W·m⁻³·Hz⁻¹. Under real water wave environment, the output of the MC-TENG is regularized and keeps stable regardless of any wave conditions. Moreover, the potential applications of the MC-TENG are demonstrated in powering environmental temperature, humidity, and wind speed sensors. This work renders a simple approach to achieve effective regularized ocean wave energy harvesting, promoting the TENG industrialization toward practical application of maritime IoTs.

In the context of advocating a green and low-carbon era, ocean energy, as a renewable strategic resource, is an important part of planning and building a new energy system. Triboelectric nanogenerator (TENG) arrays provide feasible and efficient routes for large-scale harvesting of ocean energy. In previous work, a spherical rolling-structured TENG with three-dimensional (3D) electrodes based on rolling motion of dielectric pellets was designed and fabricated for effectively harvesting low-frequency water wave energy. In this work, the external shape of the scalable rolling-structured TENG (SR-TENG) and internal filling amount of pellets were mainly optimized, achieving an average power density of 10.08 W∙m⁻³ under regular triggering. In actual water waves, the SR-TENG can deliver a maximum peak power density of 80.29 W∙m⁻³ and an average power density of 6.02 W∙m⁻³, which are much greater than those of most water wave-driven TENGs. Finally, through a power management, an SR-TENG array with eight units was demonstrated to successfully power portable electronic devices for monitoring the marine environment. The SR-TENGs could promote the development and utilization of ocean blue energy, providing a new paradigm for realizing the carbon neutrality goal.