In this research, in order to increase the oxidation resistance of graphite, kaolin and alumina powder with different ratios (26A-74S, 49A-51S, 72A-28S) and slurry method were used to create an aluminosilicate coating on the graphite substrate. In order to reduce the difference in the coefficients of thermal expansion of graphite with aluminosilicate coating, aluminum metaphosphate coating as an interlayer was prepared on the surface of graphite by cathodic electrochemical treatment. The isothermal oxidation test of the samples was carried out in air at a temperature of 1250 °C for 1, 3 and 5 h. The microstructure, chemical composition, and phase components of the coating were, respectively, analyzed by scanning electron microscope equipped with an energy-dispersive spectrometer and X-ray diffraction. The results indicated that, by increasing the withdrawal speed of the samples in slurry method, the amount of changes in the weight of the samples has increased and therefore had a direct effect on oxidation. In addition, it was approved that, at high-temperature oxidation, AlPO4 glass phase forms on aluminum metaphosphate interlayer which retards graphite oxidation. Along with aluminum metaphosphate, aluminosilicate coating also produces a glass phase which fills and seals the voids on the surface which prevents the oxygen to reach the surface of graphite. The created double-layer coating including an interlayer of aluminum metaphosphate + slurry coating prepared with the ratio of 26A-74S as the optimal coating in this research was able to increase the oxidation resistance of graphite by 73% at a temperature of 1250 °C.

The dyeing process is a very important unit operation in the leather and textile industries; it produces significant amounts of waste effluent containing dyes and poses a substantial threat to the environment. Therefore, degradation of the industrial dye-waste liquid is necessary before its release into the environment. The current is focusing on the reduction of pollutant loads in industrial wastewater through remediating azo and thiazine dyes (synthetic solutions of textile dye consortium). The current research work is focused on the degradation of dye consortium through photo-electro-Fenton (PEF) processes via using dimensionally stable anode (Ti) and graphite cathode. The ideal conditions, which included a pH of 3, 0.1 (g/L) of textile dye consortium, 0.03 (g/L) of iron, 0.2 (g/L) of H2O2, and a 0.3 mAcm-2 of current density, were achieved to the removal of dye consortium over 40 min. The highest dye removal rate was discovered to be 96%. The transition of azo linkages into N2 or NH3 was confirmed by Fourier transforms infra-red spectroscopic analysis. PEF process reduced the 92% of chemical oxygen demand (COD) of textile dye consortium solution, and it meets the kinetics study of the pseudo-first-order. The degradation of dye through the PEF process was evaluated by using the cyclic voltammetric method. The toxicity tests showed that with the treated dye solution, seedlings grew well.

The objective of this study is development of graphite-boron composite material as a replacement for metal canisters to Improve the heat dissipation and radiation shielding performance of dry spent nuclear fuel storage system and reduce the volume of waste storage system. KEARI research team plan to use the graphite matrix manufacturing technology to pelletize the graphite matrix and adjust the content of phenolic resin binder to minimize pore formation. Specifically, we plan to adjust the ratio of natural and synthetic graphite powder and use uniaxial pressing technology to manufacture black graphite matrix with extremely high radial thermal conductivity. After optimizing the thermal conductivity of the graphite matrix, we plan to mix it with selected boron compounds, shape it, and perform sintering and purification heat treatments at high temperatures to manufacture standard composite materials.

This paper proposes the optimal molecular weight for a petroleum-based binder pitch to enhance the density and strength of the prepared graphite block. The effect of the molecular weight on the binder properties, which was quantified using solvent fractionation, was considered based on the evaluation of the coking and viscosity characteristics. The affinity of the pitch to coke influenced the carbonization yield of the block, and the proportion of closed pores was reduced via the use of a highaffinity binder pitch. In addition, the viscosity was found to influence the uniformity of the coke and pitch dispersions, and numerous open pores were formed in the graphite block under high-viscosity conditions. In terms of the molecular weight, a reduction in the content of the insoluble 1-methyl-2-pyrrolidone (NMP) fraction, which was the heaviest fraction present in the pitch, was found to reduce the affinity of the binder to coke while increasing its viscosity. Therefore, the density and strength of the prepared graphite block were reduced upon increasing the insoluble NMP content of the binder pitch. Consequently, it was necessary to control the content of this fraction within < 13.81 wt% to obtain high-density and high-strength graphite blocks.

To study the effect of inorganic electrolyte solution on graphite flotation, 19 kinds of inorganic electrolytes, including nitrate, chloride and sulfate were selected as experimental electrolytes. The flotation experiment was carried out on graphite and the contact angle and surface potential of the interaction between inorganic electrolyte solution and graphite were studied. The results show that flotation effect and flotation rate of the three ion valence inorganic electrolytes follow the order: nitrate < chloride < sulfate and univalent < bivalent < trivalent (except Ba(NO3)2 and Pb(NO3)2). When the ion valence are the same, the larger the ion atomic number, the better effect on graphite flotation. Cations in inorganic electrolyte solutions are the main factors affecting mineral flotation. When the cationic type and concentration are the same, different flotation effects are attributed to different anions. For low ion valence inorganic electrolyte solution with weak foaming effect, a certain dose of frother can be added appropriately to improve the flotation effect of graphite. The high ion valence inorganic electrolyte solution has strong foaming effect, and it is not necessary to add a frother. The principle of inorganic electrolyte solution promoting graphite flotation is analyzed from the aspects of liquid phase property, gas–liquid interface property, contact angle and surface potential. It is proved that inorganic electrolyte solution as flotation medium can promote the effective flotation of graphite.

The synthesis of a novel first stage GIC containing simultaneously lithium, potassium and barium through a solid–liquid reaction by molten salts method is described. Such a route has been largely developed in our laboratory for intercalation of metals into graphite. The interplanar distance of this quaternary compound reaches 950 pm and exhibits poly-layered intercalated sheets defined by X-ray measurements. The Li0.2K0.75Ba0.6C6 chemical formula of the compound is determined by ion beam analysis and this GIC is remarkably homogeneous. This GIC is the first poly-layered one containing barium.

The fast expanding field of wearable technology requires light-weight, low-cost, scalable, flexible and efficient energy harvesters as a source of uninterrupted green power. This work reports fabrication of sub-micron graphite platelet/PVDF composite film-based flexible piezoelectric energy harvester (PGEH) for scavenging the wasted mechanical energy associated with human body motion. The addition of graphite platelet leads to the enhancement of electroactive β phase in PVDF; consequently, the piezoelectric and dielectric properties of the composite are enhanced. 0.5 wt% filler-loaded composite has 96% β phase fraction and dielectric constant 32 at 100 Hz (tanδ = 0.18).The PGEH produces open circuit voltage of 40 V and instantaneous power density of 3.35 mW cm− 3 with energy conversion efficiency of 22.5% under periodic finger tapping. It can generate fair electrical output under gentle heel (0.8 V) and toe movements (1.2 V). A PGEH is directly employed for powering 50 commercial LEDs and quick charging of a 2.2-μF capacitor upto 19.2 V. The device is also employed as self-powered dynamic pressure sensor which shows high sensitivity (0.9 VkPa− 1) with fast response time (1 ms). Therefore, this durable, flexible, efficient PGEH can have promising applications in wearable electronics as a green power source cum self-powered mechanosensor.

Renewed interest in the reinforced carbon graphite composites has intrigued the community in the advanced materials fields. In this work, we present a simple carbon nanofibers reinforced carbon graphite composites synthetic method by incorporating mixture of coal tar pitch, synthetic graphite, pitch coke and the dispersion liquid of carbon nanofibers via liquid-phase mixing process. The impact of carbon nanofiber utilization on the microstructures and mechanical properties of carbon graphite composites are studied systematically. The covalent surface modification of carbon nanofibers effectively improves its microstructure and thereby promotes the carbon graphite composites’ dispersion behavior. We propose that a small amount of carbon nanofibers could promote the carbonization process of carbon graphite composites, facilitating the densification of carbon graphite composites and reducing the undesired open porosity. The amount of 0.7 wt % of carbon nanofiber concentration allows the enhancement of bend and compressive strength of carbon graphite composites up to 36.50 MPa and 60.46 MPa, increased by 167.9% and 146.9% compared with the pure carbon graphite composite, respectively. Our findings can be rationalized due to the improvement in the mechanical strength of carbon graphite composites could be attributed due to pull-out of carbon nanofibers from the matrix and bridging effect across the crack pores within the matrix.

In this study, graphene oxide (GO) was synthesized by the improved Hummers’ method. The degree of oxidation from graphite (Gi) to GO was determined through interlayer spacing calculated from X–ray diffraction. Besides, the effect of KMnO4: Gi ratios (X1), H2SO4 volume (X2), oxidation temperature (X3), oxidation time of stage 1 (X4), and oxidation time of stage 2 (X5) was screened by the Plackett–Burman model. The simultaneous impact of three factors that influenced the degree of oxidation (X1, X2, and X3) was studied by the Box–Behnken experimental model of response surface methodology to achieve suitable conditions for the GO synthesis process. The characterization of GO product was investigated via the modern analytical methods: X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, UV–Vis spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Inaddition, the study was also carried out on a pilot scale for orientation in industrial application with the yield of 14 g/batch.

For practical applications of graphene sheets in a variety of fields, mass production of high-quality graphene sheets is necessary. Herein, we reported a cost-effective, green, and simple approach to synthesizing mass production exfoliated graphene (EG) flakes employing electrochemical exfoliation of pencil graphite in neutral aqueous electrolytes. Pencil graphite cores of different grades were applied as anode and cathode electrodes and exposed to the electrolyte solution at a different voltage. Several parameters were examined and optimized, including pencil grade (2,4,6,8 B), applied voltage (10, 15, 20, 30 V), different inorganic electrolytes ((NH4)2SO4, Na2SO4, NaNO3, NaCl, and CH3COONa), and the concentration of electrolytes. The optimal condition was chosen by considering the mass of produced graphene and the conductivity of the graphene solution. The optimal conditions were as follow: pencil grade: 6B; applied voltage: 10 V; electrolyte type: Na2SO4; electrolyte concentration: 0.1 M. Under these conditions, the production yield was > 95% within 3 h and 9 min. The EG was characterized by utilizing FT-IR, XRD, Raman spectroscopy, FE-SEM, Cyclic Voltammetry, and Electrochemical Impedance Spectroscopy (EIS). Characterization indicates that the synthesized EG had an XRD peak at 2θ = 26.6° and an ID/ IG ratio of 0.36. Furthermore, the EG showed good conductivity when tested by cyclic voltammetry and EIS whereas the R2 values were 985.8 and 76.3 Ω for bare GCE and EG/GCE, respectively. In addition, EG effectively removed cadmium (Cd(II)) with an adsorption level of 8.72 mg/g. The results from this study suggest that EG can be scaled up and commercialized in an environmentally friendly and low-cost manner, especially in low-income countries, and using it to rectify metal ions.

The preparation and exfoliation of graphite oxide at low temperatures (near room temperature) to produce exfoliated graphite (EG) instead of rapid heating to a high temperature (conventional process) are reviewed. The exfoliation by microwave irradiation, electrochemical exfoliation and surfactant-assisted exfoliation of graphite are also included because these techniques can be applied under ambient atmosphere, although last two techniques were mainly applied for thinning the graphite flakes to obtain “graphene” flakes. The applications of the resultant exfoliated graphite (EG) for oil/water separation, adsorptive removal of the environment pollutants and microwave shielding are shortly reviewed.

Graphite felt is a felt-like porous material made of high-temperature carbonized polymers. It is widely used in electrode materials because of its good temperature resistance, corrosion resistance, large surface area and excellent electrical conductivity. In this paper, the surface functional group modification is of graphite felt electrodes (mainly nitrogen doping modification, nitrogen–sulfur or nitrogen–boron co-doping modification) and surface catalytic modification (metal/ion surface modification and metal oxide surface modification as Main). There are two main methods and research progresses to improve the performance of graphite felt electrodes, and the comprehensive performance of surface functional group-modified graphite felt electrodes and surface catalytically modified graphite felt electrodes are compared respectively. The results show that both surface functional group modification and surface catalytic modification can improve the comprehensive performance of graphite felt electrodes. In this paper, the future development direction of graphite felt activation modification is also prospected.

In this study, a graphite block is fabricated using artificial graphite processing byproduct and phenolic resin as raw materials. Mechanical and electrical property changes are confirmed due to the preforming method. After fabricating preforms at 50, 100, and 150 MPa, CIP molding at 150 MPa is followed by heat treatment to prepare a graphite block. 150UP-CIP shows a 12.9% reduction in porosity compared with the 150 MPa preform. As the porosity is decreased, the bulk density, flexural strength, and shore hardness are increased by 14.9%, 102.4%, and 13.7%, respectively; and the deviation of density and electrical resistivity are decreased by 51.9% and 34.1%, respectively. Therefore, as the preforming pressure increases, the porosity decreases, and the electrical and mechanical properties improve.

Few studies have been performed on ZrB2- graphite platelet composite made by spark plasma sintering (SPS) technique. In this research, the influence of adding graphite platelets (Gp) with and without SiC on the fracture toughness of ZrB2 ceramic was studied. The ZrB2- 10Gp, ZrB2- 15Gp, ZrB2- 30SiC-10Gp, and ZrB2- 30SiC-15Gp specimens were sintered by the SPS method at the temperature of 1850 °C for 8 min. The fracture toughness and work of fracture (WOF) were evaluated using the Single-Edge Notched Beam (SENB) technique. It was found that the fracture toughness and WOF were improved by the alone and combined addition of Gp and SiC to the monolithic ZrB2. The maximum fracture toughness of 4.8 ± 0.1 MPa m1/ 2 was obtained for the ZrB2- 15Gp specimen. It seems that adding Gp alone was more effective in enhancing the fracture toughness of ZrB2 than the combined addition of Gp and SiC. While the addition of Gp and SiC simultaneously modified the densification behavior to reach full-densified samples.

Thermal management is significant to maintain the reliability and durability of electronic devices. Heat can be dissipated using thermal interface materials (TIMs) comprised of thermally conductive polymers and fillers. Furthermore, it is important to enhance the thermal conductivity of TIMs through the formation of a heat transfer pathway. This paper reports a polymer composite containing vertically aligned electrochemically exfoliated graphite (EEG). We modify the EEG via edge selective oxidation to decorate the surface with iron oxides and enhance the dispersibility of EEG in polymer resin. During the heat treatment and curing process, a magnetic field is applied to the polymer composites to align the iron oxide decorated EEG. The resulting polymer composite containing 25 wt% of filler has a remarkable thermal conductivity of 1.10 W m− 1 K− 1 after magnetic orientation. These results demonstrate that TIM can be designed with a small amount of filler by magnetic alignment to form an efficient heat transfer pathway.

Here, we have demonstrated the successful exfoliation of graphite into a layered material with scotch tape-like exfoliation. Sulfur acts as an exfoliating agent and exfoliates the loosely bounded graphite stacks. The shear force by ball milling provides the force required to overcome the van der Waals force between the layers. The MnO2 nanorods were synthesized using a KMnO4 precursor in a hydrothermal arrangement, and due to their intrinsic chemisorption capability, they were doped for polysulfide trapping. With an initial capacity of 1150 mAh/g achieved by the MnO2 nanorod-doped exfoliate-graphite/sulfur composite material, the material has displayed its application in lithium–sulfur batteries, but its use is not limited; it can be a low-cost eco-friendly solution to various energy storage systems with extensive structural qualities.

High-temperature friction performances of graphite blocks (GBs) and zinc phosphate impregnated graphite blocks (IGBs) were evaluated under various friction temperatures. The surface of IGB exhibited extremely lower average friction coefficient values, that was 0.007 at 400 °C and 0.008 at 450 °C, in comparison to that of GB (0.13 at 400 °C and 0.16 at 450 °C, respectively). The worn surface of IGB in the high-temperature friction test was smoother and more complete than that of GB. The wear under high temperature and load caused the transformation of zinc pyrophosphate to zinc metaphosphate and the formation of a continuous large-area boundary lubrication layer combined with graphite and metallic element on the wear surface. The superior tribology property of IGB could be attributed to the digestion of iron oxides by tribo-chemical reactions and passivation of the exposed dangling covalent bonds. Specifically, the layered structure generated on the IGB wear interface effectively decreased the adhesive forces and prevented the surface from serious damage.

One of the promising supercapacitors for next-generation energy storage is zinc-ion hybrid supercapacitors. For the anode materials of the hybrid supercapacitors, three-dimensional (3D) graphene frameworks are promising electrode materials for electrochemical capacitors due to their intrinsic interconnectivity, excellent electrical conductivity, and high specific surface area. However, the traditional route by which 3D graphene frameworks are synthesized is energy- and time-intensive and difficult to apply on a large scale due to environmental risks. Here, we describe a simple, economical, and scalable method of fabricating grafoil (GF) directly into a graphite–graphene architecture. Both synthesizing of a porous structure and functionalization with interconnected graphene sheets can be simultaneously achieved using electrochemically modified graphite. The resultant graphite electrode provides a high capacitance of 140 mF/cm2 at 1 mA/cm2, 3.5 times higher than that of pristine grafoil, keeping 60.1% of its capacitance when the current density increases from 1 to 10 mA/cm2. Thus, the method to produce 3D graphene-based electrodes introduced in the current study is promising for the applications of energy storage devices.

Two kinds of mesocarbon microbeads (MCMBs) with different chemical composition have been synthesized. The MCMBs were molded and heat treated at temperatures above 2000 °C to obtain graphite blocks. The effects of chemical composition of MCMBs on the pore morphology, carbon texture and thermal properties of the derived graphite blocks have been explored. The pore morphology was investigated by small angle X-ray scattering technique and a graphitization-induced morphology transition was observed. When the graphitic crystallite size exceeded a threshold value, the association of crystallites and migration of randomly distributed pores took place extensively. For the graphite blocks made of MCMBs which had light components with higher aromaticity value, the growth of crystallites caused a significant enhancement in thermal conductivity for the specimens. However, for the other kind of MCMBs, their light components tended to form solid porous carbon texture after graphitization, and the thermal conductivity coefficients of their graphite blocks could only increase slightly as crystallites grew. It was suggested that the thermal resistance at the granule’s boundary became noticeable in the latter case and thus the growth of thermal conductivity coefficients was prominently hindered.