Improving Relative Permittivity and Suppressing Dielectric Loss of Triboelectric Layers for High-Performance Wearable Electricity Generation

High relative permittivity and low dielectric loss are two desired parameters of a triboelectric layer to enhance its mechanical-to-electrical energy conversion efficiency in a triboelectric nanogenerator (TENG). However, the elevated permittivity of the triboelectric layer is always accompanied by increasing dielectric loss, limiting further improvement or even reducing the electrical output. Herein, we report a method for improving the relative permittivity and suppressing the dielectric loss of the triboelectric layer via nanoscale design at the particle–polymer interface. When incorporated with 2 wt % Ag@C, the triboelectric-layer-enhanced TENG (TLE-TENG) presents a 2.6-fold increment in relative permittivity and a 302% current enhancement. An instantaneous peak power density of 1.22 W m–2, an excellent pressure sensitivity of 90.95 V kPa–1, and an optimized sheet resistance (∼0.14 Ω/sq) are attributes of this greatly enhanced device. Such improvements bode well for the implementation of these enhancing strategies to help position TLE-TENGs as pervasive and sustainable power sources and active self-powered sensors in the era of the Internet of Things

Transition From Ion Root to Electron Root in NBI Heated Plasmas in LHD

Recent Large Helical Device (LHD) experiments revealed that the transition from ion root to electron root occurred for the first in neutral beam heated discharges, where there is no non-thermal electrons exist. The measured values of the radial electric field were found to be in qualitative agreement with those estimated by neoclassical theory. For the configuration with a magnetic axis of 3.75m, where the ion transport loss was comparable to the neoclassical ion loss, a clear reduction of ion therrnal diffusivity was observed after the mode transition from ion root to electron root as predicted by neoclassical theory. On the other hand, for the inward shifted configuration (Rax=3.6m), where the neoclassical ion loss is reduced below the anomalous loss, no change in the ion thermal diffusivity was observed