Electrochemical and Capacitive Properties of Carbon Dots/Reduced Graphene Oxide Supercapacitors

Abstract

There is much recent interest in graphene-based composite electrode materials because of their excellent mechanical strengths, high electron mobilities, and large specific surface areas. These materials are good candidates for applications in supercapacitors. In this work, a new graphene-based electrode material for supercapacitors was fabricated by anchoring carbon dots (CDs) on reduced graphene oxide (rGO). The capacitive properties of electrodes in aqueous electrolytes were systematically studied by galvanostatic charge-discharge measurements, cyclic voltammetry, and electrochemical impedance spectroscopy. The capacitance of rGO was improved when an appropriate amount of CDs were added to the material. The CD/rGO electrode exhibited a good reversibility, excellent rate capability, fast charge transfer, and high specific capacitance in 1 M H2SO4. Its capacitance was as high as 211.9 F/g at a current density of 0.5 A/g. This capacitance was 74.3% higher than that of a pristine rGO electrode (121.6 F/g), and the capacitance of the CD/rGO electrode retained 92.8% of its original value after 1000 cycles at a CDs-to-rGO ratio of 5:1.

Development of New Carbon-Based Electrode Material from Oil Palm Waste-Derived Reduced Graphene Oxide and Its Capacitive Performance Evaluation

“…All the plots encompass two different parts which comprise of an arc in the high frequency region and a nearly vertical line in the low frequency region. It has been reported that the linear impedance curve adjacent to the imaginary impedance axis (-Z ″ ) in the lower frequency region of the Nyquist plots indicates capacitance features of the reduced graphene oxide sample [13,38], which is in good agreement with this work (Figure 12(b)). The nearly small curve in the higher frequency region of the rGOEFB-E1 electrode (Figure 12…”

Patching laser-reduced graphene oxide with carbon nanodots

“…23,24 Despite the low surface area, the benefits of CNDs or reduced CNDs, in particular, are higher electrical conductivity and faster frequency response in the final electrodes. [29][30][31][32] Moreover, they act as suitable starting materials for uniform functional composite materials. 25 In general, CNDs and GO can be considered related materials.…”

Design and Preparation of Biomass-Derived Carbon Materials for Supercapacitors: A Review

“…Among the mentioned applications, the supercapacitor is considered one of the most suitable utilizations for the biomass-derived carbons, since their major features are in good accordance with the above-mentioned EDLC properties. Highly specific capacitance exceeding 400 F g −1 can be obtained from the porous carbon flakes and nanosheets derived from human hair [18], dry elm samara [19] and orange peels [20], which is higher than many other EDLC-type supercapacitors, even carbon nanodots [21], carbon nanofibers [22] and carbon nanotubes [23] (CNT); while highly conductive biomass-derived carbons (with conductivity~1.12 × 10 3 S m −1 ) with low ESR can be obtained from the porous carbon nanosheets and nanofibrous carbon microspheres derived from chicken egg-shell membrane [24], gelatin [25], auricularia [26], and chitin [27]. Moreover, superior rate performance with over 68% capacitance retention at high current densities (~30-50 A g −1 ) has been achieved for the N,O-co-doped, N,S-co-doped and B,N-co-doped porous carbon nanosheets derived from poplar catkins [28], willow catkins [29], and gelatin [25].…”