Modeling and Numerical Simulation of a Triboelectric Nanogenerator to Achieve Optimal Performance by Considering the Dielectric Constant Effect

A popular class of efficient energy harvesting technologies is the triboelectric nanogenerator (TENG). There has been considerable research demonstrating the feasibility of converting mechanical motions into electrical energy by using these devices. In the design of TENGs, the power generated and its optimization are the most important aspects. However, not all factors affecting TENG performance are well understood. The main criteria for choosing materials is surface charge density, flexibility, and mechanical resistance. In some types of TENGs that are time-varying capacitors, the dielectric constant of the material can be a significant factor affecting the performance of these nanogenerators. In this research, using simulation, we investigate the effect of increasing the dielectric constant on the performance of the TENG in the contact-separation model (CSTENG). We find that increasing the dielectric constant is very effective in thick structures; it boosts the charge transferred under short-circuit conditions (Q_SC), current, maximum power, and figure of merit. However, there is little effect of the dielectric constant on thin CSTENG performance. Hence, the high-K material utilization effect is relaxed by thin dielectric layers. We then analyze the conditions of frequency matching and we obtain the optimal condition to achieve maximum power. To achieve optimal power output, thin CSTENGs require materials with a low dielectric constant. In contrast, thick structures can be optimized by utilizing high-K materials. Based on these findings, design rules for TENGs can be derived.

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