Maximizing the Energy Density of Dielectric Elastomer Generators Using EquiBiaxial Loading

Dielectric elastomer generators (DEGs) for harvesting electrical energy from mechanical work have been demonstrated but the energy densities achieved are still small compared with theoretical predictions. In this study, signifi cant improvements in energy density (560 J/kg with a power density of 280 W/ kg and an effi ciency of 27%) are achieved using equi-biaxial stretching, a mechanical loading confi guration that maximizes the capacitance changes. The capacitance of dielectric elastomers subjected to equi-biaxial stretches is demonstrated to be proportional to the fourth power of the stretch. Quantifi cation of the individual energy contributions indicates that attaining higher conversion effi ciencies is limited by viscous losses within the acrylic elastomer, suggesting that still higher conversion effi ciencies with other elastomers should be attainable with our novel mechanical loading design.