Swelling-reconstructed chitosan-viscose nonwoven fabric for high-performance quasi-solid-state supercapacitors

Fabrics are often used as freestanding substrates for energy storage devices owing to their hierarchical porous structure and excellent mechanical flexibility. However, it is still a challenge to achieve a high loading mass of electroactive materials for outstanding electrochemical performance. In this work, with the help of high swelling property of chitosan, the chitosan-viscose nonwoven fabric (CVF) is successfully reconstructed to expand its specific surface area for flexible conductive substrates in the supercapacitors. Then, multi-walled carbon nanotubes (MWCNTs) are coated on the surface of crosslinked chitosanviscose nonwoven fabric (c-CVF) to form the conductive framework. Subsequently, polypyrrole (PPy) is deposited by in-situ interfacial polymerization on the above conductive MWCNT/c-CVF substrate. The optimized PPy/MWCNT/c-CVF composite electrode shows not only a high electrical conductivity of 285.9 +/- 1.2 S.cm(1), but also a prominent specific capacitance of 10112.9 mF.cm(-2) at 2 mA.cmz. Moreover, the prepared composite electrode also exhibits a high flexibility and good rate capability, in which the 70.3% capacitance is retained when the current density increases from 2 mA.cm(-2) to 10 mA.cm(-2) . Besides, the quasi-solid-state symmetric supercapacitor, being assembled with the optimized composite fabric electrodes, produces the maximum areal specific capacitance of 1748.0 mF.cm(-2) at 2 mA.cm(2) and the outstanding energy density of 155.4 mF.cm(-2) at a power density mF.cm(-2). This work provides an effective approach to reconstruct the blended nonwoven fabric structure for high-performance flexible conductive substrate in the supercapacitors. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

In this work, a chitosan-viscose nonwoven fabric (CVF) was reconstructed using the high swelling property of chitosan, resulting in a flexible conductive substrate with a high specific surface area for supercapacitors. Multi-walled carbon nanotubes (MWCNTs) were coated on the surface of crosslinked chitosan-viscose nonwoven fabric (c-CVF) to provide a conductive framework, and polypyrrole (PPy) was deposited on this substrate through in-situ interfacial polymerization. The optimized composite electrode exhibited high electrical conductivity and specific capacitance, as well as flexibility and good rate capability. When used in a quasi-solid-state symmetric supercapacitor, the composite fabric electrodes achieved a high areal specific capacitance and energy density. This work presents an effective approach for developing high-performance flexible conductive substrates for supercapacitors.