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• MnO 2 /CNF/Ag nanofabric electrodes are developed for flexible supercapacitors. • The brittle issue in the CNF electrode is greatly improved by an Ag incorporation. • The optimized MnO 2 /CNF/Ag electrode has a specific capacitance of 184 F/g at 1 A/g. • An energy density of 16.3 Wh/kg and a power density of 400 W/kg was achieved. • A capacitance retention rate of 87 % was demonstrated when subjected to bending. Flexible supercapacitors are gaining increasing popularity due to their potential in powering portable, wearable, and lightweight electronic devices. In this study, we have successfully developed a high-performance flexible electrode for quasi-solid-state supercapacitors by incorporating Ag into carbon nanofibers (CNF) through electrospinning, and growing MnO 2 as an active material on the electrode using an in-situ redox method. The Ag and MnO 2 co-decorated CNF electrode offers several advantages over conventional CNF electrodes, including an enlarged reaction area, higher charge storage capacity, and improved resistance to brittleness issues. Among all the quasi-solid-state supercapacitors tested, the MnO 2 -decorated electrode with an optimized Ag incorporation exhibited the highest specific capacitance of 184 F/g at a current density of 1 A/g, representing a remarkable 17-fold increase compared to the reference CNF electrode. Furthermore, the Ag and MnO 2 co-decorated electrode demonstrated an energy density of 16.3 Wh/kg and a power density of 400 W/kg at the same current density. Notably, the electrode exhibited excellent flexibility, with a capacitance retention rate of 87 % when subjected to bending with a curvature ranging from 5 to 1.25 cm. Our results suggest that the Ag and MnO 2 co-decorated CNF electrode holds great promise for flexible energy storage applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract Mesoporous ribbon-shaped graphitic carbon nanofibers (MRCNFs) have been prepared by combination of electrospinning technique, template method and catalytic graphitization of transition metal. Transition metal Co, originated from Co(NO 3) 2 ·6H 2 O doped in spinning solution, serves as both template of mesopores and catalyst for graphitic structure. The microstructure of MRCNFs has been optimized by adjusting doping amount of Co(NO 3) 2 ·6H 2 O. The resultant MRCNFs present a relatively centralized distribution of 2–10 nm mesopores, modest specific surface area of 463 m2 g−1 and pore volume of 0.575 cm3 g−1. In addition, considerable nitrogen- and oxygen-containing functionalities (2.88 at.% of N and 4.88 at.% of O) are detected on MRCNFs. In view of electrode materials for supercapacitors, as-obtained ribbon-shaped morphology, mesoporous structure, considerable surface heteroatom-containing functionalities and high graphitization degree synergistically enhance the electrolyte ion diffusion and electron conduction. In a three-electrode test system, the resultant MRCNFs electrodes exhibit high specific capacitance (228 F g−1 at 0.2 A g−1), rate capability (of 58% capacitance retention at 20A g−1) and excellent cycle stability(of 95% capacitance retention after 5000 cycles at 2 A g−1). Graphical abstract Image 1 Highlights • Mesoporous ribbon-shaped graphitic carbon nanofibers (MRCNFs) have been prepared. • Co particles serves as template of mesopores and catalyst for graphitic carbon. • With SSA of 463 m2 g−1, MRCNFs present a capacitance of 228 F g−1 at 0.2 A g−1. [ABSTRACT FROM AUTHOR]

• Hierarchical porous carbon (HPC) is obtained with three-dimensional (3D) structure. • The HPC with highly fluffy 3D continuous network is found as an ideal support. • HPC-supported MnO 2 nanofibers composite is achieved as a supercapacitor material. • The as-prepared MnO 2 @HPC composite has 3D interpenetrating network structure. • The MnO 2 @HPC composite presents excellent electrochemical performance. For improving the conductivity of porous carbon and the utilizations of its pore structures, a hierarchical porous carbon (HPC) had been developed with highly fluffy three-dimensional (3D) continuous network structure. Using the HPC as a support, a novel MnO 2 @HPC composite with 3D interpenetrating network structure was prepared as electrode material of supercapacitor via simple hydrothermal method. When the hydrothermal reaction temperature was 100°C, the MnO 2 nanofibers (∼5 nm) were uniformly grown on and within the fluffy 3D porous network of the HPC, forming a composite with interpenetrating network structure. The as-prepared composite (MnO 2 @HPC-100) exhibited the characteristics of both electric double-layer capacitance and pseudo-capacitance, which had a high specific capacity of 368 F g−1 at a current density of 0.5 A g−1 and 186 F g−1 at 10 A g−1 (50.5% retention). In addition, the asymmetric supercapacitor device was assembled with a relatively high energy density of 88.2 Wh Kg−1 at a power density of 162 W Kg−1. The device had a high capacity retention rate of 95% after 10000 cycles, and the coulomb efficiency was stable at 99.7%, showing the excellent stability of the composite. Therefore, the MnO 2 @HPC-100 composite has great application prospects in energy storage. [Display omitted] [ABSTRACT FROM AUTHOR]

Nanostructural carbon nanofibers are prepared through electrospinning in a precursor solution composed of polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), and N,N-dimethylformamide. We investigate the effect of PMMA molecular weight on the morphology and electrochemical performance of the nanofibers. During pyrolysis, PMMA decomposition causes the nanofibers to develop from a porous structure into a hollow structure with increased PMMA molecular weight. The removal of PMMA also substantially increases the specific surface area and the pore volume of the carbon nanofibers. Electrochemical measurements reveal that the specific capacitance of the PAN/PMMA-derived carbon nanofibers with a low-molecular-weight PMMA exhibits a specific capacitance of 210 F/g, which is approximately 38% higher than that of the neat PAN-derived carbon nanofibers. Additionally, the fibers exhibit favorable cycling stability with a retention ratio of almost 100% after 2000 cycles. [ABSTRACT FROM AUTHOR]

Highlights: [•] The interconnected carbon nanofibers were prepared by an electrospinning technique. [•] The interconnected fibers developed conductive pathways. [•] The interconnected fibers showed 24% enhancement on the specific capacitance. [•] The interconnected fibers are promising to be used as electrodes for supercapacitors. [ABSTRACT FROM AUTHOR]