A piezoelectric nanogenerator promotes highly stretchable and self-chargeable supercapacitors

The rapid development of soft wearable electronics raises an ever-growing demand for power sources with both built-in stretchability and sustainability. Herein, highly stretchable and self-chargeable supercapacitors were fabricated by using graphene-coated elastic styrene–ethylene–butylene–styrene electrodes and KNN/PVA/H3PO4-based piezoelectric electrolytes. The as-designed supercapacitor shows not only a high biaxial stretchability up to 300%, but also an intriguing self-charging performance by harnessing and transforming ambient mechanical energy into electricity in a persistent pattern. This highly stretchable device can be finally charged to about 1.0 V by pure palm patting for 300 s (2 Hz) or 0.8 V by repeated stretching for 40 s (1 Hz). Such a stretchable design enables the integration of such supercapacitors with soft/stretchable electronics as an energy collectable, self-rechargeable and sustainable power source for a compact and reasonable structure.