Harnessing Flexoelectric and Piezoelectric Effects for Self-Charging Power Systems
Chongsei Yoon, Swathi Ippili, Alphi Maria Thomas, Batzorig Buyantogtokh, Seungbum Hong, Venkatraju Jella, Van‐Dang Tran, Soon‐Gil Yoon
Abstract
Stretchable mechanical energy harvesters are in high demand as sustainable power sources and self-powered systems for wearable electronics and biomedical devices. In this study, a stretchable flexoelectric–piezoelectric nanogenerator (FPENG) composed of a zinc–aluminum layered double hydroxide nanosheets–ZnO nanorods (ZnAl:LDH NSs–ZnO NRs) heterostructure is developed. The coupling of the flexoelectric effect of ZnAl:LDH NSs and the piezoelectric effect of ZnO NRs enhances the output performance of the FPENG. The FPENG generates an open-circuit voltage ( V oc ) of 41.5 V, a short-circuit current density ( J sc ) of 4.57 μA/cm 2, and a maximum power density of 68.2 μW/cm 2 with good mechanical durability, while the device under stretching at 60% strain generates a V oc of 1.85 V and J sc of 0.09 μA/cm 2 . The energy generated from the FPENG is stored in a Li-ion battery, demonstrating a self-charging power unit. These findings present a simple method to develop FPENGs with enhanced performance by coupling flexoelectric and piezoelectric effects for wearable devices.