硬炭凭借较高的储钠容量、低电压平台以及优异的循环稳定性成为了钠离子电池(SIBs)最具应用潜力的负极材料。硬炭材料的微观孔隙结构是影响其储钠性能的关键因素之一,合理调控硬炭材料的孔隙结构大小及分布对提升钠离子电池性能至关重...硬炭凭借较高的储钠容量、低电压平台以及优异的循环稳定性成为了钠离子电池(SIBs)最具应用潜力的负极材料。硬炭材料的微观孔隙结构是影响其储钠性能的关键因素之一,合理调控硬炭材料的孔隙结构大小及分布对提升钠离子电池性能至关重要。本文以β-环糊精为碳源,采用NaCl辅助水热法制备了一系列具有不同微观孔隙结构的硬炭材料,考察了NaCl浓度对硬炭微观孔隙结构的影响,研究了硬炭材料的储纳性能。采用非原位X射线衍射仪、拉曼光谱仪及高倍率透射电镜等进行表征,结果表明,调控NaCl浓度能够优化硬炭材料的孔隙结构,提升硬炭材料闭孔体积。当NaCl浓度为2mol L^(-1)时,制备的硬炭材料(CD-2)的无序程度与石墨微晶尺寸最大,具有最大的闭孔体积与梯度孔隙结构。电化学测试表明,在0.02Ag^(-1)的电流密度下,CD-2硬炭材料具有360 mA hg^(-1)的高储钠比容量及90.2%的首次库伦效率。提出的NaCl辅助水热炭化调控硬炭闭孔结构的策略,为硬炭材料孔隙结构的合理设计提供了有效的技术方法,指导了高性能SIBs硬炭负极材料的开发。展开更多
锂硫电池宿主材料的成份与结构区别,是引起电池性能差异的重要原因。经济性好且环保的碳基宿主材料是实现锂硫电池实用化的最有效策略之一。本研究利用油棕树叶柄为原料,采用尿素浸泡和化学活化的方法,制备出具有堆叠纳米片层结构的氮...锂硫电池宿主材料的成份与结构区别,是引起电池性能差异的重要原因。经济性好且环保的碳基宿主材料是实现锂硫电池实用化的最有效策略之一。本研究利用油棕树叶柄为原料,采用尿素浸泡和化学活化的方法,制备出具有堆叠纳米片层结构的氮掺杂多孔炭材料(NPPCNs)用作硫正极宿主材料,显著提高了电池的性能。N-PPCNs实现了N元素的均匀掺杂,作为硫的宿主材料,增加了对多硫化物的吸附能,加速了多硫化物的转化动力学。复合多孔结构和氮的有效掺杂共同作用,抑制了“穿梭效应”,使复合电极达到1257 mAh g^(−1)的高比容量,在1 C倍率下循环500圈仍可保持490 mA h g^(−1)的比容量。这项工作充分证明了废弃生物质再利用的潜力。展开更多
Graphdiyne(GDY)is a two-dimensional carbon allotrope with exceptional physical and chemical properties that is gaining increasing attention.However,its efficient and scalable synthesis remains a significant challenge....Graphdiyne(GDY)is a two-dimensional carbon allotrope with exceptional physical and chemical properties that is gaining increasing attention.However,its efficient and scalable synthesis remains a significant challenge.We present a microwave-assisted approach for its continuous,large-scale production which enables synthesis at a rate of 0.6 g/h,with a yield of up to 90%.The synthesized GDY nanosheets have an average diameter of 246 nm and a thickness of 4 nm.We used GDY as a stable coating for potassium(K)metal anodes(K@GDY),taking advantage of its unique molecular structure to provide favorable paths for K-ion transport.This modification significantly inhibited dendrite formation and improved the cycling stability of K metal batteries.Full-cells with perylene-3,4,9,10-tetracarboxylic dianhydride(PTCDA)cathodes showed the clear superiority of the K@GDY anodes over bare K anodes in terms of performance,stability,and cycle life.The K@GDY maintained a stable voltage plateau and gave an excellent capacity retention after 600 cycles with nearly 100%Coulombic efficiency.This work not only provides a scalable and efficient way for GDY synthesis but also opens new possibilities for its use in energy storage and other advanced technologies.展开更多
The design of cost-effective and efficient metal-free carbon-based catalysts for the hydrogen evolution reaction(HER)is of great significance for increasing the production of clean hydrogen by the electrolysis of alka...The design of cost-effective and efficient metal-free carbon-based catalysts for the hydrogen evolution reaction(HER)is of great significance for increasing the production of clean hydrogen by the electrolysis of alkaline water.Precise control of the electronic structure by heteroatom doping has proven to be efficient for increasing catalytic activity.Nevertheless,both the structural characteristics and the underlying mechanism are not well understood,especially for doping with two different atoms,thus limiting the use of these catalysts.We report the production of phosphorus and nitrogen co-doped hollow carbon nanospheres(HCNs)by the copolymerization of pyrrole and aniline at a Triton X-100 micelle-interface,followed by doping with phytic acid and carbonization.The unique pore structure and defect-rich framework of the HCNs expose numerous active sites.Crucially,the combined effect of graphitic nitrogen and phosphorus-carbon bonds modulate the local electronic structure of adjacent C atoms and facilitates electron transfer.As a res-ult,the HCN carbonized at 1100°C exhibited superior HER activity and an outstanding stability(70 h at a current density of 10 mA cm^(−2))in alkaline water,because of the large number of graphitic nitrogen and phosphorus-carbon bonds.展开更多
Pitch produced by the lique-faction of coal was divided into two frac-tions:soluble in toluene(TS)and insol-uble in toluene but soluble in pyridine(TI-PS),and their differences in molecu-lar structure and oxidation ac...Pitch produced by the lique-faction of coal was divided into two frac-tions:soluble in toluene(TS)and insol-uble in toluene but soluble in pyridine(TI-PS),and their differences in molecu-lar structure and oxidation activity were studied.Several different carbon materi-als were produced from them by oxida-tion in air(350℃,300 mL/min)fol-lowed by carbonization(1000℃ in Ar),and the effect of the cross-linked structure on their structure and sodium storage properties was investigated.The results showed that the two pitch fractions were obviously different after the air oxidation.The TS fraction with a low degree of condensation and abundant side chains had a stronger oxidation activity and thus introduced more cross-linked oxygen-containing functional groups C(O)―O which prevented carbon layer rearrangement during the carbonization.As a result,a disordered hard carbon with more defects was formed,which improved the electrochemical performance.Therefore,the carbon materials derived from TS(O-TS-1000)had an obvious disordered structure and a larger layer spacing,giving them better sodium storage perform-ance than those derived from the TI-PS fraction(O-TI-PS-1000).The specific capacity of O-TS-1000 was about 250 mAh/g at 20 mA/g,which was 1.67 times higher than that of O-TI-PS-1000(150 mAh/g).展开更多
Aqueous zinc ion batteries are regarded as one of the most promising candidates for large-scale energy stor-age due to their high safety,cost-effectiveness,and environ-mental friendliness.However,uncontrolled zinc den...Aqueous zinc ion batteries are regarded as one of the most promising candidates for large-scale energy stor-age due to their high safety,cost-effectiveness,and environ-mental friendliness.However,uncontrolled zinc dendrite growth and side reactions of the zinc anode decrease the sta-bility of Zn batteries.We report the synthesis of an air-oxid-ized carbon nanotube(O-CNT)film by chemical vapor de-position followed by heat treatment in air which is used as a protective layer on the Zn foil to suppress zinc dendrite growth.The increase in the hydrophilicity of the O-CNT film caused by air oxidation facilitates zinc deposition between the film and the anode instead of deposition on the film surface.The porous structure of the O-CNT film homogenizes the Zn^(2+)ion flux and the electric field on the surface of the Zn foil,leading to the uniform deposition of Zn.As a result,a O-CNT@Zn symmetric cell has a much better cycling stability with a life of more than 3000 h at 1 mA cm^(−2) with a capacity of 1 mAh cm^(−2),and values of more than 2000 h and 1 mAh cm^(−2) at 5 mA cm^(−2).In addition,a O-CNT@Zn||Mn^(2+)inserted hydrated vanadium pentoxide(MnVOH)full cell has a better rate per-formance than a Zn||MnVOH cell,achieving a high discharge capacity of 194 mAh g^(−1) at a high current density of 8 A g^(−1).In a long-term cycling test,the O-CNT@Zn||MnVOH full cell has a capacity retention of 58.8%after 2000 cycles at a current density of 5 A·g^(−1).展开更多
Because of their low electrical conductivity,sluggish ion diffusion,and poor stability,conventional electrode materials are not able to meet the growing demands of energy storage and portable devices.Graphene assemble...Because of their low electrical conductivity,sluggish ion diffusion,and poor stability,conventional electrode materials are not able to meet the growing demands of energy storage and portable devices.Graphene assembled films(GAFs)formed from graphene nanosheets have an ultrahigh conductivity,a unique 2D network structure,and exceptional mechanical strength,which give them the potential to solve these problems.However,a systematic understanding of GAFs as an advanced electrode material is lacking.This review focuses on the use of GAFs in electrochemistry,providing a comprehensive analysis of their synthesis methods,surface/structural characteristics,and physical properties,and thus understand their structure-property relationships.Their advantages in batteries,supercapacitors,and electrochemical sensors are systematically evaluated,with an emphasis on their excellent electrical conductivity,ion transport kinetics,and interfacial stability.The existing problems in these devices,such as chemical inertness and mechanical brittleness,are discussed and potential solutions are proposed,including defect engineering and hybrid structures.This review should deepen our mechanistic understanding of the use of GAFs in electrochemical systems and provide actionable strategies for developing stable,high-performance electrode materials.展开更多
Pitch is a complex mixture of polycyclic aromatic hydrocarbons and their non-metal derivatives that has a high carbon content.Using pitch as a precursor for carbon materials in alkali metal ion(Li^(+)/Na^(+)/K^(+))bat...Pitch is a complex mixture of polycyclic aromatic hydrocarbons and their non-metal derivatives that has a high carbon content.Using pitch as a precursor for carbon materials in alkali metal ion(Li^(+)/Na^(+)/K^(+))batteries has become of great interest.However,its direct pyrolysis often leads to microstructures with a high orientation and small interlayer spacing due to uncontrolled liquid-phase carbonization,resulting in subpar electrochemical performance.It is therefore important to control the microstructures of pitch-derived carbon materials in order to improve their electrochemical properties.We evaluate the latest progress in the development of these materials using various microstructural engineering approaches,highlighting their use in metal-ion batteries and supercapacitors.The advantages and limitations of pitch molecules and their carbon derivatives are outlined,together with strategies for their modification in order to improve their properties for specific applications.Future research possibilities for structure optimization,scalable production,and waste pitch recycling are also considered.展开更多
Biomass-derived hard carbons,usually prepared by pyrolysis,are widely considered the most promising anode materials for sodium-ion bat-teries(SIBs)due to their high capacity,low poten-tial,sustainability,cost-effectiv...Biomass-derived hard carbons,usually prepared by pyrolysis,are widely considered the most promising anode materials for sodium-ion bat-teries(SIBs)due to their high capacity,low poten-tial,sustainability,cost-effectiveness,and environ-mental friendliness.The pyrolysis method affects the microstructure of the material,and ultimately its so-dium storage performance.Our previous work has shown that pyrolysis in a sealed graphite vessel im-proved the sodium storage performance of the car-bon,however the changes in its microstructure and the way this influences the sodium storage are still unclear.A series of hard carbon materials derived from corncobs(CCG-T,where T is the pyrolysis temperature)were pyrolyzed in a sealed graphite vessel at different temperatures.As the pyrolysis temperature increased from 1000 to 1400℃ small carbon domains gradually transformed into long and curved domains.At the same time,a greater number of large open pores with uniform apertures,as well as more closed pores,were formed.With the further increase of pyrolysis temperature to 1600℃,the long and curved domains became longer and straighter,and some closed pores gradually became open.CCG-1400,with abundant closed pores,had a superior SIB performance,with an initial reversible ca-pacity of 320.73 mAh g^(-1) at a current density of 30 mA g^(-1),an initial Coulomb efficiency(ICE)of 84.34%,and a capacity re-tention of 96.70%after 100 cycles.This study provides a method for the precise regulation of the microcrystalline and pore structures of hard carbon materials.展开更多
文摘硬炭凭借较高的储钠容量、低电压平台以及优异的循环稳定性成为了钠离子电池(SIBs)最具应用潜力的负极材料。硬炭材料的微观孔隙结构是影响其储钠性能的关键因素之一,合理调控硬炭材料的孔隙结构大小及分布对提升钠离子电池性能至关重要。本文以β-环糊精为碳源,采用NaCl辅助水热法制备了一系列具有不同微观孔隙结构的硬炭材料,考察了NaCl浓度对硬炭微观孔隙结构的影响,研究了硬炭材料的储纳性能。采用非原位X射线衍射仪、拉曼光谱仪及高倍率透射电镜等进行表征,结果表明,调控NaCl浓度能够优化硬炭材料的孔隙结构,提升硬炭材料闭孔体积。当NaCl浓度为2mol L^(-1)时,制备的硬炭材料(CD-2)的无序程度与石墨微晶尺寸最大,具有最大的闭孔体积与梯度孔隙结构。电化学测试表明,在0.02Ag^(-1)的电流密度下,CD-2硬炭材料具有360 mA hg^(-1)的高储钠比容量及90.2%的首次库伦效率。提出的NaCl辅助水热炭化调控硬炭闭孔结构的策略,为硬炭材料孔隙结构的合理设计提供了有效的技术方法,指导了高性能SIBs硬炭负极材料的开发。
文摘锂硫电池宿主材料的成份与结构区别,是引起电池性能差异的重要原因。经济性好且环保的碳基宿主材料是实现锂硫电池实用化的最有效策略之一。本研究利用油棕树叶柄为原料,采用尿素浸泡和化学活化的方法,制备出具有堆叠纳米片层结构的氮掺杂多孔炭材料(NPPCNs)用作硫正极宿主材料,显著提高了电池的性能。N-PPCNs实现了N元素的均匀掺杂,作为硫的宿主材料,增加了对多硫化物的吸附能,加速了多硫化物的转化动力学。复合多孔结构和氮的有效掺杂共同作用,抑制了“穿梭效应”,使复合电极达到1257 mAh g^(−1)的高比容量,在1 C倍率下循环500圈仍可保持490 mA h g^(−1)的比容量。这项工作充分证明了废弃生物质再利用的潜力。
基金supported by National Natural Science Foundation of China(52302034,52402060,52202201,52021006)Beijing National Laboratory for Molecular Sciences(BNLMS-CXTD202001)+1 种基金Shenzhen Science and Technology Innovation Commission(KQTD20221101115627004)China Postdoctoral Science Foundation(2024T170972)。
文摘Graphdiyne(GDY)is a two-dimensional carbon allotrope with exceptional physical and chemical properties that is gaining increasing attention.However,its efficient and scalable synthesis remains a significant challenge.We present a microwave-assisted approach for its continuous,large-scale production which enables synthesis at a rate of 0.6 g/h,with a yield of up to 90%.The synthesized GDY nanosheets have an average diameter of 246 nm and a thickness of 4 nm.We used GDY as a stable coating for potassium(K)metal anodes(K@GDY),taking advantage of its unique molecular structure to provide favorable paths for K-ion transport.This modification significantly inhibited dendrite formation and improved the cycling stability of K metal batteries.Full-cells with perylene-3,4,9,10-tetracarboxylic dianhydride(PTCDA)cathodes showed the clear superiority of the K@GDY anodes over bare K anodes in terms of performance,stability,and cycle life.The K@GDY maintained a stable voltage plateau and gave an excellent capacity retention after 600 cycles with nearly 100%Coulombic efficiency.This work not only provides a scalable and efficient way for GDY synthesis but also opens new possibilities for its use in energy storage and other advanced technologies.
基金financially supported by the project of the National Natural Science Foundation of China(52322203)the Key Research and Development Program of Shaanxi Province(2024GHZDXM-21)。
文摘The design of cost-effective and efficient metal-free carbon-based catalysts for the hydrogen evolution reaction(HER)is of great significance for increasing the production of clean hydrogen by the electrolysis of alkaline water.Precise control of the electronic structure by heteroatom doping has proven to be efficient for increasing catalytic activity.Nevertheless,both the structural characteristics and the underlying mechanism are not well understood,especially for doping with two different atoms,thus limiting the use of these catalysts.We report the production of phosphorus and nitrogen co-doped hollow carbon nanospheres(HCNs)by the copolymerization of pyrrole and aniline at a Triton X-100 micelle-interface,followed by doping with phytic acid and carbonization.The unique pore structure and defect-rich framework of the HCNs expose numerous active sites.Crucially,the combined effect of graphitic nitrogen and phosphorus-carbon bonds modulate the local electronic structure of adjacent C atoms and facilitates electron transfer.As a res-ult,the HCN carbonized at 1100°C exhibited superior HER activity and an outstanding stability(70 h at a current density of 10 mA cm^(−2))in alkaline water,because of the large number of graphitic nitrogen and phosphorus-carbon bonds.
文摘Pitch produced by the lique-faction of coal was divided into two frac-tions:soluble in toluene(TS)and insol-uble in toluene but soluble in pyridine(TI-PS),and their differences in molecu-lar structure and oxidation activity were studied.Several different carbon materi-als were produced from them by oxida-tion in air(350℃,300 mL/min)fol-lowed by carbonization(1000℃ in Ar),and the effect of the cross-linked structure on their structure and sodium storage properties was investigated.The results showed that the two pitch fractions were obviously different after the air oxidation.The TS fraction with a low degree of condensation and abundant side chains had a stronger oxidation activity and thus introduced more cross-linked oxygen-containing functional groups C(O)―O which prevented carbon layer rearrangement during the carbonization.As a result,a disordered hard carbon with more defects was formed,which improved the electrochemical performance.Therefore,the carbon materials derived from TS(O-TS-1000)had an obvious disordered structure and a larger layer spacing,giving them better sodium storage perform-ance than those derived from the TI-PS fraction(O-TI-PS-1000).The specific capacity of O-TS-1000 was about 250 mAh/g at 20 mA/g,which was 1.67 times higher than that of O-TI-PS-1000(150 mAh/g).
基金supported by the National Natural Science Foundation of China(22179093 and21905202)。
文摘Aqueous zinc ion batteries are regarded as one of the most promising candidates for large-scale energy stor-age due to their high safety,cost-effectiveness,and environ-mental friendliness.However,uncontrolled zinc dendrite growth and side reactions of the zinc anode decrease the sta-bility of Zn batteries.We report the synthesis of an air-oxid-ized carbon nanotube(O-CNT)film by chemical vapor de-position followed by heat treatment in air which is used as a protective layer on the Zn foil to suppress zinc dendrite growth.The increase in the hydrophilicity of the O-CNT film caused by air oxidation facilitates zinc deposition between the film and the anode instead of deposition on the film surface.The porous structure of the O-CNT film homogenizes the Zn^(2+)ion flux and the electric field on the surface of the Zn foil,leading to the uniform deposition of Zn.As a result,a O-CNT@Zn symmetric cell has a much better cycling stability with a life of more than 3000 h at 1 mA cm^(−2) with a capacity of 1 mAh cm^(−2),and values of more than 2000 h and 1 mAh cm^(−2) at 5 mA cm^(−2).In addition,a O-CNT@Zn||Mn^(2+)inserted hydrated vanadium pentoxide(MnVOH)full cell has a better rate per-formance than a Zn||MnVOH cell,achieving a high discharge capacity of 194 mAh g^(−1) at a high current density of 8 A g^(−1).In a long-term cycling test,the O-CNT@Zn||MnVOH full cell has a capacity retention of 58.8%after 2000 cycles at a current density of 5 A·g^(−1).
基金the National Natural Science Foundation of China(22279097)the Key R&D Program of Hubei Province(2023BAB103)the PhD Scientific Research and Innovation Foundation of The Education Department of Hainan Province Joint Project of Sanya Yazhou Bay Science and Technology City(HSPHDSRF-2024-03-022)。
文摘Because of their low electrical conductivity,sluggish ion diffusion,and poor stability,conventional electrode materials are not able to meet the growing demands of energy storage and portable devices.Graphene assembled films(GAFs)formed from graphene nanosheets have an ultrahigh conductivity,a unique 2D network structure,and exceptional mechanical strength,which give them the potential to solve these problems.However,a systematic understanding of GAFs as an advanced electrode material is lacking.This review focuses on the use of GAFs in electrochemistry,providing a comprehensive analysis of their synthesis methods,surface/structural characteristics,and physical properties,and thus understand their structure-property relationships.Their advantages in batteries,supercapacitors,and electrochemical sensors are systematically evaluated,with an emphasis on their excellent electrical conductivity,ion transport kinetics,and interfacial stability.The existing problems in these devices,such as chemical inertness and mechanical brittleness,are discussed and potential solutions are proposed,including defect engineering and hybrid structures.This review should deepen our mechanistic understanding of the use of GAFs in electrochemical systems and provide actionable strategies for developing stable,high-performance electrode materials.
文摘Pitch is a complex mixture of polycyclic aromatic hydrocarbons and their non-metal derivatives that has a high carbon content.Using pitch as a precursor for carbon materials in alkali metal ion(Li^(+)/Na^(+)/K^(+))batteries has become of great interest.However,its direct pyrolysis often leads to microstructures with a high orientation and small interlayer spacing due to uncontrolled liquid-phase carbonization,resulting in subpar electrochemical performance.It is therefore important to control the microstructures of pitch-derived carbon materials in order to improve their electrochemical properties.We evaluate the latest progress in the development of these materials using various microstructural engineering approaches,highlighting their use in metal-ion batteries and supercapacitors.The advantages and limitations of pitch molecules and their carbon derivatives are outlined,together with strategies for their modification in order to improve their properties for specific applications.Future research possibilities for structure optimization,scalable production,and waste pitch recycling are also considered.
文摘Biomass-derived hard carbons,usually prepared by pyrolysis,are widely considered the most promising anode materials for sodium-ion bat-teries(SIBs)due to their high capacity,low poten-tial,sustainability,cost-effectiveness,and environ-mental friendliness.The pyrolysis method affects the microstructure of the material,and ultimately its so-dium storage performance.Our previous work has shown that pyrolysis in a sealed graphite vessel im-proved the sodium storage performance of the car-bon,however the changes in its microstructure and the way this influences the sodium storage are still unclear.A series of hard carbon materials derived from corncobs(CCG-T,where T is the pyrolysis temperature)were pyrolyzed in a sealed graphite vessel at different temperatures.As the pyrolysis temperature increased from 1000 to 1400℃ small carbon domains gradually transformed into long and curved domains.At the same time,a greater number of large open pores with uniform apertures,as well as more closed pores,were formed.With the further increase of pyrolysis temperature to 1600℃,the long and curved domains became longer and straighter,and some closed pores gradually became open.CCG-1400,with abundant closed pores,had a superior SIB performance,with an initial reversible ca-pacity of 320.73 mAh g^(-1) at a current density of 30 mA g^(-1),an initial Coulomb efficiency(ICE)of 84.34%,and a capacity re-tention of 96.70%after 100 cycles.This study provides a method for the precise regulation of the microcrystalline and pore structures of hard carbon materials.
