Theoretical model and optimal output of a cylindrical triboelectric nanogenerator

Abstract

Conversion of mechanical energy into electricity using triboelectric nanogenerators is at the forefront of alternative energy technology. However, the advancement of accurate modeling of cylindrical TENG energy harvesting process is proceeding slowly. Previous theoretical models are built based on charged finite-sized planes which cannot be applied to more general situations where charges are distributed in complex geometric configurations. Such models are inaccurate and inadequate to describe field phenomena on a larger spatial scale. Here, a systematic theoretical analysis of a three-dimensional cylindrical triboelectric nanogenerator is presented based on expanded Maxwell's equations which establishes a standard framework for modeling non-planar elementary geometric structures such as cones, arcs, disks, etc. Most importantly, the time- and spatial-dependent electric field and electric displacement produced by the cylindrical distribution of charges are fully unveiled, clarifying how the energy conversion mechanism is using Maxwell's displacement current as well as allowing quantitative analyses of the power dynamics, energy output efficiency, and basic output characteristics of the cylindrical triboelectric nanogenerator. The model analysis presented in this work is helpful to improve the fundamental theory of triboelectric nanogenerators and allows constructing complex mechanical energy harvesting systems conforming accurately and more realistically to practical situations.