Elucidation of an intrinsic parameter for evaluating the electrical quality of graphene flakes

Abstract

A test method for evaluating the quality of graphene flakes, such as reduced graphene oxide (rGO) and graphene nanopowder (GNP), was developed in this study. The pelletizer was selected for a sampling tool, which enables us to formulate the flake sample as a measurable sample. Various parameters were measured from the pelletized sample in order to elucidate the best parameter for representing the quality of the graphene flakes in terms of their electrical properties. Based on the analysis of 4-probe measurement data on the pelletized sample, the best intrinsic parameter is volume resistivity (or volume conductivity) rather than resistivity (or conductivity). Additionally, the possible modification of a sample before and after the pressurization was investigated by electron microscopy and Raman spectroscopy. No significant modification was observed. The volume conductivity in the two types of the graphene was different from their individual conductivities by one order of magnitude. Based on the results of X-ray photoelectron spectroscopy and Raman spectroscopy measurements, the volume conductivity of the graphene flake samples was governed by the oxygen content in the sample. Our achievements will promote the effective use of powder-type graphene products for further applications.

Dependence of Precursor Graphite Flake Size on Nitrogen Doping in Graphene Oxide and Its Effect on OER Catalytic Activity

“…Additionally, the intrinsic electrochemical activity of the flakes of higher sizes will be greater due to their enhanced conductivity compared to the flakes of smaller sizes. 37 , 38 …”

“…Additionally, the intrinsic electrochemical activity of the flakes of higher sizes will be greater due to their enhanced conductivity compared to the flakes of smaller sizes. 37,38 For further analysis of OER behavior on the IrO 2 catalysts, the Tafel slopes (b) for the three catalysts were calculated using the Tafel equation [η = a + b log j, where η = E − E o (E o = 1.23 vs the RHE)] by plotting log j versus η. The Tafel slopes were ca.…”

“…The higher durability of IrO 2 -N-rGO-20 can be associated with other factors, namely, a differently processed graphite (synthetic graphite) precursor, bigger flake size (20 μm), higher density of defects, and better stability of the intrinsic N-rGO support. Additionally, the intrinsic electrochemical activity of the flakes of higher sizes will be greater due to their enhanced conductivity compared to the flakes of smaller sizes. , …”

Boron and nitrogen doping in graphene: an experimental and density functional theory (DFT) study

“…The arrow marks in figure 2(c) also indicate the number of layers, which is in good agreement with our Raman results. Graphene has the 0.213∼0.215 nm spacing for the hexagonal diffraction pattern [31]. BNG has ∼0,248 nm spacing due to structures distortion caused by the intercalation of N and B atoms.…”

Synergistic Effects of Hybrid Carbonaceous Fillers of Carbon Fibers and Reduced Graphene Oxides on Enhanced Heat-Dissipation Capability of Polymer Composites

“…The detailed material properties were characterized using micro-Raman spectroscopy with an excitation laser wavelength of 514 nm (inVia Reflecx Raman microscope, Renishaw, Wotton-under-Edge, Gloucestershire, UK). The electrical conductivities of the MPCFs and rGOs fillers were measured using a powder resistivity measurement system (HPRM-M2, Hantech Co. Ltd., Gunpo, Korea) [24]. Sheet conductances of epoxy-based composites were inductively measured with non-contact resistivity measurement system (M-RES-5210D-400, KITEC microelectronic technologie GmbH, Erding, Germany).…”