The genesis mechanism of low-resistivity oil formation in the medium-deep Shahejie Formation of Bohai C Oilfield is unclear,and there is a lack of effective methods for identifying low-resistivity oil layers.This arti...The genesis mechanism of low-resistivity oil formation in the medium-deep Shahejie Formation of Bohai C Oilfield is unclear,and there is a lack of effective methods for identifying low-resistivity oil layers.This article conducts a comprehensive analysis based on core sample experiments,and research shows that the formation of low-resistivity oil layers in the oilfield is mainly caused by the superposition of three factors:1)microcapillary development,high irreducible water;2)additional conductive effect of clay;3)deep invasion of high salinity mud filtrate.The low-resistivity oil layer in this oilfield is mainly characterized by high mud content and strong additional conductivity of clay,and the complex pore throat structure leads to high irreducible water saturation,and the impact of saline mud intrusion,resulted in low-resistivity oil layers.The oil-field is mainly a lightweight oil layer with hydrophilic wettability,studying the response characteristics of oil and water layers through core nuclear magnetic resonance experiments,effectively identifying low-resistivity oil layers based on the correlation between resistivity and physical properties.展开更多
Energy storage is a key factor in the drive for carbon neutrality and carbon nanotubes(CNTs)may have an important role in this.Their intrinsic sp2 covalent structure gives them excellent electrical conductivity,mechan...Energy storage is a key factor in the drive for carbon neutrality and carbon nanotubes(CNTs)may have an important role in this.Their intrinsic sp2 covalent structure gives them excellent electrical conductivity,mechanical strength,and chemical stability,making them suitable for many uses in energy storage,such as lithium-ion batteries(LIBs).Currently,their use in LIBs mainly focuses on conductive networks,current collectors,and dry electrodes.The review outlines advances in the use of CNTs in the cathodes and anodes of LIBs,especially in the electrode fabrication and mechanical sensors,as well as providing insights into their future development.展开更多
Organic batteries have attracted a lot of attention due to the advantages of flexibility,light weight,vast resources,low cost,recyclability,and ease to be functionalized through molecular design.The biggest difference...Organic batteries have attracted a lot of attention due to the advantages of flexibility,light weight,vast resources,low cost,recyclability,and ease to be functionalized through molecular design.The biggest difference between organic materials and inorganic materials is the relatively weak intermolecular interactions in organic materials but strong covalent or ionic bonds in inorganic materials,which is the inherent reason of their different physiochemical and electrochemical characteristics.Therefore,the relatively weak intermolecular interactions can indisputably affect the electrochemical performance of organic batteries significantly.Herein,the intermolecular interactions that are closely related to organic redox-active materials and unique in organic batteries are summarized into three parts:1)between neighbor active molecules,2)between active molecules and the conduction additives,and 3)between active molecules and the binders.We hope this short review can give a distinct viewpoint for better understanding the internal reasons of high-performance batteries and stimulate the deep studies of relatively weak intermolecular interactions for strengthening the performance of organic batteries.展开更多
Binary carbon mixtures, carbon black ECP 600JD(ECP) combined with vapor grown carbon fiber(VGCF) or carbon nanotube(CNT), or graphene(Gr) in different mass ratios, are investigated as the conductive additives for the ...Binary carbon mixtures, carbon black ECP 600JD(ECP) combined with vapor grown carbon fiber(VGCF) or carbon nanotube(CNT), or graphene(Gr) in different mass ratios, are investigated as the conductive additives for the cathode material polyoxomolybadate Na_3[AlMo_6O_(24)H_6](NAM). Field emission scanning electron microscopy and energy dispersive X-ray spectroscopy show that the surfaces of NAM particles are covered homogeneously with the binary conductive additive mixtures except the combination of ECP and CNT. The optimum combination is the mixture of ECP and VGCF, which shows higher discharge capacity than the combinations of ECP and CNT or Gr. Initial discharge capacities of 364, 339, and 291 m A·h/g are obtained by the combination of ECP and VGCF in the mass ratios of 2:1, 1:1, and 1:2, respectively. The results of electrochemical impedance spectra and 4-pin probe measurements demonstrate that the combination of ECP and VGCF exhibits the highest electrical conductivity for the electrode.展开更多
CONSPECTUS:Sulfur,being lightweight,cost-effective,and offering a remarkably high lithium-ion storage capacity,has positioned lithium−sulfur(Li−S)batteries as promising candidates for applications that demand high ene...CONSPECTUS:Sulfur,being lightweight,cost-effective,and offering a remarkably high lithium-ion storage capacity,has positioned lithium−sulfur(Li−S)batteries as promising candidates for applications that demand high energy density.These range from electric vehicles(EVs)to urban air mobility(UAM)systems.Despite this potential,Li−S batteries still face significant performance challenges,limiting their practical application.Chief among these challenges are the limited lifespan and low charge−discharge efficiency,predominantly caused by the dissolution of lithium polysulfide intermediate products formed during battery cycling in ether-based electrolytes.Moreover,sulfur and lithium sulfide,which constitute the active material in the cathode,are intrinsically insulating,complicating efforts to increase the active material content in the cathode and fabricate thick cathodes with high conductivity.These issues have long stood in the way of Li−S batteries achieving commercial viability.Overcoming these obstacles requires a multifaceted approach that focuses on modifications at the level of the cathode materials such as the active material,conductive agents,binders,and additives.This Account delves into these key challenges and presents a comprehensive overview of research strategies aimed at enhancing the performance of Li−S batteries with a particular focus on the sulfur cathode.First,the Account addresses practical challenges in Li−S batteries,such as the complex composition of the cathode,the low sulfur utilization efficiency,suboptimal electrolyte-to-sulfur ratios,and nonuniform sulfur conversion reactions.Strategies to overcome these barriers include the design of advanced cathode architectures that promote high sulfur utilization and an improved energy density.Modifications to the components of the cathode and the adjoining materials,such as the incorporation of conductive additives,help mitigate the insulating nature of sulfur.Additionally,the Account places particular emphasis on the innovative use of pelletizing techniques in sulfur cathode fabrication,which has demonstrated notable improvements in the cathode performance.One of the Account’s highlights is the discussion of lowtemperature operation strategies for Li−S batteries,which is a critical area for real-world application,especially in aerospace and cold-environment operations.There are significant performance differences when transitioning from lab-scale coin cells to larger pouch cells,underscoring the importance of considering cell geometries and their impact on the scalability and performance.Finally,the Account explores the development of all-solid-state Li−S batteries,a promising approach that could fundamentally address the issue of lithium polysulfide dissolution by eliminating the use of liquid electrolytes altogether.The inherent drawbacks of Li−S batteries,such as the insulating nature of sulfur and the challenges of high sulfur loading,can be strategically addressed to pave the way for their commercialization.In doing so,Li−S batteries offer a clear pathway beyond the limitations of conventional lithium-ion batteries,making them a highly attractive option for applications requiring high gravimetric and volumetric energy densities.展开更多
The development of lit;triton ion batteries （LIBs） relies on the improvement in the performance of electrode materials with higher capacity, higher rate capability, and longer cycle lift;. In this review article, th...The development of lit;triton ion batteries （LIBs） relies on the improvement in the performance of electrode materials with higher capacity, higher rate capability, and longer cycle lift;. In this review article, the recent advances in carbon nanotube （CNT） anodes, CNT-based composite electrodes, and CNT current collectors for high performance LIBs are concerned. CNT has received considerable attentions as a candidate material for the LIB applications. In addition to a possible choice for anode, CNT has been recognized as a solution in improving the performance of the state-of-the-art electrode materials. The CNT-based composite electrodes can be fabricated by mechanical or chem- ical approaches. Owing to the large aspect ratio and the high electrical conductivity, CNTs at very low loading can lead to an efficient conductive network. The excellent mechanical strength suggests the great potential in forming a structure scaffold to accommodate nano-sized electrode materials. Accordingly, the incorporation of CNTs will enhance the conductivity of the composite electrodes, mitigatc the agglomeration problem, decrease the dependence on inactive binders, and improve the clcctrochenfical properties of both anode and cathode materials remarkably. Freestanding CNT network can be used as lightweight current collectors to increase the overall energy density of LIBs. Finally, research perspectives for exploiting CNTs in high-performance LIBs are discussed.展开更多
Direct mass exfoliation of graphene from bulk graphite with high yield and productivity for commercial applications is challenging.This work proposes self-grinding exfoliation using the mutual shear friction of graphi...Direct mass exfoliation of graphene from bulk graphite with high yield and productivity for commercial applications is challenging.This work proposes self-grinding exfoliation using the mutual shear friction of graphite particles to fabricate graphene from microcrystalline graphite.The concept is implemented using microbeads as the grinding medium to drive the shear friction between graphite nanocrystals in a high-concentration paste.The proposed approach substantially improves graphene yield from 6.3% to 100% and simultaneously generates a record productivity of 7.5 g h^(-1)L^(-1),achieving total graphite-to-graphene conversion on the kilogram scale.The as-prepared graphene nanosheets have an average lateral size of 298 nm and the same C/O atomic ratio as the pristine graphite.In addition,the well-exfoliated,small nanosheets display good electrical conductivity and exhibit significant potential as conductive additives that improve the specific capacity and cyclic stability of Li-ion batteries better than commercial carbon-based conductive particles.展开更多
文摘The genesis mechanism of low-resistivity oil formation in the medium-deep Shahejie Formation of Bohai C Oilfield is unclear,and there is a lack of effective methods for identifying low-resistivity oil layers.This article conducts a comprehensive analysis based on core sample experiments,and research shows that the formation of low-resistivity oil layers in the oilfield is mainly caused by the superposition of three factors:1)microcapillary development,high irreducible water;2)additional conductive effect of clay;3)deep invasion of high salinity mud filtrate.The low-resistivity oil layer in this oilfield is mainly characterized by high mud content and strong additional conductivity of clay,and the complex pore throat structure leads to high irreducible water saturation,and the impact of saline mud intrusion,resulted in low-resistivity oil layers.The oil-field is mainly a lightweight oil layer with hydrophilic wettability,studying the response characteristics of oil and water layers through core nuclear magnetic resonance experiments,effectively identifying low-resistivity oil layers based on the correlation between resistivity and physical properties.
文摘Energy storage is a key factor in the drive for carbon neutrality and carbon nanotubes(CNTs)may have an important role in this.Their intrinsic sp2 covalent structure gives them excellent electrical conductivity,mechanical strength,and chemical stability,making them suitable for many uses in energy storage,such as lithium-ion batteries(LIBs).Currently,their use in LIBs mainly focuses on conductive networks,current collectors,and dry electrodes.The review outlines advances in the use of CNTs in the cathodes and anodes of LIBs,especially in the electrode fabrication and mechanical sensors,as well as providing insights into their future development.
基金financialy supported by the National Natural Science Foundation of China(51773071)the National 1000-Talents Program+2 种基金Innovation Fund of WNLOthe Fundamental Research Funds for the Central Universities(HUST:2017KFYXJJ023,2017KFXKJC002,2018KFYXKJC018,and 2019kfy RCPY099)Hubei Provincial Natural Science Foundation of China(2019CFA002)
文摘Organic batteries have attracted a lot of attention due to the advantages of flexibility,light weight,vast resources,low cost,recyclability,and ease to be functionalized through molecular design.The biggest difference between organic materials and inorganic materials is the relatively weak intermolecular interactions in organic materials but strong covalent or ionic bonds in inorganic materials,which is the inherent reason of their different physiochemical and electrochemical characteristics.Therefore,the relatively weak intermolecular interactions can indisputably affect the electrochemical performance of organic batteries significantly.Herein,the intermolecular interactions that are closely related to organic redox-active materials and unique in organic batteries are summarized into three parts:1)between neighbor active molecules,2)between active molecules and the conduction additives,and 3)between active molecules and the binders.We hope this short review can give a distinct viewpoint for better understanding the internal reasons of high-performance batteries and stimulate the deep studies of relatively weak intermolecular interactions for strengthening the performance of organic batteries.
文摘Binary carbon mixtures, carbon black ECP 600JD(ECP) combined with vapor grown carbon fiber(VGCF) or carbon nanotube(CNT), or graphene(Gr) in different mass ratios, are investigated as the conductive additives for the cathode material polyoxomolybadate Na_3[AlMo_6O_(24)H_6](NAM). Field emission scanning electron microscopy and energy dispersive X-ray spectroscopy show that the surfaces of NAM particles are covered homogeneously with the binary conductive additive mixtures except the combination of ECP and CNT. The optimum combination is the mixture of ECP and VGCF, which shows higher discharge capacity than the combinations of ECP and CNT or Gr. Initial discharge capacities of 364, 339, and 291 m A·h/g are obtained by the combination of ECP and VGCF in the mass ratios of 2:1, 1:1, and 1:2, respectively. The results of electrochemical impedance spectra and 4-pin probe measurements demonstrate that the combination of ECP and VGCF exhibits the highest electrical conductivity for the electrode.
基金supported by the National Research Council of Science&Technology(NST)grant by the Korea government(MSIT)(No.GTL24011-000)supported by Nano·Material Technology Development Program through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(RS-2024-00455177).
文摘CONSPECTUS:Sulfur,being lightweight,cost-effective,and offering a remarkably high lithium-ion storage capacity,has positioned lithium−sulfur(Li−S)batteries as promising candidates for applications that demand high energy density.These range from electric vehicles(EVs)to urban air mobility(UAM)systems.Despite this potential,Li−S batteries still face significant performance challenges,limiting their practical application.Chief among these challenges are the limited lifespan and low charge−discharge efficiency,predominantly caused by the dissolution of lithium polysulfide intermediate products formed during battery cycling in ether-based electrolytes.Moreover,sulfur and lithium sulfide,which constitute the active material in the cathode,are intrinsically insulating,complicating efforts to increase the active material content in the cathode and fabricate thick cathodes with high conductivity.These issues have long stood in the way of Li−S batteries achieving commercial viability.Overcoming these obstacles requires a multifaceted approach that focuses on modifications at the level of the cathode materials such as the active material,conductive agents,binders,and additives.This Account delves into these key challenges and presents a comprehensive overview of research strategies aimed at enhancing the performance of Li−S batteries with a particular focus on the sulfur cathode.First,the Account addresses practical challenges in Li−S batteries,such as the complex composition of the cathode,the low sulfur utilization efficiency,suboptimal electrolyte-to-sulfur ratios,and nonuniform sulfur conversion reactions.Strategies to overcome these barriers include the design of advanced cathode architectures that promote high sulfur utilization and an improved energy density.Modifications to the components of the cathode and the adjoining materials,such as the incorporation of conductive additives,help mitigate the insulating nature of sulfur.Additionally,the Account places particular emphasis on the innovative use of pelletizing techniques in sulfur cathode fabrication,which has demonstrated notable improvements in the cathode performance.One of the Account’s highlights is the discussion of lowtemperature operation strategies for Li−S batteries,which is a critical area for real-world application,especially in aerospace and cold-environment operations.There are significant performance differences when transitioning from lab-scale coin cells to larger pouch cells,underscoring the importance of considering cell geometries and their impact on the scalability and performance.Finally,the Account explores the development of all-solid-state Li−S batteries,a promising approach that could fundamentally address the issue of lithium polysulfide dissolution by eliminating the use of liquid electrolytes altogether.The inherent drawbacks of Li−S batteries,such as the insulating nature of sulfur and the challenges of high sulfur loading,can be strategically addressed to pave the way for their commercialization.In doing so,Li−S batteries offer a clear pathway beyond the limitations of conventional lithium-ion batteries,making them a highly attractive option for applications requiring high gravimetric and volumetric energy densities.
基金Acknowledgements This work was supported by the National Basic Research Program of China （Grant No. 2012CB932301）, the National Natural Science Foundation of China （Grant Nos. 51102146 and 50825201）, and the Chhmse Postdoctoral Science Foundation （2012NI520261）.
文摘The development of lit;triton ion batteries （LIBs） relies on the improvement in the performance of electrode materials with higher capacity, higher rate capability, and longer cycle lift;. In this review article, the recent advances in carbon nanotube （CNT） anodes, CNT-based composite electrodes, and CNT current collectors for high performance LIBs are concerned. CNT has received considerable attentions as a candidate material for the LIB applications. In addition to a possible choice for anode, CNT has been recognized as a solution in improving the performance of the state-of-the-art electrode materials. The CNT-based composite electrodes can be fabricated by mechanical or chem- ical approaches. Owing to the large aspect ratio and the high electrical conductivity, CNTs at very low loading can lead to an efficient conductive network. The excellent mechanical strength suggests the great potential in forming a structure scaffold to accommodate nano-sized electrode materials. Accordingly, the incorporation of CNTs will enhance the conductivity of the composite electrodes, mitigatc the agglomeration problem, decrease the dependence on inactive binders, and improve the clcctrochenfical properties of both anode and cathode materials remarkably. Freestanding CNT network can be used as lightweight current collectors to increase the overall energy density of LIBs. Finally, research perspectives for exploiting CNTs in high-performance LIBs are discussed.
基金supported by the National Natural Science Foundation of China(51973054)the High-level Innovative Talent Project in Hunan Province(2018RS3055)+2 种基金the Young Talents Program in Hunan Province(2020RC3024)the Natural Science Funds of Hunan Province for Distinguished Young Scholars(2021JJ10018)the Science Research Project of Hunan Provincial Education Department(21B0027)。
文摘Direct mass exfoliation of graphene from bulk graphite with high yield and productivity for commercial applications is challenging.This work proposes self-grinding exfoliation using the mutual shear friction of graphite particles to fabricate graphene from microcrystalline graphite.The concept is implemented using microbeads as the grinding medium to drive the shear friction between graphite nanocrystals in a high-concentration paste.The proposed approach substantially improves graphene yield from 6.3% to 100% and simultaneously generates a record productivity of 7.5 g h^(-1)L^(-1),achieving total graphite-to-graphene conversion on the kilogram scale.The as-prepared graphene nanosheets have an average lateral size of 298 nm and the same C/O atomic ratio as the pristine graphite.In addition,the well-exfoliated,small nanosheets display good electrical conductivity and exhibit significant potential as conductive additives that improve the specific capacity and cyclic stability of Li-ion batteries better than commercial carbon-based conductive particles.
