Figure 1.

Device structure and working mechanism. A) Photographs of DENG at original state (inset) and stretched state. B) Structural schematic of DEC. DEC is a soft capacitor, made of a dielectric elastomer film sandwiched between two compliant electrodes. C) Structural schematic of electret electrostatic voltage source. D) Photograph of the front and back sides of the pump circuit, next to a Chinese 1‐yuan coin. E) Uniaxial tensile test of the DEG. F) Stress–strain curve of the elastomer in cyclic stress–strain test (600% strain) under successive stretching. Sample width, 10 mm; thickness, 0.1 mm; gage length, 40 mm. Stretching speed, 50 mm min⁻¹. G) Circuit diagrams of the DENG. This DENG consists of three parts: DEC, pump circuit, and EEVS. H) Surface potential decay of the electret PTFE film with negative charges. The inset: surface potential image. I) Schematic illustration of AC method working mechanism. J) Output voltage and current curve of the DENG (operation frequency: 0.8 Hz).