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Rare Metals 2007年第6期26卷 547-551页

作者： LIU Meifeng LU Shigang KAN Surong LI Guoxun General Research Institute for Non-ferrous Metals Beijing 100088 China

The electrochemical reduction of solid TiO2 directly to solid metal is a promising alternative to the current Kroll process. The present work is aimed at studying the effect of electrolysis voltage on the rate of electrochemical reduction. The products of electrochemical reduction of TiO2 and Ti2O were examined using the scanning electron microscopy （SEM） and X-ray diffraction （XRD） techniques. The results show that Ti2O was reduced to low valent titanium oxide at 1.5 -1.7 V, which was the result of ionization of oxygen. TiO2 and Ti20 were reduced to titanium metal at 2.1-3.1 V, which was the co-action of ionization of oxygen and calciothermic reduction. The oxygen content decreased rapidly with voltage increasing from 2.1 to 2.6 V, while it changed little from 2.6 to 3.1 V. The optimized cell voltage was 2.6-3.1 V.

关键词： electrochemical reduction electrolysis voltage molten salt titanium TiO2

Electrochemical Reaction Processes of Niobium Ions in FLINAK melt

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International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 83-89页

作者： Wang X. Duan S. Christensen E. Bjerrum N.J. Ito Y. Metallurgy School University of Science and Technology Beijing Beijing 100083 China Materials Science Group Chemistry Department A Technical University of Denmark DK-2800 Lyngby Denmark Department of Energy Science and Engineering Kyoto University Kyoto 606 Japan

ThecathodicProcessmechanismofniobiumreductionfromchloride-fluorideandfiuoridemeltshasbeenstudiedindetail[l-],batthereseemsstilltobesomedismpemelltconcerningthereductionmechanism.Essentially,threehoesofmodelshaVebeenPu... 详细信息

关键词： electrochemistry molten salt FLINAK niobium reduction

Amorphous silicon from low-temperature reduction of silica in the molten salts and its lithium-storage performance

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Chinese Chemical Letters 2021年第2期32卷 598-603页

作者： Xi Huang Xuyun Guo Yicheng Ding Run Wei Shengnan Mao Ye Zhu Zhihao Bao Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology School of Physics Science and EngineeringTongji University.Shanghai 200092China Department of Applied Physics Research Institute for Smart EnergyHong Kong Polytechnic UniversityHong KongChina

Amorphous silicon(a-Si) is one of the most promising anode-materials for the lithium-ion battery owing to its large capacity and superior fracture resistance.However,a-Si is usually fabricated with the sophisticated chemical vapor deposition or pulse laser deposition in a limited scale.In this work,we have succes s fully pre pared a-Si spheres(~200 nm) by reducing the TiO2-coated silica spheres with Al powders in the molten salts at 300℃.The coated TiO2 layer acts as a protective layer for structural maintenance during the reduction and a precursor for doping.The doped Ti element may suppress the crystal growth of Si to facilitate the formation of a-Si.The observation with in-situ transmission electron microscopy(TEM) further reveals that lithiation kinetics of the synthesized a-Si is controlled by the interfacial reaction.The Li^(+) diffusivity in a-Si determined from the observation is in the order of 10^(-14) cm^(2)/s.The anode of a-Si spheres together with crystalline Si nanoparticles exhibits excellent electrochemical performance,delivering a reversible capacity of 1604 mAh/g at 4 A/g and a capacity retention of 78,3%after 500 cycles.The low temperature reduction process reported in this study provides a low-cost method to fabricate a-Si nanostructures as high-capacity durable anode materials.

关键词： Amorphous molten salt Lithium-ion battery Silicon anode Doping

Electrochemical formation and phase control of Mg-Li alloys

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Chinese Chemical Letters 2007年第9期18卷 1124-1128页

作者： Zhang, Mi Lin Chen, Zeng Han, Wei Lv, Yan Zhuo Wang, Jun Harbin Engn Univ Key Lab Superlight Mat & Surface Technol Minist Educ Harbin 150001 Peoples R China

The electrochemical formation of Mg-Li alloys was investigated in a molten LiCl-KCl (58-42 mol%) eutectic melt at 723 K. The cyclic voltammogram. for a Mo electrode showed that the electroreduction of Li+ proceeds in a single step and the deposition potential of Li metal was -2.40 V (vs. Ag/AgCl). For Mg electrode, the electroreduction of Li+ takes place at less cathodic potential than that at the Mo electrode which was caused by the formation of Mg-Li alloys. Phase of the deposited Mg-Li alloys could be controlled by the electrolysis potential, and the samples were characterized by X-ray diffraction and scanning electron microscopy. The results showed that alpha-Mg and beta-Li phases were obtained at -2.35 and -2.55 V, respectively. (c) 2007 Mi Lin Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

关键词： LiCl-KCl molten salt electrodeposition Mg-Li alloy

Electroreduction of Tungsten Oxide（VI） in molten salts with Added Metaphosphate

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Chemical Research in Chinese Universities 2013年第4期29卷 771-775页

作者： MALYSHEV Victor GAB Angelina POPESCU Ana-Maria CONSTANT1N Virgil Faculty of Chemistry & Technology National Technical University of Ukraine "Kyiv Polytechnical Institute " Kyiv 05056 Ukraine" Open International University of Human Development of Ukraine Kyiv 04071 Ukraine Laboratory of molten salts Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy Bucharest 006021 Roumania

Tungstate ions WO4^2- are not electrochemically active in chloride melts. Upon introduction of PO3 ions into the melt, two waves appear in the voltammograms at potentials -0.1-- -0.2 V and -0.3-- -0.5 V vs. Pb/Pb2＋ reference electrode. With a PO3- concentration ratio of 0.01〈[PO3-]/[WO42-]〈0.18, the potentiostatic electrolysis product of WO42 at the above mentioned potentials is metallic tungsten; a NaPO3 concentration increase for ratios [PO3-]/[WO42-]〉〉0.18 results in tungsten phosphide in electrolysis product. Cyclic voltammograms and dependence of half-peak potentials on electrode polarization rate indicate the irreversible character of the electrode process. Elec- trode process modeling allows us to state that the first wave in the voltammogram of KC1-NaC1-Na2WOa-NaPO3 sys- tem corresponds to tungsten oxychlorides discharge while the second wave appears due to the discharge of di- tungstate ions. In the voltammograms of Na2WOa-NaPO3 melts, reduction wave was observed at -1.1-- -1.2 V po- tentials. Proportionality of limiting current to NaPO3 concentration, constancy of ld/V1/2 ratio, and IJnFc constant ki- netic value equal to （8.3--9.5）×10-5 cm/s for steady-state wave indicate that electrode process rate is limited by elec- trochemically active particle diffusion to the electrode. Nascent ditungstate ions become electrochemically active in the overall electrode process. Charge transfer stage is reversible.

关键词： Tungsten oxide Electroreduction molten salt Cyclic voltammetry

Thermodynamic Description of the MCl2-ThCl4 （M： Mg, Ca, Sr, Ba） Systems

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Chemical Research in Chinese Universities 2017年第5期33卷 794-798页

作者： XIE Mengya LI Xiang DING Yaping ZHANG Guoxin Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 P. R. China Department of Chemistry Shanghai University Shanghai 200444 P. R. China

The phase equilibria for the MCl2-ThCl4（M; Mg, Ca, St, Ba） binary systems were critically evaluated and optimized based upon the CALPHAD approach. The substitutional solution model（SSM） was used to describe the liquid phase. All the intermediate eompounds were treated as stoichiometric compounds of which Gibbs energies comply with the Neumalm-Kopp rule. Thermodynamic model parameters optimization for respective phases was conducted by the least squares minimization procedure with required input data available from experimental mea- surements. Satisfactory agreements between all calculated results and experimental data were achieved which demonstrates that thermodynamic databases for the MCl2-ThCl4（M： Mg, Ca, St, Ba） binary systems were ultimately derived in the present work allowing safe extrapolation into multi-component system for guiding relative industrial applications.

关键词： Thermodynamics molten salt Phase diagram

Experimental Investigation and Thermodynamic Modeling of the NaCI-NaNO3-Na2SO4 Ternary System

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Chemical Research in Chinese Universities 2018年第3期34卷 475-479页

作者： LI Xiang FEI Zejie WANG Yang XIE Leidong Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 P R. China University of Chinese Academy of Sciences Beijing 100049 P R. China

molten salts as heat transfer and storage materials have been used to nuclear energy and concentrated solar power（CSP） applications. In this work, the system of molten salt mixture based on thermodynamic principles was designed as thermal energy storage（TES） materials. The substitutional solution model can be employed to describe the Gibbs energies of all liquid phase. Thermodynamic model parameters for the NaCl-NaNO3-Na2SO4 subsystems were conducted by thermodynamic evaluation and optimization based on experimental phase-equilibria data. Thus, a set of self-consistent thermodynamic database was eventually obtained to reliably calculate the whole phase diagram and thermodynamic properties for the NaCl-NaNO3-Na2SO4 ternary system. The results manifest that the eutectic point of theternary system located at T=280 ℃ and XNaCl=8.4%, XNaNO3=86.3% and xNa2SO4=5.3%. Moreover, the results predicted were verified experimentally using differential scanning calorimetry（DSC） and the agreement between the measured value[T=（287±2） ℃] and predicted value（T=280 ℃） was satisfactory. Thus, the thermodynamic calculation method will be used to design and develop novel molten salt mixture as thermal energy storage materials.

关键词： Thermodynamics modeling molten salt Thermal energy storage Phase diagram

CeO_2 as the Oxygen Carrier for Partial Oxidation of Methane to Synthesis Gas in molten salts: Thermodynamic Analysis and Experimental Investigation

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Journal of Natural Gas Chemistry 2007年第1期16卷 6-11页

作者： Yonggang Wei Hua Wang Fang He Xianquan Ao Chiyuan Zhang Faculty of Materials and Metallurgy Engineering Kunming University of Science and Technology Kunming 650093 Yunnan China

A new technique -- the direct partial oxidation of methane to synthesis gas using lattice oxygen in molten salts medium has been introduced. Using CeO2 as the oxygen carrier, thermodynamic data were calculated in the reaction process, and the results indicated that direct partial oxidation of methane to synthesis gas using lattice oxygen of cerium oxide is feasible in theory. In a stainless steel reactor, the effects of temperature and varying amounts of γ-Al2O3 supported CeO2 on cn4 conversion, H2 and CO selectivity, were investigated, respectively. The results show that 10% CeO2/γ-Al2O3 has the maximal reaction activity at a temperature of 865 ℃ and above, the H2/CO ratio in the gas that has been produced reaches 2 and the CH4 conversion, H2 and CO selectivity reached the following percentages： i.e. 61%, 89%, and 91% at 870 ℃, respectively. In addition, increase of reaction temperature is favorable for the partial oxidation of methane.

关键词： partial oxidation methane cerium oxide synthesis gas molten salt

Electrochemical Behavior of Dissolved Fe_2O_3 in molten CaCl_2-KF

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Journal of Iron and Steel Research(International) 2008年第6期15卷 48-51页

作者： WANG Shu-lan Geir Martin Haarberg Eirin Kvalheim Department of Chemistry Northeastern University Shenyang 110004 Liaoning China Department of Materials Science and Engineering NTNU Trondheim 7429 Norway

The electrochemical behavior of dissolved Fe2O2 in 82.5CaCl2-17.5KF （mole percent, %） was studied using cy clic voltammetry, chronoamperometry, and galvanostatic electrolysis at 827 ℃, and the deposits were characterized by XRD and SEM. Pure iron was deposited on a rotating cylinder （210 r/min） with a cell voltage less than -- 1.0 V. Deposition rate was controlled by diffusion on a molybdenum electrode. The diffusion coefficient of iron species Fe（ Ⅲ ） in the melt at 827 ℃ was found to be 9.7×10^-5 cm^2/s.

关键词： iron electrolysis electrochemistry molten salt

Thermodynamic and Phase Diagram Modeling of CsF-MF4（M=U, Th） Systems

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Chemical Research in Chinese Universities 2017年第3期33卷 454-459页

作者： LI Xiang WANG Kun XIE Mengya WU Zhu XIE Leidong Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 P. R. China University of Chinese Academy of Sciences Beijing 100049 R R. China Department of Chemical and Materials Engineering University of Alberta Edmonton AB T6G 2V4 Canada College of Sciences Shanghai University Shanghai 200072 P. R. China Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai 200050 P. R. China

Phase diagrams for the CsF-UF4 and CsF-ThF4 systems were modeled in the present work through computational thennodynamics. The associate solution model with various complex species（CsMFs, Cs2MF6 and Cs3MF7; M=Th, U） was used to thermodynamically describe the binary molten salts. A total of ten intermediate phases were treated as stoichiometric compounds with their Gibbs energies modeled according to the Neumann-Kopp rule. All these model parameters were optimized by the least squares procedure until good coincidence was achieved between the calculated results and most of the experimental data. The derived thermodynamic parameters will be merged into the multicomponent CsF-LiF-BeF2-ThF4-UF4 database for analyzing physicochemical behavior of CsF in the fuel salt of the molten salt breeder reactor.

关键词： molten salt Metal fluoride Thermodynamic and phase diagram modeling