Functionalization of Defect Sites in Graphene with RuO₂ for High Capacitive Performance

Abstract

Graphene is an attractive material for its physicochemical properties, but for many applications only chemically synthesized forms such as graphene oxide (GO) and reduced graphene oxide (rGO) can be produced in sufficient amounts. If considered as electrode material, the intrinsic defects of GO or rGO may have negative influence on the conductivity and electrochemical properties. Such defects are commonly oxidized sites that offer the possibility to be functionalized with other materials in order to improve performance. In this work, we demonstrate how such ultimately efficient functionalization can be achieved: namely, through controlled binding of very small amount of materials such as RuO2 to rGO by atomic layer deposition (ALD), in this way substituting the native defect sites with RuO2 defects. For the example of a supercapacitor, we show that defect functionalization results in significantly enhanced specific capacitance of the electrode and that its energy density can be stabilized even at high consumption rates.

Graphene and its electrochemistry – an update

“…The rGO-RuO 2 material showed a specific capacitance of 1132 F g À1 at a scan rate of 50 mV s À1 . 87 Other studies proposed the combination of graphene with Fe 2 O 3 , 88 95 In situ anodic electropolymerization (AEP) was used by Wang et al to prepare polyaniline/graphene composite paper (GPCP) material which showed a specific capacitance of 233 F g À1 at a scan rate of 2 mV s À1 (Fig. 9).…”

Geogrid‐Inspired Nanostructure to Reinforce a CuxZnySnzS Nanowall Electrode for High‐Stability Electrochemical Energy Conversion Devices

“…We determined no considerable change in the Raman spectra of the NWD electrode Adv. [56] Compared with the NOD electrode, the NWD electrode possessed higher crystallinity, viz., fewer defects, and thus demonstrating higher electrochemical stability. 2017, 7, 1602210 www.advenergymat.de www.advancedsciencenews.com after the reaction (Figure 7c).…”

Deposition of copper from Cu(i) and Cu(ii) precursors onto HOPG surface: Role of surface defects and choice of a precursor

“…Upon thermal annealing, the presence of C− −O− −C groups has also been reported. [41][42][43][44][45][46][47] It is important to realize that there are very few defects expected to be available on a freshly prepared HOPG surface and thus additional defects can be introduced intentionally by ion sputtering followed by annealing in oxygen. The chemical nature of both types of defects is expected to be similar based on the detailed previous studies; [48][49][50] however, the amount can be varied by varying the surface preparation conditions.…”