Improved electric energy density and conversion efficiency of natural rubber composites as dielectric elastomer generators

Dielectric elastomer generators (DEGs), which can harvest energy from environmental sources, have gained considerable research attention over the past few decades. However, the current dielectric elastomers exhibit low electric energy density and conversion efficiency, which limit their practical application. Herein, the electric energy density and conversion efficiency of natural rubber (NR) composites have been enhanced by adding of barium titanate (BT) nanoparticles and dioctyl phthalate (DOP) plasticizer in NR matrix. Due to the synergistic effect of BT and DOP, a high dielectric constant and a low elastic modulus are exhibited by NR composites, which can be attributed to the adjusting of filler network and polymeric intermolecular attractions. The as-prepared BT/DOP/NR composites have exhibited an enhanced harvested electric energy density of 0.71 mJ/cm3 and energy conversion efficiency of 3.8%, which are ∼3.8 and 4.7 times higher than pure NR, respectively. In addition, the as-prepared NR composites exhibit excellent actuation properties, which indicate that these composites have great potential in a wide range of applications, such as energy harvesters and soft sensors.