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WB x /C composite materials were fabricated by adjusting the molar ratio of B 4 C and WC. Specifically, a molar ratio of 0.3–0.5 resulted in the formation of WB, while a ratio of 0.8–1.2 led to the production of W 2 B 5. The WB x phase was uniformly dispersed on carbon phase surface, and density of WB x /C composites increased with higher B 4 C molar ratios, rising from 89.5 % to 99.6 %. W15B15 composite exhibited a flexural strength of 223.5 MPa, fracture toughness of 3.86 MPa m1/2, and Vickers hardness of 2.31 GPa. The conductivity of W15B5 composite was lowest at 13.1 mΩ mm. Fracture analysis revealed a combination of transgranular and intergranular fracture modes, with a well-bonded interface. Additionally, localized areas showed the presence of irregularly shaped B 13 C 2 solid solution phase, which enhanced the properties. During graphitization process, an increase in B 4 C molar ratio intensified the promotion effect, leading to a graphitization degree rise from 53.8 % to 60.5 %. The study also explored the mechanisms responsible for oxidation behavior. [ABSTRACT FROM AUTHOR]

Waste gourd shells enriched with ash-forming elements are selected as raw materials in this paper, discovering that the K and Ca compounds in the precursor not only exhibit the ability of self-forming pores, but also demonstrate catalytic graphitization of the hard carbon during the pyrolysis procedure. [ABSTRACT FROM AUTHOR]

Aqueous Zn–I2 batteries have considerable potential owing to their environmental friendliness and high safety. However, the slow iodine conversion kinetics and shuttle effect prevent their practical applicability. In this study, a series of Zn‐MOF‐74 rods with controllable diameters of 40–500 nm are facilely prepared, denoted as P1–P5. A size confinement strategy effect of Zn‐MOF‐74 derived porous carbon as iodine hosts is proposed to suppress the formation of undesirable iodine species, such as I3− and I5−. Moreover, the graphitization degree of porous carbon samples, including P2‐900, P2‐1000, and P2‐1100, play a critical effect on the iodine conversion kinetics. The P2‐1000 sample possesses a high conductive skeleton and abundant mesopores, which improve the adsorption ability toward iodine species. The electrochemical tests and the in situ technology reveal the size confinement strategy effect and the conversion mechanism of iodine. As a result, the I2@P2‐1000 cathode exhibits a superior discharge capacity of 179.9 mA h g−1 at 100 mA g−1 and exceptional long‐term cycle ability after 5000 cycles. Furthermore, the soft batteries and the flexible quasi‐solid‐state batteries are capable of powering devices, promising to exhibit tremendous adaptability and realize flexible electronic devices in various scenarios. [ABSTRACT FROM AUTHOR]

Overcoming the trade‐off between the graphitization of the carbon substrate and enhanced electronic metal–support interaction (EMSI) and intrinsic activity of Pt‐C catalysts remains a major challenge for ensuring the durable operation of energy conversion devices. This article presents a hybrid catalyst consisting of PtFe nanoparticles and single Pt and Fe atoms supported on N‐doped carbon (PtFeNPs@PtFeSAs‐N‐C), which exhibits improved activities in hydrogen evolution and oxygen reduction reactions (HER and ORR, respectively) and has excellent durability owing to the high graphitization, rich edge defects, and porosity of the carbon in PtFeNPs@PtFeSAs‐N‐C, as well as strong EMSI between the PtFe nanoparticles and edge‐defective carbon embedded with Pt and Fe atoms. According to theoretical calculations, the strong EMSI optimizes the H* adsorption–desorption and facilitates the adsorption OOH*, accelerating the HER and ORR processes. A novel flow seawater‐Al/acid hybrid fuel cell using the PtFeNPs@PtFeSAs‐N‐C cathode can serve as a high‐efficiency energy conversion device that delivers a high power density of 109.5 mW cm−2 while producing H2 at a significantly high rate of 271.6 L m−2 h−1. Moreover, PtFeNPs@PtFeSAs‐N‐C exhibits a remarkable performance (high power density of 298.0 mW cm−2 and long‐term durability of 1000 h) in a flow Zn–air battery. [ABSTRACT FROM AUTHOR]

Diamond-like carbon (DLC)/poly-α-olefin (PAO) composite system attracts much attention in reducing the tribo-induced risks for mechanical mobility systems and energy saving. However, the coupled effect of applied load and PAO viscosity on the tribological behavior of the DLC/PAO system, which normally causes the transition between different lubrication states of mated surfaces, and the corresponding synergistic mechanism remain unclear. Here, we fabricated the DLC/PAO composite system, and the evolutions of microstructure, morphologies, and tribological properties induced by both PAO viscosity and applied load were investigated systematically. Results indicated that under low applied load, the system with moderate PAO viscosity exhibited the best tribological performance, while the PAO with high viscosity was suggested with increasing the applied load. Moreover, the variations of PAO viscosity and applied load seriously affected the distribution and load-bearing capacity of oil, interfacial graphitization degree, and formation of lubricating oil film, which brought complicated effects on the tribological properties of composite systems. The present results guide the selection and design of an advanced DLC/PAO lubrication system according to the working conditions. [ABSTRACT FROM AUTHOR]

Graphite made from coal will not only widen the graphite mineral resource, but also significantly improve the value of coal utilization. In this study, anthracite coal was heated in the temperature range of 500 to 2900 °C to study the size increase of nanometric graphite crystallites from anthracite to real graphite. The carbon content rapidly increases to 99.2% when heated from room temperature to 1600 °C, and then gradually increases to 100% when the treated temperature increases to 2900 °C. The FTIR results show that methyl, methylene, and aromatic hydrocarbon, preexisting in the raw anthracite, were preserved in the JZS-500 sample, but that when the treated temperature ≥ 1000 °C, these C-H bonds almost disappear. The basic structural units (nano graphitic carbon) grow into distorted columns, and the basic structural units and micro-columns re-oriented and coalesced to form local molecular oriented domains with the temperature increase from anthracite to JZS-1500. When the temperature ≥ 1600 °C, amorphous carbon, onion-like carbon, turbostratic layers, and graphitic carbon co-occur within the graphitized coals. At the sub-micron scale, carbonization is a homogenous process, whereas graphitization is a heterogenous process. The average graphite crystalline size (La, lateral extension; Lc, stacking height) rapidly increases as the treatment temperature increases from 1600 to 2300 °C. Three coal structural transformation stages were classified according to the nanometric carbon structural evolution with temperature. This study will contribute to the efficient and value-added utilization of coal to make graphite materials. [ABSTRACT FROM AUTHOR]

We discuss the direct fabrication of embedded, graphitized features within high-purity, synthetic single-crystal diamond through ultrafast laser micromachining for the purpose of developing diamond-based capacitive structures. As an incorporating substrate, carbon in the form of highly pure synthetic diamond offers numerous advantageous physicochemical properties, including hardness, durability, optical transparency, and extremely high electrical resistance. On the other hand, graphitic carbon can exhibit exceptionally low electrical resistance. A simple sandwich structure of a thin sheet of diamond between two sheets of graphite could, therefore, form a simple plate-type capacitive structure. For a single structure consisting of 1 μm thick plates with areal dimensions of 5 × 1 mm2 and 1 μm gaps between plates, we estimate a capacitance of 240 pF, with a 3 kV/μm breakdown voltage in diamond. ∼2500 plates thus fabricated in a ∼5 × 5 × 1 mm3 diamond chip could, therefore, store ∼300 mJ of energy. To realize this kind of structure, we employ ultrafast laser micromachining with high numerical aperture focusing and precise positioning control to disrupt the crystalline matrix of a well-confined volume within single-crystal synthetic diamond, forming embedded graphitic features. Graphitized plate regions 1 μm thick with 1 μm separations can be fabricated in this manner, and empirical I–V measurements indicate resistances in the plates as low as ∼kΩ. We also address challenges involved with fabricating closely parallel, embedded graphitic plates in thick diamond substrates, including aberration, machining time, and cracking. [ABSTRACT FROM AUTHOR]

When compared to natural graphite, artificial graphite has advantages such a longer cycle life, faster charging rates, and better performance. However, the process of producing it, which frequently uses coal, raises questions about the impact on the environment and the depletion of resources. Eco-friendly, wood-based graphite must be developed in order to solve these problems. This study assessed and investigated the characteristics of charcoals derived from bamboo and oak which were utilized to produce graphite. After heating to 1500 °C at 10 K/min, 86.87 wt% of oak charcoal and 88.33 wt% of bamboo charcoal remained, indicating a yield of more than 85% when charcoal was graphitized. Depending on the species of wood, different-sized pores showed different shapes as the graphitization process advanced, as revealed by SEM surface analyses. The carbon atoms seen in the XRD crystal development changed into graphite crystals when heated to 2400 °C, and the isotropic peaks vanished. Bamboo charcoal has a higher degree of crystallinity than other wood-based charcoals, such as oak charcoal, which is made up of turbostratic graphite, according to Raman spectroscopic research. Lithium-ion batteries employ bamboo charcoal as their anode material. At this point, the values for soft carbon were determined to be 196 mAh/g and for hard carbon to be 168 mAh/g at a current density of 0.02 A/g. [ABSTRACT FROM AUTHOR]

Carbon material has emerged as a highly promising anode for sodium‐ion batteries (SIBs) due to its abundance of resources, cost‐effectiveness, and high carbon yield. This work elaborately designs the precursor structure for the self‐assembly of melamine‐cyanuric acid on the anthracite surface through hydrogen bonding, and successfully constructs N‐doped carbon with tailored microstructure and expanded interlayer spacing. Serving as anode for SIBs, the optimized sample delivers high specific capacity (371.3 mAh g−1 at 0.05 A g−1), superior rate capability (295.8 mAh g−1 at 10.0 A g−1), and excellent ultra‐long cycling performance (the retention of 91.5% after 3000 cycles at 0.5 A g−1). The systematic investigations reveal the enhancement of sodium‐ion storage in the low‐voltage plateau region involving the interlayer intercalation coupled with nanopores filling. It is discovered that the microporous structure formed by the appropriate graphite sheet angle influences the migration and storage of sodium ions. Density functional theory calculations indicate that the adsorption capacity for sodium ion is enhanced and the migration energy barrier perpendicular to the graphite layer is reduced at the appropriate angle of 8°. This study provides novel insights into the sodium‐ion storage mechanism, offering guidance for the better design of anthracite‐based carbon anode with superior performance. [ABSTRACT FROM AUTHOR]

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Maintaining body temperature within safe and comfortable range is crucial; however, thermoregulatory materials face challenges in variable environments and extreme application scenarios. Here, a unique dual air‐gelation strategy is developed to synthesize carbon aerogel nanofiber metafabric for energy‐harvesting thermoregulation. By manipulating polyacrylonitrile/water interaction and charge density of the solution, phase separation and Coulombic repulsion in electrospun jets are promoted, forming curly nanofibers with internal nanopores (size 30–60 nm) that entangle to create nanofibrous dual‐aerogel structure; the carbon aerogel nanofiber metafabric is obtained following pre‐oxidation and optimized graphitization. The resulting metafabric exhibits high elasticity, robust temperature resistance from −196 to 600 °C, exceptional thermal insulation performance, high‐efficiency electrothermal capability (adjustable from 15 to 150 °C), and photothermal property (radiation raised temperature by 22 °C). This work provides rich possibilities to develop advanced carbon nanomaterials for thermal management. [ABSTRACT FROM AUTHOR]

Optimized sodium ion battery (SIB) carbon anodes with high stability supporting high power densities are a much‐needed material class and therefore intensively researched. The optimum graphitization degree to accommodate sodium ions, while providing high conductivity, as well as the influence of particle size distribution or pore sizes on the performance of carbon anodes, is one of the most discussed topics in this field. While a lot of studies have been published discussing these questions, the convoluted nature of these parameters, originating from material synthesis constraints, usually prevents their independent optimization. Based on Mesoporous N‐doped Carbon Nanospheres (MPNC) as model carbon material systems, the graphitization temperaturefor spherical particles with a monomodal particle size distribution (≈280 nm) and a narrow pore size distribution (≈30 nm) is optimized for faradaic sodium ion storage (plateau capacity) and electrodes with a very high power density of 2680 W kg−1 at 1000 mA g−1 and a remarkable capacity retention over 2000 cycles of 86 %, only losing 0.04 % of its specific capacity per cycle, are demonstrated. [ABSTRACT FROM AUTHOR]

Carbon deposit of the aero-engine combustor, resulting from incomplete combustion and fuel pyrolysis, can cause nozzle blockage, fuel consumption increase, power decrease, and even flight unsafety. In this work, an in situ combustion carbon deposit diagnostic instrument is developed to reveal the crystalline structure and the changes under real combustion conditions. The instrument integrates the in situ microscopic Raman technique and the combustion system. The burner is characterized by a sloping tip, making it possible to observe the coke from the side view. The burner is installed to the optical positioning stage by a specially made adapter so that the relative location is fixed and it is possible to observe the carbon deposit from the ignition. The carbon deposit of acetylene/air diffusion jet flame was studied. A 50× objective lens was used to collect the Raman scattering signal of carbon deposits continuously 30 s after ignition. A five-band model was used to fit the Raman spectra. The time-resolved information was calculated, including the normalized total area, area proportion, peak ratio, and crystalline size. The results show that the carbon deposit of acetylene flames with different velocities presents different tendencies of formation and degree of graphitization, which is attributed to the influence of temperature and flow. The performance of this system is evaluated quantitatively. The signal-to-noise ratio of Raman spectra of carbon deposits ranges from 6.4 to 28.9. This work provides an in situ method to analyze the dynamic change of carbon deposit on the burner, and further work is needed to reveal the mechanism. [ABSTRACT FROM AUTHOR]

1.6 Million metric tons of spent carbon electrodes modify carbon-rich solid wastes from aluminum electrolysis are produced annually, threatening ecosystems by cyanide and fluoride pollution. Here, we review carbon-rich solid wastes with focus on sources and hazards, detoxification, separation, recovery, recycling and disposal. Treatment techniques include roasting, calcination, vacuum distillation, flotation, water leaching, acid leaching, alkali leaching, complexation leaching, and alkali fusion. Waste can be disposed of alone or in combination with other waste such as cooper slag, sludge, red mud, and coal gangue. Recovery of fluorides and applications of recycled carbon are presented. Fluoride and carbon materials are separated based on differences in hydrophobicity, volatility, flammability, acidity, and alkalinity. The fluorides prepared from the solution are mainly aluminum hydroxyfluoride hydrate and cryolite. [ABSTRACT FROM AUTHOR]

The burning and melting of elastic fastening bands in high-temperature environments are major contributors to empyrosis and ambustion owing to their snug fit to human body parts in practical usage. Conventionally fabricated fastening bands show poor degradation, negative environmental impact, and poor flame-retardant performance. Herein, we report an ecofriendly cyclic phosphate ester-based flame-retardant polylactic acid (PLA) elastic band prepared using an impregnation-baking process, and experimental investigation was conducted on the optimized finishing process. The band was characterized using scanning electron microscopy, energy-dispersive spectroscopy, and thermogravimetry. The band exhibited a damage length of 3.9 cm after vertical combustion and self-extinguishing effect after being removed from the fire source without generating molten droplets. The cross-linking phenomenon between the modified PLA fibers was beneficial in improving the flame retardancy of the PLA elastic band in the condensed phase. The strength loss of the band was <5%. Thus, the prepared band can be widely used in real-world applications. [ABSTRACT FROM AUTHOR]

To gain insights into the spectroscopy characteristics from coal to graphite, we investigated different metamorphic degrees of coal-based graphite which were collected from Hunan Province China. In this paper, by means of Xray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy, graphite with different metamorphism degrees has been characterized to explore the evolution of macromolecular structure of organic matter during graphitization. The results show that with the increase of metamorphism degree, the 002-diffraction peak of the series of samples gradually shrinks and narrows, and the peak intensity becomes stronger, indicating that the microcrystalline structure gradually becomes regular and ordered. As the degree of graphitization increase, the uniformity of particle size in coal samples observed gradually increases, and the morphology becomes more regular, transitioning from disordered and irregular shapes to a structured large-scale flake pattern. The crystallinity improves, and the massive coal particles gradually coalesce into large plate crystals, with the inter-particle pores gradually closing. The graphite structure becomes increasingly evident. The FTIR spectra show that as the degree of graphitization increases, the peak at 1,581 cm-1 corresponding to C=C vibrations gradually intensifies. Some inert functional groups are retained throughout the graphitization process. The pores between coal particles gradually close, and the morphology of graphite particles becomes more regular and ordered. Additionally, during the graphitization process, structures similar to carbon nanotubes may develop. Throughout the structural transformation from coal macromolecules to graphite crystals, the size of the sp2 planar domains in single-layer graphene increases, and the lattice structure of carbon atoms gradually enlarges. These findings contribute to a comprehensive understanding of the properties and characteristics of coal-derived graphite, and can provide theoretical reference and basis for the metallogenic mechanism of coal-derived graphite and the efficient utilization of coal. [ABSTRACT FROM AUTHOR]

Abstract The application of biomass energy is one of the important ways to achieve carbon neutrality and deal with global warming. The study on the combustion mechanism of anisole, an oxygen-containing fuel, is helpful for biofuel large-scale application. In this study, the soot formation and laminar combustion characteristics of anisole were analyzed by reactive force field molecular dynamics (ReaxFF MD) and kinetic simulation, respectively. ReaxFF MD simulation studies had shown that soot formation of anisole combustion occurred in three stages, stage 1 (0–1 ns), stage 2 (1–2.5 ns), stage 3 (2.5–6 ns). The three stages represented the pyrolysis of the fuel, the developmental stage of the soot, and the graphitization stage of the soot, respectively. During the combustion of anisole, primary mechanisms for the soot formation were as follows: H-abstraction-C2H2-addition, carbon-addition-hydrogen-addition, internal ring formation and long carbon chain link. The formation of soot graphitization exhibited different morphologically behaviors: from flakes to onions to spheres with fewer branched chains. From the study of the laminar combustion characteristics of anisole, it can be found that the laminar burning velocities increased along with the increase of temperature, while the opposite trend was shown along with the increase of pressure. The sensitivity coefficient of naphthalene, the main soot precursor, revealed that the main promotional reactions for soot formation were R5 (O2 + H O + OH), R36 (CO + OH CO2 + H).

Nanoporous carbon materials have attracted significant attention in the fields of sensing and catalysis owing to their unique reticular structure, designable composition and pore size. In this study, a multifunctional nanoporous carbon platform with the integration of thermal transformation, thermal activation and sonochemical exfoliation is proposed, which can be applied in electrochemical analysis, enzyme-like catalysis and fluorescence analysis. Using zeolitic imidazolate frameworks (ZIFs) as self-templates, N-doped nanoporous carbon was prepared via pyrolysis. Next, the as-prepared intermediate carbon material was transformed into four- to eight-layer carbon nanosheets via sonochemical exfoliation. The carbon nanosheets exhibited high electrical conductivity, electrochemical activity and dual enzyme-like catalytic properties owing to their high graphitization, large surface area, doped N and pore size. The resulting nanosheets can be used as precursors for the synthesis of quantum dots with green photoluminescence for fluorescence analysis. The multifunctional nanoporous carbon platform shows great potential for sensing. Furthermore, the fabrication procedure provides a new opportunity for devising carbon materials with special functions. [ABSTRACT FROM AUTHOR]

Facilitating the transition and new application of fossil energy sources are crucial to attaining carbon neutrality. Conversion of coals into graphitic carbons represents an effective route to achieve their high‐value utilization, while this process always involves corrosive/toxic chemical reagents and time‐intensive heating treatment. Here, this work reports a green, rapid, and efficient flash Joule heating (FJH) technique to produce high‐quality carbons from diverse coals within 1 s. The surface groups, defects, and graphitization degree of the resultant carbon materials are controlled during the instantaneous thermal shock process, and the relationships between the coal structures and the product properties are established. The results suggest that the anthracite with high coalification degree tends to form highly graphitic carbons at a peak temperature of ≈3300 K, presenting higher rate capability (79.1% capacity retention at 30 A g–1) and low relaxation time constant (τ0 = 0.27 s) toward capacitive energy storage. Besides, the flash carbon materials derived from lignite and bituminous coal with low coal rank show better capacitive performance with capacity above 80 F g–1 at 1 A g–1. This study evidences that the FJH technology holds great potential to steer coals into valuable carbon materials. [ABSTRACT FROM AUTHOR]

The closed pores play a critical role in improving the sodium storage capacity of hard carbon (HC) anode, however, their formation mechanism as well as the efficient modulation strategy at molecular level in the polymer‐derived HCs is still lacking. In this work, the steric hindrance effect has been proposed to create closed pores in the polymer‐derived HCs for the first time through grafting the aromatic rings within and between the main chains in the precursor. The experimental data and theoretical calculation demonstrate that steric‐hindrance effect from the aromatic ring side group can increase backbone rigidity and the internal free volumes in the polymer precursor, which can prevent the over graphitization and facilitate the formation of closed pores during the carbonization process. As a result, the as‐prepared HC anode exhibits a remarkably enhanced discharge capacity of 340.3 mAh/g at 0.1 C, improved rate performance (210.7 mAh/g at 5 C) as well as boosted cycling stability (86.4 % over 1000 cycles at 2 C). This work provides a new insight into the formation mechanisms of closed pores via steric hindrance engineering, which can shed light on the development of high‐performance polymer‐derived HC anode for sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

Wear failure of cutting inserts is the main form of failure that occurs when cutting difficult-to-machine materials at high speeds. To obtain cutting inserts with outstanding tribological properties, multilayered cubic boron nitride (cBN) and nanocrystalline diamond (NCD) coatings (cBN/NCD) were prepared on WC-6 wt% Co tool substrates. The tribological properties of the multilayered cBN/NCD coatings were studied at different temperatures, and the results showed that the coefficient of friction (COF) and wear rate of the coatings were closely interrelated to the temperatures, and the COF gradually decrease and the wear rate gradually increase as the temperature increased from room temperature (25 °C) to 600 °C. The COF and wear rate of the multilayer coatings at 600 °C were ∼0.05 and 8.43 × 10−6 mm3/(N⋅m), respectively. The wear resistance of the cBN/NCD coatings was higher than that of TiAlN coatings and PcBN tool materials by more than 3 and 4.5 times, respectively. The high-temperature wear failure modes of the multilayered cBN/NCD coatings were abrasive wear, diamond graphitization, and BN hydrolysis. Coating wear accelerated when pores were formed on the cBN surface of a multilayered cBN/NCD coating due to the low nucleation density of diamond. These results would guide the application of cBN/NCD-coated cutting tools in high-speed cutting processes. [ABSTRACT FROM AUTHOR]

Hard carbon, characterized by high ion storage capacity, low operating voltage, and excellent cycling stability, is considered an ideal negative electrode material for sodium‐ion batteries. However, the high cost and low carbon yield of thermosetting precursors limit their practical application in SIBs, while low‐cost and high‐yield raw materials exhibit highly ordered carbon structures and narrow interlayer spacing under high‐temperature carbonization. Discarded polyimide materials are inexpensive, which offer a high carbon yield and possess good thermal stability and thermoplasticity, with functional groups of imide rings (−CO−N−CO−) on their main chains. This study recycled and converted polyimide materials into hard carbon materials from discarded engineering plastics, investigating the influence of carbonization temperature on the degree of graphitization, interlayer spacing, and pore structure of the materials to achieve high reversible sodium storage capacity. After carbonization at 1300 °C, the polyimide material exhibited 319 mAh g−1 reversible capacity and excellent electrochemical performance (with a capacity retention of 91.92 % after 100 cycles at a 0.5 C current rate) and rate performance (up to 242.5 mAh g−1 at 2 C). This study provided a simple, high‐yield, and effective method for the reuse of discarded organic polymers, promoting the sustainable utilization of resources. [ABSTRACT FROM AUTHOR]

Polymer-derived silicon oxycarbide (SiOC) ceramics have garnered significant attention as novel silicon-based anode materials. However, the low conductivity of SiOC ceramics is a limiting factor, reducing both their rate capability and cycling stability. Therefore, controlling the free carbon content and its degree of graphitization within SiOC is crucial for determining battery performance. In this study, we regulated the free carbon content using divinylbenzene (DVB) and controlled the graphitization of free carbon with the transition metal iron (Fe). Through a simple pyrolysis process, we synthesized SiOC ceramic materials (CF) and investigated the impact of Fe-induced changes in the carbon phase and the amorphous SiOC phase on the comprehensive electrochemical performance. The results demonstrated that increasing the DVB content in the SiOC precursor enhanced the free carbon content, while the addition of Fe promoted the graphitization of free carbon and induced the formation of carbon nanotubes (CNTs). The electrochemical performance results showed that the CF electrode material exhibited a high reversible capacity of approximately 1154.05 mAh g−1 at a low current density of 100 mA g−1 and maintained good rate capability and cycling stability after 1000 cycles at a high current density of 2000 mA g−1. [ABSTRACT FROM AUTHOR]

Aluminum electrolysis spent cathode carbon (SCC), as typical solid hazardous waste, poses significant environmental risks. Harmless treatment of SCC and recycling of its carbon component are important research areas. In this study, SCC was subjected to microwave hydrothermal acid leaching to remove harmful components, followed by the production of high-quality graphite via iron-catalyzed graphitization. The effects of reaction temperature, heating time, and catalyst loading on the graphitization conversion of SCC were investigated. The catalytic graphitization process of SCC was optimized using the response surface method. The results show that when the reaction temperature is 1520 °C, the heating time is 85.24 min, and the catalyst loading is 46.15 wt%, the graphitization degree of the sample is 97.61 %. The samples prepared under the optimal conditions were characterized using XRD, Raman, SEM, and TEM. The results reveal that the catalytic graphitization process significantly influences the conversion of microcrystalline structures in SCC into graphite structures. The iron-catalyzed transformation of microcrystalline carbon was analyzed to elucidate the graphitization transformation mechanism. This study offers an effective pathway for the high-value utilization of SCC. It also serves as a technical reference for the catalytic graphitization conversion of carbon materials. [ABSTRACT FROM AUTHOR]

Potassium‐ion hybrid capacitors (PIHCs) are regarded as one of the promising candidates for large‐scale energy storage technologies. Nevertheless, the lack of suitable anode materials combined with fast ion diffusion kinetics and favorable cycle stability restricts their application. Herein, a catalyst‐confined graphitization strategy is proposed to synthesize low‐cost coal‐based carbon anodes, which have controllable heteroatom co‐doping and rich defect sites, together with local graphitic domains. Density functional theory calculations and kinetic analysis are performed to uncover the coupling effect for heteroatom dual‐doping and defective structures. Importantly, the introduction of graphitic domains ensures good electric conductivity and charge transfer kinetics while preserving rich defects and active sites. The optimized NC‐950 exhibits superior potassium storage capacity, which delivers a high reversible specific capacity (363.3 mAh g−1), impressive rate capability (93.9 mAh g−1 at 2 A g−1), and stable cycling performance. As a practical device application, the PIHCs (NC‐950//AC) are assembled using the NC‐950 anode and commercial activated carbon (AC) cathode, which exhibits the maximum energy density of 97.0 Wh kg−1 and excellent cycling stability (10 000 cycles). Significantly, this work unveils a new pathway to developing low‐cost and fast reaction kinetics carbon anode for advanced electrochemical supercapacitors. [ABSTRACT FROM AUTHOR]

The incorporation of an iron source into NH2-MOF-5, followed by thermal decomposition, yields a porous metal–carbon catalyst (MOF5A-Fe@NC). This catalyst possesses significant N content, a high degree of graphitization, and abundant Fe–Nx sites, which contribute to enhanced oxygen reduction. Specifically, the obtained MOF5A-Fe@NC demonstrates a positive onset potential (0.972 V), a substantial limiting current density (4.815 mA cm−2), and a small Tafel slope (58.7 mV dec−1), and maintains a high current retention of 96.3% after 10 hours. [ABSTRACT FROM AUTHOR]

In this work, the effect of substrate bias on the properties of amorphous carbon (a-C) films, which are fabricated by electron cyclotron resonance (ECR) ion irradiation on cemented carbide substrate is reported. The microstructure of a-C films is investigated with the aid of atom force microscope (AFM), Raman spectrometer and X-ray photoelectron spectroscopy (XPS). The mechanical and tribological properties of a-C films are analyzed through the scratch and nanoindentation experiments, and the liner reciprocating ball-on-plate tests, respectively. The results indicate that, the average roughness of a-C films is proportional to the negative substrate bias, and the increase of negative substrate bias contributes to the formation of sp 3 bond while the negative substrate biases exceed −30 V. The adhesion strength is excellent under low negative substrate biases, but the strongest adhesion strength is obtained when the substrate bias at −50 V. The average hardness decreases slightly at first and then increases to 16.2 GPa with the increment of negative substrate bias. Additionally, the influence of friction cycle to graphitization level is not obvious. Both transfer film (TF) and roughness of a-C film play significant roles in coefficient of friction (COF). This work sheds light on the fabrication of a-C films on cemented carbide by ECR ion irradiation. [ABSTRACT FROM AUTHOR]

A series of synthetic graphite was fabricated through metal oxide catalytic graphitization using purified anthracite (TYC). The effects of graphitization temperature, catalyst type and its addition methods on structure and properties of graphite products were investigated through the methods of XRD, Raman spectra, SEM, TEM, FTIR and resistivity tester. Increasing graphitization temperature favors the enhancement of order and size of graphite microcrystals, graphitization degree, and conductivity of graphitized products. TiO2 exhibited the best catalytic effects in catalytic graphitization. Compared to directly graphitized TYC at 2800°C (TYC-28), the graphite catalyzed by TiO2 added physically (TYC-28-TiO2) and added chemically (TYC-28-C-TiO2) demonstrated a 13.0 and 16.7% increase in graphitization degree, respectively. Meanwhile, chemical addition method (0.61 × 10−4 Ω·m) outperformed physical addition method (1.21 × 10−4 Ω·m) in improving the electrical conductivity of graphitized products. Moreover, at 2400°C, TYC catalyzed by TiO2 added physically and added chemically presented a graphitization degree of 73.7 and 77.6%, respectively, both exceeding that of TYC-28 (70.7%). Therefore, metallic oxides can enhance the graphitization degree while lowering the required graphitization temperature. This method holds promise for cost-effective and energy-efficient production of high-conductivity graphitized anthracite for batteries, supercapacitors, conductive coatings, and conductive adhesives. [ABSTRACT FROM AUTHOR]

The ever-growing energy demand and environmental issues have stimulated the development of sustainable energy technologies. Herein, an efficient and environmentally friendly electrochemical transformation technology was proposed to prepare highly graphitized carbon materials from an abundant natural resource - lignin (LG). The preparation process mainly includes pyrolytic carbonization of raw LG material and electrochemical conversion of amorphous carbon precursor. Interestingly, with the assistance of Co catalyst, the graphitization degree of the products was significantly improved, in which the mechanism was the removal of heteroatoms in LG and the rearrangement of carbon atoms into graphite lattice. Furthermore, tunable microstructures (nanoflakes) under catalytic effects could also be observed by controlling the electrolytic parameters. Compared with the products CN1 (without catalyst) and CN5 (with 10% catalyst), the specific surface area are 158.957 and 202.246 m2 g1, respectively. When used as the electrode material for lithium-ion batteries, CN5 delivered a competitive specific capacity of -350 mAh g1 (0.5 C) compared with commercial graphite. The strategy proposed in this work provides an effective way to extract value-added graphite materials from lignin and can be extended to the graphitization conversion of any other amorphous carbon precursor materials. [ABSTRACT FROM AUTHOR]

[Display omitted] Regarding carbon-based electrodes, simultaneously establishing a well-defined meso -porous architecture, introducing abundant hetero-atoms and improving the graphitization degree can effectively enhance their capacitive performance. However, it remains a significant challenge to achieve a good balance between defects and graphitization degree. In this study, the porous structure and composition of carbon materials are co-optimised through a 'dual-function' strategy. Briefly, K 3 Fe(C 2 O 4) 3 and H 3 BO 3 were hybridised with a gelatin aqueous solution to form a homogeneous composite hydrogel, followed by lyophilisation and carbonisation. Owing to the dual functionality of raw materials, the graphitization, activation and hetero-atom doping processes can occur simultaneously during a one-step high-temperature treatment. The resultant carbon material exhibits a high graphitization degree (I D /I G = 0.9 ± 0.1), high hetero-atom content (N: 9.0 ± 0.3 at.%, B: 6.9 ± 0.5 at.%) and a large specific area (1754 ± 58 m2/g). The as-prepared electrode demonstrates a superior capacitance of 383 ± 1F g−1 at 1 A/g. Interestingly, the cyclic voltammetry (CV) curves exhibit a distinctive pair of broad redox peaks, which is uncommon in KOH electrolyte. Experiment data and density functional theory (DFT) simulation verify that N-5, B co-doping enhances the activity of the faradic reaction of carbon electrodes in KOH electrolyte. Furthermore, the fabricated Zn-ion hybrid supercapacitor (ZHSC) based on this carbon electrode delivers a high-energy density of 140.7 W h kg−1 at a power density of 840 W kg−1. [ABSTRACT FROM AUTHOR]

Fine control over the graphitization level of carbonized nanostructures can play a strategic role in tuning the crystallization of supported nanocatalysts, thereby modulating the kinetics of catalysis. However, realizing the synergistic interplay of graphitization‐tunable support and supported catalysts poses a significant challenge. This study proposes a current pulse‐induced ultrafast strategy for developing MOF‐derived graphitic nano‐leaves (GNL) and supported ultrafine ruthenium nanoclusters exhibiting selective crystallization states depending on the tunable graphitization level of GNL. The resulting ultrafine (≈0.7 nm) amorphous‐ruthenium nanoclusters linked with GNL (a‐Ru@GNL500) exhibit state‐of‐the‐art performance in the hydrogen evolution reaction (HER), requiring very low overpotentials of only 23.0 and 285.0 mV to achieve current densities of 10 and 500 mA cm−2, respectively. Furthermore, a‐Ru@GNL500 demonstrates exceptional operational stability for 100 h under high HER currents of 200 and 400 mA cm−2. Density functional theory reveals that the unique electronic structure of a‐Ru and the cooperative effect of cobalt embedded in the graphitic layer lower the occupancy of the antibonding orbital, resulting in an accelerated HER process. Additionally, the unique electronic structure, highly conducting GNL, and efficient bubble release dynamics of super‐aerophobic a‐Ru@GNL500 contribute to reduced overpotentials, particularly at high HER current densities. [ABSTRACT FROM AUTHOR]

Graphite demand is increasing rapidly due to the popularity of electric vehicles (EVs) and mobile devices. Lithium-ion batteries (LIBs) are the power source of EVs and mobile devices and the anodes of LIBs are mostly made of graphite, which is currently produced in an unsustainable and costly manner. For the first time, battery-grade biographite is produced from a renewable and sustainable precursor, biomass-derived pyrolysis oil, using iron as the graphitizing catalyst. Considering battery-grade graphite production at scale, pyrolysis oil offers several advantages as feedstock over biomass in terms of higher carbon density, low inorganics, easy handling, and low transportation cost. Catalytic graphitization of pyrolysis oil can be induced at low temperature (∼1100 °C). Herein, catalytic graphitization using iron powder was carried out under relatively moderate conditions (1500 °C) to reduce costs and environmental impact as compared to incumbent technologies. After graphitization, the residual catalyst was removed by refluxing the biographite + iron solid mixture with hydrochloric acid. The efficiency of iron removal was studied using the X-ray fluorescence (XRF) technique. The structural and morphological properties of biographites were assessed via X-ray diffraction (XRD), Raman spectroscopy, and high-resolution transmission electron microscopy (HR-TEM). The in situ XRD experiments provided a mechanistic understanding of the iron-catalyzed graphitization process. In addition, the effect of pyrolysis oil aging on the biographite crystalline structure was elucidated. The optimal biographite sample demonstrated impressive electrochemical performance with a reversible capacity of 350 mA h g−1, an initial coulombic efficiency of 90.2%, and minimal capacity loss over 100 cycles when applied as an LIB anode, thereby making pyrolysis oil-derived biographite potentially competitive with commercially available battery-grade graphite. [ABSTRACT FROM AUTHOR]

Graphitic carbon plays a pivotal role in numerous technological applications, including energy storage, energy conversion, and different fields of material science. The transformation of amorphous carbon into graphitic carbon, a process known as graphitization, is important for optimizing the properties of carbon materials. In this study, we explore the catalytic graphitization of polyacrylonitrile (PANs) using various metal salts (LiNO3, Ca(NO3)2·4H2O, and Ni(NO3)2·6H2O). We prepared dimethyl sulfoxide (DMSO) solutions of PAN with different salt concentrations of 5, 10, and 15 wt.%. The different prepared metal salt-mixed PAN/DMSO solutions were dried at 45 °C and this was followed by carbonization processes at 950 °C, with a heating rate of 1 °C min−1 for 1 h under an N2 atmosphere. The resulting graphitic carbon was characterized to determine the influence of salt type and concentration on the degree of graphitization. Our findings provide valuable insights into PAN-derived graphitic carbon's structural and compositional properties. This work underscores the influence of salt concentration in optimizing the graphitization process, offering a pathway to design facile and cost-effective graphitic carbon materials. [ABSTRACT FROM AUTHOR]

Phenolic resin pyrolytic carbons were obtained by catalytic pyrolysis of phenolic resin at 500 °C, 600 °C, 700 °C, and 800 °C for 3 h in an argon atmosphere using copper nitrate as a catalyst precursor. The effects of copper salts on the pyrolysis process of phenolic resin as well as the structural evolution and oxidation resistance of phenolic resin pyrolytic carbons were studied. The results showed that copper oxide (CuO) generated from the thermal decomposition of copper nitrate was reduced to copper (Cu) by the gas generated from the thermal decomposition of the phenolic resin. Carbon nanofibers with tapered structures were synthesized by Cu catalysis of pyrolysis gas at 500–800 °C. The catalytic pyrolysis of phenolic resin with Cu increased the graphitization degree and reduced the pore volume of the phenolic resin pyrolytic carbons. The combined action improved the oxidation resistance of phenolic resin pyrolytic carbons. [ABSTRACT FROM AUTHOR]

The graphitization process of nano-crystalline diamond (NCD) under high pressure significantly influences the performance of sintered polycrystalline diamond bulks. Here, we investigated the graphitization temperature of both pure nano-diamond, with an average grain size of 50 nm, and a mixture of NaCl and nano-diamond powder in a pressure and temperature range of 5-9 GPa and 600-1 500 °C, respectively. With a quantitative analysis method employing powder X-ray diffraction, we analyzed the graphitization degree of NCD under different pressures and temperatures, examining both non-hydrostatic pressure conditions (pure NCD powder) and quasi-hydrostatic pressure conditions (NaCl-NCD mixed powder). Our findings indicate that the initial graphitization temperature of pure NCD powder exceeds 800 °C at 5 GPa, and ranges between 1 000 and 1 300 °C at 9 GPa. Notably, under quasi-hydrostatic pressure conditions at about 7 GPa, the graphitization temperature of NCD increases from 1 000 °C in non-hydrostatic pressure conditions to 1 500 °C or higher within a short holding time. [ABSTRACT FROM AUTHOR]

Femtosecond laser direct writing provides an efficient approach to fabricating single nitrogen vacancy (NV) color centers with a relatively high yield. Different from previously reported NV color centers with a random distribution in a bulk diamond or nanocrystals, this gives an opportunity to study the photophysical properties of single NV color centers with precise numbers and positions. However, ultrafast studies on single NV color centers prepared by localization femtosecond laser direct writing are still rare, especially for the graphitization inside a diamond and its relationship with single NV color centers. Here, we report the broadband transient absorption (TA) spectroscopic features of the graphitization and NV color centers in a diamond fabricated by localization femtosecond laser direct writing at room temperature under 400 nm excitation. In comparison with the graphene oxide film, the bleaching features of the graphitization point array in a diamond are similar to reduced graphene oxide, accompanied by excited state absorption signals from local carbon atom vacancy defects in graphene-like structures induced by laser writing. On the other hand, transient features of laser processing array containing single NV color centers with a yield of ∼50% are different from those of the graphitization point array. Our findings suggest that for ultrashort pulse processing of diamonds, broadband TA spectral signals are sensitive to the surrounding atomic environment of processing sites, which could be applied to laser writing point defects in other materials used as solid-state single photon sources. [ABSTRACT FROM AUTHOR]

At present, most synthetic graphite materials commonly used as anode active ingredients in lithium‐ion cells are produced by graphitization of petroleum cokes. The carbon footprint associated with synthetic graphite production is significant. Thus, bio‐derived and cheap precursors, such as saccharides, would be an attractive alternative for the sustainable production of graphitic carbons. However, they are non‐graphitizing at temperatures as high as 3000 °C, preserving the curved, fullerene‐like structure of graphene layers and microporosity. Consequently, many lithium ions are consumed during the formation of solid electrolyte interphase films and passivated in the nanovoids. Here, a method for the production of pure, crystalline, graphitic materials based on sucrose disposed of microporosity is presented, which also works with a variety of saccharides and other organic precursors of hard carbons—generally considered incapable of such transformation. This process employs catalytic graphitization by Si particles at high temperatures. The electrochemical response of such derived sucrose‐based graphite in Li‐ion half‐cells demonstrated its feasibility to serve as an anode active material for rechargeable Li‐ion batteries. [ABSTRACT FROM AUTHOR]

The emerging market of high-power lithium-ion batteries (LIBs) highlights the importance of developing high-voltage cathodes. Lithium nickel phosphate (LiNiPO 4) with the highest theoretical discharge potential (∼5.1V) has attracted increasing attention due to its stable olivine structure. In this study, ultrathin carbon layer-coated LiNiPO 4 was synthesized using oleylamine-assisted solvothermal method under different solvothermal times, and the effect of solvothermal time (1h–18h) on LiNiPO 4 samples is fully investigated. X-ray diffraction (XRD) shows that high-purity LiNiPO 4 materials can be prepared after calcination of the solvothermal product under N 2 , but adding part of H 2 to the calcination atmosphere will lead to the generation of impurities in the target product. As the solvothermal time increases, the product will agglomerate and grow, the particle size will increase, and the morphology will change from nanoparticle to rodlike structure. After the high-temperature calcination step, the oleylamine is completely carbonized, and a conductive carbon layer is successfully coated on the LiNiPO 4 with the thickness of 2 nm. As the solvothermal time increases, the graphitization degree of oleylamine increases after carbonization. The existence of the carbon layer and the increase in the degree of graphitization are beneficial to improving the electrical conductivity and Li-ion diffusion rate of LiNiPO 4. The initial discharge capacity of LNP@C-12h product prepared with 12 h solvothermal time is 35 mA h g−1 at 0.1 C. Rietveld analysis shows that the anti-site defect concentration of the LNP@C material is 1.07 %, and the proportion increases to 2.83 % after several cycles. This work provides a positive contribution to the synthesis and modification of high-voltage LiNiPO 4 materials and explains the electrochemical performance degradation of LiNiPO 4 from the perspective of increasing the concentration of anti-site defects. • The core-shell carbon-coated LiNiPO 4 is synthesized. • The pure phase LiNiPO 4 is prepared by adjusting the calcination atmosphere. • Uniformly distributed nanostructured LiNiPO 4 is prepared. [ABSTRACT FROM AUTHOR]

This paper presents a study of the characteristic effects of the physicochemical properties of microcrystalline cellulose and a series of biocarbon samples produced from this raw material through thermal conversion at temperatures ranging from 200 °C to 850 °C. Structural studies revealed that the biocarbon samples produced from cellulose had a relatively low degree of graphitization of the carbon and an isometric shape of the carbon particles. Based on thermal investigations using the differential thermal analysis/differential scanning calorimeter method, obtaining fully formed biocarbon samples from cellulose feedstock was possible at about 400 °C. The highest direct carbon solid oxide fuel cell (DC-SOFC) performance was found for biochar samples obtained via thermal treatment at 400–600 °C. The pyrolytic gases from cellulose decomposition had a considerable impact on the achieved current density and power density of the DC-SOFCs supplied by pure cellulose samples or biochars derived from cellulose feedstock at a lower temperature range of 200–400 °C. For the DC-SOFCs supplied by biochars synthesised at higher temperatures of 600–850 °C, the "shuttle delivery mechanism" had a substantial effect. The impact of the carbon oxide concentration in the anode or carbon bed was important for the performance of the DC-SOFCs. Carbon oxide oxidised at the anode to form carbon dioxide, which interacted with the carbon bed to form more carbon oxide. The application of biochar obtained from cellulose alone without an additional catalyst led to moderate electrochemical power output from the DC-SOFCs. The results show that catalysts for the reverse Boudouard reactions occurring in a biocarbon bed are critical to ensuring high performance and stable operation under electrical load, which is crucial for DC-SOFC development. [ABSTRACT FROM AUTHOR]

A sodium linoleate (SL)-assisted approach is developed to design the phenol–formaldehyde (PF) hard carbon (HC) microspheres with reduced diameter, increased interlayer spacing and heightened graphitization, because SL, acting both as a surfactant and a catalyst, plays a pivotal role in modulating the size and molecular structure of precursor PF microspheres. [Display omitted] The phenol–formaldehyde (PF) resin is an economical precursor for spherical hard carbon (HC) anodes for sodium-ion batteries (SIBs). However, achieving precise molecular-level control of PF-based HC microspheres, particularly for optimizing ion transport microstructure, is challenging. Here, a sodium linoleate (SL)-assisted strategy is proposed to enable molecular-level engineering of PF-based HC microspheres. PF microspheres are synthesized through the polymerization of 3-aminophenol and formaldehyde, initially forming oxazine rings and then undergoing ring-opening polymerization to create a macromolecular network. SL functions as both a surfactant to control microsphere size and a catalyst to enhance ring-opening polymerization and increase polymerization of PF resin. These modifications lead to reduced microsphere diameter, increased interlayer spacing, enhanced graphitization, and significantly improved electron and ion transfer. The synthesized HC microspheres exhibit a remarkable reversible capacity of 337 mAh/g, maintaining 96.9 mAh/g even at a high current density of 5.0 A/g. Furthermore, the full cell demonstrates a high capacity of 150 mAh/g, an energy density of 125.3 Wh kg−1, an impressive initial coulombic efficiency (ICE) of 930.3% at 1 A/g, and remarkable long-term stability over 3000 cycles. This study highlights the potential of surfactant-assisted molecular-level engineering in customizing HC microspheres for advanced SIBs. [ABSTRACT FROM AUTHOR]

A ZIF-derived carbon framework offered abundant platforms for the rational design and construction of high-performance nonprecious-metal catalysts. In this study, a Co-coordinated ZIF-derived carbon framework was synthesized by substituting Co for Zn in ZIF-8, followed by pyrolysis. The resultant Co–Zn@C–N, wrapped by carbon nanotubes (CNTs), exhibited superior catalytic performance in the selective oxidation of benzyl alcohol (BnOH), achieving an optimal BnOH conversion of 92% and a benzaldehyde (BzH) selectivity of 92% at room temperature. Characterization results confirmed that the reaction proceeded through a free-radical mechanism, and the CNTs, formed through catalytic graphitization induced by Co nanoparticles, provided solid–liquid reaction interfaces and enhanced the electron transfer between radicals and skeletons. The Co and Zn species, acting as the primary active sites, exhibited a synergistic effect that enabled the good performance of the Co–Zn@N–C catalyst. Moreover, the elevated graphitic degree, substantial content of Co0 and graphitic N collectively contributed to the enhanced catalytic performance. Additionally, the catalyst had excellent reusability and stability, manifesting negligible variations in activity across four consecutive experimental cycles. This Co–Zn@N–C catalyst system provides a promising foundation towards the design of highly active non-noble catalysts for organics oxidation reactions under mild conditions. [ABSTRACT FROM AUTHOR]

In this work, we aim to investigate and compare the combustion reactivities of real biofuel soot and fossil-fuel soot in the active and passive regeneration conditions of DPF and GPF through temperature-programmed oxidation (TPO). Higher reactivity of biofuel soot is achieved even under GPF conditions with extremely low oxygen concentration (~ 1%), which provides a great potential for low-temperature regeneration of GPF. Such a result is mainly attributed to the low graphitization and less surface C = C groups of biofuel soot. Unfortunately, the presence of high-content ashes (~ 47%) and P impurity in real biofuel soot hinder its combustion reactivity. TPO evidences that the O2/NOX-lacking conditions in GPF are key factors to impact the combustion of soot, especially fossil-fuel soot. This work provides some useful information for understanding real biofuel and fossil-fuel soot combustion in GPF and DPF regeneration and further improvement in filter regeneration process. [ABSTRACT FROM AUTHOR]

The utilization of high‐sulfur coal, especially high‐organic coal, has always been a difficult hot spot in the energy field. To study the influence of sulfur in coal on coal‐based graphite products, a series of coal samples with different sulfur content and different degrees of coalification were collected for proximate analysis, ultimate analysis, and sulfur species analysis. The structural characteristics of coal‐based graphite products were analyzed by X‐ray diffraction (XRD). The relationships between the sulfur in coal and the yield (Y), graphitization degree (G), cell diameter (La), and stacking height (Lc) of coal‐based graphite products were explored. The yield of coal‐based graphite ranges from 8.92 % to 64.45 %, and it was found that the yield of coal‐based graphite is not only affected by the degree of coalification, fixed carbon content, and volatile matter content of coal but also significantly inhibited by organic sulfur in coal when the reflectance is less than 2.00 %. The graphitization degree (G) of coal‐based graphite is distributed between 76.02 % and 91.02 %, and positively related to the degree of coalification, and negatively related to the content of volatile matter. Organic sulfur in coal is an unfavorable factor for the graphitization degree (G) of coal‐based graphite. Both the cell diameter (La) and stacking height (Lc) of coal‐based graphite are positively correlated with the degree of coalification and negatively correlated with the volatile matter content in coal. Organic sulfur in coal plays an important inhibitory role on the cell diameter (La) of coal‐based graphite. Still, it has almost no effect on the stacking height (Lc) of coal‐based graphite, resulting in a low ratio of horizontal‐to‐vertical (La/Lc), which is not conducive to the horizontal development of coal‐based graphite cells. [ABSTRACT FROM AUTHOR]

For high negative oxygen balance explosives, the phase state of solid product carbon will affect the detonation performance parameters of CJ and energy release process. The description of the solid carbon by the Viral theory-based VLWR thermodynamic code only allows the selection of single-phase carbon, which does not correspond to the real physical situation. We set up a thermodynamic calculation model that gives the initial graphite/diamond ratio, and by validating the model with experimental data based on the additional graphite and RDX (C3H6O6N6) systems, we found that considering the graphitization process during isentropic expansion, the simulated data can match well with the experimental values, so the mixed-phase model we proposed can describe the more specific morphology of solid detonation product carbon. Also, based on this model, the effect of diamond/graphite ratio on the detonation performance of negative oxygen explosives TNT (C7H5O6N3), TATB (C6H6O6N6) and HNS(C14H6O12N6) was investigated, and the most probable diamond percentage was reverse calibrated by experimentally measured detonation performance parameters. The component and heat of detonation at the freeze temperature of 1500–1800 K were calculated at this ratio. Finally, the pressure P-volume V relationship for the isentropic expansion of TNT and HMX (C4H8O8N8) was calculated, the JWL equation of state (EOS) was fitted and the reduction of internal energy was calculated. The impact of the diamond/graphite ratio on the energy release of the isentropic expansion zone was investigated. [ABSTRACT FROM AUTHOR]

Aromatic polyimide films are widely used in high-tech fields due to their excellent combination of thermal, mechanical, and electrical properties. These films serve as precursors for the preparation of high thermal conductivity graphite films, with carbon content up to 70%, exhibits exceptional thermal and electrical conductivity, making it a promising precursor for polymer-based graphite films. This study focuses on the reserch of graphitization using commercial DuPont Kapton polyimide film. The polyimide film was rapped around a cylindrical mold and heat-treated at various temperatures. The impact of the process system on graphitization was thoroughly investigated, along with the evolution of polyimide's structure and properties during heat treatment. Results demonstrated that the size of the prepared films initially increased and then decreased with the increase in graphitization temperature. Additionally, the color of the prepared films transitioned from yellow-brown to black and eventually gray matte. The brittleness of the prepared films followed a similar pattern of initially increasing and then decreasing. When the temperature was below 2200 °C, the surface of the graphite films was smooth and defectless. However, at 2200 °C, small holes appeared on the surface, and at 2300 °C, the surface began to exhibit a "foaming" phenomenon, which intensified with temperature. XRD and Raman spectra analysis revealed that the degree of graphitization, crystallinity, and order of the prepared films increased with temperature. At 2800 °C, the sample achieved a theoretical degree of graphitization of 95.35% and a thermal conductivity of 1246.36 W/(m·K). [ABSTRACT FROM AUTHOR]

This research aims to optimize the graphitization process of carbon derived from Empty Palm Oil Fruit Bunches (EPOFB), a renewable biomass source, using a single-step K₂FeO₄-KOH impregnation-activation method. The results demonstrate that increasing the mass of K₂FeO₄, up to the optimal level, enhances the degree of graphitization, as confirmed by XRD and Raman spectroscopy. Optimal performance is observed with a catalyst mass of 0.11 g K₂FeO₄ in the C_ K₂FeO₄(0.11)KOH_800 sample, which exhibits a d002 spacing of 0.3356 nm, an IG/ID ratio of 2.42, a high surface area of 787.767 m²/g, and clearly defined graphitic layers in TEM images. Electrochemical testing of C_ K₂FeO₄(0.11)_KOH_800 reveals promising results, including the lowest charge transfer resistance (Rct) of 87.18 Ω, a significant area under the curve in cyclic voltammetry, a charging capacity of 330.3 mAh g⁻¹ at 0.1 C, with an excellent rate capability of 183 mAh g⁻¹ at 1 C after 100 cycles, maintaining a retention rate of 68.2 %. The single-step K₂FeO₄-KOH impregnation-activation method effectively enhances the graphitization of EPOFB-derived carbon, offering potential applications in high-performance lithium battery anodes.

Abstract Overcoming the trade‐off between the graphitization of the carbon substrate and enhanced electronic metal–support interaction (EMSI) and intrinsic activity of Pt‐C catalysts remains a major challenge for ensuring the durable operation of energy conversion devices. This article presents a hybrid catalyst consisting of PtFe nanoparticles and single Pt and Fe atoms supported on N‐doped carbon (PtFeNPs@PtFeSAs‐N‐C), which exhibits improved activities in hydrogen evolution and oxygen reduction reactions (HER and ORR, respectively) and has excellent durability owing to the high graphitization, rich edge defects, and porosity of the carbon in PtFeNPs@PtFeSAs‐N‐C, as well as strong EMSI between the PtFe nanoparticles and edge‐defective carbon embedded with Pt and Fe atoms. According to theoretical calculations, the strong EMSI optimizes the H* adsorption–desorption and facilitates the adsorption OOH*, accelerating the HER and ORR processes. A novel flow seawater‐Al/acid hybrid fuel cell using the PtFeNPs@PtFeSAs‐N‐C cathode can serve as a high‐efficiency energy conversion device that delivers a high power density of 109.5 mW cm−2 while producing H2 at a significantly high rate of 271.6 L m−2 h−1. Moreover, PtFeNPs@PtFeSAs‐N‐C exhibits a remarkable performance (high power density of 298.0 mW cm−2 and long‐term durability of 1000 h) in a flow Zn–air battery.

This study investigates the effect of SiO2 minerals on coal graphitization under natural conditions through high-temperature and high-pressure simulation experiment to invert the coal-based graphite formation environment.We thoroughly mixed the SiO2 additive with the sorted vitrinite in coal (from the Gemudi mining area in Guizhou province[SW China]) and then carried out high-temperature and high-pressure simulation experiment with ranging from 600 ℃ to 1 200 ℃, 1.5 GPa to 2.0 GPa.The graphitization products of the samples were analyzed by X-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM) to investigate the influence of the SiO2 additive on the process of coal graphitization.Results show that in contrast to the graphitization-promoting ability exhibited in high-temperature environments, SiO2 demonstrates a hindering effect on graphitization in high-temperature and high-pressure environments, inhibiting the growth of coal graphitization.This finding provides an hypothesis for the lower graphitization of coal in areas with strong tectonics under natural conditions.

Thermal decomposition of SiC at high temperature usually brings about excessively fast Si sublimation and a very rough surface. In order to fabricate high-quality homogeneous epitaxial graphene on a SiC(0001) substrate, highly reactive erbium atoms are employed in this work. Scanning tunneling microscopy and Raman spectroscopy have been utilized to investigate the modulations of Er atoms on graphitization evolution and structural defects for graphene after annealing durations. Experimental results show that Er atoms pre-deposited on clean substrates can definitely enhance the surface graphitization of SiC and make graphene grow in a controllable way. The existence of Er layer is believed to break Si–C bonds at low temperature and to decrease the Si sublimate rate. It is also demonstrated that Er atoms can modify the type of structural defects in graphene, and the areal density of flower defects increases to 1.22 × 1012 cm−2, quadrupling that in pristine graphene. This work puts forward a fabrication method for epitaxial graphene with flower defects in high density and will enlighten some future applications of graphene in nanoelectronics, electron energy filtering, and chemical catalysis. [ABSTRACT FROM AUTHOR]

Hard carbon anode demonstrates exceptional potential in sodium‐ion batteries due to their cost‐effectivenss and superior plateau capacity. However, the proximity of the plateau capacity to the cut‐off voltage of battery operation and the premature cut‐off voltage response caused by polarization at high rates greatly limit the exploitation of plateau capacities, raising big concerns about inferior rate performance of high‐plateau‐capacity hard carbon. In this work, a facile pre‐oxidation strategy is proposed for fabricating lignin‐derived hard carbon. Both high‐plateau capacity and sodiation kinetics are significantly enhanced due to the introduction of expanded pseudo‐graphitic domains and high‐speed closed pores. Impressively, the optimized hard carbon exhibits an increased reversible capacity from 252.1 to 302.0 mAh g−1, alongside superior rate performance (174.7 mAh g−1 at 5 C) and stable cyclability over 500 cycles. This study paves a low‐cost and effective pathway to modulate the microstructure of biomass‐derived hard carbon materials for facilitating plateau sodium storage kinetics. [ABSTRACT FROM AUTHOR]