Influence of structural and textural parameters of carbon nanofibers on their capacitive behavior

Abstract

Herringbone, platelet, and tubular carbon nanofibers (CNFs) were synthesized by catalytic chemical vapor deposition using methane, propane, and ethylene as carbon precursors. Alumina-supported nickel and iron catalysts were used for the syntheses. The resultant CNFs were characterized by scanning electron microscopy, transmission electron microscopy, and nitrogen sorption at 77 K. The performance of a CNF-based supercapacitor working in 6 mol L -1 KOH was analyzed using cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy techniques. The Brunauer-Emmett-Teller (BET) surface area of the CNFs ranged between 150 and 296 m 2 g -1 . An increase in the CNF diameter was accompanied by a decrease in the BET surface area. A comparison of the porous textures and the structure types of the CNFs demonstrated that the performance of the CNF-based supercapacitor is enhanced primarily by the exposed edges of the graphitic layers on the CNF surface, followed by the specific surface area. Among the studied CNFs, the highest capacitance value, 26 F g -1 at 0.2 A g -1 , was obtained for the platelet-type CNFs.Tubular CNFs exhibited the lowest capacitance value, which increased from 4 to 33 F g -1 at 0.2 A g -1 upon air treatment at 450°C. The presence of exposed graphitic edges on the air-treated CNT surface and an increase in the specific surface area are considered to be responsible for the enhancement of the capacitor performance.

Integrated Biomonitoring Sensing with Wearable Asymmetric Supercapacitors Based on Ti3C2 MXene and 1T‐Phase WS2 Nanosheets

“…[ 6 ] To date, the most commonly researched MXene is titanium carbide (Ti 3 C 2 T x , where T x define surface terminations, such as OH, F, and O), which showed much higher C sp than previously reported electrode materials such as porous carbons, [ 7 ] CNT, [ 8 ] graphene, [ 9 ] CNFs. [ 10 ] In addition, our previous research has been demonstrated that Ti 3 C 2 produced via HF etching and subsequent delamination with tetrabutylammonium hydroxide (TBAOH) shows enhanced capacitive behavior. [ 11 ] Furthermore, transitional metal dichalcogenides and particularly tungsten sulphide (WS 2 ) reveals enhanced electrical and [ 12 ] thermal properties, [ 13 ] shorter ions transfer pathway (compared to bulk materials), [ 14 ] metallicity in nature, [ 15 ] and yield when employed as FSC electrode materials.…”

Efficient synthesis of alkynyl carbon materials derived from CaC2 through solvent-free mechanochemical strategy for supercapacitors

“…Meanwhile, the pore size of ACMs decreases from 7.71 nm (ACM-1) to 5.34 nm (ACM-2) when the PHHC precursor changes from C 2 Cl 6 to C 6 Br 6 . These results illustrate that the rigid brace effect of benzene rings and the placeholder effect of large size halogens facilitate the formation of the developed pore structure, which is beneficial to their application in supercapacitors [36,37]. As shown in Fig.…”

Porous materials: microporosity induced by the shape and length of the pores

“…Two samples of CNTs were made: dried (CNT) and calcined at 450°С (CNT450). "Among the studied CNFs, the highest capacitance value was obtained for the platelet-type CNFs; tubular CNFs exhibited the lowest capacitance value" [16]. The average values of pore diameter Dav (Table 1) were calculated by us as arithmetic mean of the diameters of the DpTEM interval measured by the uthors using the TEM method [16].…”