Lithium-ion batteries (LIBs) are widely used as key components in electric vehicles (EVs) and energy storage systems (ESS) owing to their high energy density, long cycle life, and stable operation. The rapid expansion of the EV market has intensified the demand for advanced graphite anode materials that combine cost competitiveness with superior electrochemical performance, including fast-charging capability and structural stability. This study presents an integrated approach for optimizing the physical spheronization of natural graphite and synthesizing a high-performance coating pitch (CP) for chemical spheronization. The correlation between mechanical stress and morphological evolution during the process was quantitatively analyzed using an Air Classifier Mill (ACM). Optimal spheronization was achieved by aligning theoretically calculated stress levels (≈ 3.72 MPa for particle rounding and > 14.86 MPa for fracture) with experimental results. High-performance coating pitches were prepared via stepwise polymerization of pyrolysis fuel oil (PFO), followed by Thin Layer Evaporation (TLE)-based molecular weight distribution tailoring. The resulting pitch exhibited a softening point of 279.4 °C, coking value of 70.7%, and zero quinoline insoluble (QI) content, and was applied as a coating precursor. The optimized spheronized graphite anode showed excellent electrochemical properties, including an initial Coulombic efficiency of 92.6% and 97.4% capacity retention after 50 cycles. Electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT) analyses further confirmed efficient lithium-ion diffusion at both the surface and core, demonstrating suitability for fast-charging LIB applications.

Here we report self-propagated growth of lanthanum hexaboride (LaB6) decorated Carbon Nano Tubes (CNTs) from the pyrolytic graphite rods treated with nitrogen arc plasma. The system so formed is named as LaB6-CNTs. Two pyrolytic graphite rods were used as electrodes in the arc plasma reactor whereas, the LaB6 sample kept onto anode acts as catalyst. The anode left out with residue of LaB6 was exposed to normal atmospheric conditions which show ignition of selfpropagated growth of CNTs decorated with LaB6 . Such growth was observed within a couple of days after exposure to the environment without any external supply of energy. The growth is found to be slow and continues till complete erosion of the pyrolytic graphite block. The self-propagated powder obtained was characterized thoroughly using XRD, Raman spectroscopy, FESEM and TEM techniques. These nanostructures were found to exhibit efficient field-emitting properties with a low turn-on electric field of ~ 2 V/μm, and a current density of ~ 1.5 A/cm2 at an applied electric field of 1.8 V/m. Therefore, the nanostructures obtained can be explored for electron emission applications.

Owing to its excellent properties, graphite shows great potential for applications in engineering. However, the removal mechanism of brittle materials results in the formation of randomly distributed craters of varying sizes on the machined surface of graphite during machining. The difficult machining characteristics lead to the importance of studying the cutting mechanism of graphite. In this paper, the cutting process of graphite has been numerically simulated by the finite element method. In numerical simulations, the accuracy of the simulation results depends largely on the accuracy of the selected intrinsic model parameters. To determine the parameters of the Johnson‒Holmquist II (JH-2) constitutive model, this paper presents systematic mechanical testing of graphite materials. The compressive and impact strengths of graphite were found to be 142.17 MPa and 133.6 MPa via quasistatic compression and Hopkinson compression rod experiments, respectively, and the damage patterns of graphite were obtained. The constant HEL of the equation in the Hugoniot state was measured to be 1.056 GPa using plate impact tests. Finally, the experimental data obtained were combined with the theoretical derivation to finalize the parameters of the JH-2 model. To ensure the reliability of the model parameters, the cutting simulation results were compared with the actual experimental results.

To enhance the fixed carbon content and recovery rate of flotation concentrates from low-grade natural flake graphite (NFG), this study employed synchronous ultrasonic flotation in combination with inorganic salt ion (NaCl) enhancement. Flotation experiments were conducted to investigate the synergistic effects of these two methods. X-ray photoelectron spectroscopy, contact angle analysis, laser particle-size analysis, Raman spectroscopy, infrared spectroscopy, zeta potential measurements, electron microscopy, and Debye length calculations confirmed that ultrasonic cavitation disrupted particle agglomeration and cleaned the graphite surface. This process generated fine micro-/nanobubbles with enhanced hydrophobicity, significantly improving concentrate recovery rates. NaCl addition compressed the double electric layer on particle surfaces and suppressed bubble coalescence, stabilizing the froth and promoting graphite–bubble adhesion, which markedly increased the fixed carbon content of the concentrate. The results demonstrated that through the integrated approach, low-grade NFG with an initial fixed carbon content of 7.98% was upgraded after rough processing to a concentrate containing 79.24% fixed carbon, with a recovery rate of 65.76%. These findings demonstrate that combining ultrasonic flotation with NaCl addition substantially improved both fixed carbon content and recovery rate in the concentrate. Overall, this study provides a novel technical pathway for the efficient utilization of low-grade graphite ore resources.

Bimetallic sulfides, as high-performance anode materials, exhibit high theoretical capacity. However, their practical application is hindered by inherent limitations, such as low electrical conductivity, sluggish charge transfer kinetics, and severe volume expansion. Interface-engineered heterostructures have emerged as a universal strategy to synergistically enhance conductive networks and suppress mechanical degradation. Carbon-based composites serve as optimal substrates due to their high conductivity and structural flexibility. In this study, we leverage the hierarchical porous architecture of expanded graphite (EG) to confine the self-assembly of Zn/Co precursors via a thiourea-assisted hydrothermal method, enabling in situ growth of Zn0.76Co0.24S nanoparticles within EG interlayers. Interfacial S–C covalent bonding, induced by π–π conjugation, establishes robust nanoscale coupling between Zn0.76Co0.24S and the carbon framework. The resulting “sandwich” heterostructure demonstrates exceptional cyclability (1086.9 mAh·g−1 after 500 cycles at 1.0 A·g−1) and rate capability (541.7 mAh·g−1 at 2.0 A·g−1). This work provides a generalizable design paradigm for high-performance multimetallic sulfide anodes through atomic-scale interface engineering.

Graphite crystals consist of a layered structure with stacked graphene sheets, and exhibit self-lubricating properties due to the facile sliding of graphene layers in the horizontal direction, facilitated by weak Van der Waals bonds along the c-axis. When this graphite material is impregnated with a lubricating liquid, it forms a solid and stable lubricating layer, and effectively reduces damage to the counter material from friction-induced wear under conditions of high-load reciprocating motion. This study investigates how oxidation-induced pore expansion and the silane treatment of graphite affect lubricating oil impregnation behavior, the friction coefficient of impregnated graphite, frictional stability, and microstructural changes at the friction surface. It was found that graphite oxidation within the chemical reaction temperature range enhanced porosity and increased the rate of lubricating oil impregnation. The functionalization of the graphite surface with hydrophobic silane coupling agents also significantly enhanced oil uptake, with a pronounced observed improvement when utilizing hydrophobic oils. Under a vertical load of 360 kgf and a surface pressure of 3 MPa, the graphite surface treated with hydrophobic silane and impregnated with oil exhibited the lowest average friction coefficient of 0.192 over 600 cycles. During the friction and wear process, a lubricating layer formed on the graphite surface, which contributes to stable wear performance. This surface modification strategy offers high applicability in industries such as automotive, aerospace, and heavy machinery, with the potential to significantly enhance component performance and extend service life under high-load, low-speed reciprocating conditions.

Thermal property represents a critical metric when evaluating the performance of next generation nuclear graphite. Despite the extensive measurement data available, a detailed investigation into the influence of microstructure on graphite’s thermal conductivity remains underexplored. In this work, taking advantage of the distinct microstructures between different graphite grades, a comparative study of four graphite grades was conducted to elucidate the structure–property relationship. The microstructures of graphite were characterized by Raman spectroscopy and X-ray diffraction techniques, demonstrating specimen preparation induced damage and annealing induced restoration. Thermal properties were investigated across multiple scales using laser flash analysis and photothermal radiometry. The results indicate that despite similar densities, thermal conductivity varies significantly between different grades and correlates positively with crystallite sizes. By interpolating an infinitely large crystallite and removing the impact of macroscale porosity, an upper bound for the thermal conductivity of isotropic defect-free nuclear graphite has been established.

All-vanadium redox flow battery (VRFB) has been considered as a promising candidate for the construction of renewable energy storage system. Expanded graphite possesses immense potential for use as typical bipolar plates in VRFB stacks. Nevertheless, the pure expanded graphite bipolar plates suffer from severe swelling in electrolyte, resulting in the losses of mechanical stability and electrical conductivity, thus leading to the efficiency decay within several cycles. Herein, we present a “nanoglue” strategy for tuning the structure/surface properties of expanded graphite by employing polyvinylidene fluoride (PVDF) polymer as structural sealant. Such PVDF “nanoglue” on expanded graphite results in the fine-repairment toward the surface microcracks and cross-section edges, which is beneficial to suppress the electrolyte permeation and improve the anti-swelling capacity. Moreover, it has been found that the PVDF “nanoglue” can improve the flexibility, allowing for the fabrication of ultrathin bipolar plates (0.67 mm) with low electrical resistivity. Benefiting from these integrated characteristics, the VRFB employing the as-fabricated composite bipolar plates delivers excellent cyclic efficiencies (voltage efficiency, coulombic efficiency, and energy efficiency) and ultralow ohmic voltage loss of less than 1.1 mV (< 0.1% of the VRFB rated voltage of 1.25 V) at a high current density of 200 mA cm− 2.

Polyethylene (PE) is one of the most widely used plastics, and vast amounts of waste PE are either buried or incinerated, leading to environmental concerns. Significant research efforts have focused on converting waste PE into carbon materials, particularly as carbon anodes for lithium-ion batteries (LIBs). However, most previously developed PE-based carbon anodes have underperformed compared to graphite-based commercial anode materials (CAM). In this study, LIB anode materials were prepared based on both commercial high-density polyethylene (CPE) and waste high-density polyethylene (WPE). Through thermal oxidative stabilization and high-temperature graphitization, both CPE and WPE were successfully transformed into highly crystalline carbon materials comparable to CAM. However, despite the high crystallinity, both CPE and WPE derived carbon contained significant number of fine particles and exhibited a broad particle size distribution. When used as an anode for LIBs, fine particles led to unwanted side reactions, resulting in an initial coulombic efficiency (ICE) of around 85%, which is lower than the ICE value of 92.5% observed in CAM. To tackle the low ICE problem, recarbonization after coal tar (CT) coating was adopted as a mean to induce secondary particle formation. After CT coating, the average particle size increased, and the size distribution became narrower. Although CT coating reduced the crystallinity slightly, the overall level remained comparable to that of CAM. As a result, the CT-coated graphitized CPE (GCPE@10CT) and CT-coated graphitized WPE (GWPE@10CT) exhibited performance comparable to CAM as LIB anodes, achieving an ICE of over 93% and a capacity of approximately 349 mAh g− 1.

Efforts to mass-produce high-quality graphene sheets are crucial for advancing its practical and industrial applications across various fields. In this study, we present an innovative electrochemical exfoliation method designed to enhance graphene quality and increase yield. Our approach combines two key techniques: expanding the tightly packed graphite interlayer used as the electrode medium and precisely controlling voltage polarity. The dual-exfoliation technique optimizes the use of anions and cations of varying sizes in the electrolyte to facilitate meticulous intercalation, allowing ions to penetrate deeply and evenly into the graphite interlayer. The newly designed dual-exfoliation technique using biased switching polarity minimizes the generation of oxygen-containing radicals, while the incorporation of expanded graphite accelerates exfoliation speed and reduces oxidation, maintaining high graphene purity. With these improvements, we produced 1–3 layer graphene sheets with minimal defects ( ID/IG ≈ 0.13) and high purity (C/O ratio ≈ 20.51), achieving a yield 3.1 times larger than previously reported methods. The graphene sheets also demonstrated excellent electrochemical properties in a three-electrode system, with an electrical conductivity of 92.6 S cm− 1, a specific capacitance of 207.4 F g− 1, and a retention of 94.8% after 5,000 charge/discharge cycles, highlighting their superior stability and performance.

Graphite cores in nuclear reactors are critical components subjected to severe irradiation conditions. Despite the known susceptibility of graphite to radiation-induced damage, detailed microstructural analyses are limited. Existing works of literature have identified changes in crystallite morphology and orientation as early indicators of structural degradation, but the precise micro-mechanisms are not fully understood. This research explicates these micro-mechanisms using advanced analytical transmission electron microscopy (TEM) to examine irradiated graphite at doses up to 1 dpa (displacements per atom). TEM imaging and diffraction analysis captured detailed changes in crystallite structure. Even at low radiation doses (~ 0.1 dpa), a 15% alteration in crystallite morphology and orientation was observed. Significant crystal lattice rotations up to 5 degrees and micro-deformations were also detected. Additionally, the formation of micro-kinks and kink bands, ranging from 50 to 200 nm, were identified as potential deformation processes, consistent with phenomena in other layered materials. These results advance our understanding of the micro-mechanisms driving structural degradation and deformation in irradiated graphite. This research has significant implications for developing improved models and strategies to enhance the performance and longevity of graphite cores in nuclear reactors, contributing to the advancement of nuclear energy technology.

In this study, ester co-solvents and fluoroethylene carbonate (FEC) were used as low-temperature electrolyte additives to improve the formation of the solid electrolyte interface (SEI) on graphite anodes in lithium-ion batteries (LIBs). Four ester co-solvents, namely methyl acetate (MA), ethyl acetate, methyl propionate, and ethyl propionate, were mixed with 1.0 M LiPF6 ethylene carbonate:diethyl carbonate:dimethyl carbonate (1:1:1 by vol%) as the base electrolyte (BE). Different concentrations were used to compare the electrochemical performance of the LiCoO2/ graphite full cells. Among various ester co-solvents, the cell employing BE mixed with 30 vol% MA (BE/MA30) achieved the highest discharge capacity at − 20 °C. In contrast, mixing esters with low-molecular-weight degraded the cell performance owing to the unstable SEI formation on the graphite anodes. Therefore, FEC was added to BE/MA30 (BE/MA30-FEC5) to form a stable SEI layer on the graphite anode surface. The LiCoO2/ graphite cell using BE/MA30-FEC5 exhibited an excellent capacity of 127.3 mAh g− 1 at − 20 °C with a capacity retention of 80.6% after 100 cycles owing to the synergistic effect of MA and formation of a stable and uniform inorganic SEI layer by FEC decomposition reaction. The low-temperature electrolyte designed in this study may provide new guidelines for resolving low-temperature issues related to LIBs, graphite anodes, and SEI layers.

This study involved the heterogenization of a binder pitch (BP) using a small amount of nanocarbon to improve physical properties of the resulting graphite electrode (GE). Heterogenization was carried out by adding 0.5–2.0 wt.% platelet carbon nanofiber (PCNF) or carbon black (CB) to a commercial BP. To evaluate the physical properties of the BPs, we designed a new model graphite electrode (MGE) using needle coke as a filler. The heterogenized binder pitch (HBP) with PCNF or CB clearly increased the coking value by 5–13 wt.% compared to that of the as-received BP. Especially, the model graphite electrodes prepared with HBPs containing 1.0 wt.% PCNF or CB showed significantly improved physical properties compared to the control MGE from the as-received BP. Although the model graphite electrodes prepared with HBPs showed similar properties, they had smaller pore sizes than the control. This indicates that heterogenization of the BP can effectively decrease the pore size in the MGE matrix. Correlating the average pore sizes with the physical properties of the model graphite electrodes showed that, for the same porosity, matrices formed by the HBP with a smaller average pore size can effectively improve the apparent density, tensile strength, and oxidation resistance of the model graphite electrodes.

Efforts have been extensively undertaken to tackle overheating problems in advanced electronic devices characterized by high performance and integration levels. Thermal interface materials (TIMs) play a crucial role in connecting heat sources to heat sinks, facilitating efficient heat dissipation and thermal management. On the other hand, increasing the content of TIMs for high thermal conductivity often poses challenges such as poor dispersion and undesired heat flow pathways. This study aims to enhance the through-plane heat dissipation via the magnetic alignment of a hybrid filler system consisting of exfoliated graphite (EG) and boron nitride (BN). The EG acts as a distributed scaffold in the polymer matrix, while the BN component of the hybrid offers high thermal conductivity. Moreover, the magnetic alignment technique promotes unidirectional heat transfer pathways. The hybrid exhibited an impressive thermal conductivity of 1.44 W m− 1 K− 1 at filler contents of 30 wt. %, offering improved thermal management for advanced electronic devices.

This study comprehensively investigates three types of graphite materials as potential anodes for potassium-ion batteries. Natural graphite, artificial carbon-coated graphite, and mesocarbon microbeads (MCMB) are examined for their structural characteristics and electrochemical performances. Structural analyses, including HRTEM, XRD, Raman spectroscopy, and laser particle size measurements, reveal distinct features in each graphite type. XRD spectra confirm that all graphites are composed of pure carbon, with high crystallinity and varying crystal sizes. Raman spectroscopy indicates differences in disorder levels, with artificial carbon-coated graphite exhibiting the highest disorder, attributed to its outer carbon coating. Ex-situ Raman and HRTEM techniques on the electrodes reveal their distinct electrochemical behaviors. MCMB stands out with superior stability and capacity retention during prolonged cycling, attributed to its unique spherical particle structure facilitating potassium-ion diffusion. The study suggests that MCMB holds promise for potassium-ion full batteries. In addition, artificial carbon-coated graphite, despite challenges in hindering potassium-ion diffusion, may find applications in commercial potassium-ion battery anodes with suitable coatings. The research contributes valuable insights into potassiumion battery anode materials, offering a significant extension to the current understanding of graphite-based electrode performance.

Despite enormous popularity of graphene oxide (GO) several open questions remain regarding the structure and properties of this material. One of those questions is the role of a graphite precursor on the properties of GO product. In this study, we investigate the oxidation process and the structure of GO products, made from the four different graphite precursors: synthetic graphite, two natural flaky graphites, and expanded graphite. The highest rate of the oxidation reaction was registered for the small particle size synthetic graphite. Thermal expansion of natural flaky graphite did not significantly affect the rate of the reaction. The nature of the graphite precursor does not notably affect the chemical composition of the synthesized GO products. However, it affects stability of respective aqueous dispersions. The solutions of the three GO samples, prepared from the natural graphite sources demonstrate excellent stability due to complete exfoliation of GO to single-atomic-layer sheets. GO from synthetic graphite forms unstable dispersions due to the presence of numerous multi-layered particles. This, in turn, is explained by the presence of not fully graphitized, amorphous inclusions in synthetic graphite. Our observations suggest that synthetic graphite should not be used as GO precursor when the ability to completely exfoliate and the stability of dispersions are critical for intended applications.

A combination of a series of epoxy coatings filled with octadecylamine (ODA)-modified graphene oxide (mGO) or commercial exfoliated graphite nanoplatelets (xGnP) was developed to boost the anticorrosion performances of mild steel substrates in acidic and NaCl aqueous solutions. The xGnP and mGO were applied successfully as fillers for the preparation of layer by layer (LBL) xGnP or mGO/epoxy coatings, respectively, which were coated on the clean steel surfaces to form LBLassembled layers. The LBL-assembled xGnP or mGO/epoxy coating-coated steel substrates exhibit excellent anticorrosion performances. The corrosion potentials (Ecorr) of xGnP-1/xGnP-2/3 and mGO-1/mGO-2/3 display at − 193 and − 150 mV, respectively, while Ecorr of the bare steel shows at − 871 mV of immersion in the 3.5 wt% NaCl solution. The most positive Ecorr values are obtained for xGnP-1/2/3 (− 117 mV) and mGO-1/2/3 (− 66 mV), showing the best anticorrosion performances compared to the bare steel (− 404 mV) in 17 wt% HCl solution.

Efficient Li-ion transport in anode materials is paramount for electric vehicles (EVs) and energy storage systems. The rapid charging demands of EVs can lead capacity decay at high charging rate. To overcome this challenge, we focus on graphite geometric characteristics that effect to interparticle space. We interpret the correlation between the utilization of the electrode and the interparticle space where solvated Li-ion transports in liquid electrolyte. To introduce variability into this space, two main coke precursors, coal cokes and petroleum cokes, were prepared and further categorized as normal cokes and needle cokes. Manufactured graphite samples were observed with distinct geometric characteristics. In this study, investigates the impact of these geometric variations on electrochemical performance, emphasizing rate capability and cycle stability during fast charging. By analyzing the transport properties of electrochemical species within these graphite samples, we reveal the critical role of morphology in mitigating concentration polarization and side reaction, such as Li-plating. These findings offer promising contribution for the development of advanced anode materials, in fast-charging condition in Li-ion.

Disposable masks manufactured in response to the COVID-19 pandemic have caused environmental problems due to improper disposal methods such as landfilling or incineration. To mitigate environmental pollution, we suggest a new process for recycling these disposable masks for ultimate application as a conductive material in lithium-ion batteries (LIBs). In our work, the masks were chemically processed via amine functionalization and sulfonation, followed by carbonization in a tube furnace in the Ar atmosphere. The residual weight percentages, as evaluated by thermogravimetric analysis (TGA), of the chemically modified masks were 30.6% (600 °C, C-600), 24.5% (750 °C, C-750), and 24.1% (900 °C, C-900), respectively, thereby demonstrating the possibility of using our proposed method to recycle masks intended for disposal. The electrochemical performance of the fabricated carbonized materials was assessed by fabricating silicon/graphite (20:80) anodes incorporating these materials as additives for use in LIBs. Using a coin-type half-cell system, cells with the aforementioned carbonized materials exhibited initial capacities of 553 mAh/g, 607 mAh/g, and 571 mAh/g, respectively, which are comparable to those of commercial Super P (591 mAh/g). Cell cycled at the rate of 0.33 C with C-600, C-750, and C-900 as additives demonstrated capacity retention of 53.2%, 47.4%, and 51.1%, respectively, compared with that of Super P (48.3%). In addition, when cycled at rates from 0.2 to 5 C, the cells with anodes containing the respective additives exhibited rate capabilities similar to those of Super P. These results might be attributable to the unique surface properties and morphologies of the carbonized materials derived from the new recycling procedure, such as the size and number of heteroatoms on the surface.

This work utilizes the commercial finite element software ABAQUS to investigate the factors influencing the mechanical behavior of tantalum carbide (TaC)-based/graphite fibrous monolithic ceramics (FMCs), such as core/shell volume ratio and fiber orientation. The good compliance between experimental and simulated results demonstrates the suitability of the finite element software ABAQUS for exploring mechanical properties in FMCs. According to the results, it was observed that the bending strength of TaC-based/graphite FMC decreased with the change in fiber orientation from 0° to 90°. The displacement amount in the core/shell volume ratio of 75/25 ( C75S25) sample with a fiber orientation of 90° was maximum (with a value of 0.0524 mm), indicating that crack propagation occurred later. Therefore, the sample exhibited better resistance to failure. Generally, C75S25 specimens started to crack later than the core/shell volume ratio of 65/35 ( C65S35) in both fiber orientations and released more energy during crack initiation. Additionally, when the 0°-fiber-oriented specimen failed, more energy was released than the [90°] sample with the same core/shell volume ratio.