Characterization of YSZ solid oxide fuel cells electrolyte deposited by atmospheric plasma spraying and low pressure plasma spraying

Yttria doped zirconia has been widely used as electrolyte materials for solid oxide fuel cells (SOFC). Plasma spraying is a cost-effective process to deposit YSZ electrolyte. In this study, the 8 mol% Y₂O₃ stabilized ZrO₂ (YSZ) layer was deposited by low pressure plasma spraying (LPPS) and atmospheric plasma spraying (APS) with fused-crushed and agglomerated powders to examine the effect of spray method and particle size on the electrical conductivity and gas permeability of YSZ coating. The microstructure of YSZ coating was characterized by scanning electron microscopy and x-ray diffraction analysis. The results showed that the gas permeability was significantly influenced by powder structure. The gas permeability of YSZ coating deposited by fused-crushed powder is one order lower in magnitude than that by agglomerated powder. Moreover, the gas permeability of YSZ deposited by LPPS is lower than that of APS YSZ. The electrical conductivity of the deposits through thickness direction was measured by potentiostat/galvanostat based on three-electrode assembly approach. The electrical conductivity of YSZ coating deposited by low pressure plasma spraying with fused-crushed powder of small particle size was 0.043 S cm⁻¹ at 100 °C, which is about 20% higher than that of atmospheric plasma spraying YSZ with the same powder. This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials Park, OH, 2006.     

Sm2O3和Nd2O3共同掺杂CeO2基电解质材料的研究

采用柠檬酸-硝酸盐法合成出单一相、均匀的Ce0.8SmxNd0．2-xO19粉体，XRD结果表明该粉体为单相萤石结构，粒径约在11．7nm～20．1nm之间。将粉体干压成型，在1400℃下无压烧结5h可得到高致密度陶瓷。SEM照片显示陶瓷微观结构均匀，晶粒尺寸在2μm～4μm。经直流四端电极法测试得到该样品在500℃时电导率约在0．012 S／cm。该结果说明与单项掺杂相比，两相共掺杂会进一步提高材料的电导率。     

200kA预焙槽强化电流过程中发生电解质粘度增加的实践探讨

通过分析200kA预焙槽在强化电流条件下电解质粘度增大的原因及对电解生产的影响,提出了规范电解生产作业制度及处理电解质粘度过大的建议,以实现降低工人劳动强度,达到工艺参数优化和提高电流效率的目的。     

Synthesis of tertiary amines and their inhibitive performance on carbon steel corrosion

Some tertiary amines in the series of 1,3-di-amino-propan-2-ol, referred as 1,3-di-morpholin-4-yl-propan-2-ol (DMP) and 1,3-bis-diethylamino-propan-2-ol (DEAP), had been synthesized by alkylation reaction. These compounds were checked by MS, IR, ¹H NMR and ¹³C NMR. The electrochemical performance of these products was investigated through potentiodynamic polarization measurement and electrochemical impedance spectroscopy (EIS) under thin electrolyte layer with thickness of 100 μm, and their inhibition efficiencies were measured using gravimetric method. These compounds, retarding the anodic dissolution of iron by the protective layer bonding on the metal surface, were anodic inhibitors under thin electrolyte layer. Polarization data indicated that the inhibitive performance of DMP for carbon steel was improved with the increasing of concentration, whereas DEAP showed a maximum inhibiting power at 2.5 × 10⁻² M. The values of the charge transfer resistance, obtained from impedance plots of carbon steel, showed that DEAP was a promising inhibitor. The gravimetric results showed that the inhibition efficiency of DEAP at 2.5 × 10⁻² M was 95%. The adsorption on the carbon steel surface followed Langmuir isotherm model. The Fourier transform spectroscopy (FTIR) was used to analyze the surface adsorbed film.     

Neutral electrolyte aluminum air battery with open configuration

A kind of new long life aluminum air batteries with open configuration was developed, using aluminum alloy doped with Ga, In, Sn, Bi, Pb and Mn as anode, NaCl solution as electrolyte and air electrode as cathode. The polarization curves of aluminum electrode and air electrode were tested. And the cell's performance was tested to calculate the utilization of aluminum electrode and the energy density. It is shown that, in the 3.5% NaCl solution, the cell can discharge at 0.29 A for 140 h with the working voltage keeping over 1.1 V. The utilization ratio of aluminum anode is over 44%, and the life of battery is longer than 2400 h.     

Solid-state potentiometric SO2 sensor combining NASICON with V2O5-doped TiO2 electrode

A compact tubular sensor based on NASICON (sodium super ionic conductor) and V₂O₅-doped TiO₂ sensing electrode was designed for the detection of SO₂. In order to reduce the size of the sensor, a thick-film of NASICON was formed on the outer surface of a small Al₂O₃ tube; furthermore, a thin layer of V₂O₅-doped TiO₂ with nanometer size was attached on the NASICON as a sensing electrode. This paper investigated the influence of V₂O₅ doping and sintering temperature on the characteristics of the sensor. The sensor attached with 5 wt% V₂O₅-doped TiO₂ sintered at 600 °C exhibited excellent sensing properties to 1–50 ppm SO₂ in air at 200–400 °C. The EMF value of the sensor was almost proportional to the logarithm of SO₂ concentration and the sensitivity (slope) was −78 mV/decade at 300 °C. It was also seen that the sensor showed a good selectivity to SO₂ against NO, NO₂, CH₄, CO, NH₃ and CO₂. Moreover, the sensor had speedy response kinetics to SO₂ too, the 90% response time to 50 ppm SO₂ was 10 s, and the recovery time was 35 s. On the basis of XPS analysis for the SO₂-adsorbed sensing electrode, a sensing mechanism involving the mixed potential at the sensing electrode was proposed.     

固体电解质电位型CO气体传感器的研究

以NASICON(钠超离子导体)固体电解质为离子导电层,Y2O3为敏感电极研制了一种用于测定CO的电化学气体传感器.结果表明,器件对(5～50)×10-6范围内的CO具有较好的敏感特性.在400℃下,器件对CO的灵敏度为-45 mV/decade.并且器件对CO具有较高的选择性和良好的响应恢复特性.     

Progress of Phosphate-based Polyanion Cathodes for Aqueous Rechargeable Zinc Batteries

Aqueous rechargeable zinc batteries (ARZBs) are recently prevailing devices that utilize the abundant Zn resources and the merits of aqueous electrolytes to become a competitive alternative for large-scale energy storage. Benefiting from the unique inductive effect and flexible structure, the past five years have experienced a diversiform of phosphate-based polyanion materials that are used as cathodes in ARZBs. In this review, the most recent advances in the Zn²⁺ storage mechanisms and electrolyte optimization of the phosphate-based cathodes of ARZBs, which mainly focus on vanadium/iron-based phosphates and their derivatives are presented. Furthermore, in addition to significant progress on polyanion phosphate-based cathode materials, the design strategies both for electrode materials and compatible electrolytes are also elaborated to improve the energy density and extend the cycling life of aqueous Zn/polyanion batteries.     

Interfacial Proton Supply/Filtration Regulates the Dynamics of Electrocatalytic Nitrogen Reduction Reaction: A Perspective

As a promising energy carrier, ammonia synthesis by electrocatalytic nitrogen reduction reaction (eNRR) is a promising green and low-carbon ammonia synthesis strategy that can replace the traditional Haber–Bosch process. However, the development of eNRR processes is mainly severely constrained by competitive hydrogen evolution reaction (HER), and the corresponding strategies to inhibit this adverse side reaction to obtain high eNRR selectivity are still limited. In addition, for this complex reaction involving gas–liquid–solid three-phase interface and proton/electron transfer, it is great significance to analyze and summarize the existing inhibition HER strategies from the viewpoint of dynamics. In view of this, this work reviews proton supply/filtration regulation strategy in catalytic system, allowing a systematic survey of the literature focusing on interface membrane regulation (inorganic membrane and organic membrane), electrolyte regulation (metal-mediated strategy and electrolyte ion regulation strategy) and system device design (electrode structure design and electrolytic cell device design). Constructive catalytic system design guidance is also suggested to inhibit hydrogen evolution and improve NH₃ selectivity, aiming for scalable and economically feasible applications.     

Hydrofluoric Acid-Removable Additive Optimizing Electrode Electrolyte Interphases with Li+ Conductive Moieties for 4.5 V Lithium Metal Batteries

High-voltage lithium metal batteries (LMBs) are capable to achieve the increasing energy density. However, their cycling life is seriously affected by unstable electrolyte/electrode interfaces and capacity instability at high voltage. Herein, a hydrofluoric acid (HF)-removable additive is proposed to optimize electrode electrolyte interphases for addressing the above issues. N, N-dimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) aniline (DMPATMB) is used as the electrolyte additive to induce PF₆⁻ decomposition to form a dense and robust LiF-rich solid electrolyte interphase (SEI) for suppressing Li dendrite growth. Moreover, DMPATMB can help to form highly Li⁺ conductive Li₃N and LiBO₂, which can boost the Li⁺ transport across SEI and cathode electrolyte interphase (CEI). In addition, DMPATMB can scavenge traced HF in the electrolyte to protect both SEI and CEI from the corrosion. As expected, 4.5 V Li|| LiNi_0.6Co_0.2Mn_0.2O₂ batteries with such electrolyte deliver 145 mAh g⁻¹ after 140 cycles at 200 mA g⁻¹. This work provides a novel insight into high-voltage electrolyte additives for LMBs.