CB/PDMS electrodes for dielectric elastomer generator with low energy loss, high energy density and long life

Abstract

Dielectric elastomer generator (DEG), consisting of highly deformable dielectric elastomer (DE) film sandwiched between compliant electrodes, can convert mechanical energy into electrical energy. The widely used carbon grease (CG) electrode has short service life. The conductive rubber electrode is the most promising electrode, but its properties still need to be improved to obtain DEG with high energy density and long life. In this study, thin electrode film of superconducting carbon black (CB)/Polydimethylsiloxane (PDMS) composite with smooth surface, uniform thickness and good dispersion of CB in PDMS matrix was prepared by using solution blending combined with ultrasonication followed by freeze drying and mask scraping technique. The strong interfacial bonding between the electrode and DE substrate was obtained by optimizing CB content and mask scraping technique and by using PDMS in both electrode and DE substrate. High elongation at break, good compliance, high electrical conductivity (EC) and high stability of EC were successfully obtained. Compared with DEG using CG electrode, the energy loss at the same conditions of DEG using the electrodes with 6 wt% CB is reduced by 40.3%, and the harvested energy density (up to 20.5 mJ/cm3) increases by 32%. More importantly, CB/PDMS electrode can withstand 60,000 cycles of stretching under 200% strain, much higher than that reported in previous studies.