Capacitive Energy Harvesting Using Highly Stretchable Silicone–Carbon Nanotube Composite Electrodes

Capacitive energy harvesters utilizing elastic dielectrics offer a simple way to harvest energy from natural mechanical energy sources. While the technology is promising due to its simplicity and low cost combined with high efficiency and energy density, there are still material challenges that must be addressed. For effective energy conversion, the dielectric material should have low dielectric and mechanical losses, while the compliant electrodes should be able to withstand large strains over an extended lifetime without any substantial loss of conductivity. The development of soft flexible and stretchable silicone–carbon nanotube composite electrodes is presented for use in capacitive energy harvesting and strain sensing. The composite is capable of being stretched to over 150% strain with a minimal increase in the baseline resistance and excellent recovery of electrical properties upon relaxation. The electrode displays excellent strain‐rate stability and is capable of being stretched at a strain rate of 1000% s^?1 with only a small increase in resistance. The electrode also displays excellent electrical stability. Applications of the composite electrode include highly stretchable soft capacitors and energy generators. The capacitance change along with stretching could be either linear for sensor purposes or superlinear for improved energy gains as an energy harvester.