On the force and energy conversion in triboelectric nanogenerators

Triboelectric Nanogenerator (TENG) has been a burgeoning focus as a powerful mechanical energy harvester, with advantages of high-efficiency, cost-effective and easy-scalable. Recently, intensive efforts have been focused on how to improve the performance such as the power output and the efficiency of TENG, which demands further understandings on the force and energy conversion. This paper presents a thorough model and methods to illustrate the force and energy of TENG, which will greatly help researchers to understand the energy conversion from mechanical energy to electrical energy. Through two demonstrated methods, the electrostatic force, which represents the minimum-required input force to drive TENG, is calculated. In addition, the corresponding input mechanical energy was simulated, and the single-cycle energy conversion efficiency was derived for various TENG modes. The model is further demonstrated by analyzing energy conversion in a rotational TENG, which can reveal its performance in practical situations. The proposed model provides a novel perspective to understand the mechanism of energy conversion, and serve as an essential approach to optimize TENG's performance for practical applications.