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With the advancement of internet of things and wireless sensing technology, the need for personnel track and position monitoring are greatly increasing. Commercial global positioning system (GPS) and Global system for mobile communications (GSM) position methods cannot meet the demand for low power consumption and three‐dimensional indoor position monitoring. Herein, a self‐powered position monitoring system (SPMS) based on an insole‐type wearable triboelectric nanogenerator (IW‐TENG) and Bluetooth beacon for human kinetic energy harvesting and sustainable position monitoring is proposed. The SPMS consists of an insole‐type wearable triboelectric nanogenerator, an energy management module (EMM), and a Bluetooth low energy (BLE) beacon module. Benefitting from the multilayers structure, a maximum energy of 120 µJ per step can be harvested by the IW‐TENG with EMM for a typical adult. By every 3–4 steps, SPMS can transmit Bluetooth signals to obtain the location information. A single BLE signal transmission consumes only 136 µJ, and the transmission distance can reach 100 m. The SPMS is applied to intelligent attendance in office rooms and shows great prospects in intelligent navigation and trajectory tracking in local area network. [ABSTRACT FROM AUTHOR]

The tribovoltaic effect can convert semiconductor interfacial frictional mechanical energy into direct current (DC) electricity, but the flexibility and durability of semiconductor materials limit its application in wearable electronic. Herein, a robust flexible textile tribovoltaic nanogenerator is presented based on a 2D dynamic heterojunction of 2H‐MoS2/Ta4C3 (MTNG). During the friction process, a built‐in electric field (Eb) and an additional interfacial electric field (ECE) are generated in a continuous dynamic contact of 2H‐MoS2/Ta4C3, and through the 2H‐MoS2/Ta4C3 dynamic heterojunction, a significant number of electron‐hole pairs are excited and move directionally to generate a DC. The influences of mechanical pressure and sliding speed on output performance of MTNGs are systematically investigated. The MTNGs deliver excellent output power density (39.15 mW m2) and outstanding robustness (43 000 cycles). Ten MTNGs can be connected in series to obtain a DC voltage of 3.3 V and in parallel to obtain a DC current of 75 µA. Furthermore, the MTNGs can effectively power a variety of commercial electronic watches and calculators by harvesting human kinetic energy. A 2D dynamic heterojunction 2H‐MoS2/Ta4C3 DC nanogenerator is described and offers a workable option for the creation of flexible DC power sources and self‐powered wearable electronics. [ABSTRACT FROM AUTHOR]

A series of direct‐current tribovoltaic nanogenerators (TVNGs) with high current density have been developed for energy harvesting and mechanical sensing recently, but the lead wires that need to be connected to two relatively moving parts have greatly restricted the application of TVNG. Herein, a freestanding‐mode TVNG (FTVNG) is proposed based on metal, p‐type silicon (p‐Si), and n‐type silicon (n‐Si). As the freestanding part of metal simultaneously rubs against p‐Si and n‐Si, opposite direct current (DC) outputs can be generated, thus forming a DC output from p‐Si to n‐Si in the external circuit. Resulting from the distinctive structure, FTVNGs are applicable for harvesting energy from moving objects without attached wires. Additionally, by using steel needles to precisely control the actual contact area, the electrical output characteristics and influence laws of the tribovoltaic effect under different working parameters such as area and speed are studied. Moreover, FTVNG is integrated into the traditional rolling bearing as a triboelectric bearing, realizing energy recovery from the rotational motion of mechanical parts and speed sensing, which demonstrates the great application potential of TVNG in basic components and parts. [ABSTRACT FROM AUTHOR]

The triboelectric nanogenerator (TENG) is a new energy technology that is enabled by coupled contact electrification and electrostatic induction. The conventional TENGs are usually based on organic polymer insulator materials, which have the limitations and disadvantages of high impedance and alternating output current. Here, a tribovoltaic effect based metal–semiconductor direct‐current triboelectric nanogenerator (MSDC‐TENG) is reported. The tribovoltaic effect is facilitated by direct voltage and current by rubbing a metal/semiconductor on another semiconductor. The frictional energy released by the forming atomic bonds excites nonequilibrium carriers, which are directionally separated to form a current under the built‐in electric field. The continuous average open‐circuit voltage (10–20 mV), short‐circuit direct‐current output (10–20 µA), and low impedance characteristic (0.55–5 kΩ) of the MSDC‐TENG can be observed during relative sliding of the metal and silicon. The working parameters are systematically studied for electric output and impedance characteristics. The results reveal that faster velocity, larger pressure, and smaller area can improve the maximum power density. The internal resistance is mainly determined by the velocity and the electrical resistance of semiconductor. This work not only expands the material candidates of TENGs from organic polymers to semiconductors, but also demonstrates a tribovoltaic effect based electric energy conversion mechanism. [ABSTRACT FROM AUTHOR]

Ocean waves are one of the most promising renewable energy sources for large‐scope applications. Recently, triboelectric nanogenerator (TENG) network has been demonstrated to effectively harvest water wave energy possibly toward large‐scale blue energy. However, the absence of effective power management severely restricts the practicability of TENGs. In this work, a hexagonal TENG network consisting of spherical TENG units based on spring‐assisted multilayered structure, integrated with a power management module (PMM), is constructed for harvesting water wave energy. The output performance of the TENG network is found to be determined by water wave frequencies and amplitudes, as well as the wave type. Moreover, with the implemented PMM, the TENG network could output a steady and continuous direct current (DC) voltage on the load resistance, and the stored energy is dramatically improved by up to 96 times for charging a capacitor. The TENG network integrated with the PMM is also applied to effectively power a digital thermometer and a wireless transmitter. The thermometer can constantly measure the water temperature with the water wave motions, and the transmitter can send signals that enable an alarm to go off once every 10 s. This study extends the application of the power management module in the water wave energy harvesting. [ABSTRACT FROM AUTHOR]