The advancement of planar micro-supercapacitors(PMSCs)for micro-electromechanical systems(MEMS)has been significantly hindered by the challenge of achieving high energy and power densities.This study addresses this is...The advancement of planar micro-supercapacitors(PMSCs)for micro-electromechanical systems(MEMS)has been significantly hindered by the challenge of achieving high energy and power densities.This study addresses this issue by leveraging screen-printing technology to fabricate high-performance PMSCs using innovative composite ink.The ink,a synergistic blend of few-layer graphene(Gt),carbon black(CB),and NiCo_(2)O_(4),was meticulously mixed to form a conductive and robust coating that enhanced the capacitive performance of the PMSCs.The optimized ink formulation and printing process result in a micro-supercapacitor with an exceptional areal capacitance of 18.95 mF/cm^(2)and an areal energy density of 2.63μW·h/cm^(2)at a current density of 0.05 mA/cm^(2),along with an areal power density of 0.025 mW/cm^(2).The devices demonstrated impressive durability with a capacitance retention rate of 94.7%after a stringent 20000-cycle test,demonstrating their potential for long-term applications.Moreover,the PMSCs displayed excellent mechanical flexibility,with a capacitance decrease of only 3.43%after 5000 bending cycles,highlighting their suitability for flexible electronic devices.The ease of integrating these PMSCs into series and parallel configurations for customized power further underscores their practicality for integrated power supply solutions in various technologies.展开更多
Electroless Cu plating was used for flake G powder and CNTs, Cu-G-CNTs （copper/graphite/carbon nanotubes） composites were manufactured by means of powder metallurgical method. The influences of CNTs on the mechanica...Electroless Cu plating was used for flake G powder and CNTs, Cu-G-CNTs （copper/graphite/carbon nanotubes） composites were manufactured by means of powder metallurgical method. The influences of CNTs on the mechanical properties, conductivity properties, friction, and wear performance of the composite were examined. The results indicate that adding a small amount of CNTs can improve comprehensive property of the composites, especially mechanical property. However, excessive CNT, which is easily winding reunion and grain boundary seg- regation, results in performances degradation.展开更多
Graphite,encompassing both natural graphite and synthetic graphite,and graphene,have been extensively utilized and investigated as anode materials and additives in lithium-ion batteries(LIBs).In the pursuit of carbon ...Graphite,encompassing both natural graphite and synthetic graphite,and graphene,have been extensively utilized and investigated as anode materials and additives in lithium-ion batteries(LIBs).In the pursuit of carbon neutrality,LIBs are expected to play a pivotal role in reducing CO_(2)emissions by decreasing reliance on fossil fuels and enabling the integration of renewable energy sources.Owing to their technological maturity and exceptional electrochemical performance,the global production of graphite and graphene for LIBs is projected to continue expanding.Over the past decades,numerous researchers have concentrated on reducing the material and energy input whilst optimising the electrochemical performance of graphite and graphene,through novel synthesis methods and various modifications at the laboratory scale.This review provides a comprehensive examination of the manufacturing methods,environmental impact,research progress,and challenges associated with graphite and graphene in LIBs from an industrial perspective,with a particular focus on the carbon footprint of production processes.Additionally,it considers emerging challenges and future development directions of graphite and graphene,offering significant insights for ongoing and future research in the field of green LIBs.展开更多
Fine-grained nuclear graphite is a key material in high-temperature gas-cooled reactors(HTGRs).During air ingress accidents,core graphite components undergo severe oxidation,threatening structural integrity.Therefore,...Fine-grained nuclear graphite is a key material in high-temperature gas-cooled reactors(HTGRs).During air ingress accidents,core graphite components undergo severe oxidation,threatening structural integrity.Therefore,understanding the oxidation behavior of nuclear graphite is essential for reactor safety.The influence of oxidation involves multiple factors,including temperature,sample size,oxidant,impurities,filler type and size,etc.The size of the filler particles plays a crucial role in this study.Five ultrafine-and superfine-grained nuclear graphite samples(5.9-34.4μm)are manufactured using identical raw materials and manufacturing processes.Isothermal oxidation tests conducted at 650℃-750℃ are used to study the oxidation behavior.Additionally,comprehensive characterization is performed to analyze the crystal structure,surface morphology,and nanoscale to microscale pore structure of the samples.Results indicate that oxidation behavior cannot be predicted solely based on filler grain size.Reactive site concentration,characterized by active surface area,dominates the chemical reaction kinetics,whereas pore tortuosity,quantified by the structural parameterΨ,plays a key role in regulating oxidant diffusion.These findings clarify the dual role of microstructure in oxidation mechanisms and establish a theoretical and experimental basis for the design of high-performance nuclear graphite capable of long-term service in high-temperature gas-cooled reactors.展开更多
To enhance the electrochemical performance of lithium-ion battery anodes with higher silicon content,it is essential to engineer their microstructure for better lithium-ion transport and mitigated volume change as wel...To enhance the electrochemical performance of lithium-ion battery anodes with higher silicon content,it is essential to engineer their microstructure for better lithium-ion transport and mitigated volume change as well.Herein,we suggest an effective approach to control the micropore structure of silicon oxide(SiO_(x))/artificial graphite(AG)composite electrodes using a perforated current collector.The electrode features a unique pore structure,where alternating high-porosity domains and low-porosity domains markedly reduce overall electrode resistance,leading to a 20%improvement in rate capability at a 5C-rate discharge condition.Using microstructure-resolved modeling and simulations,we demonstrate that the patterned micropore structure enhances lithium-ion transport,mitigating the electrolyte concentration gradient of lithium-ion.Additionally,perforating current collector with a chemical etching process increases the number of hydrogen bonding sites and enlarges the interface with the SiO_(x)/AG composite electrode,significantly improving adhesion strength.This,in turn,suppresses mechanical degradation and leads to a 50%higher capacity retention.Thus,regularly arranged micropore structure enabled by the perforated current collector successfully improves both rate capability and cycle life in SiO_(x)/AG composite electrodes,providing valuable insights into electrode engineering.展开更多
N-doped graphite carbon sphere coated cobalt nanoparticle catalyst(Co@C-N-900),prepared by solvothermal-calcination method,is applied to activate peroxymonosulfate(PMS)for bisphenol A(BPA)elimination.The outcomes demo...N-doped graphite carbon sphere coated cobalt nanoparticle catalyst(Co@C-N-900),prepared by solvothermal-calcination method,is applied to activate peroxymonosulfate(PMS)for bisphenol A(BPA)elimination.The outcomes demonstrate that the Co@C-N-900 could effectively activate PMS,thereby causing efficient removal of BPA in water.In addition,the Co@C-N-900/PMS system also has the advantages of low metal leaching,applicability in high salinity environments,good selectivity and stability.Further investigations using electron paramagnetic resonance,chronoamperometry,and quenching experiments demonstrated that the Co@C-N-900/PMS system is a typical non-radical route with singlet oxygen(^(1)O_(2))as the main reactive oxygen species(ROS).Density functional theory calculations(DFT)indicate that N-doping can effectively regulate the charge distribution on the catalyst surface,generating acidic/alkaline sites favorable for PMS adsorption and activation.Furthermore,it also can enhance the interaction and charge transfer capacity between the Co@C-N-900 and PMS.Lastly,LC-QTOF-MS/MS analysis revealed two possible BPA degradation pathways:(1)^(1)O_(2)attacked the isopropyl group in BPA between the two phenyl groups,causingβ-scission to occur.(2)Following the oxidation of the hydroxyl group in the aromatic ring of BPA,^(1)O_(2)could cause furtherβ-scission.The prepared Co@C-N-900 catalyst is a very promising catalyst,which would offer a workable remedy for treating water pollution.展开更多
Herein,nanosized Hf_(6)Ta_(2)O_(17) encapsulated graphite flakes were firstly constructed using the sol-gel method,then deposited on the surface of carbon/carbon(C/C)composites by plasma spraying technique to prolong ...Herein,nanosized Hf_(6)Ta_(2)O_(17) encapsulated graphite flakes were firstly constructed using the sol-gel method,then deposited on the surface of carbon/carbon(C/C)composites by plasma spraying technique to prolong their service span in critical environments.Nanoindentation results affirmed the active influ-ence of graphite flakes on elevating the toughness of the Hf_(6)Ta_(2)O_(17) coating.Besides,after being exposed to the oxyacetylene torch with a peak temperature of about 2000℃,the sample achieved near zero ab-lation(0.06 mg/s),meanwhile its porosity and mass ablation rate showed 39.5%and 60.0%reduction when compared to pure Hf_(6)Ta_(2)O_(17) sample.During exposure,the external Hf_(6)Ta_(2)O_(17) served as an oxy-gen barrier for internal graphite flakes,inversely internal graphite flakes provided a“pinning”effect on external Hf_(6)Ta_(2)O_(17),which accounted for its exceptional ablation performance.This work offers a new insight into the design of surface modification of C/C composites and other high-temperature structural materials.展开更多
Mixed polyanion phosphate Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP)is regarded as the most promising cathode material for sodium-ion batteries(SIBs),due to its high structural stability and low-cost environmental frien...Mixed polyanion phosphate Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP)is regarded as the most promising cathode material for sodium-ion batteries(SIBs),due to its high structural stability and low-cost environmental friendliness.However,its intrinsic low conductivity and sluggish Na^(+)diffusion restricted the fast-charge and low-temperature sodium storage.Herein,an NFPP composite encapsulated by in-situ pyrolytic carbon and coupled with expanded graphite(NFPP@C/EG)was constructed via a sol-gel method followed by a ballmill procedure.Due to the dual-carbon modified strategy,this NFPP@C/EG only enhanced the electronic conductivity,but also endowed more channels for Na^(+)diffusion.As cathode for SIBs,the optimized NFPP(M-NFPP@C/EG)delivers excellent rate capability(capacity of~80.5 mAh/g at 50 C)and outstanding cycling stability(11000 cycles at 50 C with capacity retention of 89.85%).Additionally,cyclic voltammetry(CV)confirmed that its sodium storage behavior is pseudocapacitance-controlled,with in-situ electrochemical impedance spectroscopy(EIS)further elucidating improvements in electrode reaction kinetics.At lower temperatures(0℃),M-NFPP@C/EG demonstrated exceptional cycling performance(8800 cycles at 10 C with capacity retention of 95.81%).Moreover,pouch cells also exhibited excellent stability.This research demonstrates the feasibility of a dual carbon modification strategy in enhancing NFPP and proposes a low-cost,high-rate,and ultra-stable cathode material for SIBs.展开更多
Effects of film-forming additive on stability of electrode and cycling performance of LiFePO4/graphite cell at elevated temperature were studied. Two 18650 cells with and without VC additive were investigated by galva...Effects of film-forming additive on stability of electrode and cycling performance of LiFePO4/graphite cell at elevated temperature were studied. Two 18650 cells with and without VC additive were investigated by galvanostatic cycling, electrochemical impedance spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis and Raman spectroscopy. The results show that in the presence of VC additive, dissolution of Fe from LiFePO4 material is greatly depressed and stability of graphite structure is improved; the additive can not only reduce reaction of electrolyte on surface of LiFePO4 electrode but also suppress reduction of solvent and thickening of the solid electrolyte interface （SEI） layer on graphite surface. Electrolyte with VC is considered to be a good candidate for improving cycling performance of the LiFePOa/graphite cell at elevated temperature.展开更多
Ti-doped graphite-like carbon （Ti-GLC） films were synthesized successfully by magnetron sputtering technique. The compositions, microstructures and properties of the Ti-doped GLC films dependent on the parameter of ...Ti-doped graphite-like carbon （Ti-GLC） films were synthesized successfully by magnetron sputtering technique. The compositions, microstructures and properties of the Ti-doped GLC films dependent on the parameter of Ti target current were systemically investigated by Raman spectra, X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, atomic force microscopy （AFM）, nanoindentation and ball-on-disk tribometer. With the increase of the Ti target current, the ratio of sp2 bond and the content of Ti as well as the film hardness and compressive internal stress increase, but the high content of the Ti would result in the loose film due to the formation of the squamose structure. Less incorporated Ti reduces the friction of the GLC film in dry-sliding condition, while pure GLC film exhibits the lowest friction coefficient in water-lubricated condition. Ti-GLC film deposited with low Ti target current shows high wear resistance in both dry-sliding and water-lubricated conditions.展开更多
Based on the hexagonal crystallite model of graphite,the electrochemical characteristics of carbon atoms on the edge and basal plane were proposed by analyzing graphite crystal structure and bonds of carbon atoms in d...Based on the hexagonal crystallite model of graphite,the electrochemical characteristics of carbon atoms on the edge and basal plane were proposed by analyzing graphite crystal structure and bonds of carbon atoms in different sites.A spherical close-packed model for graphite particle was developed.The fractions of surface carbon atoms（SCA） and edge carbon atoms（ECA） were derived in the expression of crystallographic parameters and particle size,and the effects of ECA on the initial irreversible capacity and the mechanisms of action were analyzed and verified.The results show that the atoms on the edge are more active for electrochemical reactions,such as electrolyte decomposition and tendency to form stable bond with other atoms and groups.For the practical graphite particle,corresponding modifying factors were introduced to revise the difference in calculating results.The revised expression is suitable for the calculation of the fractions of SCA and ECA for carbon materials such as graphite,disordered carbon and modified graphite.展开更多
Stable carbon isotope geochemistry provides important information for the recognition of funda- mental isotope exchange processes related to the movement of carbon in the lithosphere and permits the elab- oration of m...Stable carbon isotope geochemistry provides important information for the recognition of funda- mental isotope exchange processes related to the movement of carbon in the lithosphere and permits the elab- oration of models for the global carbon cycle. Carbon isotope ratios in fluid-deposited graphite are powerful tools for unravelling the ultimate origin of carbon （organic matter, mantle, or carbonates） and help to constrain the fluid history and the mechanisms involved in graphite deposition. Graphite precipitation in fluid-deposited occurrences results from C02- and/or CH4-bearing aqueous fluids. Fluid flow can be considered as both a closed （without replenishment of the fluid） or an open system （with renewal of the fluid by successive fluid batches）. In closed systems, carbon isotope systematics in graphite is mainly governed by Rayleigh precipi- tation and/or by changes in temperature affecting the fractionation factor between fluid and graphite. Such processes result in zoned graphite crystals or in successive graphite generations showing, in both cases, isotopic variation towards progressive 13C or 12C enrichment （depending upon the dominant carbon phase in the fluid, C02 or CH4, respectively）. In open systems, in which carbon is episodically introduced along the fracture systems, the carbon systematics is more complex and individual graphite crystals may display oscillatory zoning because of Rayleigh precipitation or heterogeneous variations of 613C values when mixing of fluids or changes in the composition of the fluids are the mechanisms responsible for graphite precipitation.展开更多
The self-monitoring application of asphalt concrete containing graphite and carbon fibers using indirect tensile test and wheel rolling test were introduced. The experiment results indicate that this kind of pitch-bas...The self-monitoring application of asphalt concrete containing graphite and carbon fibers using indirect tensile test and wheel rolling test were introduced. The experiment results indicate that this kind of pitch-based composite is effective for strain/stress self-monitoring. In the indirect tensile test, for a completely conductive asphalt concrete specimen, the piezoresistivity was very weak and slightly positive, which meant the resistivity increase with the increment of tensile strain at all stress/strain amplitudes, with the gage factor as high as 6. The strain self-sensing ability was superior in the case of higher graphite content. However, when the conductive concrete was embedded into common asphalt concrete specimen as a partial structure function, the piezoresistivity was positive at all stress/strain amplitudes and with the gage factor of 13, which was much higher than that of completely conductive specimen. Thus, the strain self-sensing ability was superior when conductive asphalt concrete was taken in as a partial structure function. In the wheel-rolling test, the piezoresistivity was highly positive. At any stress amplitude, the piezoresistivity was strong, with the gage factor as high as 100, which was higher for a stress amplitude of 0.7 MPa than that of 0.5 MPa.展开更多
An electromagnetic interference （EMI） shielding composite based on ultrahigh molecular weight polyethylene （UHMWPE） loaded with economical graphite-carbon black （CB） hybrid fillers was prepared via a green and f...An electromagnetic interference （EMI） shielding composite based on ultrahigh molecular weight polyethylene （UHMWPE） loaded with economical graphite-carbon black （CB） hybrid fillers was prepared via a green and facile methodology, i.e., high-speed mechanical mixing combined with hot compression thus avoiding the assistance of the intensive ultrasound dispersion in volatile organic solvents. In this composite, the graphite-CB hybrid fillers were selectively distributed in the interfacial regions of UHMWPE domains resulting a typical segregated structure. Thanks to the specific morphology of segregated conductive networks along with the synergetic effect of large-sized graphite flakes and small-sized CB nanoparticles, a low filler loading of 7.7 vol% （15 wt%） yielded the graphite-CB/UHMWPE composites with a satisfactory electrical conductivity of 33.9 S/m and a superior shielding effectiveness of 40.2 dB, manifesting the comparable value of the pricey large-aspect-ratio carbon nanofillers （e.g., carbon nanotubes and graphene nanosheets） based polymer composites. More interestingly, with the addition of 15 wt% graphite-CB （1/3, W/W） hybrid fillers, the tensile strength and elongation at break of the composite reached 25.3 MPa and 126%, respectively; with a remarkable increase of 58.1% and 2420% over the conventional segregated graphite/UHMWPE composites. The mechanical reinforcement could be attributed to the favor of the small-sized CB particles in the polymer molecular diffusion between UHMWPE domains which in tuna provided a stronger interfacial adhesion. This work provides a facile, green and affordable strategy to obtain the polymer composites with high electrical conductivity, efficient EMI shielding, and balanced mechanical performance.展开更多
Silver matrix composite brushes were fabricated by means of powder metallurgy, which included pressing at 300 MPa and then sintering for 1 h in pure H2 protective atmosphere at 700 ℃ and repressing at 500 MPa. Four k...Silver matrix composite brushes were fabricated by means of powder metallurgy, which included pressing at 300 MPa and then sintering for 1 h in pure H2 protective atmosphere at 700 ℃ and repressing at 500 MPa. Four kinds composites with different compositions were produced, and the mechanical properties and electrical wear performance were investigated. The results showed that the composite added with carbon nanotubes had a higher hardness and strength, a lower contact voltage drop and an excellent anti-wear property in electrical sliding wear, because of the reinforcement ability of carbon nanotubes. Adding graphite to the composite also decreased the wear loss and contact voltage drop, because graphite had an electrical current conducting ability which not only made the current pass the lubricating films easily but also eliminated and reduced the arc and spark effectively.展开更多
It is essential to replace lithium-ion batteries(LIBs)from the perspective of the Earth's resources and the sustainable development of mankind.Sodium-ion batteries(SIBs)are important candidates due to their low pr...It is essential to replace lithium-ion batteries(LIBs)from the perspective of the Earth's resources and the sustainable development of mankind.Sodium-ion batteries(SIBs)are important candidates due to their low price and abundant storage capacity.Hard carbon(HC)and graphite have important applications in anode materials of SIBs.In this review,the research progress in electrolyte and interface between HC and graphite anode for SIBs is summarized.The properties and performance of three types of widely used electrolytes(carbo nate ester,ether,and ionic liquid)with additives,as well as the formation of solid electrolyte interface(SEI),which are crucial to the reversible capacity and rate capability of HC anodes,are also discussed.In this review,the co-intercalation performance and mechanism of solvation Na+into graphite are summarized.Besides,the faced challenges and existing problems in this field are also succinctly highlighted.展开更多
The thermodynamic and kinetic mechanisms of Taixi anthracite during its graphitization process were explored.To understand the variation trends of carbon arrangement order,microcrystal size,and graphitization degree a...The thermodynamic and kinetic mechanisms of Taixi anthracite during its graphitization process were explored.To understand the variation trends of carbon arrangement order,microcrystal size,and graphitization degree against temperature during the graphitization process,a series of experiments were performed using Raman spectroscopy and X-ray diffraction(XRD).Subsequently,the influencing factors of the dominant reaction at different temperatures were analyzed using thermodynamics and kinetics.The results showed that the graphitization process of Taixi anthracite can be divided into three stages from the perspective of reaction thermodynamics and kinetics.Temperature played a crucial role in the formation and growth of a graphitic structure.Meanwhile,multivariate mechanisms coexisted in the graphitization process.At ultrahigh temperatures,the defects of synthetic graphite could not be completely eliminated and perfect graphite crystals could not be produced.At low temperatures,the reaction is mainly controlled by dynamics,while at high temperatures,thermodynamics dominates the direction of the reaction.展开更多
Graphite, as a strategic mineral resource, the recycling from spent lithium-ion batteries(LIBs) has attracted considerable attention for meeting considerable economic value. However, closed-circuit recycling still suf...Graphite, as a strategic mineral resource, the recycling from spent lithium-ion batteries(LIBs) has attracted considerable attention for meeting considerable economic value. However, closed-circuit recycling still suffers from the lack of effective repair methods. Considering the existing defects, a series of Cchain length carbons have been successfully introduced to repair spent graphite. Obviously, with the evolution of carbon resources, the thickness and pores of the coating layer were tailored with the functional groups. Benefitting from the increased active sites and created fold structure, their coulombic efficiency is obviously restored from 14% to 86.89%, while the stable capacity is kept at approximately 384.9 mAh gafter 100 cycles. Moreover, their excellent rate properties are kept about approximately 200 mAh gat2 C, meeting the standard of commercial materials. Supported by the detailed kinetic behaviors, the enhanced rate is mainly dominated by pseudocapacitive behaviors, accompanied by deepening redox reactions. Meanwhile, the cost of the proposed approach for recycling spent graphite is 894.87 $ t^(-1),and the recycling profit for regenerating graphite is approximately 7000 $ t^(-1). Given this, this work is anticipated to shed light on the closed-circuit recycling of spent graphite and offer significant strategies to repair graphite.展开更多
Natural graphite is investigated as the cathode for aluminum ion batteries in recent years. However, some drawbacks of the natural graphite such as severe volume swelling shorten its lifetime, In this work, we prepare...Natural graphite is investigated as the cathode for aluminum ion batteries in recent years. However, some drawbacks of the natural graphite such as severe volume swelling shorten its lifetime, In this work, we prepared a composite material by depositing an amorphous carbon on the graphite paper, The composite was used as a cathode to study the electrochemical performance in aluminum ion batteries. The charge/discharge results showed that the composite could exhibit a longer cycle life than the graphite paper, Electrochemical analyses demonstrated that the interface between the amorphous carbon and the graphite paper made a major contribution to the improvement of the cycling stability.展开更多
Potassium-ion batteries(PIBs) have attracted tremendous attention for large-scale energy storage fields based on abundant potassium resources. Graphite is a promising anode material for PIBs due to its low potassium i...Potassium-ion batteries(PIBs) have attracted tremendous attention for large-scale energy storage fields based on abundant potassium resources. Graphite is a promising anode material for PIBs due to its low potassium ion intercalation voltage and mature industrialized preparation technology. However, the inability of graphitic structures to endure large volume change during charge/discharge cycles is a major limitation in their advancement for practical PIBs. Herein, a soft carbon-coated bulk graphite composite is synthesized using PTCDA as a carbon precursor. The PTCDA-derived soft carbon coating layer with large interlayer distance facilities fast potassium ion intercalation/extraction in the BG@C composite and buffers severe volume change during the charge/discharge cycles. When tested as anode for PIBs, the composite realizes enhanced rate capability(131.3 mAh/g at 2 C, 1 C=279 m A/g) and cycling performance(capacity retention of 76.1% after 150 cycles at 0.5 C). In general, the surface modification route to engineer graphite anode could inherently improve the electrochemical performance without any structural alteration.展开更多
基金supported by the Shanxi Province Central Guidance Fund for Local Science and Technology Development Project(YDZJSX2024D030)the National Natural Science Foundation of China(22075197,22278290)+2 种基金the Shanxi Province Key Research and Development Program Project(2021020660301013)the Shanxi Provincial Natural Science Foundation of China(202103021224079)the Research and Development Project of Key Core and Common Technology of Shanxi Province(20201102018).
文摘The advancement of planar micro-supercapacitors(PMSCs)for micro-electromechanical systems(MEMS)has been significantly hindered by the challenge of achieving high energy and power densities.This study addresses this issue by leveraging screen-printing technology to fabricate high-performance PMSCs using innovative composite ink.The ink,a synergistic blend of few-layer graphene(Gt),carbon black(CB),and NiCo_(2)O_(4),was meticulously mixed to form a conductive and robust coating that enhanced the capacitive performance of the PMSCs.The optimized ink formulation and printing process result in a micro-supercapacitor with an exceptional areal capacitance of 18.95 mF/cm^(2)and an areal energy density of 2.63μW·h/cm^(2)at a current density of 0.05 mA/cm^(2),along with an areal power density of 0.025 mW/cm^(2).The devices demonstrated impressive durability with a capacitance retention rate of 94.7%after a stringent 20000-cycle test,demonstrating their potential for long-term applications.Moreover,the PMSCs displayed excellent mechanical flexibility,with a capacitance decrease of only 3.43%after 5000 bending cycles,highlighting their suitability for flexible electronic devices.The ease of integrating these PMSCs into series and parallel configurations for customized power further underscores their practicality for integrated power supply solutions in various technologies.
基金financially supported by the National Nature Science Foundation of China (No. 51003060)the Distinguished Young Talents in Higher Education of Guangdong China (No. 2012LYM_0118)the Shenzhen Innovation and Technology Commission under the Strategic Emerging Industries Development Project (No. ZDSY20120612094418467)
文摘Electroless Cu plating was used for flake G powder and CNTs, Cu-G-CNTs （copper/graphite/carbon nanotubes） composites were manufactured by means of powder metallurgical method. The influences of CNTs on the mechanical properties, conductivity properties, friction, and wear performance of the composite were examined. The results indicate that adding a small amount of CNTs can improve comprehensive property of the composites, especially mechanical property. However, excessive CNT, which is easily winding reunion and grain boundary seg- regation, results in performances degradation.
基金supported by European Union's Horizon Europe,UK Research and Innovation(UKRI).
文摘Graphite,encompassing both natural graphite and synthetic graphite,and graphene,have been extensively utilized and investigated as anode materials and additives in lithium-ion batteries(LIBs).In the pursuit of carbon neutrality,LIBs are expected to play a pivotal role in reducing CO_(2)emissions by decreasing reliance on fossil fuels and enabling the integration of renewable energy sources.Owing to their technological maturity and exceptional electrochemical performance,the global production of graphite and graphene for LIBs is projected to continue expanding.Over the past decades,numerous researchers have concentrated on reducing the material and energy input whilst optimising the electrochemical performance of graphite and graphene,through novel synthesis methods and various modifications at the laboratory scale.This review provides a comprehensive examination of the manufacturing methods,environmental impact,research progress,and challenges associated with graphite and graphene in LIBs from an industrial perspective,with a particular focus on the carbon footprint of production processes.Additionally,it considers emerging challenges and future development directions of graphite and graphene,offering significant insights for ongoing and future research in the field of green LIBs.
基金supported by the National Key Research and Development Program of China(2024YFA1612900)the National Natural Science Foundation of China(Grant No.52103365 and No.12375270)the Guangdong Innovative and Entrepreneurial Research Team Program,China(Grant No.2021ZT09L227).
文摘Fine-grained nuclear graphite is a key material in high-temperature gas-cooled reactors(HTGRs).During air ingress accidents,core graphite components undergo severe oxidation,threatening structural integrity.Therefore,understanding the oxidation behavior of nuclear graphite is essential for reactor safety.The influence of oxidation involves multiple factors,including temperature,sample size,oxidant,impurities,filler type and size,etc.The size of the filler particles plays a crucial role in this study.Five ultrafine-and superfine-grained nuclear graphite samples(5.9-34.4μm)are manufactured using identical raw materials and manufacturing processes.Isothermal oxidation tests conducted at 650℃-750℃ are used to study the oxidation behavior.Additionally,comprehensive characterization is performed to analyze the crystal structure,surface morphology,and nanoscale to microscale pore structure of the samples.Results indicate that oxidation behavior cannot be predicted solely based on filler grain size.Reactive site concentration,characterized by active surface area,dominates the chemical reaction kinetics,whereas pore tortuosity,quantified by the structural parameterΨ,plays a key role in regulating oxidant diffusion.These findings clarify the dual role of microstructure in oxidation mechanisms and establish a theoretical and experimental basis for the design of high-performance nuclear graphite capable of long-term service in high-temperature gas-cooled reactors.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.NRF-2021M3H4A1A02048529)the Ministry of Trade,Industry and Energy(MOTIE)of the Korean government under grant No.RS-2022-00155854support from the DGIST Supercomputing and Big Data Center.
文摘To enhance the electrochemical performance of lithium-ion battery anodes with higher silicon content,it is essential to engineer their microstructure for better lithium-ion transport and mitigated volume change as well.Herein,we suggest an effective approach to control the micropore structure of silicon oxide(SiO_(x))/artificial graphite(AG)composite electrodes using a perforated current collector.The electrode features a unique pore structure,where alternating high-porosity domains and low-porosity domains markedly reduce overall electrode resistance,leading to a 20%improvement in rate capability at a 5C-rate discharge condition.Using microstructure-resolved modeling and simulations,we demonstrate that the patterned micropore structure enhances lithium-ion transport,mitigating the electrolyte concentration gradient of lithium-ion.Additionally,perforating current collector with a chemical etching process increases the number of hydrogen bonding sites and enlarges the interface with the SiO_(x)/AG composite electrode,significantly improving adhesion strength.This,in turn,suppresses mechanical degradation and leads to a 50%higher capacity retention.Thus,regularly arranged micropore structure enabled by the perforated current collector successfully improves both rate capability and cycle life in SiO_(x)/AG composite electrodes,providing valuable insights into electrode engineering.
基金the financial support from Sichuan Science and Technology Program(No.2023NSFSC0847)Scientific Research and Innovation Team Program of Sichuan University of Science and Technology(No.SUSE652A003)+3 种基金Talent Introduction Project of Sichuan University of Science and Engineering(No.2021RC03)Talent Introduction Project of Sichuan University of Science and Engineering(No.2021RC05)the Undergraduate Training Program for Innovation and Entrepreneurship(No.CX2024042)The Innovation Fund of Postgraduate,Sichuan University of Science&Engineering(No.Y2024094)。
文摘N-doped graphite carbon sphere coated cobalt nanoparticle catalyst(Co@C-N-900),prepared by solvothermal-calcination method,is applied to activate peroxymonosulfate(PMS)for bisphenol A(BPA)elimination.The outcomes demonstrate that the Co@C-N-900 could effectively activate PMS,thereby causing efficient removal of BPA in water.In addition,the Co@C-N-900/PMS system also has the advantages of low metal leaching,applicability in high salinity environments,good selectivity and stability.Further investigations using electron paramagnetic resonance,chronoamperometry,and quenching experiments demonstrated that the Co@C-N-900/PMS system is a typical non-radical route with singlet oxygen(^(1)O_(2))as the main reactive oxygen species(ROS).Density functional theory calculations(DFT)indicate that N-doping can effectively regulate the charge distribution on the catalyst surface,generating acidic/alkaline sites favorable for PMS adsorption and activation.Furthermore,it also can enhance the interaction and charge transfer capacity between the Co@C-N-900 and PMS.Lastly,LC-QTOF-MS/MS analysis revealed two possible BPA degradation pathways:(1)^(1)O_(2)attacked the isopropyl group in BPA between the two phenyl groups,causingβ-scission to occur.(2)Following the oxidation of the hydroxyl group in the aromatic ring of BPA,^(1)O_(2)could cause furtherβ-scission.The prepared Co@C-N-900 catalyst is a very promising catalyst,which would offer a workable remedy for treating water pollution.
基金supported by the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(Grant No.CX2021006)the National Natural Science Foundation of China(Grant Nos.91860203,51727804,and 52130205)the Fundamental Research Funds for the Central Universities(Grant No.3102019TS0409).
文摘Herein,nanosized Hf_(6)Ta_(2)O_(17) encapsulated graphite flakes were firstly constructed using the sol-gel method,then deposited on the surface of carbon/carbon(C/C)composites by plasma spraying technique to prolong their service span in critical environments.Nanoindentation results affirmed the active influ-ence of graphite flakes on elevating the toughness of the Hf_(6)Ta_(2)O_(17) coating.Besides,after being exposed to the oxyacetylene torch with a peak temperature of about 2000℃,the sample achieved near zero ab-lation(0.06 mg/s),meanwhile its porosity and mass ablation rate showed 39.5%and 60.0%reduction when compared to pure Hf_(6)Ta_(2)O_(17) sample.During exposure,the external Hf_(6)Ta_(2)O_(17) served as an oxy-gen barrier for internal graphite flakes,inversely internal graphite flakes provided a“pinning”effect on external Hf_(6)Ta_(2)O_(17),which accounted for its exceptional ablation performance.This work offers a new insight into the design of surface modification of C/C composites and other high-temperature structural materials.
基金supported by the National Key Research and Development Program of China(No.2022YFB2502000)the National Natural Science Foundation of China(Nos.U21A20332,51771076,U21A200970,52301266)the Science and Technology Planning Project of Guangzhou(No.2024A04J3332)。
文摘Mixed polyanion phosphate Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP)is regarded as the most promising cathode material for sodium-ion batteries(SIBs),due to its high structural stability and low-cost environmental friendliness.However,its intrinsic low conductivity and sluggish Na^(+)diffusion restricted the fast-charge and low-temperature sodium storage.Herein,an NFPP composite encapsulated by in-situ pyrolytic carbon and coupled with expanded graphite(NFPP@C/EG)was constructed via a sol-gel method followed by a ballmill procedure.Due to the dual-carbon modified strategy,this NFPP@C/EG only enhanced the electronic conductivity,but also endowed more channels for Na^(+)diffusion.As cathode for SIBs,the optimized NFPP(M-NFPP@C/EG)delivers excellent rate capability(capacity of~80.5 mAh/g at 50 C)and outstanding cycling stability(11000 cycles at 50 C with capacity retention of 89.85%).Additionally,cyclic voltammetry(CV)confirmed that its sodium storage behavior is pseudocapacitance-controlled,with in-situ electrochemical impedance spectroscopy(EIS)further elucidating improvements in electrode reaction kinetics.At lower temperatures(0℃),M-NFPP@C/EG demonstrated exceptional cycling performance(8800 cycles at 10 C with capacity retention of 95.81%).Moreover,pouch cells also exhibited excellent stability.This research demonstrates the feasibility of a dual carbon modification strategy in enhancing NFPP and proposes a low-cost,high-rate,and ultra-stable cathode material for SIBs.
基金Project(2007BAE12B01)supported by the National Key Technology Research and Development Program of ChinaProject(20803095)supported by the National Natural Science Foundation of China
文摘Effects of film-forming additive on stability of electrode and cycling performance of LiFePO4/graphite cell at elevated temperature were studied. Two 18650 cells with and without VC additive were investigated by galvanostatic cycling, electrochemical impedance spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis and Raman spectroscopy. The results show that in the presence of VC additive, dissolution of Fe from LiFePO4 material is greatly depressed and stability of graphite structure is improved; the additive can not only reduce reaction of electrolyte on surface of LiFePO4 electrode but also suppress reduction of solvent and thickening of the solid electrolyte interface （SEI） layer on graphite surface. Electrolyte with VC is considered to be a good candidate for improving cycling performance of the LiFePOa/graphite cell at elevated temperature.
基金Project (50905178) supported by the National Natural Science Foundation of ChinaProject (2011CB706603) supported by the National Basic Research Program of China
文摘Ti-doped graphite-like carbon （Ti-GLC） films were synthesized successfully by magnetron sputtering technique. The compositions, microstructures and properties of the Ti-doped GLC films dependent on the parameter of Ti target current were systemically investigated by Raman spectra, X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, atomic force microscopy （AFM）, nanoindentation and ball-on-disk tribometer. With the increase of the Ti target current, the ratio of sp2 bond and the content of Ti as well as the film hardness and compressive internal stress increase, but the high content of the Ti would result in the loose film due to the formation of the squamose structure. Less incorporated Ti reduces the friction of the GLC film in dry-sliding condition, while pure GLC film exhibits the lowest friction coefficient in water-lubricated condition. Ti-GLC film deposited with low Ti target current shows high wear resistance in both dry-sliding and water-lubricated conditions.
基金Project (09001232) supported by the Doctoral Foundation of Henan University of Science and Technology,China
文摘Based on the hexagonal crystallite model of graphite,the electrochemical characteristics of carbon atoms on the edge and basal plane were proposed by analyzing graphite crystal structure and bonds of carbon atoms in different sites.A spherical close-packed model for graphite particle was developed.The fractions of surface carbon atoms（SCA） and edge carbon atoms（ECA） were derived in the expression of crystallographic parameters and particle size,and the effects of ECA on the initial irreversible capacity and the mechanisms of action were analyzed and verified.The results show that the atoms on the edge are more active for electrochemical reactions,such as electrolyte decomposition and tendency to form stable bond with other atoms and groups.For the practical graphite particle,corresponding modifying factors were introduced to revise the difference in calculating results.The revised expression is suitable for the calculation of the fractions of SCA and ECA for carbon materials such as graphite,disordered carbon and modified graphite.
基金contribution from project CGL2010-16008 (Spanish Ministry for Science and Innovation)
文摘Stable carbon isotope geochemistry provides important information for the recognition of funda- mental isotope exchange processes related to the movement of carbon in the lithosphere and permits the elab- oration of models for the global carbon cycle. Carbon isotope ratios in fluid-deposited graphite are powerful tools for unravelling the ultimate origin of carbon （organic matter, mantle, or carbonates） and help to constrain the fluid history and the mechanisms involved in graphite deposition. Graphite precipitation in fluid-deposited occurrences results from C02- and/or CH4-bearing aqueous fluids. Fluid flow can be considered as both a closed （without replenishment of the fluid） or an open system （with renewal of the fluid by successive fluid batches）. In closed systems, carbon isotope systematics in graphite is mainly governed by Rayleigh precipi- tation and/or by changes in temperature affecting the fractionation factor between fluid and graphite. Such processes result in zoned graphite crystals or in successive graphite generations showing, in both cases, isotopic variation towards progressive 13C or 12C enrichment （depending upon the dominant carbon phase in the fluid, C02 or CH4, respectively）. In open systems, in which carbon is episodically introduced along the fracture systems, the carbon systematics is more complex and individual graphite crystals may display oscillatory zoning because of Rayleigh precipitation or heterogeneous variations of 613C values when mixing of fluids or changes in the composition of the fluids are the mechanisms responsible for graphite precipitation.
基金the Outstanding Youth Foundation of Hubei Province(No.2004ABB019)Program for New Century Excellent Talents in University,China(No.NCET-05-0665)
文摘The self-monitoring application of asphalt concrete containing graphite and carbon fibers using indirect tensile test and wheel rolling test were introduced. The experiment results indicate that this kind of pitch-based composite is effective for strain/stress self-monitoring. In the indirect tensile test, for a completely conductive asphalt concrete specimen, the piezoresistivity was very weak and slightly positive, which meant the resistivity increase with the increment of tensile strain at all stress/strain amplitudes, with the gage factor as high as 6. The strain self-sensing ability was superior in the case of higher graphite content. However, when the conductive concrete was embedded into common asphalt concrete specimen as a partial structure function, the piezoresistivity was positive at all stress/strain amplitudes and with the gage factor of 13, which was much higher than that of completely conductive specimen. Thus, the strain self-sensing ability was superior when conductive asphalt concrete was taken in as a partial structure function. In the wheel-rolling test, the piezoresistivity was highly positive. At any stress amplitude, the piezoresistivity was strong, with the gage factor as high as 100, which was higher for a stress amplitude of 0.7 MPa than that of 0.5 MPa.
基金financially supported by the National Natural Science Foundation of China(Nos.51421061,51120135002 and 51473102)the Innovation Team Program of Science and Technology Department of Sichuan Province(No.2014TD0002)the China Postdoctoral Science Foundation(Nos.2015M572474 and 2016T90848)
文摘An electromagnetic interference （EMI） shielding composite based on ultrahigh molecular weight polyethylene （UHMWPE） loaded with economical graphite-carbon black （CB） hybrid fillers was prepared via a green and facile methodology, i.e., high-speed mechanical mixing combined with hot compression thus avoiding the assistance of the intensive ultrasound dispersion in volatile organic solvents. In this composite, the graphite-CB hybrid fillers were selectively distributed in the interfacial regions of UHMWPE domains resulting a typical segregated structure. Thanks to the specific morphology of segregated conductive networks along with the synergetic effect of large-sized graphite flakes and small-sized CB nanoparticles, a low filler loading of 7.7 vol% （15 wt%） yielded the graphite-CB/UHMWPE composites with a satisfactory electrical conductivity of 33.9 S/m and a superior shielding effectiveness of 40.2 dB, manifesting the comparable value of the pricey large-aspect-ratio carbon nanofillers （e.g., carbon nanotubes and graphene nanosheets） based polymer composites. More interestingly, with the addition of 15 wt% graphite-CB （1/3, W/W） hybrid fillers, the tensile strength and elongation at break of the composite reached 25.3 MPa and 126%, respectively; with a remarkable increase of 58.1% and 2420% over the conventional segregated graphite/UHMWPE composites. The mechanical reinforcement could be attributed to the favor of the small-sized CB particles in the polymer molecular diffusion between UHMWPE domains which in tuna provided a stronger interfacial adhesion. This work provides a facile, green and affordable strategy to obtain the polymer composites with high electrical conductivity, efficient EMI shielding, and balanced mechanical performance.
基金supported by National Natural Science Foundation of China(No50741003)Key Project of Science and Technology of Ministry of Education of China (No107066)Anhui Provincial Natural Science Foundation(No070414181)
文摘Silver matrix composite brushes were fabricated by means of powder metallurgy, which included pressing at 300 MPa and then sintering for 1 h in pure H2 protective atmosphere at 700 ℃ and repressing at 500 MPa. Four kinds composites with different compositions were produced, and the mechanical properties and electrical wear performance were investigated. The results showed that the composite added with carbon nanotubes had a higher hardness and strength, a lower contact voltage drop and an excellent anti-wear property in electrical sliding wear, because of the reinforcement ability of carbon nanotubes. Adding graphite to the composite also decreased the wear loss and contact voltage drop, because graphite had an electrical current conducting ability which not only made the current pass the lubricating films easily but also eliminated and reduced the arc and spark effectively.
基金supported by the International Science&Technology Cooperation of China under 2019YFE0100200National Natural Science Foundation of China(Grant No.51902024)+2 种基金Beijing Institute of Technology Research Fund Program for Young Scholars,the National Postdoctoral Program for Innovative Talents of China(BX20180038)China Postdoctoral Science Foundation(2019M650014)Beijing Natural Science Foundation(L182022).
文摘It is essential to replace lithium-ion batteries(LIBs)from the perspective of the Earth's resources and the sustainable development of mankind.Sodium-ion batteries(SIBs)are important candidates due to their low price and abundant storage capacity.Hard carbon(HC)and graphite have important applications in anode materials of SIBs.In this review,the research progress in electrolyte and interface between HC and graphite anode for SIBs is summarized.The properties and performance of three types of widely used electrolytes(carbo nate ester,ether,and ionic liquid)with additives,as well as the formation of solid electrolyte interface(SEI),which are crucial to the reversible capacity and rate capability of HC anodes,are also discussed.In this review,the co-intercalation performance and mechanism of solvation Na+into graphite are summarized.Besides,the faced challenges and existing problems in this field are also succinctly highlighted.
基金financially supported by the China Postdoctoral Science Foundation and China National “Twelfth Five-Year” Plan for Science & Technology (No. 2014BAB01B02)Shenhua Ningxia Coal Industry Group for financial support and providing Taixi anthracite samplesthe support of Advanced Analysis & Computation Center of China University of Mining and Technology
文摘The thermodynamic and kinetic mechanisms of Taixi anthracite during its graphitization process were explored.To understand the variation trends of carbon arrangement order,microcrystal size,and graphitization degree against temperature during the graphitization process,a series of experiments were performed using Raman spectroscopy and X-ray diffraction(XRD).Subsequently,the influencing factors of the dominant reaction at different temperatures were analyzed using thermodynamics and kinetics.The results showed that the graphitization process of Taixi anthracite can be divided into three stages from the perspective of reaction thermodynamics and kinetics.Temperature played a crucial role in the formation and growth of a graphitic structure.Meanwhile,multivariate mechanisms coexisted in the graphitization process.At ultrahigh temperatures,the defects of synthetic graphite could not be completely eliminated and perfect graphite crystals could not be produced.At low temperatures,the reaction is mainly controlled by dynamics,while at high temperatures,thermodynamics dominates the direction of the reaction.
基金financially supported by the National Key Research and Development Program(2019YFC1907801,2019YFC1907804)the National Natural Science Foundation of China(51904340)the Natural Science Foundation of Hunan(2020JJ4733,2021JJ20066)。
文摘Graphite, as a strategic mineral resource, the recycling from spent lithium-ion batteries(LIBs) has attracted considerable attention for meeting considerable economic value. However, closed-circuit recycling still suffers from the lack of effective repair methods. Considering the existing defects, a series of Cchain length carbons have been successfully introduced to repair spent graphite. Obviously, with the evolution of carbon resources, the thickness and pores of the coating layer were tailored with the functional groups. Benefitting from the increased active sites and created fold structure, their coulombic efficiency is obviously restored from 14% to 86.89%, while the stable capacity is kept at approximately 384.9 mAh gafter 100 cycles. Moreover, their excellent rate properties are kept about approximately 200 mAh gat2 C, meeting the standard of commercial materials. Supported by the detailed kinetic behaviors, the enhanced rate is mainly dominated by pseudocapacitive behaviors, accompanied by deepening redox reactions. Meanwhile, the cost of the proposed approach for recycling spent graphite is 894.87 $ t^(-1),and the recycling profit for regenerating graphite is approximately 7000 $ t^(-1). Given this, this work is anticipated to shed light on the closed-circuit recycling of spent graphite and offer significant strategies to repair graphite.
文摘Natural graphite is investigated as the cathode for aluminum ion batteries in recent years. However, some drawbacks of the natural graphite such as severe volume swelling shorten its lifetime, In this work, we prepared a composite material by depositing an amorphous carbon on the graphite paper, The composite was used as a cathode to study the electrochemical performance in aluminum ion batteries. The charge/discharge results showed that the composite could exhibit a longer cycle life than the graphite paper, Electrochemical analyses demonstrated that the interface between the amorphous carbon and the graphite paper made a major contribution to the improvement of the cycling stability.
基金financially supported by the National Natural Science Foundation of China(NSFC,Nos.52072021,22005023)the Fundamental Research Funds for the Central Universities(No.buctrc202141)。
文摘Potassium-ion batteries(PIBs) have attracted tremendous attention for large-scale energy storage fields based on abundant potassium resources. Graphite is a promising anode material for PIBs due to its low potassium ion intercalation voltage and mature industrialized preparation technology. However, the inability of graphitic structures to endure large volume change during charge/discharge cycles is a major limitation in their advancement for practical PIBs. Herein, a soft carbon-coated bulk graphite composite is synthesized using PTCDA as a carbon precursor. The PTCDA-derived soft carbon coating layer with large interlayer distance facilities fast potassium ion intercalation/extraction in the BG@C composite and buffers severe volume change during the charge/discharge cycles. When tested as anode for PIBs, the composite realizes enhanced rate capability(131.3 mAh/g at 2 C, 1 C=279 m A/g) and cycling performance(capacity retention of 76.1% after 150 cycles at 0.5 C). In general, the surface modification route to engineer graphite anode could inherently improve the electrochemical performance without any structural alteration.
