JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2025
·Vol. 172
·期 3
·032506
·
IF 3.3
Wenqiang Li,Aimin Liu,Yanying Jiang,Chengdan He,Fengguo Liu,Yongjun Wang,Xianwei Hu,Jin Wang,Zhongning Shi
Silicate minerals on S-type asteroids are a potential resource for in situ production of silicon. We investigated the feasibility of synthesizing silicon from Mg2Si3O8 through electrolysis in NaF-LiF molten salt. Solubility of Mg2Si3O8 in NaF-LiF molten salt was determined using isothermal saturation. Dissolution equilibrium is reached after 120 min, and the solubility of Mg2Si3O8 in NaF-LiF molten salt at 750 °C is 28.9%. Electrochemical studies revealed that the reduction of Si(IV) in NaF-LiF molten salt is a two-step process. Si(IV) was reduced to Si(II) at −1.1 V (vs Pt), and Si(II) was further reduced to metallic silicon at −1.2 V (vs Pt). Electrolysis of Mg2Si3O8 in NaF-LiF molten salt was conducted at 750 °C using a high-purity graphite sheet as anode and a silver sheet as cathode. Electrolysis products were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). XRD indicated that the main phase of the electrolysis products was silicon when cell voltages were 2.0, 2.5, 3.0, and 3.5 V. Raman spectroscopy confirmed the presence of crystal silicon. SEM and EDS revealed that the electrolysis products exhibit granular morphology, and silicon concentration reached a maximum value of 98.14% when the cell voltage was 2.5 V.
研究领域:
材料科学
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天体资源开发
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DOI
高影响因子
ACS Omega
·
2022
·
IF 4.132
Yu Jiang,Qian Wang,Sisi Tian,Zhenhua Luo,Dong Wang,Yun Bai,Wu Lu,Tong Zhao
A novel NaF phase change microcapsule with a carbon shell (NaF@C microcapsule) was prepared by a simple approach. The carbon shell was synthesized by carbonization of a resole-type phenolic resin shell, which was encapsulated onto the surface of NaF particles by a simple phase separation process induced by tetraethoxysilane. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis were used to characterize the morphology, composition, crystal phase, and thermal properties of the microcapsules. The size of the NaF@C microcapsule was 3–5 μm with a core–shell structure. DSC results showed that the melting point of the prepared NaF@C microcapsule was 988 °C, and the enthalpy value was 192 J/g. The prepared NaF@C microcapsules retained the powder morphology after 30 times of heat treatment at 1100 °C, with no NaF leakage detected, and the micromorphology remained stable, presenting good thermal stability. The NaF@C microcapsules can be used in the fields of thermal protection and thermal management in extreme high-temperature environments such as aerospace and solar energy.
研究领域:
材料科学
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能源工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2011
·
IF 2.089
Hengwei Yan,Jianhong Yang,Wangxing Li
The surface tension and density of molten KF–NaF–AlF3-based electrolytes were determined as a function of the melting composition and temperature by the Archimedean method and maximum bubble-pressure method, respectively. The investigated temperatures range from (1013 to 1103) K, and the total cryolite molar ratio (CRt = ([KF] + [NaF])/[AlF3]) is 1.3 to 1.41; the mole fraction of NaF ranges from 0.15 to 0.4. The effects of temperature and the content of CaF2 and Al2O3 on surface tension and density were also investigated. The results indicate that the density and the surface tension tend to increase with the NaF content and CRt. The density and the surface tension fit the linear relationship with temperature.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 7
·3653-3660
·
IF 3.049
Guang Xiong,Miaomiao Feng,Jiaxu Liu,Qingrun Meng,Liping Liu,Hongchen Guo
An aerosol-assisted hydrothermal method has been applied to synthesizing hierarchical beta zeolites with SiO2/Al2O3 ratios ranging from 44 to 392 in NaF media. Two different morphologies, including nano-aggregates with interparticle mesopores and plate-like zeolites with intracrystalline mesopores, can be formed depending on the SiO2/Al2O3 ratios of the synthesis gels. A possible mechanism for the formation of the beta zeolites has been proposed. The obtained beta zeolites show hierarchical pores, good Al species distribution and less internal defect sites. Evaluation, by the cracking of 1,3,5-triisopropylbenzene (1,3,5-TIPB), is consistent with the acidic properties and the pore structure of beta zeolites with different ratios of SiO2/Al2O3.
研究领域:
材料科学
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催化化学
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产品关联
DOI
PubMed
高影响因子
JOM
·
2019
·Vol. 72
·期 1
·247-252
·
IF 2.305
Yan Hengwei,Liu Zhanwei,Ma Wenhui,Huang Liqiang,Wang Chengzhi,Liu Yingxin
The development of low-temperature aluminum electrolysis makes it possible to reduce energy consumption and greenhouse gas emissions. The KF-NaF-AlF 3 -based electrolyte is a promising low-temperature electrolyte for aluminum reduction. The liquidus temperatures of KF-NaF-AlF 3 electrolytes with a total cryolite ratio (CR t ) fixed at 1.3–2.0, and with different concentrations of NaF (with a step change of 5 mol.%), were investigated by the cooling curve method. The results showed that the liquidus temperature of KF-NaF-AlF 3 mixtures increases with the increase of the CR t , which has a bigger influence on the liquidus temperature than the traditional NaF-AlF 3 electrolyte currently used in aluminum smelters. When the content of NaF is 10–20 mol.%, the curves of the liquidus temperature vs. NaF content reach a peak. When the NaF content ranges from 30 to 40 mol.%, the liquidus temperature is relatively low (695–900°C). The precipitated order of the compounds in molten KF-NaF-AlF 3 electrolytes with a CR t of 1.3 is as follows: K 2 NaAlF 6 (or K 3 AlF 6 ) → Na 3 Al 5 F 14 → K 2 NaAl 3 F 12 → KAlF 4 .
研究领域:
材料科学
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冶金学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2023
·
IF 6.6
Nian Sha,Hari Bala,Can Chen,Bowen Zhang,Wei Zhang,Xiangli An,Diandian Chen,Zhiyong Zhao
In this study, we report a facile method to enhance the photovoltaic performance of solar cells based on carbon-counter-electrode by introducing NaF additives into the CH 3 NH 3 PbI 3 (MAPbI 3 ) film. The NaF additives can not only promote the crystallization of perovskite polycrystals but also help to form uniform, high-coverage, and high-quality perovskite films, leading to better light absorption and hydrophobicity. The device with addition of NaF has a maximum power conversion efficiency (PCE) of 11.26%, which is significantly higher than those without NaF (7.66%). Furthermore, the devices with the NaF additive exhibit superior stability, as they retained more than 95% of the original PCE after 2400 h in a humid atmosphere, which is considered to be associated with the presence of NaF and carbon electrode.
研究领域:
材料科学
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能源技术
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2025
·
IF 4.7
Qiuping Li,Zerong Duan,Guanghua Wen,Ping Tang,Zibing Hou
Low-basicity fluorine-containing mold flux, which forms a porous slag film with NaF pores, is expected to solve the contradiction between heat transfer and lubrication in the continuous casting process of peritectic steel. Herein, slag films were obtained by slag film heat flow simulator, and the thermal control of NaF pores in the slag film was evaluated by COMSOL. Based on the influence of fluorides on NaF gas generation, mold fluxes consisting of NaF, CaF 2 , and Na 3 AlF 6 were investigated separately at a basicity of 0.9 and a fluorine content of 6 wt%. The comprehensive heat control ability of these slag films ranked in the order: Na 3 AlF 6 > CaF 2 > NaF. Firstly, the slag film using NaF raw material exhibited larger NaF pores (30–50 μm), resulting in higher radiative transmittance and reduced thermal resistance. Its heat control is primarily dominated by the thickness of the film. Further, using CaF 2 raw material, the heat control ability and pore size were between NaF and Na 3 AlF 6 . Its slag film exhibited the highest surface roughness (27.32 μm), with interfacial thermal resistance playing a dominant role. With Na 3 AlF 6 as the fluorine source, the slag film exhibited finer and more uniformly distributed pores (10–30 μm), which enhanced reflectivity and reduced radiative heat transfer. Therefore, this study highlights that Na 3 AlF 6 as a raw material is conducive to low-basicity mold fluxes achieving thermal control through finely dispersed NaF pores.
研究领域:
材料科学
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冶金工程
✓ 已验证
DOI
高影响因子
VACUUM
·
2024
·
IF 3.8
Yonghui Yang,Hengwei Yan,Zhanwei Liu,Shenghui Guo,Jin Zhang,Rui Xia
The potential for the preparation of titanium metal through molten salt electrolysis is significant. However, the conventional process of molten salt electrolysis uses chloride molten salt as the electrolyte, which has low solubility for titanium dioxide (TiO 2 ). This paper introduces an innovative approach using a NaF-K 2 TiF 6 system as the molten salt electrolyte, which offered high solubility for TiO 2 . The solubility and dissolution behavior of TiO 2 in NaF-K 2 TiF 6 were analyzed carbon, oxygen and nitrogen analysis (LECO), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-temperature Fourier transform infrared spectroscopy (FT-IR). By optimizing the electrolysis temperature, cathode current density, and electrolysis time, titanium metal was successfully prepared, and impurities were removed through water washing and salt washing to obtain pure sponge-like titanium powder. Focused ion beam-scanning electron microscopy (FIB-SEM) analysis revealed that the titanium purity and oxygen content were consistent across both the surface and interior of the powder, thereby indicating effective prevention of oxidation in a vacuum argon (Ar) environment. This method offers the possibility of continuous production of titanium metal through molten salt electrolysis.
研究领域:
材料科学
·
冶金工程
✓ 已验证
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2018
·Vol. 49
·期 4
·2071-2076
·
IF 1.834
Yan Hengwei,Yang Jianhong,Liu Zhanwei,Wang Chengzhi,Ma Wenhui
The cryolite ratio (CR) is an important parameter for the electrolyte in aluminum reduction cells. The measurement method for the CR of the KF-NaF-AlF 3 system acid (CR < 3) electrolyte by means of electrical conductivity was initially developed, and the formula for calculating the CR was deduced. This method has the advantages of simple operation and high precision. In addition, the relative standard deviations (RSD) of the measurement are < 1.2 pct, and the analysis error of the NaF or KF content has little effect on the determination of the CR.
研究领域:
冶金学
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材料科学
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产品关联
DOI
高影响因子
IONICS
·
2023
·Vol. 29
·期 4
·1459-1468
·
IF 2.8
Yang Shuo,Xue Kui,Li Chen,Wang Hongbin,Shi Shaojun,Zhou Liujiang,Zhang Yongqi
The severe dendrite growth on Zn anode during the platting process is still a serious roadblock to the commercialization of rechargeable aqueous Zn-based energy storage devices. Introducing electrolyte additives is a facile and efficient strategy to suppress the formation of dendrites. In this work, we found that Na + cations can inhibit the growth of dendrites via the shielding effect during the Zn platting process, and F − can effectively inhibit the formation of Zn 4 (OH) 6 SO 4 ·nH 2 O during Zn stripping process. Benefiting from the synergetic effects of anion (F − ) and cation (Na + ), NaF delivers a stronger ability to suppress the formation of Zn dendrites than that of Na 2 SO 4 during stripping/platting processes. The systematic Zn//Zn cell with 0.1 M NaF as additive shows a 368 h stable cycling performance, significantly longer than those of Na 2 SO 4 (253 h) and blank sample (171 h). Our work provides a novel strategy to alleviate the growth of dendrite via optimizing the anion of additives. The excellent electrochemical performances of various Zn-based energy storage devices verify that the aqueous electrolyte with NaF additive has broad commercial prospects.
研究领域:
材料科学
·
电化学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Yifan Zhang,Xianwei Hu,Jiaxin Yang,Liyu Chen,Wenju Tao,Fengguo Liu,Zhongning Shi,Zhaowen Wang
Aluminum-vanadium intermediate alloy is a significant raw material for the fabrication of high-performance titanium alloys . In the present study, the electrochemical behavior of NaVO 3 on a solid molybdenum and liquid aluminum electrode is systematically investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV) in the NaF-KF-AlF 3 molten salt and the formation mechanism of Al-V intermetallic compounds is emphatically analyzed. The results show that the electrochemical reduction of VO 3 − on the solid molybdenum electrode is a multi-step process and low-valence vanadium oxide (V 2 O 3 ) is obtained. In contrast, the electrochemical reduction of VO 3 − to V 2 O 3 on liquid aluminum electrode is through one-step process and the deposition potential is more positive than that on molybdenum electrode owing to the depolarization effect of the liquid aluminum electrode. In addition, Al-V intermetallic compounds are obtained on the liquid aluminum electrode by potentiostatic electrolysis. The reduction process of VO 3 − on the liquid aluminum electrode is described as: the electrochemical process is started by the direct electro-reduction of VO 3 − to V 2 O 3 , which is further converted to Al-V intermetallic compounds under the combined effect of electrochemical and aluminothermic reduction, with the latter playing a dominant role.
研究领域:
冶金学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2021
·Vol. 52
·期 5
·3490-3496
·
IF 2.47
Yan Hengwei,Huang Liqiang,Ma Wenhui,Liu Zhanwei,Qin Bo
The NaF-KF-AlF 3 -based electrolyte is a promising low-temperature electrolyte for aluminum reduction. The solubility and dissolution rate of alumina in NaF-KF-AlF 3 -LiF-CaF 2 melt with a cryolite ratio (CR) ranging from 1.5 to 1.8 were investigated by the rotating corundum disk method at 1073 K to 1153 K. The effect of the composition and temperature of the melt on the solubility and dissolution rate of alumina were discussed. The results show that the solubility and dissolution rate of alumina in the melt decrease with the increase of LiF and CaF 2 content, and the effect of LiF on the alumina solubility is greater than that of CaF 2 . The decrease of the CR and temperature lead to a marked reduction of the alumina solubility and alumina dissolution rate. The dissolution rate of alumina depends on the dissolution rate in the first 5 minutes. The alumina dissolution is a zero-order reaction in the first 5 minutes, and a first-order reaction in the next 30 minutes.
研究领域:
材料科学
·
冶金工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）