Flexible all-solid-state supercapacitors based on an integrated electrode of hollow N-doped carbon nanofibers embedded with graphene nanosheets. (1st February 2020)

• Record Type: Journal Article
• Authors: Li, Xinlu; Chen, Xiangyu; Zhao, Yujie; Deng, Yuanyuan; Zhu, Jiawei; Jiang, Shunhua; Wang, Ronghua
• Is Part Of: Electrochimica acta. Volume 332(2020)
• Publication Date: 2020-02-01
• Subjects: Coaxial electrospinning -- Supercapacitors -- Carbon nanofibers -- Graphene nanosheets -- All-solid-state; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2019.135398
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: A novel facile and scalable strategy is developed to prepare a hierarchical porous nonwoven of hollow N-doped carbon nanofibers embedded with graphene nanosheets (HN-CNFs/GNs) as an integrated electrode for flexible all-solid-state supercapacitors. It was found that graphene nanosheets (GNs) were curled inside the electrospun fibers, but freely expanded and connected adjacent CNFs in the form of nanosheets after carbonization, thereby increasing the electrochemical capacitance interface and conductivity as well. When the weight ratio of GNs is 2 wt%, the HN-CNFs/GNs delivers high capacitance of 249 F g − 1 at 1 A g − 1 in a three-electrode configuration. A two-electrode symmetrical cell delivers extraordinary cycling stability with no capacitance degradation after 5000 cycles. The symmetric all-solid-state supercapacitor provides a remarkable cycling stability with a capacity retention of 90% after 2000 cycles and high rate capacity. The device also displays outstanding flexibility with no obvious capacitance decay even when bent to 180°. This research proves the potential application of the nonwoven of HN-CNFs/GNs in high efficient, wearable and flexible energy storage devices. Graphical abstract: Image 1 Highlights: A hierarchical porous nonwoven of hollow N-doped carbon nanofibers embedded with graphene nanosheets (HN-CNFs/GNs) was sythesized by a one-step method. Graphene nanosheets (GNs) were found to be curled inside the electrospun fibers, but freely expanded and connected adjacent CNFs in the form of nanosheets after carbonization, thereby increasing the electrochemical capacitance interface. The particular characteristics of the HN-CNFs/GNs, such as N-doping, hierarchical porosity and hollow fibers, providing a high specific capacitance (249 F g − 1 at a current density of 1 A g − 1 in three-electrode system), excellent cycle stability (99% retention of 5000 cycles in symmetric two-electrode system) and outstanding flexibility (no obvious decay when bending to 180° in all-solid-state device) when the adding ratio of GNs is 2 wt%.