Publications

With the excellent structural design, rotary triboelectric nanogenerator (R-TENG) is suitable for harvesting mechanical energy such as wind energy and water energy to build a self-powered electrochemical system for environmental science. The electrochemical performance has been greatly improved by using the pulsed direct-current (PDC) output of a TENG; however, a full-wave PDC (FW-PDC) is hardly realized in R-TENG devices due to existence of phase superposition. Here, a R-TENG with FW-PDC output is reported to perform a self-powered electro-Fenton system for enhancing the removal efficiency of levofloxacin (OFL). By adjusting the rotation center angle ratio between each rotator and stator unit, the phase superposition of R-TENG caused by multiple parallel electrodes can be effectively eliminated, thus achieving the desired FW-PDC output. Because of the reduced electrode passivation effect, the removal efficiency of OFL is improved by 30% under equal electric charges through using the designed R-TENG with FW-PDC output compared to traditional R-TENG. This study provides a promising methodology to improve the performance of self-powered electrochemical process for treating environment pollutions.

Fish-Wearable Data Snooping Platform In article number 2107232, Xiangyu Chen and co-workers report a fish-wearable data snooping platform (FDSP) based on an air sac triboelectric nanogenerator, which is integrated with multiple functions of disinfection, mechanical energy harvesting, real-time monitoring and wireless data transmission. The FDSP offers an alternative for studying fish kinematics and has promising prospects for building underwater wireless sensor networks.

The metal-insulator transition of vanadium dioxide (VO2 ) is exceptionally sensitive to charge density and electron orbital occupancy. Thus three-terminal field-effect transistors with VO2 channels are widely adopted to control the phase transition by external gating voltage. However, current leakage, electrical breakdown, or interfacial electrochemical reactions may be inevitable if conventional solid dielectrics or ionic-liquid layers are used, which possibly induce Joule heating or doping in the VO2 layer and make the voltage-controlled phase transition more complex. Here, a triboelectric nanogenerator (TENG) and a VO2 film are combined for a novel TENG-VO2 device, which can overcome the abovementioned challenges and achieve electron-doping-induced phase modulation. By taking advantage of the TENG structure, electrons can be induced in the VO2 channel and thus adjust the electronic states of the VO2 , simultaneously. The modulation degree of the VO2 resistance depends on the temperature, and the major variation occurs when the temperature is in the phase-transition region. The accumulation of electrons in the VO2 channel also is simulated by finite element analysis, and the electron doping mechanism is verified by theoretical calculations. The results provide a promising approach to develop a novel type of tribotronic transistor and new electronic doping technology.

A novel approach is presented for the large-scale fabrication of ordered TiO2 nanobowl arrays. The process starts with a self-assembled monolayer of polystyrene spheres, which is used as a template for atomic layer deposition of a TiO2 layer. After ion-milling, toluene-etching, and annealing of the TiO2-coated spheres, ordered arrays of nanostructured TiO2 nanobowls have been fabricated. The nanobowls exhibit smooth interior and exterior surfaces and uniform sizes and thickness. The nanobowl arrays have been demonstrated to be useful for selecting spheres smaller than the inner diameter of the bowls. This approach can be extended to a wide range of coating materials and substrates (ceramics, metals, polymers, glasses) with controlled wall thickness and size.

Double-side-fixed triboelectric nanogenerator (DTENG) arrays, compared to single-side-fixed triboelectric nanogenerator arrays for harvesting single-pathway wind energy, are developed by Zhong Lin Wang and co-workers in article number 1501799, to harvest bidirectional wind energy. Short-circuit current, durability, and stability of the optimized DTENG can be dramatically improved by a 4 × 1 array connected in parallel because of the improved device configuration, stickiness, and abrasion by adhering Ti buffer layers.

Abstract The multi‐operating robustness of triboelectric nanogenerators (TENGs) is still an awkward issue that must be solved to achieve practicality and industrialization. Here, an aerodynamics‐based TENG (AB‐TENG) is developed by combining it with a propeller and rotor, which can switch automatically between contact and separation mode. The separation speed can be reduced to 150 rpm by optimizing the spring stiffness coefficient, which maintains 95.18% of the electrical output after continuous operation for more than 1.378 million cycles. Combining with power management circuit, these capacitors of 0.56, 1, 3.3, and 10 mF can be charged quickly to 3 V within 7.3, 9.3, 16.7, and 43.4 s, respectively. In addition, AB‐TENG can power 6 digital hygrothermographs in parallel by harvesting irregular airflow or drive one Bluetooth‐enabled, 6 commercial LED bulbs of 3 W or 240 green LED lamp beads in parallel, respectively. This work provides an effective strategy to improve the multi‐operating robustness of TENGs, and more importantly, to overcome the mechanical durability and electrical stability difficulties of the technique at high rotational speed caused by abrasion limit of triboelectric materials, and may reveal its potential in the distributed energy and Internet of Things.

Lenz’s law states that the change in magnetic flux over time induces an electromotive force around a circuit, commonly referred to as the flux rule. However, exceptions to the “flux rule” were discussed by Richard Feynman in The Feynman Lectures on Physics in 1963. The anti-flux phenomenon occurs when there is a large-size and rotating metal medium present in the circuit. This phenomenon has attracted the attention of many researchers, although most studies have predominantly focused on theoretical and mathematical calculations. Here, we have designed an experimental setup to investigate the generation of the electromagnetic waves by gear-driven rotating metal/semiconductor/dielectric disks with the presence of a static magnetic field. Low-frequency electromagnetic waves were surprisingly observed with frequencies up to 2 kHz for a disk rotating at 6.67 Hz (400 rpm) and energy levels reaching up to −70 dBm. Theoretically, such a result was not expected according to the classical Maxwell’s equations. Our interpretation is that the theory is based on Maxwell’s equations for a mechano-driven media system, which is to describe the electromagnetic behavior of a system that involves accelerated moving media/objects. This study proves that a moving medium is a source for generating electromagnetic waves.