Optimizing energy harvesting performance of cone dielectric elastomer generator based on VHB elastomer

Dielectric Elastomer Generator (DEG) has been used to harvest energy from reciprocating mechanical motion due to its variable capacitance under tension, and thus it has attracted widespread attention in the last decade. In this study, a cone DEG based on VHB elastomer was developed and its energy harvesting performance was optimized by combining equibiaxial prestretching to cone stretching mode and then tailoring the variables such as the equibiaxial prestretch ratio, input bias voltage and cone displacement. The coupling relationship among these variables and their combined influences on generated energy, energy density and conversion efficiency were systematically studied for the first time. The results indicate that prestretching plays an important role in achieving the target energy harvesting performance at shorter displacement and lower bias voltage, which means lighter weight and portability of the device. More importantly, an up-to-date highest energy density of 130 mJ/g or a maximum electromechanical conversion efficiency of 40% could be obtained by optimizing the variables. In addition, the concept of “displacement threshold” in DEG was firstly proposed and discussed based on leakage and viscoelastic. This work provides ideas for future applications of DEG on portable power and array power generators with high energy harvesting performance.