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The rational use of energy is of great significance for the long-term stable development of the economy. However, energy such as solar energy and industrial waste heat are difficult to be utilized stably. The development of thermal storage technology can alleviate the instability of energy. In this paper, 96 wt% NaNO 3 -4 wt% NaCl (NN) was used as the thermal storage material and expanded graphite (EG) was used to adsorb NN binary phase change material (PCM). The effect of EG with different particle sizes on the thermal performance of NaNO 3 –NaCl/EG composite phase change material (CPCM) was studied. The results showed that the addition of EG reduced the supercooling degree of NN from 4.7 °C to 1.1 °C. The addition of EG powder increased the contact probability between fillers and provided more adsorption positions for PCM, increasing the latent heat of composites. The addition of 32 mesh EG–EG powder greatly increased the thermal conductivity of NN from 1.24 W·m −1 ·K −1 to 5.43 W·m −1 ·K −1 . It is because the pores of large particle size EG are filled with EG powder, which is easy to form chain or network structure, forming more heat conduction pathways. The research provides some technical support for the application of phase change heat storage technology.

Supercapacitors have gained e wide attention because of high power density, fast charging and discharging, as well as good cycle performance. Recently, expanded graphite (EG) has been widely investigated as an effective electrode material for supercapacitors owing to its excellent physical, chemical, electrical, and mechanical properties. Based on charge storage mechanism, supercapacitors have been divided into symmetric, asymmetric, and hybrid supercapacitors. Here, we review the study progress of EG-based materials to be electrode materials. Furthermore, we discuss the application prospects and challenges of EG-based materials in supercapacitors.

Modified expanded graphite was prepared from expanded graphite and characterized by FT-IR, XRD and SEM. The results showed that the modified linear alkyl was successfully grafted onto the surface of expanded graphite, and the crystal structure and overall morphology did not change significantly after modification. Expanded graphite and modified expanded graphite adsorption columns were prepared, the adsorption experiment of emulsified oil was carried out. When the initial concentration of emulsion oil solution is 100 mg·L −1 , the filling density is 3.5 g·L −1 , and the flow rate is 3 L·h −1 , the emulsion oil concentration decreases to 93 mg·L −1 and 6.5 mg·L −1 , respectively, after adsorption by expanded graphite and modified expanded graphite, indicating that the adsorption performance of modified expanded graphite on emulsified oil is obviously improved. The saturated adsorbed modified expanded graphite was recycled by vacuum filtration. The results show that the modified expanded graphite still has good adsorption performance for emulsified oil after 1-3 times of regeneration, and can be used as adsorption material or recycled into sealing material.

Carbonaceous materials (CMs) have gained great attention as heterogeneous catalysts in water treatment because of their high efficiency and potential contribution to achieving carbon neutrality. Expanded graphite (EG) is ideal for studying CMs because the reactivity in CMs largely depends on graphitic structures, and most surface of EG is exposed, minimizing mass transfer resistance. However, EG is poor in adsorption and catalysis. In this study, EG was modified by simple thermal treatment to investigate the effects of characteristics of graphitic structures on reactivity. Tetracycline (TC) removal rate via activating peroxydisulfate (PDS) by the EG treated at 550 °C (EG550) was more than 10 times that of EG. The thermal modification did not significantly increase surfaces but led to increases in damaged, rough surfaces, graphitization degree, C content, defects, and C=O. Radical and non-radical pathways, such as SO4•−, O2•−, 1O2, and electron transfer, were involved in TC removal in EG550+PDS. TC degradation in EG550+PDS was initiated by hydroxylation, followed by demethylation, dehydroxylation, decarbonylation, and ring-opening. The ions ubiquitous in water systems did not significantly affect the performance of EG550+PDS, except for H2PO4− and HCO3−, suggesting the high potential of practical applications. This study demonstrated that graphitic structure itself and surface area are not detrimental in the catalytic reactivity of CMs, which is different from previous studies. Rather, the reactivity is governed by the characteristics, i.e., defects and functional groups of the graphitic structure. It is thought that this study provides valuable insights into the development of highly reactive CMs and the catalytic systems using them.

Here, we report on a new automated electrochemical process for the production of graphene oxide (GO) from graphite though electrochemical exfoliation. The effects of the electrolyte and applied voltage were investigated and optimized. The morphology, structure and composition of the electrochemically exfoliated GO (EGO) were probed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS), FTIR spectroscopy and Raman spectroscopy. Important metrics such as the oxygen content (25.3 at.%), defect density (ID/IG = 0.85) and number of layers of the formed EGO were determined. The EGO was also compared with the GO prepared using the traditional chemical method, demonstrating the effectiveness of the automated electrochemical process. The electrochemical properties of the EGO, CGO and other carbon-based materials were further investigated and compared. The automated electrochemical exfoliation of natural graphite powder demonstrated in the present study does not require any binders; it is facile, cost-effective and easy to scale up for a large-scale production of graphene-based nanomaterials for various applications.

The goal of this study was to create a high-filled composite material based on polysulfone using various graphite materials. Composite material based on graphite-filled polysulfone was prepared using a solution method which allows the achievement of a high content of fillers up to 70 wt.%. Alongside the analysis of the morphology and structure, the thermal conductivity and mechanical properties of the composites obtained were studied. Structural analysis shows how the type of filler affects the structure of the composites with the appearance of pores in all samples which also has a noticeable effect on composites’ properties. In terms of thermal conductivity, the results show that using natural graphite as a filler gives the best results in thermal conductivity compared to artificial and expanded graphite, with the reduction of thermal conductivity while increasing temperature. Flexural tests show that using artificial graphite as a filler gives the composite material the best mechanical load transfer compared to natural or expanded graphite.

Using paraffin as the phase change material, expanded graphite (EG) as the carrier, due to the good absorption and the high thermal conductivity of EG, the EG/paraffin composites were prepared. The EG/paraffin composites were characterized by scanning electron microscope (SEM), differential scanning calorimeter (DSC), thermal conductivity meter and temperature patrol instrument. The results show that with the decrease of paraffin content, the latent heat and temperature of phase change of EG/ paraffin composites decrease slightly, and the highest endothermic peak shifts to the left, however, in EG/ paraffin composites, with the increase of EG mass fraction, the thermal conductivity, thermal diffusivity and heat transfer enhancement ability are greatly improved.

As graphene and related materials increasingly integrate into various industries, producing high-quality graphene sheets on a large scale becomes crucial. Here, we present a unique approach to the large-scale production of graphene through laser-assisted graphite expansion followed by ultrasonic exfoliation. The present method utilizes laser technology to significantly expand graphite, achieving an expansion rate of 800 mL g −1 with a deficient energy consumption of just two watts laser. The graphene produced via ultrasonication of expanded graphite samples exhibited high quality (I D /I G ) ~ 0.13 and a few layers with a (I 2D /I G ) ~ 0.52. Free-standing films with different thicknesses (11–69 µm) were successfully prepared through filtration, reaching significant electrical conductivity up to (~ 1707 S cm −1 ). The as-prepared graphene films are further explored for electromagnetic interference (EMI) shielding. The highest shielding effectiveness (SE) was recorded for the graphene film with a thickness of 69 µm, reaching a value of ~ 72 dB. Meanwhile, the graphene film with an 11 µm thickness achieves the highest absolute effectiveness (SSE/t) of ~ 58,666 dB cm 2  g −1 , surpassing most current graphene and MXene films, which typically present values in the range of 10,000 to 40,000 dB cm 2  g −1 . This present laser-assisted expansion incorporating a sonication exfoliation strategy paves a new way to produce graphene on a large scale.

In order to study the effects of the pore structure and pore size of porous carrier material on the phase transformation behavior of composite phase change materials (CPCMs), the pore structure and pore sizes of three different sizes of expanded graphites (EGs) (50, 80, 100 mesh) were studied using N2 adsorption-desorption isotherms and scanning electron microscopy. Then, the thermal characterization of CPCMs prepared with paraffin wax and EGs were tested using differential scanning calorimetry and a thermal conductivity tester. The results showed that EG-50 had a more web-like pore structure, and thus, higher adsorption capacity for paraffin wax. The addition of EG could reduce the supercooling degree of CPCMs and improve the thermal conductivity of CPCMs. CPCM with EG-50 had better performance due to its large specific surface area and low interfacial resistance. Compared with paraffin wax, the phase transition temperature (ΔT) of CPCMs increased slightly and the latent heat of CPCMS decreased to varying degrees. As the pore size of EG decreased, its constraint on PCM increased, but ΔT of CPCMs decreased, which was due to the combination of phase transformation behavior of different components in paraffin wax, which violates the conventional change law. It could be seen that the phase change behavior of CPCMs was related not only to the pore size of EG but also to the composition of PCM.

In view of the growing demand for flexible, conductive and functional materials for textile gas sensor applications, the effects of ozonation on the properties of expanded graphite (EG) in textile structures were analyzed. Four types of fabrics (cotton, polyamide, viscose, para-aramid) coated with pastes containing EG, which had previously been subjected to a 15-min and 30-min ozonation process, were examined. The paste was prepared using Ebecryl 2002 and the photoinitiator Esacure DP250 and then applied by screen printing. Surface resistance, scanning microscopy and wetting angle analyses were performed. The results showed that short-term ozonation (15 min) notably improved the electrical conductivity and adhesion of EG to the textile substrate, while longer exposure (30 min) led to deterioration of the conductive properties due to excessive functionalization and fragmentation of the conductive layer. The lowest surface resistance was observed in the sample subjected to 15 min of ozonation. The conclusions indicate that a properly controlled ozonation process can increase the usability of EG in sensor applications, especially in the context of smart clothing; however, the optimization of the modification time is crucial for maintaining the integrity and durability of the conductive layer.