Reduced Graphene Oxide as a Monolithic Multifunctional Conductive Binder for Activated Carbon Supercapacitors

Abstract

Using reduced graphene oxide (r-GO) as a multifunctional conductive binder, a simple, cost-effective, and environmentally friendly approach is developed to fabricate activated carbon/reduced graphene oxide (AC/r-GO) composite electrodes for supercapacitors with outstanding performance. In such a composite, r-GO provides several much needed critical functions: r-GO not only serves as the binder material improving the AC particle/particle cohesion and electrode-film/substrate adhesion but also improves the electrical conductivity of the composite and provides additional surfaces for ion adsorption. Furthermore, during electrode fabrication, initial GO precursor functions as an effective dispersant for AC, resulting in a stable electrode material slurry. Employing characterization by advanced microscopy techniques, we show that AC and r-GO assemble into an interconnected network structure, resulting in a composite with high specific capacitance, excellent rate capability, and long cycling life stability. Such high-performance electrodes coupled with their relatively simple, scalable, and low-cost fabrication process thereby provide a clear pathway toward large-scale implementation of supercapacitors.

Carbon Black and Reduced Graphene Oxide Nanocomposite for Binder-Free Supercapacitors with Reduced Graphene Oxide Paper as the Current Collector

“…A possible explanation of this improvement could be in a different interaction of rGO in the active material when coated on a current collector consisting of the same material, such as rGO paper, rather than a metal sheet, such as Al foil: in the studied electrodes, the adhesion derives from interactions of the nonremoved oxygen-containing groups of rGO with the substrate surface. 20 While Al is a metal with an easy tendency to oxidize that often requires chemical etching to allow carbon coating, rGO paper does not need etching to form this bonding since, chemically, it is almost pure carbon. This is particularly true for the used rGO paper collector because, as in the XRD analysis on this material showed in our previous work, 51 it is characterized by a high degree of reduction of GO.…”

“… 14 There are however different methods to improve the reduction process and to prevent topological defects in the wide literature about rGO. 15 − 20 Nowadays, one of the most common ways to obtain graphene-like materials relies on the oxidation of graphite to obtain graphite oxide (GtO). 21 − 23 From GtO, sheets of GO can be produced as intermediates thanks to mechanical exfoliation.…”

“… 27 Their practical use is however limited by the manufacturing method: electrospinning is not readily scalable to industrial processes. In the work of Galhena et al, 20 rGO was adopted as an alternative binder with good results. However, as in other studies, 28 , 29 the use of toxic and expensive organic solvents was still necessary, especially for the electrical double layer capacitors (EDLCs; i.e., a type of SC relying only on electrostatic charge storage).…”

Two-Dimensional Mn3O4Nanowalls Grown on Carbon Fibers as Electrodes for Flexible Supercapacitors

“…7−9 On the other hand, electrochemical capacitors or supercapacitors emerged as an alternative for these applications. 10−12 Supercapacitors utilizing flexible electrodes have received high demand in the scientific community due to their feasible incorporation in the flexible electronic devices. 13,14 Not only the electrodes but also the current collector substrates should be flexible to achieve the total flexibility.…”

Highly Flexible and Tailorable Cobalt‐Doped Cross‐Linked Polyacrylamide‐Based Electrolytes for Use in High‐Performance Supercapacitors

“…This nearly symmetric behavior of GCD profiles implies the dominance of double-layer capacitance over pseudocapacitive effect. The galvanostatic capacitance (Cg, F) of the prepared ACSCs was calculated using the equation [3]: Cg = I/(~V/~t), [48] where I is the applied galvanostatic discharge current (A),~V and~t are the corresponding discharge potential window (V) and time (s) of the most linear part of discharge curve (i. e., 25-85% of discharge curve). The calculations showed that Cg increases by adding Co to reach its optimum value at 5% of Co in HPEs, which is equivalent to 7 times higher than Co-free HPE (PAMBG).…”