KOH activated carbon/graphene nanosheets composites as high performance electrode materials in supercapacitors

Abstract

The importance of developing high performance electrode materials with low cost for supercapacitor is self-evident. In this paper, KOH activated carbon/graphene nanosheet composites were prepared via a simple hydrothermal treatment of graphite oxide and KOH activated carbon. Next electrochemical experiments conducted have demonstrated that these composites exhibited synergistically improved electrochemical performance as electrodes in supercapacitor. The specific capacitance of these composites can reach as large as 205 and 173 F g -1 in 6M KOH aqueous solution and 1M TEABF4 in acetonitrile solution respectively. In addition, as fabricated electrodes using these composites show a reduced internal resistance and higher capacitance retention performance. Furthermore, the entire preparation process is simple, low cost and easily scalable to mass production, leading to great potential for composites.

Ion Intercalation Induced Capacitance Improvement for Graphene‐Based Supercapacitor Electrodes

“…For example, Yu et al. reported a porous carbon/graphene nanosheets composite that achieved a specific capacitance of 205 F g −1 at 2 A g −1 . Zheng et al.…”

Hydrothermal preparation of Phyllostachys pubescens – nanocellulose/graphene aerogel as a simple device for supercapacitors

“…Carbon materials, such as activated graphene (Zhu et al 2011), carbon nanotubes (CNTs) (Izadi -Najafabadi et al 2010), mesoporous carbons (Sun et al 2012), and carbide-derived carbons (Merlet et al 2012), as a kind of EDLC electrode material, can provide efficient charge separation in electrolyte solutions and enhance the overall electron transport efficiency in the electrode (Li et al 2016). In recent years, there has been an increasing interest in combining two carbon materials, such as graphene and activated carbons (ACs) (Xu et al 2015;Yu et al 2014), graphene and CNTs (Saeed et al 2018), or carbon nanofibers and ACs (Gryglewicz et al 2013), to improve the electrochemical properties of materials. However, the composites with two carbon materials usually do not achieve the desired results because of the lack of affinity between the different carbon materials, which results in a poor distribution and aggregation of the same material (Du et al 2017).…”

KOH-assisted microwave post-treatment of activated carbon for efficient symmetrical double-layer capacitors

“…However, the capacitance of AC is only 40–70 F/g because of its large number of micropores, which are not easily accessed for electrolyte ions. Great efforts have been made to tune the properties of AC . For example, AC could be modified by sulfur functional groups, leading to 40% increase of capacitance at current density of 1.4 A/g .…”