Flexible triboelectric nanogenerator based on silk fibroin-modified carbon nanotube arrays

Triboelectric nanogenerators have recently attracted significant attention due to the needs of sustainable and clean energy. Herein, we fabricate a flexible triboelectric nanogenerator (SF@CNTA-TENG) based on silk fibroin (SF)-coated carbon nanotube array (CNTA). We demonstrate the role of the structures of the composite in the triboelectric output performance. Highly porous CNTA has extremely large surface areas. The silk fibroin film forms on the surface of carbon nanotubes (CNTs) in CNTA and between the adjacent CNTs where the silk fibroin films bridge the CNTs. The 3D network structure of CNTA and the formation of silk fibroin film have significant implications for increasing the specific surface area of the triboelectric layer, which greatly benefits the triboelectric output performance of SF@CNTA-TENG. This SF@CNTA-TENG with highly porous structures in the triboelectric layer exhibits an excellent triboelectric output performance and achieves the charge density of 0.19 mC/m2 and power density of 5.8 W/m2. The large deformation of the triboelectric layers under the strong external force leads to the increase of the effective contact area that dramatically improves the triboelectric output performance of SF@CNTA-TENG. This highly flexible SF@CNTA-TENG has potential applications in wearable devices.