High-Performance Coaxial Asymmetry Fibrous Supercapacitors with a Poly(vinyl alcohol)–Montmorillonite Separator
Wen He, Xiang Fu, Peijia Bai, Ding Zhang, Heng Cui, Rujun Ma
Abstract
Fibrous supercapacitors have garnered great interest from researchers because of their large electrode/electrolyte interface area, short ion transport path, and high flexibility. However, obtaining a thin gel electrolyte interlayer with a high ion transport rate and uniform thickness is still challenging. Here, we proposed an efficient wet-spinning technique to fabricate uniform polyvinyl-montmorillonite tubular layers for the preparation of a high-performance coaxial asymmetry fibrous supercapacitor (AFSC). The coaxial AFSC shows ultrahigh energy densities in the range of 2.86–4.04 μW h cm–2 at power densities of 0.16–1.61 mW cm–2 while maintaining a long cycling life (94% retention even after 20 000 cycles). After charging at a constant voltage of 2.4 V for 30 s, the flexible watchband which is composed of three series-connected AFSCs could power a commercial electronic watch for more than 2 min. This work provides a universal strategy to fabricate high-performance and wearable energy storage devices.