Theoretical study of superlubric nanogenerators with superb performances

Abstract

Nanogenerators promise self-powered sensors and devices for extensive applications in internet of things, sensor networks, big data, personal healthcare systems, artificial intelligence et al. However, low electric current densities and short product lifespans have blocked nanogenerators' applications. Here we show that structural superlubricity, a state of nearly zero friction and wear between two contacted solid surfaces, provides a revolutionary solution to the above challenge. We propose the first three types of superlubric nanogenerators (SLNGs), namely the capacitor-based, triboelectric, and electret-based SLNGs. With a systematical analysis on the influences of material and structural parameters to these SLNGs’ performances, we demonstrate that these SLNGs can achieve not only enduring lifespans, but also superb performances – three orders of magnitude in current densities and output powers higher than those of conventional nanogenerators. Furthermore, we show that SLNGs can be driven by very weak external loads (down to ~1 μN) in very low frequencies (down to ~1μHz), and are thus capable to harvest electric energies from an extremely board spectrum of environments and biosystems. Among the three types of SLNGs, the capacitor-based is synthetically most competitive in the senses of performance, fabrication and maintaining. These theoretical results can guide designs and accelerate fabrications of SLNGs toward real applications.