Largely Enhanced Energy Harvesting Performance of Silicone-Based Dielectric Elastomer Generators through Controlling the Uniaxial Device Structure

Dielectric elastomer generators (DEGs) offer a novel and sustainable energy solution that can efficiently convert mechanical energy from natural motion into electricity. Among various structures, uniaxial DEGs are particularly promising due to their simplicity. However, the ideal uniaxial configuration remains unclear, and a performance-enhancing principle has not been proposed. In this study, a silicone-based composite with exceptional dielectric and mechanical properties was fabricated, and a uniaxial DEG was designed with an adjustable aspect ratio (L/W) and its harvesting performance was systematically studied and improved. In addition, a three-dimensional finite element model is constructed to reveal the underlying mechanism by investigating the nonuniform deformation of the dielectric elastomer (DE) film and its effect on energy harvesting. The results indicate that DEGs with larger L/W exhibit more uniform and extensive deformation, which increases the electric field strength and is beneficial for performance enhancement. On the other hand, an excessively large L/W can lead to a rapid reduction in the permittivity of DE and an increase in charge leakage, which hinder performance enhancement. As a result, a well-designed DEG with a moderate L/W achieves the up-to-date highest power conversion efficiency of 40.5% and a high energy density (54.4 mJ/g), surpassing previously reported uniaxial DEGs.