A flexible fiber-shaped supercapacitor utilizing hierarchical NiCo₂O₄@polypyrrole core–shell nanowires on hemp-derived carbon

Abstract

a High-performance fiber-shaped electrode composed of hierarchical NiCo2O4@polypyrrole core-shell nanowires on hempderived carbon (HDC) microfiber is successfully fabricated, which takes advantage of the high electrical conductivity of polypyrrole and carbon microfiber to boost the pseudocapacitive performance. The as-synthesized electrode exhibits an ultrahigh specific capacitance of 2055 F/g, excellent rate performance and outstanding cycling stability (90% capacity retention over 5000 cycles). Based on the good mechanical flexibility and stability of the HDC, a fiber-shaped all-solid-state symmetric supercapacitor is designed and demonstrated a high energy density of 17.5 Wh/kg at a power density of 500 W/kg, good stability over 10000 cycles and high physical flexibility.A flexible fiber-shaped supercapacior is assembled based on the highly conductive, interconnected and flexible hemp-derived carbon scaffold (HDC), and after the incorporation of the NiCo 2 O 4 @Polypyrrole Core-Shell Nanowires, the as-synthesized fiber-shaped electrode HDC@NiCo 2 O 4 @Polypyrrole exhibits outstanding electrochemical performance and mechanical stability.

Highly Hydrophilic Carbon Dots' Decoration on NiCo2O4 Nanowires for Greatly Increased Electric Conductivity, Supercapacitance, and Energy Density

“…The GCD experiments of the supercapacitor were carried out in the voltage range of 0–1 V for the two‐electrode system (Figure b) . As previously reported, there will be residual amorphous carbon in the system with urea as the reactant, which has an effect on the Coulomb efficiency, and the charge–discharge curves are symmetrical . In this work, as shown in Figure b, the symmetrical GCD curves are probably due to the existence of amorphous carbon and the decoration of CDs .…”

“…As shown in Figure d, the specific capacitances of CNCO‐3 are calculated to be 2202, 1602, 612, 552, 525, and 460 F g −1 , respectively, which show a comparable or even superior specific capacitance to that of the reported electrode materials, as listed in Table 1 . In addition, it can be seen in Figure c that the capacitance of CNCO‐3 can still be retained as the largest one from NiCo 2 O 4 and CDs/NiCo 2 O 4 samples, although the specific capacitance of all the samples decreases when the current density is increased from 1 to 10 A g −1 , demonstrating a preferably capacitance retention and low polarization of the NiCo 2 O 4 electrode materials . As shown in Figure S11 (Supporting Information), it is noted that the CDs/NiCo 2 O 4 samples show the rather symmetrical charge–discharge curves, which are mainly due to Faradic redox reaction between CDs/NiCo 2 O 4 electrode and Na 2 SO 4 electrolyte .…”

Recent Advances in Nanowire‐Based, Flexible, Freestanding Electrodes for Energy Storage

“…For instance, lightweight and flexible symmetric supercapacitors with high energy/power densities were obtained with rGO-F/PANI (rGO-F = reduced graphene oxide foam) electrodes, in which PANI NW arrays were alignedo nt he porousr GO-F. [58] An all-hydrogel-state supercapacitorw as obtained by using the PANI/rGO hydrogel as the electrodes and PVA/H 2 SO 4 as the gel electrolyte/separator. Af ew three-component systems have been reported, including NiCo 2 O 4 NW/PPy@carbon, [61] MnO 2 /PPy/C, and V 2 O 5 /PPy/C [57] (Figure 9). [60] Because CPs can closely attach to the surface of active materials due to the flexible nature and rich functional groups of polymers, if they form ac omposite with the 3D carbon matrix, the activem aterial-CP-carbon matrix composites are expected to achieve high electrochemical performance, as ar esult of continuous electron/ion transport.…”

Construction of Hierarchical 2D PANI/Ni3S2 Nanosheet Arrays on Ni Foam for High‐Performance Asymmetric Supercapacitors

“…The electrochemical data suggests that the introduction of a PANI layer can significantly improve the electrochemical performance of Ni 3 S 2 /NF. The high capacity of the PANI/Ni 3 S 2 /NF‐100 electrode is ascribed to following aspects: (1) The hierarchical 3D open network facilitates the electrolyte ions diffusion . (2) The ultrathin 2D Ni 3 S 2 nanosheets can expose more electroactive sites for Faradaic reactions.…”