Highly Flexible and Self‐Healable Zinc‐Ion Hybrid Supercapacitors Based on MWCNTs‐RGO Fibers

Abstract

As the flexible wearable devices are developing rapidly, the requirement for energy storage devices with high energy and power density, excellent flexibility, and high reliability is increasing. Fiber‐shaped supercapacitors offering high power density and excellent flexibility have attracted widespread attention. However, the low energy density and poor reliability limit the practical application of these fiber‐shaped supercapacitors. To overcome these problems, a new zinc‐ion hybrid fiber supercapacitor (ZHFSC) is designed and realized. As both capacitor‐type and battery‐type energy storage mechanisms can be used, the energy density of ZHFSC is expected to be improved. Furthermore, the excellent self‐healability of poly(vinyl alcohol) (PVA)/Zn(CF3SO3)2 aqueous gel electrolyte contributes to the high reliability of the ZHFSC. As a proof of concept, the maximum power density and energy density of the ZHFSC are, respectively, as high as 1433.2 mW cm−3 and 13.1 mWh cm−3, and the capacitance retention, respectively, has the high values of 87.8% and 70.5% under the bending degree of 150° and after the fifth self‐healing. This study offers an efficient method to realize the high‐performance supercapacitors for flexible wearable devices in the future.

Zinc‐ion Hybrid Capacitor with High Energy Density Constructed by Bamboo Shavings Derived Spongy‐like Porous Carbon

“…The high energy density of 197.7 Wh kg −1 can be achieved at power density of 66.5 W kg −1 , the high‐power density of 15221.2 W kg −1 (22.24 Wh kg −1 ), which can be as good as some advanced reports [5d,8a,b,d,e,16] . The Rs and Rct values of solid‐state ZIHC are larger than that of aqueous ZIHC (Figure 7e), but lower than that of the same type of hybrid capacitor, [8i,k] indicating low charge transfer resistance and good ion diffusion capability in solid‐state electrolyte (PVA/KOH/Zn (Ac) 2 ). The capacitance retention rate is maintained at 94.73 %, and the Coulomb efficiency is 94.98 % after 5000 cycles at 1 A g −1 (Figure 7f).…”

Synergistic effects of B/S co-doped spongy-like hierarchically porous carbon for a high performance zinc-ion hybrid capacitor

“…Thus, this flexible solid-state ZIHC device has considerable potential in renewable energy storage. 38,53–55…”

Carbon‐Based Materials for a New Type of Zinc‐Ion Capacitor

“…Ni et al developed fibrous ZICs based on MWCNTs-RGO composites by using an MWCNTs-RGO hybrid fiber as a cathode, an MWCNTs-RGOÀ Zn hybrid fiber as an anode and a poly(vinyl alcohol) (PVA)/Zn(CF 3 SO 3 ) 2 aqueous gel as an electrolyte. [79] The as-assembled ZICs deliver excellent areal capacitance (41.2 F cm À 3 at 400 mA cm À 3 ) and a maximum areal energy density (13.1 mWh cm À 3 at a power density of 1433.2 mW cm À 3 ). Under the action of the highly flexible and healthy PVA/Zn(CF 3 SO 3 ) 2 hydrogel electrolyte, the capacitance retention rates of ZICs after bending to 150°and the fifth selfhealing are 87.8 % and 70.5 %, respectively.…”