Supercapacitors based on free-standing reduced graphene oxides/carbon nanotubes hybrid films

Abstract

The freestanding of reduced graphene oxides/carbon nanotubes (rGO/CNTs) hybrid films are synthesized via the simple vacuum filtration and thermal reduction methods. And the electrochemical behaviors of rGO/CNTs hybrid films are investigated in KOH and in Et 4 NBF 4 /AN electrolyte, respectively. In three-electrode systems, the rGO/CNTs hybrid films show a maximum specific capacitance of 221 F g −1 , a 71% capacitance retention, and an excellent cycle life in 1 M KOH electrolyte. And the electrochemical behaviors of rGO/CNTs films in Et 4 NBF 4 /AN electrolyte under three-electrode systems show a maximum specific capacitance of 174 F g −1 and good rate capability. Moreover, a symmetric supercapacitor of rGO/ CNTs//rGO/CNTs demonstrates a maximum specific capacitance of 24 F g −1 at 1 A g −1 , a energy density of 20.8 Wh kg −1 at 1.27 kW kg −1 , and an excellent cycle life of 86.1% retention after 5000 cycles. It suggests that the symmetric supercapacitor could be regarded as an ideal energy storage system.

Phosphorus and nitrogen co-doped reduced graphene oxide as superior electrode nanomaterials for supercapacitors

“…In addition, the capacitance retention of PN-rGO was 70% in the range of 0.5 to 20 A g −1 , which indicates good rate capability. 75 The specific capacitance values obtained for PN-rGO (292 F g −1 at 0.5 A g −1 ) supersedes those reported in the literature, which ranged between 178 and 227 F g −1 . 76 Moreover, the cycling stability of PN-rGO was investigated through 10 000 charge/discharge cycles at a current density of 10 A g −1 (Fig.…”

A Review of Supercapacitors: Materials Design, Modification, and Applications

“…It was found to be an excellent electrode material in energy storage devices. Additionally, RGO and MnO 2 /RGO hydrogels [144], graphene-based nickel foam [145], graphene/activated carbon/polypyrrole (GN/AC/PPy) [121], GO/CNTs hybrid film [146], rGO/MWCNT film [147] were reported. RGO synthesized via vacuum filtration was used as an electrode material for supercapacitors.…”

Flexible planar supercapacitors by straightforward filtration and laser processing steps

“…Their electrical conductivity, high surface area, chemical stability, light weight as well as mechanical flexibility make them the material of choice in electrodes for electrochemical energy storage, especially for supercapacitors with high power density and excellent cycle stability [4][5][6]. Among the carbon nanomaterials graphene/reduced graphene oxide (RGO) , carbon nanotubes (CNTs) [21][22][23][24][25][26][27][35][36][37][38][39][40][41][42][43][44][45][46], carbon black [7,8,47], activated carbon [20,25,35,48], carbon nanofibers [35,[49][50][51] as well as biomass derived carbon [51][52][53] have been the most prominent materials for supercapacitor electrodes. Moreover, silver in the form of nanowires [14,35] and nanoparticles [54] have also been utilized in in the electrode material enhancing the performance of the electrode due to its superior intrinsic electrical conductivity [55].…”

“…Vacuum filtration has long been used to make carbon-based films that are then utilized as electrodes. The process itself is facile and quick to produce highly porous carbon films that are either supported by the filter membrane [12-15, 27-29, 37-39] or completely freestanding after removal [7,20,[23][24][25]48]. The films can also be patterned into an interdigital structure by etching the filtered thin film [14] or by multi-step photolithography process [37].…”