The high-temperature requirement for liquid iron smelting via molten oxide electrolysis presents significant challenges.This study investigates the electrochemical reduction of Fe(Ⅲ)in a novel low-temperature electro...The high-temperature requirement for liquid iron smelting via molten oxide electrolysis presents significant challenges.This study investigates the electrochemical reduction of Fe(Ⅲ)in a novel low-temperature electrolyte,Na_(2)SiO_(3)-SiO_(2)-Fe_(2)O_(3),utilizing cyclic voltammetry and square wave voltammetry techniques.The results show that Fe(Ⅲ)reduction occurs in two steps:Fe(Ⅲ)+e^(−)→Fe(Ⅱ),Fe(Ⅱ)+2e^(−)→Fe,and that the redox process of Fe(Ⅲ)/Fe(Ⅱ)at the tungsten electrode is an irreversible reaction controlled by diffusion.The diffusion coefficients of Fe(Ⅲ)in the molten Na_(2)SiO_(3)-SiO_(2)-Fe_(2)O_(3)in the temperature range of 1248–1278 K are between 1.86×10^(−6)cm^(2)/s and 1.58×10^(−4)cm^(2)/s.The diffusion activation energy of Fe(Ⅲ)in the molten salt is 1825.41 kJ/mol.As confirmed by XRD analysis,potentiostatic electrolysis at−0.857 V(vs.O_(2)/O_(complex)^(2-))for 6 h produces metallic iron on the cathode.展开更多
Cyclic voltammetry and chronopotentiometry were used to study the reaction mechanism of Pb（Ⅱ） and the co-deposition of Pb,Mg and Li on molybdenum electrodes in LiCl-KCl-PbCl2-MgCl2 melts.The diffusion coefficient o...Cyclic voltammetry and chronopotentiometry were used to study the reaction mechanism of Pb（Ⅱ） and the co-deposition of Pb,Mg and Li on molybdenum electrodes in LiCl-KCl-PbCl2-MgCl2 melts.The diffusion coefficient of lead ions in the melts was determined by different electrochemical techniques.The results obtained by cyclic voltammetry and chronopotentiometry indicated that the underpotential deposition of lithium on pre-deposited Pb leads to the formation of a liquid Li-Pb alloy,and the Mg-Li-Pb alloys are formed after the addition of MgCl2.X-ray diffraction confirmed that in the Mg-Li-Pb alloy,PbLi3,Mg2Pb and Li7Pb2 phases exist by galvanostatic electrolysis at 6.21 A/cm2 for 2 h at 873 K and the phases can be controlled by changing the concentration of PbCl2 and MgCl2.展开更多
Nanofiltration separation has become a popular technique for removing largeorganic molecules and inorganic substances from water. It is achieved by a combination of threemechanisms: electrostatic repulsion, sieving an...Nanofiltration separation has become a popular technique for removing largeorganic molecules and inorganic substances from water. It is achieved by a combination of threemechanisms: electrostatic repulsion, sieving and diffusion. In the present work, a model based onirreversible thermodynamics is extended and used to estimate rejection of inorganic salts andorganic substances. Binary systems are modeled, where the feed contains an ion that is much lesspermeable to the membrane as compared with the other ion. The two model parameters are estimated byfitting the model to the experimental data. Variation of these parameters with the composition ofthe feed is described by an empirical correlation. This work attempts to describe transport throughthe nanofiltration membranes by a simple model.展开更多
As promising,low-cost alternatives of lithiumion batteries for large-scale electric energy storage,sodiumion batteries(SIBs)have been studied by many researchers.However,the relatively large size of Na+leads to sluggi...As promising,low-cost alternatives of lithiumion batteries for large-scale electric energy storage,sodiumion batteries(SIBs)have been studied by many researchers.However,the relatively large size of Na+leads to sluggish diffusion kinetics and poor cycling stability in most cathode materials,restricting their further applications.In this work,we demonstrated a novel K+-intercalated Mn/Ni-based layered oxide material(K0.7Mn0.7Ni0.3O2,denoted as KMNO)with stabilized and enlarged diffusion channels for high energy density SIBs.A spontaneous ion exchange behavior in forming K0.1Na0.7Mn0.7Ni0.3O2between the KMNO electrode and the sodium ion electrolyte was clearly revealed by in situ X-ray diffraction and ex situ inductively coupled plasma analysis.The interlayer space varied from 6.90 to 5.76?,larger than that of Na0.7Mn0.7Ni0.3O2(5.63?).The enlarged ionic diffusion channels can effectively increase the ionic diffusion coefficient and simultaneously provide more K+storage sites in the product framework.As a proof-of-concept application,the SIBs with the as-prepared KMNO as a cathode display a high reversible discharge capacity(161.8 mA h g-1at0.1 A g-1),high energy density(459 W h kg-1)and superior rate capability of 71.1 mA h g-1at 5 A g-1.Our work demonstrates that the K+pre-intercalation strategy endows the layered metal oxides with excellent sodium storage performance,which provides new directions for the design of cathode materials for various batteries.展开更多
基金Project(52074084)supported by the National Natural Science Foundation of China。
文摘The high-temperature requirement for liquid iron smelting via molten oxide electrolysis presents significant challenges.This study investigates the electrochemical reduction of Fe(Ⅲ)in a novel low-temperature electrolyte,Na_(2)SiO_(3)-SiO_(2)-Fe_(2)O_(3),utilizing cyclic voltammetry and square wave voltammetry techniques.The results show that Fe(Ⅲ)reduction occurs in two steps:Fe(Ⅲ)+e^(−)→Fe(Ⅱ),Fe(Ⅱ)+2e^(−)→Fe,and that the redox process of Fe(Ⅲ)/Fe(Ⅱ)at the tungsten electrode is an irreversible reaction controlled by diffusion.The diffusion coefficients of Fe(Ⅲ)in the molten Na_(2)SiO_(3)-SiO_(2)-Fe_(2)O_(3)in the temperature range of 1248–1278 K are between 1.86×10^(−6)cm^(2)/s and 1.58×10^(−4)cm^(2)/s.The diffusion activation energy of Fe(Ⅲ)in the molten salt is 1825.41 kJ/mol.As confirmed by XRD analysis,potentiostatic electrolysis at−0.857 V(vs.O_(2)/O_(complex)^(2-))for 6 h produces metallic iron on the cathode.
基金Projects(50871033,21173060,21103033) supported by the National Natural Science Foundation of ChinaProject supported by the Fundamental Research Funds for the Central Universities,ChinaProjects(2011AA03A409,2009AA050702,2007CB200906) supported by the Basic Research Foundation of Harbin Engineering University,China
文摘Cyclic voltammetry and chronopotentiometry were used to study the reaction mechanism of Pb（Ⅱ） and the co-deposition of Pb,Mg and Li on molybdenum electrodes in LiCl-KCl-PbCl2-MgCl2 melts.The diffusion coefficient of lead ions in the melts was determined by different electrochemical techniques.The results obtained by cyclic voltammetry and chronopotentiometry indicated that the underpotential deposition of lithium on pre-deposited Pb leads to the formation of a liquid Li-Pb alloy,and the Mg-Li-Pb alloys are formed after the addition of MgCl2.X-ray diffraction confirmed that in the Mg-Li-Pb alloy,PbLi3,Mg2Pb and Li7Pb2 phases exist by galvanostatic electrolysis at 6.21 A/cm2 for 2 h at 873 K and the phases can be controlled by changing the concentration of PbCl2 and MgCl2.
文摘Nanofiltration separation has become a popular technique for removing largeorganic molecules and inorganic substances from water. It is achieved by a combination of threemechanisms: electrostatic repulsion, sieving and diffusion. In the present work, a model based onirreversible thermodynamics is extended and used to estimate rejection of inorganic salts andorganic substances. Binary systems are modeled, where the feed contains an ion that is much lesspermeable to the membrane as compared with the other ion. The two model parameters are estimated byfitting the model to the experimental data. Variation of these parameters with the composition ofthe feed is described by an empirical correlation. This work attempts to describe transport throughthe nanofiltration membranes by a simple model.
基金supported by the National Natural Science Foundation of China(51872218 and 51832004)the National Key R&D Program of China(2016YFA0202603)the Fundamental Research Funds for the Central Universities(WUT:2017III009)。
文摘As promising,low-cost alternatives of lithiumion batteries for large-scale electric energy storage,sodiumion batteries(SIBs)have been studied by many researchers.However,the relatively large size of Na+leads to sluggish diffusion kinetics and poor cycling stability in most cathode materials,restricting their further applications.In this work,we demonstrated a novel K+-intercalated Mn/Ni-based layered oxide material(K0.7Mn0.7Ni0.3O2,denoted as KMNO)with stabilized and enlarged diffusion channels for high energy density SIBs.A spontaneous ion exchange behavior in forming K0.1Na0.7Mn0.7Ni0.3O2between the KMNO electrode and the sodium ion electrolyte was clearly revealed by in situ X-ray diffraction and ex situ inductively coupled plasma analysis.The interlayer space varied from 6.90 to 5.76?,larger than that of Na0.7Mn0.7Ni0.3O2(5.63?).The enlarged ionic diffusion channels can effectively increase the ionic diffusion coefficient and simultaneously provide more K+storage sites in the product framework.As a proof-of-concept application,the SIBs with the as-prepared KMNO as a cathode display a high reversible discharge capacity(161.8 mA h g-1at0.1 A g-1),high energy density(459 W h kg-1)and superior rate capability of 71.1 mA h g-1at 5 A g-1.Our work demonstrates that the K+pre-intercalation strategy endows the layered metal oxides with excellent sodium storage performance,which provides new directions for the design of cathode materials for various batteries.
