Improved Ion‐Transfer Behavior and Capacitive Energy Storage Characteristics of SnO₂ Nanospacer‐Incorporated Reduced Graphene Oxide Electrodes

Abstract

This report demonstrates the modification of reduced graphene oxide (RGO) nanosheets by decorating SnO 2 nanorod bundles and nanoparticles on the surface for effective use of the graphene as supercapacitor electrode materials. The shape-and density-controlled SnO 2 nanostructures were prepared through hydrothermal synthesis and acted as spacer materials to physically inhibit the overlapping of the RGO sheets; this is known as the restacking effect. When measuring the electrochemical properties, the electrode comprising RGO with SnO 2 nanorod bundles (RGOÀ SnO 2 À NR) revealed a higher capacitance, rate capability, and cyclic stability than the RGO electrode with SnO 2 nanoparticles (RGOÀ SnO 2 À NP) and the bare RGO electrode, indicating the effective role of the surface-implanted SnO 2 spacer during the electrode reactions of the double-layer capacitor. The electrochemical superiority of RGOÀ SnO 2 À NR could be explained by the fact that wedge-like SnO 2 nanorod bundles between the RGO sheets promote fast transfer and approach of electroactive species to form the electrochemical double layer at the electrode surface. Moreover, the improved mass transfer behavior of the RGOÀ SnO 2 composite electrodes and the role of the SnO 2 nanostructures were reasonably verified by various electrochemical analyses.

Oxygen‐Deficient Homo‐Interface toward Exciting Boost of Pseudocapacitance

“…Specifically, as calculated from the corresponding GCD curves, the SnO 2− x NPs@SnO 2− x NSs electrode yields a high specific capacitance of 376.6 F g −1 at 2.5 A g −1 , which is almost 4 times and 2.5 times that of SnO 2− x NSs (95.8 F g −1 ) and SnO 2 NPs@SnO 2 NSs (153.9 F g −1 ) electrodes, respectively. The specific capacitance value of the present SnO 2− x NPs@SnO 2− x NSs electrode is also much higher than those of previously reported SnO 2 ‐based electrodes, such as functional carbon cotton@SnO 2 (197.7 F g −1 at 1 A g −1 ),30 SnO 2 @porous carbon nanofibers (225.4 F g −1 at 1 A g −1 ),16 SnO 2 @reduced graphene oxide (184.6 F g −1 at 0.1 A g −1 ),31 and RGO‐SnO 2 (85 F g −1 at 0.5 A g −1 ) 32. More impressively, the SnO 2− x NPs@SnO 2− x NSs electrode exhibits much higher rate capability than those of the SnO 2− x NSs (66.0%) and SnO 2 NPs@SnO 2 NSs (77.6%) electrodes, retaining 86.9% of the initial capacitance when the current density is increased from 2.5 to 80 A g −1 (Figure 3b).…”

Heat Treatment–Controlled Morphology Modification of Electrospun Titanium Oxynitride Nanowires for Capacitive Energy Storage and Electrocatalytic Reactions

“…The CV was performed in N 2 ‐bubbled electrolyte over the potential range of −1.0 to 0.0 V at different scan rates from 5 to 200 mV s −1 . Also, corresponding mass specific capacitance ( C m ) could be calculated from the CV curves by the following Equation where C m (F g −1 ) is the mass specific capacitance, m is the loading mass of active material in the working electrode (g), v is the potential scan rate (V s −1 ), Δ V is the potential range (V), and I is the response current (A). The galvanostatic charge/discharge measurement was conducted over the range of −0.0 to 0.0 V at different current densities from 0.5 to 10.0 A g −1 , and corresponding capacitance values could be calculated by the following Equation where I is the discharge current (A), Δ t is the discharge time (s), and Δ V is the discharge potential range.…”

Rechargeable Li-ion full batteries based on one-dimensional Li-rich Li1.13Mn0.26Ni0.61O2cathode and nitrogen-doped carbon-coated NiO anode materials

“…21 In particular, one-dimensional (1D) nanoscale electrode materials could exhibit improved capacity, cycling stability, and rate performances, because they can ensure high charge mobility with large electrolyte permeability and efficient structural buffering without serious electrode collapse. [22][23][24][25] Additionally, for the purpose of improving the charge transport rate and alleviating the electrode pulverization during repeated cycling, especially in anode materials, hybridization with carbonaceous materials such as sulfur-or nitrogen-doped carbon, [26][27][28] carbon fiber, 29 and graphene [30][31][32][33] has also been investigated. Among these various carbonaceous materials, nitrogen-doped carbon (NC) has been extensively adopted on the basis of its outstanding cycling properties and simple fabrication procedure.…”