Carbon materials have taken an important role in supercapacitor applications due to their outstanding features of large surface area,low price,and stable physicochemical properties.Considerable research efforts have b...Carbon materials have taken an important role in supercapacitor applications due to their outstanding features of large surface area,low price,and stable physicochemical properties.Considerable research efforts have been devoted to the development of novel synthesis strategy for the preparation of porous carbon materials in recent years.In particular,molten salt strategy represents an emerging and promising method,whereby it has shown great potential in achieving tailored production of porous carbon.It has been proved that the molten salt-assisted production of carbon via the direct carbonization of carbonaceous precursors is an effective approach.Furthermore,with the incorporation of electrochemical technology,molten salt synthesis of porous carbon has become flexible and diversiform.Here,this review focuses on the mainstream molten salt synthesis strategies for the production of porous carbon materials,which includes direct molten salt carbonization process,capture and electrochemical conversion of CO_(2)to value-added carbon,electrochemical exfoliation of graphite to graphene-based materials,and electrochemical etching of carbides to new-type carbide-derived carbon materials.The reaction mechanisms and recent advances for these strategies are reviewed and discussed systematically.The morphological and structural properties and capacitive performances of the obtained carbon materials are summarized to reveal their appealing points for supercapacitor applications.Moreover,the opportunities and challenges of the molten salt synthesis strategy for the preparation of carbon materials are also discussed in this review to provide inspiration to the future researches.展开更多
A series of oxygen permeable dual-phase composite oxides 60 wt% Ce0.8Gd0.2O2-δ-40 wt% LnBaCo2O5+δ (CGO-LBCO, Ln = La, Pr, Nd, Sin, Gd and Y) were synthesized through a sol-gel route and effects of the Ln3+ catio...A series of oxygen permeable dual-phase composite oxides 60 wt% Ce0.8Gd0.2O2-δ-40 wt% LnBaCo2O5+δ (CGO-LBCO, Ln = La, Pr, Nd, Sin, Gd and Y) were synthesized through a sol-gel route and effects of the Ln3+ cations on their phase structure, oxygen permeability and chemical stability against CO2 were investigated systemically by XRD, SEM, TG-DSC and oxygen permeation experiments. XRD patterns reveal that the larger Ln3+ cations (La3+, Pr3+ and Nd3+) successfully stabilized the double-layered perovskite structure of sintered LBCO, while the smaller ones (Sm3+, Gd3+, and Y3+) resulted in the partial decomposition of LBCO with some impurities formed. CGO-PBCO yields the highest oxygen permeation flux, reaching 2.8× 10^-7 mol.s-1.cm-2 at 925 ℃ with 1 mm thickness under air/He gradient. The TG-DSC profiles in 20 mol% CO2/N2 and oxygen permeability experiments with CO2 as sweep gas show that CGO-YBCO demonstrates the best chemical stability against CO2, possibly due to its minimum basicity. The stable oxygen permeation flux of CGO-YBCO under CO2 atmosphere reveals its potential application in the oxy-fuel combustion route for CO2 capture.展开更多
Sustainable and low-carbon-emission silicon production is currently one of the main focuses for the metallurgical and materials science communities.Electrochemistry,considered a promising strategy,has been explored to...Sustainable and low-carbon-emission silicon production is currently one of the main focuses for the metallurgical and materials science communities.Electrochemistry,considered a promising strategy,has been explored to produce silicon due to prominent advantages:(a)high electricity utilization efficiency;(b)low-cost silica as a raw material;and(c)tunable morphologies and structures,including films,nanowires,and nanotubes.This review begins with a summary of early research on the extraction of silicon by electrochemistry.Emphasis has been placed on the electro-deoxidation and dissolution–electrodeposition of silica in chloride molten salts since the 21st century,including the basic reaction mechanisms,the fabrication of photoactive Si films for solar cells,the design and production of nanoSi and various silicon components for energy conversion,as well as storage applications.Besides,the feasibility of silicon electrodeposition in room-temperature ionic liquids and its unique opportunities are evaluated.On this basis,the challenges and future research directions for silicon electrochemical production strategies are proposed and discussed,which are essential to achieve large-scale sustainable production of silicon by electrochemistry.展开更多
Porous active core-shell carbon material with excellent synergistic effect has been regarded as a prospective material for supercapacitors.Herein,we report an integrated method for the facile synthesis of carbide-deri...Porous active core-shell carbon material with excellent synergistic effect has been regarded as a prospective material for supercapacitors.Herein,we report an integrated method for the facile synthesis of carbide-derived carbon(CDC)encapsulated with porous N-doped carbon(CDC@NC)towards highperformance supercapacitors.Polydopamine(PDA)as nitrogen and carbon sources was simply coated on SiC nanospheres to form SiC@PDA,which was then directly transformed into CDC@NC via a onestep molten salt electro-etching/in-situ doping process.The synthesized CDC@NC with hierarchically porous structure has a high specific surface area of 1191 m^(2) g^(-1).The CDC core and NC shell are typical amorphous carbon and more ordered N-doped carbon,respectively.Benefitting from its unique dual porous structures,the CDC@NC demonstrates high specific capacitances of 255 and 193 F g^(-1) at 0.5 and20 A g^(-1),respectively.The reaction mechanism of the electro-etching/in-situ doping process has also been investigated through experimental characterizations and theoretical density functional theory calculations.It is suggested that the molten salt electro-etching/in-situ doping strategy is promising for the synthesis of active core-shell porous carbon materials with synergistic properties for supercapacitors without the need for additional doping/activation processes.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.5202205451974181+4 种基金5200415)the Shanghai Rising-Star Program(19QA1403600)the Iron and Steel Joint Research Found of National Natural Science Foundation and China Baowu Steel Group Corporation Limited(U1860203)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning(TP2019041)the CAS Interdisciplinary Innovation Team for financial support。
文摘Carbon materials have taken an important role in supercapacitor applications due to their outstanding features of large surface area,low price,and stable physicochemical properties.Considerable research efforts have been devoted to the development of novel synthesis strategy for the preparation of porous carbon materials in recent years.In particular,molten salt strategy represents an emerging and promising method,whereby it has shown great potential in achieving tailored production of porous carbon.It has been proved that the molten salt-assisted production of carbon via the direct carbonization of carbonaceous precursors is an effective approach.Furthermore,with the incorporation of electrochemical technology,molten salt synthesis of porous carbon has become flexible and diversiform.Here,this review focuses on the mainstream molten salt synthesis strategies for the production of porous carbon materials,which includes direct molten salt carbonization process,capture and electrochemical conversion of CO_(2)to value-added carbon,electrochemical exfoliation of graphite to graphene-based materials,and electrochemical etching of carbides to new-type carbide-derived carbon materials.The reaction mechanisms and recent advances for these strategies are reviewed and discussed systematically.The morphological and structural properties and capacitive performances of the obtained carbon materials are summarized to reveal their appealing points for supercapacitor applications.Moreover,the opportunities and challenges of the molten salt synthesis strategy for the preparation of carbon materials are also discussed in this review to provide inspiration to the future researches.
基金supported by the National Natural Science Foundation of China(51004069 and 51474145)the National Science Fund for Distinguished Young Scholars(51225401)
文摘A series of oxygen permeable dual-phase composite oxides 60 wt% Ce0.8Gd0.2O2-δ-40 wt% LnBaCo2O5+δ (CGO-LBCO, Ln = La, Pr, Nd, Sin, Gd and Y) were synthesized through a sol-gel route and effects of the Ln3+ cations on their phase structure, oxygen permeability and chemical stability against CO2 were investigated systemically by XRD, SEM, TG-DSC and oxygen permeation experiments. XRD patterns reveal that the larger Ln3+ cations (La3+, Pr3+ and Nd3+) successfully stabilized the double-layered perovskite structure of sintered LBCO, while the smaller ones (Sm3+, Gd3+, and Y3+) resulted in the partial decomposition of LBCO with some impurities formed. CGO-PBCO yields the highest oxygen permeation flux, reaching 2.8× 10^-7 mol.s-1.cm-2 at 925 ℃ with 1 mm thickness under air/He gradient. The TG-DSC profiles in 20 mol% CO2/N2 and oxygen permeability experiments with CO2 as sweep gas show that CGO-YBCO demonstrates the best chemical stability against CO2, possibly due to its minimum basicity. The stable oxygen permeation flux of CGO-YBCO under CO2 atmosphere reveals its potential application in the oxy-fuel combustion route for CO2 capture.
基金the National Natural Science Foundation of China(nos.52022054,51974181,5200415,62004044,and 62204048)the National Key Research and Development Program of China(no.2022YFC2906100)+3 种基金the China Postdoctoral Science Foundation(no.2022M712023)the Shanghai Postdoctoral Excellence Program(no.2021159)the Science and Technology Commission of Shanghai Municipality(no.21DZ1208900)the Iron and Steel Joint Research Fund of National Natural Science Foundation and China Baowu Steel Group Corporation Limited(U1860203).
文摘Sustainable and low-carbon-emission silicon production is currently one of the main focuses for the metallurgical and materials science communities.Electrochemistry,considered a promising strategy,has been explored to produce silicon due to prominent advantages:(a)high electricity utilization efficiency;(b)low-cost silica as a raw material;and(c)tunable morphologies and structures,including films,nanowires,and nanotubes.This review begins with a summary of early research on the extraction of silicon by electrochemistry.Emphasis has been placed on the electro-deoxidation and dissolution–electrodeposition of silica in chloride molten salts since the 21st century,including the basic reaction mechanisms,the fabrication of photoactive Si films for solar cells,the design and production of nanoSi and various silicon components for energy conversion,as well as storage applications.Besides,the feasibility of silicon electrodeposition in room-temperature ionic liquids and its unique opportunities are evaluated.On this basis,the challenges and future research directions for silicon electrochemical production strategies are proposed and discussed,which are essential to achieve large-scale sustainable production of silicon by electrochemistry.
基金sponsored by the National Natural Science Foundation of China(5197418151574164)+5 种基金the Iron and Steel Joint Research Found of National Natural Science Foundation and China Baowu Steel Group Corporation Limited(U1860203)the Shanghai Rising-Star Program(19QA1403600)China Postdoctoral Science Foundation(2019M661462)the Shanghai Postdoctoral Excellence Program(2018079)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher learning(TP2019041)the CAS Interdisciplinary Innovation Team and High Performance Computing Center,Shanghai University for financial support。
文摘Porous active core-shell carbon material with excellent synergistic effect has been regarded as a prospective material for supercapacitors.Herein,we report an integrated method for the facile synthesis of carbide-derived carbon(CDC)encapsulated with porous N-doped carbon(CDC@NC)towards highperformance supercapacitors.Polydopamine(PDA)as nitrogen and carbon sources was simply coated on SiC nanospheres to form SiC@PDA,which was then directly transformed into CDC@NC via a onestep molten salt electro-etching/in-situ doping process.The synthesized CDC@NC with hierarchically porous structure has a high specific surface area of 1191 m^(2) g^(-1).The CDC core and NC shell are typical amorphous carbon and more ordered N-doped carbon,respectively.Benefitting from its unique dual porous structures,the CDC@NC demonstrates high specific capacitances of 255 and 193 F g^(-1) at 0.5 and20 A g^(-1),respectively.The reaction mechanism of the electro-etching/in-situ doping process has also been investigated through experimental characterizations and theoretical density functional theory calculations.It is suggested that the molten salt electro-etching/in-situ doping strategy is promising for the synthesis of active core-shell porous carbon materials with synergistic properties for supercapacitors without the need for additional doping/activation processes.