Compared with solid metals,liquid metals are considered more promising cathodes for molten slat/oxide electrolysis due to their fascinating advantages,which include strong depolarization effect,strong alloying effect,...Compared with solid metals,liquid metals are considered more promising cathodes for molten slat/oxide electrolysis due to their fascinating advantages,which include strong depolarization effect,strong alloying effect,excellent selective separation,and low operating temperature.In this review,we briefly introduce the properties of the liquid metal cathodes and their selection rules,and then summarize development in liquid metal cathodes for molten salt electrolysis,specifically the extraction of Ti and separation of actinides and rare-earth metals in halide melts.We also review recent attractive progress in the preparation of liquid Ti alloys via molten oxide electrolysis by using liquid metal cathodes.Problems related to high-quality alloy production and large-scale applications are cited,and several research directions to further improve the quality of alloys are also discussed to realize the industrial applications of liquid metal cathodes.展开更多
Graphite materials are widely used as electrode materials for electrochemical energy storage.N-doping is an effective method for enhancing the electrochemical properties of graphite.A novel one-step N-doping method fo...Graphite materials are widely used as electrode materials for electrochemical energy storage.N-doping is an effective method for enhancing the electrochemical properties of graphite.A novel one-step N-doping method for complete and compact carbon paper was proposed for molten salt electrolysis in the Li Cl-KCl-Li3 N system.The results show that the degree of graphitization of carbon paper can be improved by the electrolysis of molten salts,especially at 2.0 V.Nitrogen gas was produced at the anode and nitrogen atoms can substitute carbon atoms of carbon paper at different sites to create nitrogen doping during the electrolysis process.The doping content of N in carbon paper is up to 13.0 wt%.There were three groups of nitrogen atoms,i.e.quaternary N(N-Q),pyrrolic N(N-5),and pyridinic N(N-6)in N-doping carbon paper.N-doping carbon paper as an Al-ion battery cathode shows strong charge-recharge properties.展开更多
The effects of gravity on nickel electrodeposition,the morphology and mechanical properties of deposits were studied in a super gravity field.Predictions in a microgravity field were also presented based on the obtain...The effects of gravity on nickel electrodeposition,the morphology and mechanical properties of deposits were studied in a super gravity field.Predictions in a microgravity field were also presented based on the obtained experimental tendency.Linear sweep voltammetry reveals that the nickel electrodeposition process is enhanced by increasing the gravity coefficient(G).The limiting current density changes from 10.2 to 293.0 mA·cm-2 with the increase of the G value from 10-4 to 354.The morphology of deposits was analyzed by scanning electron microscopy(SEM) and atomic force microscopy(AFM).The images show that the morphology deposited in the super gravity field has finer grain sizes and denser and smoother surfaces.The roughness reduces from 48.3 to 4.9 nm with the increase of the G value from 10-4 to 354.Meanwhile,mechanical tests indicate that the mechanical properties of nickel foils are greatly improved due to introducing a super gravity field during electrodeposition.展开更多
The preparation process of the Cr(III) bath was studied based on a perspective of accelerating the formation of active Cr(III) complexes. The results of ultraviolet-visible absorption spectroscopy (UV-Vis) and e...The preparation process of the Cr(III) bath was studied based on a perspective of accelerating the formation of active Cr(III) complexes. The results of ultraviolet-visible absorption spectroscopy (UV-Vis) and electrodeposition showed that active Cr(III) complexes in the bath prepared at room temperature in several days were rare for depositing chromium. The increase of heating temperature, time, and pH value during the bath preparation promoted the formation of active Cr(III) complexes. The chromium deposition rate increased with the concentration of active Cr(III) complexes increasing. Increasing the heating temperature from 60 to 96℃, the chromium deposition rate increased from 0.40 to 0.71μm/min. When the concentration of active Cr(III) complexes increased, the grain size of Cr coatings increased, and the carbon content of the coating decreased. It is deduced that Cr(H20)4(OH)L2+ (L is an organic ligand, and its valence is omitted) is a primary active Cr(III) complex.展开更多
Selective laser melting(SLM)technology plays an important role in the preparation of porous titanium(Ti)implants with complex structures and precise sizes.Unfortunately,the processing characteristics of this technolog...Selective laser melting(SLM)technology plays an important role in the preparation of porous titanium(Ti)implants with complex structures and precise sizes.Unfortunately,the processing characteristics of this technology,which include rapid melting and solidification,lead to products with high residual stress.Herein,an in situ method was developed to restrain the residual stress and improve the mechanical strength of porous Ti alloys during laser additive manufacturing.In brief,porous Ti6Al4V was prepared by an SLM three-dimensional(3D)printer equipped with a double laser system that could rescan each layer immediately after solidification of the molten powder,thus reducing the temperature gradient and avoiding rapid melting and cooling.Results indicated that double scanning can provide stronger bonding conditions for the honeycomb structure and improve the yield strength and elastic modulus of the alloy.Rescanning with an energy density of 75%resulted in 33.5%–38.0%reductions in residual stress.The porosities of double-scanned specimens were 2%–4%lower than those of singlescanned specimens,and the differences noted increased with increasing sheet thickness.The rescanning laser power should be reduced during the preparation of porous Ti with thick cell walls to ensure dimensional accuracy.展开更多
High-temperature molten salt consisting of metal cation and non-metal anion is a promising media to break the limits of aqueous solution due to high conductivity,wide electrochemical window,rapid mass transfer,high so...High-temperature molten salt consisting of metal cation and non-metal anion is a promising media to break the limits of aqueous solution due to high conductivity,wide electrochemical window,rapid mass transfer,high solubility to reactants,low vapor pressure,etc.In the past two hundred years,high-temperature molten salt chemistry and technology attract widely interests.Particularly,molten salt electrolysis as an indispensable metallurgy technology has been applied industrially for metal extraction of Al,rare earth,and alkali/alkaline-earth metals.It is well known that industrial aluminum electrolysis was invented by Hall and Heroult in the end of the 19 th century.It is a milestone and promotes the change of Al from noble metal to bulk metal.At present,the yield of Al has reached to 62 millions tons all over the world in 2019.High-temperature molten salt chemistry and technology has brought a revolutionary advancement to human life and infrastructure construction.展开更多
Recently,an environmentally friendly electrolysis process of soluble vanadates is proposed and successfully confirmed for V_(2)O_(3) extraction.In this paper,the solubilities of various vanadates(i.e.NaVO_(3),Na_(4)V_...Recently,an environmentally friendly electrolysis process of soluble vanadates is proposed and successfully confirmed for V_(2)O_(3) extraction.In this paper,the solubilities of various vanadates(i.e.NaVO_(3),Na_(4)V_(2)O_(7) and Na_(3)VO_(4))in NaCl molten salt are measured.The dependences of V_(2)O_(3) extraction on vanadate form,anode material and molten salt system are studied.A long-term electrolysis is carried out.The result indicates that the solubilities of all vanadates are high and meet electrolytic requirements.Compared to Na_(4)V_(2)O_(7) and Na_(3)VO_(4),NaVO_(3) exhibits larger current efficiency and lower electricity consumption.By using SnO_(2) anode instead of graphite anode,the current efficiency of NaVO_(3) electrolysis can be increased to 58.1%and carbon pollution is avoided at 700℃.The extraction rate of V_(2)O_(3) reaches 81.3%after long-term electrolysis of 51 h.This work optimizes the electrochemical preparation process of V_(2)O_(3) from various vanadates and contributes to the improvement of current efficiency and extraction rate.展开更多
基金the National Natural Science Foundation of China(Nos.51725401 and 51904030)the Fundamental Research Funds for the Cental Universities(No.FRF-TP-18-003C2).
文摘Compared with solid metals,liquid metals are considered more promising cathodes for molten slat/oxide electrolysis due to their fascinating advantages,which include strong depolarization effect,strong alloying effect,excellent selective separation,and low operating temperature.In this review,we briefly introduce the properties of the liquid metal cathodes and their selection rules,and then summarize development in liquid metal cathodes for molten salt electrolysis,specifically the extraction of Ti and separation of actinides and rare-earth metals in halide melts.We also review recent attractive progress in the preparation of liquid Ti alloys via molten oxide electrolysis by using liquid metal cathodes.Problems related to high-quality alloy production and large-scale applications are cited,and several research directions to further improve the quality of alloys are also discussed to realize the industrial applications of liquid metal cathodes.
基金the National Natural Science Foundation of China(No.51725401)the Fundamental Research Funds for the Central Universities(No.FRT-TP-18-003C2)。
文摘Graphite materials are widely used as electrode materials for electrochemical energy storage.N-doping is an effective method for enhancing the electrochemical properties of graphite.A novel one-step N-doping method for complete and compact carbon paper was proposed for molten salt electrolysis in the Li Cl-KCl-Li3 N system.The results show that the degree of graphitization of carbon paper can be improved by the electrolysis of molten salts,especially at 2.0 V.Nitrogen gas was produced at the anode and nitrogen atoms can substitute carbon atoms of carbon paper at different sites to create nitrogen doping during the electrolysis process.The doping content of N in carbon paper is up to 13.0 wt%.There were three groups of nitrogen atoms,i.e.quaternary N(N-Q),pyrrolic N(N-5),and pyridinic N(N-6)in N-doping carbon paper.N-doping carbon paper as an Al-ion battery cathode shows strong charge-recharge properties.
基金supported by the National Natural Science Foundation of China(Nos.50804043,50674011)the Major Programs on the Equipment Development of Chinese Academy of Sciences(No.YZ0618)
文摘The effects of gravity on nickel electrodeposition,the morphology and mechanical properties of deposits were studied in a super gravity field.Predictions in a microgravity field were also presented based on the obtained experimental tendency.Linear sweep voltammetry reveals that the nickel electrodeposition process is enhanced by increasing the gravity coefficient(G).The limiting current density changes from 10.2 to 293.0 mA·cm-2 with the increase of the G value from 10-4 to 354.The morphology of deposits was analyzed by scanning electron microscopy(SEM) and atomic force microscopy(AFM).The images show that the morphology deposited in the super gravity field has finer grain sizes and denser and smoother surfaces.The roughness reduces from 48.3 to 4.9 nm with the increase of the G value from 10-4 to 354.Meanwhile,mechanical tests indicate that the mechanical properties of nickel foils are greatly improved due to introducing a super gravity field during electrodeposition.
基金financially supported by the National Basic Research and Development Program of China(No.2013CB632606)the National Natural Science Foundation of China(No.51274180)
文摘The preparation process of the Cr(III) bath was studied based on a perspective of accelerating the formation of active Cr(III) complexes. The results of ultraviolet-visible absorption spectroscopy (UV-Vis) and electrodeposition showed that active Cr(III) complexes in the bath prepared at room temperature in several days were rare for depositing chromium. The increase of heating temperature, time, and pH value during the bath preparation promoted the formation of active Cr(III) complexes. The chromium deposition rate increased with the concentration of active Cr(III) complexes increasing. Increasing the heating temperature from 60 to 96℃, the chromium deposition rate increased from 0.40 to 0.71μm/min. When the concentration of active Cr(III) complexes increased, the grain size of Cr coatings increased, and the carbon content of the coating decreased. It is deduced that Cr(H20)4(OH)L2+ (L is an organic ligand, and its valence is omitted) is a primary active Cr(III) complex.
基金financially supported by the National Natural Science Foundation of China(Nos.52004026 and 51725401)the Fundamental Research Funds for the Central Universities,China(No.FRF-TP-18-003C2)。
文摘Selective laser melting(SLM)technology plays an important role in the preparation of porous titanium(Ti)implants with complex structures and precise sizes.Unfortunately,the processing characteristics of this technology,which include rapid melting and solidification,lead to products with high residual stress.Herein,an in situ method was developed to restrain the residual stress and improve the mechanical strength of porous Ti alloys during laser additive manufacturing.In brief,porous Ti6Al4V was prepared by an SLM three-dimensional(3D)printer equipped with a double laser system that could rescan each layer immediately after solidification of the molten powder,thus reducing the temperature gradient and avoiding rapid melting and cooling.Results indicated that double scanning can provide stronger bonding conditions for the honeycomb structure and improve the yield strength and elastic modulus of the alloy.Rescanning with an energy density of 75%resulted in 33.5%–38.0%reductions in residual stress.The porosities of double-scanned specimens were 2%–4%lower than those of singlescanned specimens,and the differences noted increased with increasing sheet thickness.The rescanning laser power should be reduced during the preparation of porous Ti with thick cell walls to ensure dimensional accuracy.
文摘High-temperature molten salt consisting of metal cation and non-metal anion is a promising media to break the limits of aqueous solution due to high conductivity,wide electrochemical window,rapid mass transfer,high solubility to reactants,low vapor pressure,etc.In the past two hundred years,high-temperature molten salt chemistry and technology attract widely interests.Particularly,molten salt electrolysis as an indispensable metallurgy technology has been applied industrially for metal extraction of Al,rare earth,and alkali/alkaline-earth metals.It is well known that industrial aluminum electrolysis was invented by Hall and Heroult in the end of the 19 th century.It is a milestone and promotes the change of Al from noble metal to bulk metal.At present,the yield of Al has reached to 62 millions tons all over the world in 2019.High-temperature molten salt chemistry and technology has brought a revolutionary advancement to human life and infrastructure construction.
基金supported by the National Natural Science Foundation of China (51725401)Open Projects of State Key Laboratory of Advanced Metallurgy (41616013)。
文摘Recently,an environmentally friendly electrolysis process of soluble vanadates is proposed and successfully confirmed for V_(2)O_(3) extraction.In this paper,the solubilities of various vanadates(i.e.NaVO_(3),Na_(4)V_(2)O_(7) and Na_(3)VO_(4))in NaCl molten salt are measured.The dependences of V_(2)O_(3) extraction on vanadate form,anode material and molten salt system are studied.A long-term electrolysis is carried out.The result indicates that the solubilities of all vanadates are high and meet electrolytic requirements.Compared to Na_(4)V_(2)O_(7) and Na_(3)VO_(4),NaVO_(3) exhibits larger current efficiency and lower electricity consumption.By using SnO_(2) anode instead of graphite anode,the current efficiency of NaVO_(3) electrolysis can be increased to 58.1%and carbon pollution is avoided at 700℃.The extraction rate of V_(2)O_(3) reaches 81.3%after long-term electrolysis of 51 h.This work optimizes the electrochemical preparation process of V_(2)O_(3) from various vanadates and contributes to the improvement of current efficiency and extraction rate.