The macroscopic characteristics of molten salts are governed by their microstructures.Research on the structures of molten salts provides the foundation for a full understanding of the physicochemical properties of mo...The macroscopic characteristics of molten salts are governed by their microstructures.Research on the structures of molten salts provides the foundation for a full understanding of the physicochemical properties of molten salts as well as a deeper analysis of the microscopic electrolysis process in molten salts.Information about the microstructure of matter can be obtained with the help of several speculative and experimental procedures.In this review,the advantages and disadvantages of the various test procedures used to determine the microstructures of molten salts are compared.The typical coordination configurations of metal ions in molten salt systems are also summarized.Furthermore,the impact of temperature,anions,cations,and metal oxides(O2-)on the structures of molten salts is discussed in detail.The accuracy and completeness of the information on molten salt structures need to be investigated by the integration of multiple methods and interdisciplinary fields.Information on the microstructure and coordination of molten salts deepens the understanding of the elementary elements of the microstructure of matter.This paper,which is based on the review of the coordination states of metal ions in molten salts,is hoped to inspire researchers to explore the inter-relationship between the microstructure and macroscopic properties of materials.展开更多
Cobalt has excellent electrochemical,magnetic,and heat properties.As a strategic resource,it has been applied in many hightech products.However,the recent rapid growth of the battery industry has substantially deplete...Cobalt has excellent electrochemical,magnetic,and heat properties.As a strategic resource,it has been applied in many hightech products.However,the recent rapid growth of the battery industry has substantially depleted cobalt resources,leading to a crisis of cobalt resource supply.The paper examines cobalt ore reserves and distribution,and the recent development and consumption of cobalt resources are summarized as well.In addition,the principles,advantages and disadvantages,and research status of various methods are discussed comprehensively.It can be concluded that the use of diverse sources(Cu-Co ores,Ni-Co ores,zinc plant residues,and waste cobalt products)for cobalt production should be enhanced to meet developmental requirements.Furthermore,in recovery technology,the pyro-hydrometallurgical process employs pyrometallurgy as the pretreatment to modify the phase structure of cobalt minerals,enhancing its recovery in the hydrometallurgical stage and facilitating high-purity cobalt production.Consequently,it represents a promising technology for future cobalt recovery.Lastly,based on the above conclusions,the prospects for cobalt are assessed regarding cobalt ore processing and sustainable cobalt recycling,for which further study should be conducted.展开更多
Selective surface dissolution was found to be important in spodumene flotation. In this study, we proposed to introduce ultrasound into the pretreatment process to accelerate particle vibration and cavitation, as well...Selective surface dissolution was found to be important in spodumene flotation. In this study, we proposed to introduce ultrasound into the pretreatment process to accelerate particle vibration and cavitation, as well as the migration of mineral surface components to solution. Micro-flotation results showed that the flotation recovery of spodumene can be 86.08% by ultrasound pretreatment, but only 39.30% by traditional mechanical agitation pretreatment. Compared with traditional mechanical agitation, ultrasonic pretreatment can shorten the pretreatment process, reduce the dosage of agents, reduce the mechanical agitation speed, and improve the efficiency of the pretreating process. Inductively coupled plasma analysis showed that, in the ultrasonic system, the amount of Li, Al, and Si species in the solution was twice as much as those in the traditional preprocessing system. Moreover, the scanning electron microscope results demonstrated a larger surface dissolution area in the ultrasonic system. X-Ray photoelectron spectroscopy results showed that the atomic concentration of Si species on the spodumene surface decreased, whereas the relative atomic concentrations of Li and Al species increased, indicating that the ultrasound effect strengthened the selective dissolution of elements on the mineral surface.The high-resolution spectra of O 1s showed that more collectors are adsorbed on the mineral surface treated by ultrasonic pretreatment.展开更多
In view of novel materials in the field of lithium metal batteries(LMBs), metal-organic frameworks(MOFs) have attracted extensive research interest owing to their controllable pore size, unsaturated metal sites and mu...In view of novel materials in the field of lithium metal batteries(LMBs), metal-organic frameworks(MOFs) have attracted extensive research interest owing to their controllable pore size, unsaturated metal sites and multifunctional organic groups. A variety of MOFs have been elaborately calculated and synthesized to be applied as separator coating, electrolyte modulators and solid-state electrolyte fillers in LMBs. In this mini-review, we summarize the mechanism of MOFs to limit the migration of anions, improve the Li-ion transference number and prolong the lifespan of LMBs. Suitable pore structure of MOFs can physically restrict the movement of Li^(+). Unsaturated metal sites can adsorb anions by electrostatic interaction. In addition,multifunctional organic functional groups that limit the migration of anions are discussed. Finally, the key challenges and perspectives in the development direction of MOFs-based separators and electrolytes are further elaborated.展开更多
Rational carbonate electrolyte chemistry is critical for the development of high-voltage lithium metal batteries(LMBs).However,the implementation of traditional carbonate electrolyte is greatly hindered by the generat...Rational carbonate electrolyte chemistry is critical for the development of high-voltage lithium metal batteries(LMBs).However,the implementation of traditional carbonate electrolyte is greatly hindered by the generation of an unstable electrode interphase and corrosive by-product(HF).Herein,we propose a triple-function eutectic solvent additive of N-methylacetamide(NmAc)with LiNO_(3) to enhance the stability and compatibility of carbonate electrolyte.Firstly,the addition of NmAc significantly improves the solubility of LiNO_(3) in carbonate electrolyte by forming an eutectic pair,which regulates the Li~+solvation structure and leads to dense and homogenous Li plating.Secondly,the hydrolysis of acidic PF_5 is effectively alleviated due to the strong complexation of NmAc with PF_5,thus reducing the generation of corrosive HF.In addition,the optimized cathode electrolyte interphase layer decreases the structural degradation and transition metal dissolution.Consequently,Li||LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)cells with the designed electrolyte deliver superior long-term cycle reversibility and excellent rate capability.This study unveils the rationale for incorporating eutectic solvent additives within carbonate electrolytes,which significantly contribute to the advancement of their practical application for high-voltage LMBs.展开更多
Solid-state flexible supercapacitors(SCs)have many advantages of high specific capacitance,excellent flexibility,fast charging and discharging,high power density,environmental friendliness,high safety,light weight,duc...Solid-state flexible supercapacitors(SCs)have many advantages of high specific capacitance,excellent flexibility,fast charging and discharging,high power density,environmental friendliness,high safety,light weight,ductility,and long cycle stability.They are the ideal choice for the development of flexible energy storage technology in the future,and provide a good prospect for energy storage applications.At present,solid-state flexible SCs are widely used for portable electronic equipment and wearable energy storage equipment,the research of them has become the focus of a growing number of researchers.Electrode material is the key part of SCs and always determines the electrochemical performance of SCs.It has been a hotspot and focus of research.Vanadium-based compounds are considered to be a promising electrode material for SCs because of variable valence,open structure,high theoretical capacity,and low price.Therefore,this study first gives an overview of solid-state flexible SCs,then reviews the current research status of vanadium-based electrode materials in solid-state flexible SCs,and proposes some strategies to solve some problems of vanadium-based electrode materials.展开更多
The loss of rare earths(REs)takes place during the pre-decalcification process of mixed rare earth concentrate.In an effort to reduce such RE loss,a novel idea to improve the leaching selectivity of Ca to REs by apply...The loss of rare earths(REs)takes place during the pre-decalcification process of mixed rare earth concentrate.In an effort to reduce such RE loss,a novel idea to improve the leaching selectivity of Ca to REs by applying selective mechanical activation was proposed.First,regarding the key minerals affecting the leaching selectivity of Ca to REs,the differences in the mechanical activation behaviors of CaF_(2) and REFCO_(3) were studied,and we find that the lattice strain of CaF_(2) increases from 0.21%to 0.42%,whereas that of REFCO_(3) increases from 0.31%to 0.40%.Notably,CaF_(2) demonstrates a larger lattice strain than REFCO_(3),indicating greater mechanical activation energy storage and higher leaching activity.Next,the HCl leaching process was studied.A significant leaching selectivity of Ca to REs,from 21.6 to 35.1,is achieved through mechanical activation.The Ca leaching rate reaches 80.7%when the RE loss is 2.3%in the activated sample.This study provides an novel approach for achieving selective extraction of specific components via mechanical activation pretreatment.展开更多
In situ temperature monitoring has become extremely imperative in high-temperature harsh environments and polymer-derived ceramics(PDCs)as sensing materials have attracted great attention.However,the stability and oxi...In situ temperature monitoring has become extremely imperative in high-temperature harsh environments and polymer-derived ceramics(PDCs)as sensing materials have attracted great attention.However,the stability and oxidation/corrosion resistance of PDCs cannot be simultaneously achieved at the moment,limiting their practical application.Herein,polymer-derived SiAlBCN ceramics were synthesized via polymer conversion method under different pyrolysis temperatures.Their microstructure evolution,high temperature sensing properties,and stability were investigated in detail.The results show that the amorphous SiAlBCN phase grows more orderly and the size of the free carbon phase enlarges with the increasing temperature.The defect concentration displays a decreasing tendency.Concurrently,the SiAlBCN ceramics as sensing materials exhibit a good temperature-resistance property from roo temperature to 1100℃.The fabricated SiAlBCN temperature sensor possesses excellent stability,repeatability,and accuracy.Moreover,SiAlBCN ceramics exhibit distinguished oxidation/corrosion resistance after 100 h treatment at 1200℃in a water/oxygen environment,which is attributed to their low corrosive rate constant(0.57 mg/(cm^(2)·h))and oxidative rate constant(3.43 mg^(2)/(cm^(4)·h)).Therefore,polymer-derived SiAlBCN ceramics as sensing materials,which possess outstanding stability and oxidation/corrosion resistance,have great potential for in-situ monitoring of extreme environmental temperatures in the future.展开更多
The new Ni-Co-based superalloy featuring a"fusion structure"was produced utilizing electron beam smelting layered solidification technology(EBSL).Experimental examination of hot compression deformation with ...The new Ni-Co-based superalloy featuring a"fusion structure"was produced utilizing electron beam smelting layered solidification technology(EBSL).Experimental examination of hot compression deformation with varied settings for EBSL and conventional duplex process melting Ni-Co superalloys was performed.As per the study,EBSL-Ni-Co superalloys exhibited enhanced recrystallization susceptibility during hot deformation.Furthermore,elevating deformation temperature,lowering strain rate,and augmenting strain collectively contribute to enlarging the volume fraction of dynamically recrystallized grains.Aberrant growth of grains occurred when the deformation temperature equaledγ′sub-solvus temperature and the strain rate was slower.Moreover,exceeding theγ′solvus temperature during deformation significantly increases the particle size of dynamic recrystallization(DRX)grains.Theγ′phase can effectively modulate the DRX grain size through the pegging effect.Additionally,it was revealed that the presence of the fusion structure aids in the generation of continuous dynamic recrystallization,discontinuous dynamic recrystallization,and twinning-induced dynamic recrystallization while the alloy undergoes hot deformation.This mechanism promotes DRX granule formation and permits complete recrystallization.Ultimately,the fusion structure was identified as playing a catalytic role in the dynamic recrystallization process of the new Ni-Co superalloy.展开更多
基金financially supported by the National Key Research and Development Program of China (Nos.2021YFC2901600 and 2021YFC2902305)the National Natural Science Foundation of China (No.52274356)+2 种基金the Natural Science Foundation of Henan Province,China (No.222300420545)the State Key Laboratory of Special Rare Metal Materials,China (No.SKL2020K004)the Northwest Rare Metal Materials Research Institute,China,and the State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization,China (No.CNMRCUKF2008)。
文摘The macroscopic characteristics of molten salts are governed by their microstructures.Research on the structures of molten salts provides the foundation for a full understanding of the physicochemical properties of molten salts as well as a deeper analysis of the microscopic electrolysis process in molten salts.Information about the microstructure of matter can be obtained with the help of several speculative and experimental procedures.In this review,the advantages and disadvantages of the various test procedures used to determine the microstructures of molten salts are compared.The typical coordination configurations of metal ions in molten salt systems are also summarized.Furthermore,the impact of temperature,anions,cations,and metal oxides(O2-)on the structures of molten salts is discussed in detail.The accuracy and completeness of the information on molten salt structures need to be investigated by the integration of multiple methods and interdisciplinary fields.Information on the microstructure and coordination of molten salts deepens the understanding of the elementary elements of the microstructure of matter.This paper,which is based on the review of the coordination states of metal ions in molten salts,is hoped to inspire researchers to explore the inter-relationship between the microstructure and macroscopic properties of materials.
基金the financial support of Guangxi Science and Technology Major Project(Guike AA22068078)the Natural Science Foundation of Henan Province(No.222300420548)+2 种基金Henan Province Science and Technology Research and Development plan joint Fund(No.232301420043)the Key Project of the National Key Research and Development Program of China(No.2021YFC2902604)Modern Analysis and Computing Centre in Zhengzhou University。
文摘Cobalt has excellent electrochemical,magnetic,and heat properties.As a strategic resource,it has been applied in many hightech products.However,the recent rapid growth of the battery industry has substantially depleted cobalt resources,leading to a crisis of cobalt resource supply.The paper examines cobalt ore reserves and distribution,and the recent development and consumption of cobalt resources are summarized as well.In addition,the principles,advantages and disadvantages,and research status of various methods are discussed comprehensively.It can be concluded that the use of diverse sources(Cu-Co ores,Ni-Co ores,zinc plant residues,and waste cobalt products)for cobalt production should be enhanced to meet developmental requirements.Furthermore,in recovery technology,the pyro-hydrometallurgical process employs pyrometallurgy as the pretreatment to modify the phase structure of cobalt minerals,enhancing its recovery in the hydrometallurgical stage and facilitating high-purity cobalt production.Consequently,it represents a promising technology for future cobalt recovery.Lastly,based on the above conclusions,the prospects for cobalt are assessed regarding cobalt ore processing and sustainable cobalt recycling,for which further study should be conducted.
基金financially supported by the National Key Research and Development Program of China (No. 2021YFC2903202)the National Natural Science Foundations of China (Nos. 51974366, 52174267, 52174270 and 52004250)+2 种基金the China Postdoctoral Science Foundation (No. 2020M680100 and 2020TQ0279)the Postdoctoral Research Grant in Henan Province (No. 202003025)the State Key Laboratory of Mineral Processing and Co-innovation Center for Clean and Efficient Utilization of Strategic Metal Mineral Resources。
文摘Selective surface dissolution was found to be important in spodumene flotation. In this study, we proposed to introduce ultrasound into the pretreatment process to accelerate particle vibration and cavitation, as well as the migration of mineral surface components to solution. Micro-flotation results showed that the flotation recovery of spodumene can be 86.08% by ultrasound pretreatment, but only 39.30% by traditional mechanical agitation pretreatment. Compared with traditional mechanical agitation, ultrasonic pretreatment can shorten the pretreatment process, reduce the dosage of agents, reduce the mechanical agitation speed, and improve the efficiency of the pretreating process. Inductively coupled plasma analysis showed that, in the ultrasonic system, the amount of Li, Al, and Si species in the solution was twice as much as those in the traditional preprocessing system. Moreover, the scanning electron microscope results demonstrated a larger surface dissolution area in the ultrasonic system. X-Ray photoelectron spectroscopy results showed that the atomic concentration of Si species on the spodumene surface decreased, whereas the relative atomic concentrations of Li and Al species increased, indicating that the ultrasound effect strengthened the selective dissolution of elements on the mineral surface.The high-resolution spectra of O 1s showed that more collectors are adsorbed on the mineral surface treated by ultrasonic pretreatment.
基金the financial support by National Natural Science Foundation of China(22379166,52372252)Natural Science Foundation for Distinguished Young Scholars of Hunan Province(2022JJ10089)+1 种基金Central South University Innovation-Driven Research Program(2023CXQD034)the support from the 100 Talented program of Hunan Province。
文摘In view of novel materials in the field of lithium metal batteries(LMBs), metal-organic frameworks(MOFs) have attracted extensive research interest owing to their controllable pore size, unsaturated metal sites and multifunctional organic groups. A variety of MOFs have been elaborately calculated and synthesized to be applied as separator coating, electrolyte modulators and solid-state electrolyte fillers in LMBs. In this mini-review, we summarize the mechanism of MOFs to limit the migration of anions, improve the Li-ion transference number and prolong the lifespan of LMBs. Suitable pore structure of MOFs can physically restrict the movement of Li^(+). Unsaturated metal sites can adsorb anions by electrostatic interaction. In addition,multifunctional organic functional groups that limit the migration of anions are discussed. Finally, the key challenges and perspectives in the development direction of MOFs-based separators and electrolytes are further elaborated.
基金supported by the National Natural Science Foundation of China(22379166)Natural Science Foundation for Distinguished Young Scholars of Hunan Province(2022JJ10089)+1 种基金Central South University Innovation-Driven Research Program(2023CXQD034)supported in part by the High-Performance Computing Center of Central South University。
文摘Rational carbonate electrolyte chemistry is critical for the development of high-voltage lithium metal batteries(LMBs).However,the implementation of traditional carbonate electrolyte is greatly hindered by the generation of an unstable electrode interphase and corrosive by-product(HF).Herein,we propose a triple-function eutectic solvent additive of N-methylacetamide(NmAc)with LiNO_(3) to enhance the stability and compatibility of carbonate electrolyte.Firstly,the addition of NmAc significantly improves the solubility of LiNO_(3) in carbonate electrolyte by forming an eutectic pair,which regulates the Li~+solvation structure and leads to dense and homogenous Li plating.Secondly,the hydrolysis of acidic PF_5 is effectively alleviated due to the strong complexation of NmAc with PF_5,thus reducing the generation of corrosive HF.In addition,the optimized cathode electrolyte interphase layer decreases the structural degradation and transition metal dissolution.Consequently,Li||LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)cells with the designed electrolyte deliver superior long-term cycle reversibility and excellent rate capability.This study unveils the rationale for incorporating eutectic solvent additives within carbonate electrolytes,which significantly contribute to the advancement of their practical application for high-voltage LMBs.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52004252 and 52374359)Henan Provincial Natural Science Foundation(No.232300421197)the Project of Zhongyuan Critical Metals Laboratory(No.GJJSGFYQ202310).
文摘Solid-state flexible supercapacitors(SCs)have many advantages of high specific capacitance,excellent flexibility,fast charging and discharging,high power density,environmental friendliness,high safety,light weight,ductility,and long cycle stability.They are the ideal choice for the development of flexible energy storage technology in the future,and provide a good prospect for energy storage applications.At present,solid-state flexible SCs are widely used for portable electronic equipment and wearable energy storage equipment,the research of them has become the focus of a growing number of researchers.Electrode material is the key part of SCs and always determines the electrochemical performance of SCs.It has been a hotspot and focus of research.Vanadium-based compounds are considered to be a promising electrode material for SCs because of variable valence,open structure,high theoretical capacity,and low price.Therefore,this study first gives an overview of solid-state flexible SCs,then reviews the current research status of vanadium-based electrode materials in solid-state flexible SCs,and proposes some strategies to solve some problems of vanadium-based electrode materials.
基金Project supported by the National Natural Science Foundation of China(52004252)Natural Science Foundation ofHenan Province(222300420548)Strategic Research and Consulting Project of Chinese Academy of Engineering(2022-XBZD-07)。
文摘The loss of rare earths(REs)takes place during the pre-decalcification process of mixed rare earth concentrate.In an effort to reduce such RE loss,a novel idea to improve the leaching selectivity of Ca to REs by applying selective mechanical activation was proposed.First,regarding the key minerals affecting the leaching selectivity of Ca to REs,the differences in the mechanical activation behaviors of CaF_(2) and REFCO_(3) were studied,and we find that the lattice strain of CaF_(2) increases from 0.21%to 0.42%,whereas that of REFCO_(3) increases from 0.31%to 0.40%.Notably,CaF_(2) demonstrates a larger lattice strain than REFCO_(3),indicating greater mechanical activation energy storage and higher leaching activity.Next,the HCl leaching process was studied.A significant leaching selectivity of Ca to REs,from 21.6 to 35.1,is achieved through mechanical activation.The Ca leaching rate reaches 80.7%when the RE loss is 2.3%in the activated sample.This study provides an novel approach for achieving selective extraction of specific components via mechanical activation pretreatment.
基金the National Key R&D Program of China(No.2021YFB3200500)the National Natural Science Foundation of China(Nos.52072344 and U1904180)+1 种基金the Excellent Young Scientists Fund of Henan Province(No.202300410369)the Henan Province University Innovation Talents Support Program(No.21HASTIT001).
文摘In situ temperature monitoring has become extremely imperative in high-temperature harsh environments and polymer-derived ceramics(PDCs)as sensing materials have attracted great attention.However,the stability and oxidation/corrosion resistance of PDCs cannot be simultaneously achieved at the moment,limiting their practical application.Herein,polymer-derived SiAlBCN ceramics were synthesized via polymer conversion method under different pyrolysis temperatures.Their microstructure evolution,high temperature sensing properties,and stability were investigated in detail.The results show that the amorphous SiAlBCN phase grows more orderly and the size of the free carbon phase enlarges with the increasing temperature.The defect concentration displays a decreasing tendency.Concurrently,the SiAlBCN ceramics as sensing materials exhibit a good temperature-resistance property from roo temperature to 1100℃.The fabricated SiAlBCN temperature sensor possesses excellent stability,repeatability,and accuracy.Moreover,SiAlBCN ceramics exhibit distinguished oxidation/corrosion resistance after 100 h treatment at 1200℃in a water/oxygen environment,which is attributed to their low corrosive rate constant(0.57 mg/(cm^(2)·h))and oxidative rate constant(3.43 mg^(2)/(cm^(4)·h)).Therefore,polymer-derived SiAlBCN ceramics as sensing materials,which possess outstanding stability and oxidation/corrosion resistance,have great potential for in-situ monitoring of extreme environmental temperatures in the future.
基金the financial support from the National Key Research and Development Program of China(Grant No.2019YFA0705300)the National Natural Science Foundation of China(Grant No.52004051)the Innovation Team Project for Key Fields of Dalian(Grant No.2019RT13).
文摘The new Ni-Co-based superalloy featuring a"fusion structure"was produced utilizing electron beam smelting layered solidification technology(EBSL).Experimental examination of hot compression deformation with varied settings for EBSL and conventional duplex process melting Ni-Co superalloys was performed.As per the study,EBSL-Ni-Co superalloys exhibited enhanced recrystallization susceptibility during hot deformation.Furthermore,elevating deformation temperature,lowering strain rate,and augmenting strain collectively contribute to enlarging the volume fraction of dynamically recrystallized grains.Aberrant growth of grains occurred when the deformation temperature equaledγ′sub-solvus temperature and the strain rate was slower.Moreover,exceeding theγ′solvus temperature during deformation significantly increases the particle size of dynamic recrystallization(DRX)grains.Theγ′phase can effectively modulate the DRX grain size through the pegging effect.Additionally,it was revealed that the presence of the fusion structure aids in the generation of continuous dynamic recrystallization,discontinuous dynamic recrystallization,and twinning-induced dynamic recrystallization while the alloy undergoes hot deformation.This mechanism promotes DRX granule formation and permits complete recrystallization.Ultimately,the fusion structure was identified as playing a catalytic role in the dynamic recrystallization process of the new Ni-Co superalloy.