A new triboelectric nanogenerator based on a multi-material stacking structure achieves efficient power conversion from discrete mechanical movement.

Due to its invaluable potential in discrete mechanical energy collection, TENG (triboelectric nanogenerator) is considered to satisfy the power requirements of intelligent electronic devices and drive the development of the Internet of Things (IoT). Nowadays, the promotion of TENGs has been hindered due to the limitation of their output performance and service life. Herein, a brand new triboelectric nanogenerator based on a multi-material stacking structure is proposed. By stacking various triboelectric materials in a specific order, a special charge balance state could be achieved inside the system such that the conductive layer generates more induced charges, and the output performance is significantly enhanced. Besides, due to the usage of the electropositive elastomer PU (polyurethane sponge), the design also effectively alleviates abrasion on the contact surface and adjusts its own output according to different compression environments. The experimental results show that the stacked PTFE/FKM/PU TENG (PFP-TENG) presents a more than 50% increase in transferred charge and almost 5 times the current output compared with the general contact-separation type TENG. When connected to the application circuit, the maximum output power reached 10.2 W m-2 and 145.2 W m-3, and more than 1400 LEDs could be easily lit. Finally, the PFP-TENG was also used to collect mechanical energy from simple motion and realize considerable power generation. This study not only provides new ideas for the design of TENGs by reasoning the theoretical model but also presents improved output performance, thus exemplifying the strong potential of this design in developing a power-generation device that can collect discrete mechanical energy.

Sources and distribution of microplastics in the east China sea under a three-dimensional numerical modelling.

Microplastics are new pollutants found in various environments; moreover, high concentrations of microplastics have been proved to harm aquatic organisms. To understand the high abundance of microplastics in the East China Sea (ECS), where the Zhoushan fishing ground is located, this study investigated the transportation and spatial distribution of microplastics from the Changjiang River Estuary (CE) to the ECS via three-dimensional numerical modelling. Utilising observations of microplastics at the surface of the ECS and backward particle tracking, three sources of microplastics were identified: the Changjiang River, Hangzhou Bay, and coastal area of Nantong city. Moreover, Southern Korea contributed to the microplastics in ECS. After microplastics are released from these sources, monsoons, currents, the Changjiang plume, and tides cause significant seasonal differences in the hot spots for microplastics in the ECS; moreover, the generation of ocean fronts may promote microplastic accumulation. In addition, the settling characteristics of microplastics were shown to influence their distributions; for example, large amounts of microplastics accumulated at the bottom of the riverbeds. This study enables a more complete assessment of microplastic transport from estuaries to the open sea and provides a spatial and temporal distribution of microplastics at the surface of the ECS.