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
The extensive application of lithium-ion batteries in electric vehicles has led to a torrential surge of endof-life batteries.As the dominant anode material,graphite's environmental and resource costs in productio...The extensive application of lithium-ion batteries in electric vehicles has led to a torrential surge of endof-life batteries.As the dominant anode material,graphite's environmental and resource costs in production highlight the necessity of recycling spent graphite(SG).However,SG recycling technologies remain markedly underdeveloped compared to the cathode recovery status,due to perceived lower economic value.This review provides an in-depth analysis of the current SG growth trend and highlights the cost accounting for graphite recycling and the significant importance of advanced recycling technologies.By examining the failure mechanisms of graphite,various recycling and upcycling technologies in both practical application and fundamental research are fully discussed,in terms of the regeneration principle,recycling effect,strengths,and limitations of each method.Furthermore,the multi-purpose applications of recycled graphite beyond LIB anodes are explored to enhance its high-value properties.Finally,the prospects of SG recycling and large-scale application challenges are presented,including economic feasibility,process optimization,and regulatory restrictions.This review provides a comprehensive overview of developments in SG recycling strategies,offering valuable insights for narrowing the gap between fundamental research and practical applications.展开更多
Laser-induced periodic surface structures(LIPSS)have gained increasing attention in the field of micro/nano fabrication,although achieving sub-100-nm period LIPSS with high uniformity remains a significant challenge.I...Laser-induced periodic surface structures(LIPSS)have gained increasing attention in the field of micro/nano fabrication,although achieving sub-100-nm period LIPSS with high uniformity remains a significant challenge.In this work,towards deep-subwavelength LIPSS on highly oriented pyrolytic graphite(HOPG),we demonstrate that ultra-uniform nanogratings of sub-50-nm periods and near-10-nm groove widths can be stably prepared via 800-nm femtosecond laser scanning irradiation with a high-NA objective lens under water immersion.The resulting nanogratings of strong polarization dependence,exhibiting exceptional surface flatness,period stability,and structural integrity,tend to appear at near-damage-threshold fluence regime with an appropriate effective pulse number.It turns out that the water immersion condition can significantly reduce the thermal effects of femtosecond laser ablation on HOPG,and thus via a mild,incubation-like scanning ablation process occurring in the nanogrooves with a continuous or jumping manner,this deep-subwavelength grating can achieve robust elongation growth,ensuring its long-range uniformity as well as minimal deposited debris and structural defects.Interestingly,the different incubation extension mechanisms for the mutually perpendicular and parallel settings between scanning direction and laser polarization bring not only distinct effective-pulse-number windows and somewhat different grating qualities,but also different extension stabilities in nanograting stitching via overlapping scanning lines and thus the optimal scanning strategy of parallel setting for large-area processing.In short,this study presents a convenient laser-processing approach for high precision fabrication of sub-50-nm gratings on HOPG,which would provide new insights into micro/nano-fabrication for optoelectronic metasurfaces and physics of the interaction between ultrafast laser and graphite.展开更多
The impurities and structural cracks within spent graphite(SG)in lithium-ion battery anodes hamper lithium-ion intercalation and extraction after successive charge-discharge operations,thereby yielding poor lithium st...The impurities and structural cracks within spent graphite(SG)in lithium-ion battery anodes hamper lithium-ion intercalation and extraction after successive charge-discharge operations,thereby yielding poor lithium storage behavior.Herein,low-viscosity natural deep eutectic solvent(NDES)composed of citric acid(CA)and betaine hydrochloride was employed to remove the organic impurities in SG via a one-step benign process involving hydrogen bonds and electrostatic interactions at mild conditions of 80℃ for only 30 min.After NDES leaching under optimal conditions(molar ratio of CA to betaine hydrochloride=3:1,80℃,30 min),the as-obtained sample(denoted as BG-3)exhibited an extremely clean surface,moderately enlarged interlayer distance,and more structural defects at the edge of graphite lamellae.These features facilitated lithium-ion intercalation and withdrawal,bestowing BG-3 with remarkable activity in lithium-ion battery(LIB)recycling.For instance,BG-3 delivered a capacity of 438.6 mAh g^(-1) at a current density of 0.1 A g^(-1).Its capacity retention reached 97.9%,accompanied by a Coulombic efficiency of 99.1%,upon completing 100 cycles.A molecular dynamics simulation was employed to illuminate the regeneration mechanism for anode graphite from a theoretical perspective.It revealed that NDES exhibits lower binding energy with all contaminants compared to graphite,which is favorable for NDES to eliminate impurities from graphite surfaces.This study unveils a method of recycling SG from retired LIBs by a short eco-friendly process,providing a competitive blueprint to address the shortage of battery-grade anode graphite and to achieve carbon neutrality.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
Waste graphitization cathode carbon blocks are a type of hazardous solid waste generated during the aluminum electrolysis process,and their proper disposal is a key step in the resource utilization of discarded graphi...Waste graphitization cathode carbon blocks are a type of hazardous solid waste generated during the aluminum electrolysis process,and their proper disposal is a key step in the resource utilization of discarded graphite.This study utilizes the porous“defect advantage”of a cathode carbon block matrix to prepare silicon-doped and asphalt-coated detoxified and purified waste graphitization cathode carbon blocks for use as high-performance silicon/carbon composite anode materials.The results show that the uniformly silicondoped silicon/carbon composite material features a unique amorphous carbon-encapsulated“locked silicon”structure,which effectively addresses issues such as cathode volume expansion,excessive growth of the solid electrolyte interphase(SEI)film,and poor electrical contact between active materials.Consequently,electrochemical performance is enhanced.After assembly in a half-cell,the PSCC/10%Si@C(purified waste graphitization cathode carbon/10%Si@C)material exhibits optimal electrochemical stability,with an initial charging specific capacity of 514.5 mAh/g at 0.1 C(1 C=170 mA/g)and a capacity retention rate of 95.1%after 100 cycles.At a charge rate of 2.0 C,a specific capacity of 216.9 mAh/g is achieved.This technology provides a new pathway for the economical and high-value utilization of waste cathode carbon blocks and the development of low-cost,high-performance anode materials.展开更多
Graphite and hexagonal boron nitride(h-BN),despite their structural similarity,exhibit opposing electronic properties,namely,metallic conductivity and wide-bandgap insulation,respectively.In recent years,graphene-h-BN...Graphite and hexagonal boron nitride(h-BN),despite their structural similarity,exhibit opposing electronic properties,namely,metallic conductivity and wide-bandgap insulation,respectively.In recent years,graphene-h-BN heterostructures have attracted significant research interest,with the resulting hybrid B-C-N atomic-layer systems exhibiting distinctive electronic properties.Notably,interface effects play a decisive role in governing the performance of these heterostructures.Nevertheless,owing to the lack of high-quality composites,the interfacial structure in B-C-N materials and the correlation with critical properties such as charge transport and band structure modulation are not fully clear.Here,we report the direct synthesis of a millimeter-sized hexagonal B-C-N composite via a solvent method under high-pressure and high-temperature conditions.Structural characterization reveals that the synthesized B-C-N composite contains isolated graphite and h-BN.Compared with pure h-BN,the B-C-N composite has a narrower bandgap and shows a pronounced photoelectric response in the visible light region.More interestingly,we find a graphite-like B-C compound with a thickness of about 30 nm at the graphite-h-BN interface,which forms Schottky junctions with graphite,thus realizing rectification properties.Our findings provide a method for synthesizing highquality B-C-N composites and offer new insights into the structure of the graphite-h-BN interface.展开更多
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funded by the National Key Research and Development Program of China(grant no.2023YFB3809300)Longzhong Laboratory Research Project(grant no.2024KF-20)+4 种基金the National Science Foundation of China(grant no.52373306)the Key Research and Development Program Project of Hubei Province(grant no.2023BAB140,2024BAA013)the Natural Science Foundation of Hubei Province(grant no.2023AFA053)the Key Research and Development Program of Henan Province(grant no.251111240100)the Postdoctoral Fellowship Program of CPSF(grant no.GZB20230553)。
文摘The extensive application of lithium-ion batteries in electric vehicles has led to a torrential surge of endof-life batteries.As the dominant anode material,graphite's environmental and resource costs in production highlight the necessity of recycling spent graphite(SG).However,SG recycling technologies remain markedly underdeveloped compared to the cathode recovery status,due to perceived lower economic value.This review provides an in-depth analysis of the current SG growth trend and highlights the cost accounting for graphite recycling and the significant importance of advanced recycling technologies.By examining the failure mechanisms of graphite,various recycling and upcycling technologies in both practical application and fundamental research are fully discussed,in terms of the regeneration principle,recycling effect,strengths,and limitations of each method.Furthermore,the multi-purpose applications of recycled graphite beyond LIB anodes are explored to enhance its high-value properties.Finally,the prospects of SG recycling and large-scale application challenges are presented,including economic feasibility,process optimization,and regulatory restrictions.This review provides a comprehensive overview of developments in SG recycling strategies,offering valuable insights for narrowing the gap between fundamental research and practical applications.
基金supported by grants from Natural Science Foundation of Guangdong Province(Grant No.2021A1515012335)National Natural Science Foundation of China(NSFC)(Grant No.11274400)+2 种基金Pearl River S&T Nova Program of Guangzhou(Grant No.201506010059)State Key Laboratory of Optoelectronic Materials and Technologies(Sun Yat-Sen University)(Grant No.OEMT-2024-ZTS-01)State Key Laboratory of High Field Laser Physics(Shanghai Institute of Optics and Fine Mechanics)。
文摘Laser-induced periodic surface structures(LIPSS)have gained increasing attention in the field of micro/nano fabrication,although achieving sub-100-nm period LIPSS with high uniformity remains a significant challenge.In this work,towards deep-subwavelength LIPSS on highly oriented pyrolytic graphite(HOPG),we demonstrate that ultra-uniform nanogratings of sub-50-nm periods and near-10-nm groove widths can be stably prepared via 800-nm femtosecond laser scanning irradiation with a high-NA objective lens under water immersion.The resulting nanogratings of strong polarization dependence,exhibiting exceptional surface flatness,period stability,and structural integrity,tend to appear at near-damage-threshold fluence regime with an appropriate effective pulse number.It turns out that the water immersion condition can significantly reduce the thermal effects of femtosecond laser ablation on HOPG,and thus via a mild,incubation-like scanning ablation process occurring in the nanogrooves with a continuous or jumping manner,this deep-subwavelength grating can achieve robust elongation growth,ensuring its long-range uniformity as well as minimal deposited debris and structural defects.Interestingly,the different incubation extension mechanisms for the mutually perpendicular and parallel settings between scanning direction and laser polarization bring not only distinct effective-pulse-number windows and somewhat different grating qualities,but also different extension stabilities in nanograting stitching via overlapping scanning lines and thus the optimal scanning strategy of parallel setting for large-area processing.In short,this study presents a convenient laser-processing approach for high precision fabrication of sub-50-nm gratings on HOPG,which would provide new insights into micro/nano-fabrication for optoelectronic metasurfaces and physics of the interaction between ultrafast laser and graphite.
基金supported by the National Natural Science Foundation of China(Project Nos.22372051 and 21406044)Australian Research Council/Discovery Early Career Researcher Award(DECRA)funding scheme(DE230100180).
文摘The impurities and structural cracks within spent graphite(SG)in lithium-ion battery anodes hamper lithium-ion intercalation and extraction after successive charge-discharge operations,thereby yielding poor lithium storage behavior.Herein,low-viscosity natural deep eutectic solvent(NDES)composed of citric acid(CA)and betaine hydrochloride was employed to remove the organic impurities in SG via a one-step benign process involving hydrogen bonds and electrostatic interactions at mild conditions of 80℃ for only 30 min.After NDES leaching under optimal conditions(molar ratio of CA to betaine hydrochloride=3:1,80℃,30 min),the as-obtained sample(denoted as BG-3)exhibited an extremely clean surface,moderately enlarged interlayer distance,and more structural defects at the edge of graphite lamellae.These features facilitated lithium-ion intercalation and withdrawal,bestowing BG-3 with remarkable activity in lithium-ion battery(LIB)recycling.For instance,BG-3 delivered a capacity of 438.6 mAh g^(-1) at a current density of 0.1 A g^(-1).Its capacity retention reached 97.9%,accompanied by a Coulombic efficiency of 99.1%,upon completing 100 cycles.A molecular dynamics simulation was employed to illuminate the regeneration mechanism for anode graphite from a theoretical perspective.It revealed that NDES exhibits lower binding energy with all contaminants compared to graphite,which is favorable for NDES to eliminate impurities from graphite surfaces.This study unveils a method of recycling SG from retired LIBs by a short eco-friendly process,providing a competitive blueprint to address the shortage of battery-grade anode graphite and to achieve carbon neutrality.
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supported by the National Natural Science Foundation of China(No.52274346).
文摘Waste graphitization cathode carbon blocks are a type of hazardous solid waste generated during the aluminum electrolysis process,and their proper disposal is a key step in the resource utilization of discarded graphite.This study utilizes the porous“defect advantage”of a cathode carbon block matrix to prepare silicon-doped and asphalt-coated detoxified and purified waste graphitization cathode carbon blocks for use as high-performance silicon/carbon composite anode materials.The results show that the uniformly silicondoped silicon/carbon composite material features a unique amorphous carbon-encapsulated“locked silicon”structure,which effectively addresses issues such as cathode volume expansion,excessive growth of the solid electrolyte interphase(SEI)film,and poor electrical contact between active materials.Consequently,electrochemical performance is enhanced.After assembly in a half-cell,the PSCC/10%Si@C(purified waste graphitization cathode carbon/10%Si@C)material exhibits optimal electrochemical stability,with an initial charging specific capacity of 514.5 mAh/g at 0.1 C(1 C=170 mA/g)and a capacity retention rate of 95.1%after 100 cycles.At a charge rate of 2.0 C,a specific capacity of 216.9 mAh/g is achieved.This technology provides a new pathway for the economical and high-value utilization of waste cathode carbon blocks and the development of low-cost,high-performance anode materials.
基金supported by the National Key R&D Program of China(Grant No.2023YFA1406200)the National Science Foundation of China(Grant No.U2032215)+1 种基金Jilin Province Major Science and Technology Program,China(Grant No.20240211002GX)the Science and Technology Development Project of Jilin Province(Grant No.SKL202402004).
文摘Graphite and hexagonal boron nitride(h-BN),despite their structural similarity,exhibit opposing electronic properties,namely,metallic conductivity and wide-bandgap insulation,respectively.In recent years,graphene-h-BN heterostructures have attracted significant research interest,with the resulting hybrid B-C-N atomic-layer systems exhibiting distinctive electronic properties.Notably,interface effects play a decisive role in governing the performance of these heterostructures.Nevertheless,owing to the lack of high-quality composites,the interfacial structure in B-C-N materials and the correlation with critical properties such as charge transport and band structure modulation are not fully clear.Here,we report the direct synthesis of a millimeter-sized hexagonal B-C-N composite via a solvent method under high-pressure and high-temperature conditions.Structural characterization reveals that the synthesized B-C-N composite contains isolated graphite and h-BN.Compared with pure h-BN,the B-C-N composite has a narrower bandgap and shows a pronounced photoelectric response in the visible light region.More interestingly,we find a graphite-like B-C compound with a thickness of about 30 nm at the graphite-h-BN interface,which forms Schottky junctions with graphite,thus realizing rectification properties.Our findings provide a method for synthesizing highquality B-C-N composites and offer new insights into the structure of the graphite-h-BN interface.
