Supercapacitors with porous carbon structures have high energy storage capacity. However, the porous nature of the carbon electrode, composed mainly of carbon nanotubes (CNTs) and graphene oxide (GO) derivatives, negatively impacts the volumetric electrochemical characteristics of the supercapacitors because of poor packing density (<0.5 g cm(-3)). Herein, we report a simple method to fabricate highly dense and vertically aligned reduced graphene oxide (VArGO) electrodes involving simple hand-rolling and cutting processes. Because of their vertically aligned and opened-edge graphene structure, VArGO electrodes displayed high packing density and highly efficient volumetric and areal electrochemical characteristics, very fast electrolyte ion diffusion with rectangular CV curves even at a high scan rate (20 V/s), and the highest volumetric capacitance among known rGO electrodes. Surprisingly, even when the film thickness of the VArGO electrode was increased, its volumetric and areal capacitances were maintained.

An anti-solvent for graphene oxide (GO), hexane, is introduced to increase the surface area and the pore volume of the non-stacked GO/reduced GO 3D structure and allows the formation of a highly crumpled non-stacked GO powder, which clearly shows ideal supercapacitor behavior.

Dual-function poly(L-lysine) (PLL) composites that function as antibacterial agents and promote the growth of human cell culture have been sought by researchers for a long period. In this paper, we report the preparation of new graphene derivative-PLL composites via electrostatic interactions and covalent bonding between graphene derivatives and PLL. The resulting composites were characterized by infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The novel dual function of PLL composites, specifically antibacterial activity and biocompatibility with human cells [human adipose-derived stem cells and non-small-cell lung carcinoma cells (A549)], was carefully investigated. Graphene-DS-PLL composites composed of 4-carboxylic acid benzene diazonium salt (DS) generated more anionic carboxylic acid groups to bind to cationic PLLs, forming the most potent antibacterial agent among PLL and PLL composites with high biocompatibility with human cell culture. This dual functionality can be used to inhibit bacterial growth while enhancing human cell growth.

A new chemical dual-functional reducing agent, thiophene, was used to produce high-quality reduced graphene oxide (rGO) as a result of a chemical reduction of graphene oxide (GO) and the healing of rGO. Thiophene reduced GO by donation of electrons with acceptance of oxygen while it was converted into an intermediate oxidised polymerised thiophene that was eventually transformed into polyhydrocarbon by loss of sulphur atoms. Surprisingly, the polyhydrocarbon template helped to produce good-quality rGO C (chemically reduced) and high-quality rGO CT after thermal treatment. The resulting rGO CT nanosheets did not contain any nitrogen or sulphur impurities, were highly deoxygenated and showed a healing effect. Thus the electrical properties of the as-prepared rGO CT were superior to those of conventional hydrazine-produced rGO that require harsh reaction conditions. Our novel dual reduction and healing method with thiophene could potentially save energy and facilitate the commercial mass production of high-quality graphene.G raphene has attracted great interest because of its unique physical properties 1 arising from its rigid twodimensional (2D) structure, and its potential applications in nanoelectronics 2 , energy storage materials 3 , polymer composite materials 4 and sensing 5 . Mechanical exfoliation is one of the successful approaches that have been developed for the preparation of high-quality graphene sheets suitable for fundamental studies, but large-scale production of such pure graphene sheets remains unfeasible. Instead, chemical graphitisation from graphene oxide (GO) to reduced graphene oxide (rGO) is generally used for mass production of graphene [6][7][8][9][10] . Numerous reducing chemicals such as hydrazine 11 , NaBH 4 12 , hydriodic acid (HI) 13 , NaOH 14 , ascorbic acid 15 and glucose 16 have been used to convert GO to rGO. However, all of these reducing agents produce imperfect rGOs containing a high level of defects or disorders. Recently, Amarnath et al. introduced a pyrrole as a new chemical reducing agent in this process, but the C/O ratio showed that GO was not fully reduced and the resulting rGO contained high nitrogen contamination emanating from the nitrogen source 17 . Kaminska et al. also introduced reduction and functionalization of graphene oxide using tetrathiafulvalene 18 . Despite the urgent need for production of a defect-free rGO, there have not been any reports of chemical healing of the defects of heteroatom-free rGO in the reduction process of GO to rGO. In addition, the development of novel reduction methods that are environmentally friendly, mild, and cost effective ways remains a challenge for mass production of high-quality rGOs by chemical healing.In this study, we introduce a new dual-functional reducing agent, thiophene (T) which has lower reactivity than pyrrole 17 and produces high-quality, heteroatom-free rGOs by chemical healing reduction of GO. Thiophene can be used to reduce as-prepared GO by dual-functional electron donation and oxygen consumption. It is also ...