Spine-like Nanostructured Carbon Interconnected by Graphene for High-performance Supercapacitors

Abstract

Recent studies on supercapacitors have focused on the development of hierarchical nanostructured carbons by combining two-dimensional graphene and other conductive sp2 carbons, which differ in dimensionality, to improve their electrochemical performance. Herein, we report a strategy for synthesizing a hierarchical graphene-based carbon material, which we shall refer to as spine-like nanostructured carbon, from a one-dimensional graphitic carbon nanofiber by controlling the local graphene/graphitic structure via an expanding process and a co-solvent exfoliation method. Spine-like nanostructured carbon has a unique hierarchical structure of partially exfoliated graphitic blocks interconnected by thin graphene sheets in the same manner as in the case of ligaments. Owing to the exposed graphene layers and interconnected sp2 carbon structure, this hierarchical nanostructured carbon possesses a large, electrochemically accessible surface area with high electrical conductivity and exhibits high electrochemical performance.

Pseudocapacitive Properties of Two-Dimensional Surface Vanadia Phases Formed Spontaneously on Titania

“…Furthermore, after annealing at 550 and 600 °C, the BET surfaces areas are further reduced by ∼71% and ∼94% to ∼32 and ∼6 m 2 /g, respectively, with the formation of nanoscale SAFs, but the measured capacitances further increase by >300% (>4×) to ∼55–59 F/g v 2 O 5 . These results are in contrast with numerous previous reports of higher specific capacitances for materials with higher specific surface areas for both electric double layer capacitance − as well as pseudocapacitance materials. − Nonetheless, the somewhat unusual behaviors at high scan rates can be explained by charge transfer processes. Specifically, in specimens with submonolayer and monolayer 2-D surface phases with high surface areas, the interaction of electrolyte and TiO 2 nanoparticles becomes more significant compared with specimen with multilayers/nanometer-thick SAFs which has a much lower surface area.…”

Sandwich-type ordered mesoporous carbon/graphene nanocomposites derived from ionic liquid

“…The Nyquist plots presented in Fig. 7(a) are very typical of porous carbon electrode materials for EDLCs [41]. As expected from the CVs and charge-discharging profiles, MCGC had a slightly smaller semicircle and electrode resistance than MCGE.…”

Reduced graphene oxide grafted by the polymer of polybromopyrroles for nanocomposites with superior performance for supercapacitors

“…The surface physics and chemistry of the samples were examined by the FT-IR and XPS techniques. 25 This result reveals that oxygen-containing functional groups still remain upon the carbon network aer thermal reduction of GO at 500 C for 12 h under an Ar atmosphere, producing a RGO sample. The red shi in the peak position of n(C]C) for RGO compared with that for GO is due to the removal of oxygen-containing groups linked with sp 2hybridized carbon.…”

“…7b) in the scan rate range of 1-100 mV s À1 reects a typical capacitive behavior due to the simultaneous EDLC and pseudocapacitance. 25 Moreover, the CV retains the quasi-rectangular shape as the scan rate increases to 200 mV s À1 , indicating a good high-rate capability of the cell. The plot of capacitance versus current density for a single electrode (C single ) exhibits C single values of 500.…”

“…20 As expected, the resulting RGO/PPBP nanocomposites exhibit enhanced electrochemical performance, compared with individual RGO, 4-8 graphene, 23,24 PPBP, 20 and many other carbonbased composites using graphene or RGO as the matrix in recent reports. [25][26][27][28][29][30][31][32] 2. Experimental section…”