Effect of double doping on crystal structure and electrical conductivity of CaO and WO3-doped Bi2O3

The atomic arrangement of WO₃-doped Bi₂O₃ was found similar to that of the fluorite structure. However, the electrical conductivity of WO₃-doped Bi₂O₃ is significantly lower than that of commonly used Y₂O₃-doped Bi₂O₃. The structure and electrical conductivity of samples formulated as (Ca_xW_0.15Bi_0.85−x)₂O_3.45−x (x = 0, 0.1, 0.2 and 0.3) were investigated. The as-sintered (W_0.15Bi_0.85)₂O_3.45 and (Ca_0.1W_0.15Bi_0.75)₂O_3.35 exhibit similar single tetragonal structure that is isostructural with 7Bi₂O₃·2WO₃. Therefore, (W_0.15Bi_0.85)₂O_3.45 and (Ca_0.1W_0.15Bi_0.75)₂O_3.35 formed a superstructure consisting of 10 enlarged cubic fluorite subcells. However, the as-sintered samples consist of a tetragonal structure and tetragonal CaWO₄ for x = 0.2 and 0.3 because the oxygen vacancy concentration increases. The conductivities of (Ca_xW_0.15Bi_0.85−x)₂O_3.45−x (x = 0, 0.1, 0.2 and 0.3) did not exhibit linear dependence with x value. The best conductivity is 2.35 × 10⁻² S cm⁻¹ at 700 °C for x = 0.1 that is higher than that of Ca-free (W_0.15Bi_0.85)₂O_3.45. The higher conductivity of (Ca_0.1W_0.15Bi_0.75)₂O_3.35 than (W_0.15Bi_0.85)₂O_3.45 may result from the higher anion vacancy concentration and more symmetrical structure.     

SDBS和正丁醇及NaCl对鼓泡塔中氧传质的影响

表面活性剂和醇类物质的存在很大程度上可以改变水中氧的传质效率。本实验在内径15 cm的曝气塔中研究了阴离子表面活性剂十二烷基苯磺酸钠（SDBS）和正丁醇及NaCl对KLa的影响。结果发现,SDBS的传质系数在0.1 mmol/L以内急剧下降,而后随着浓度的增大,传质系数逐渐上升。而正丁醇对氧传质系数的影响则一直呈现上升趋势。通过添加NaCl,发现SDBS在NaCl浓度低于0.2%（质量百分数）时KLa随NaCl浓度的增加而增大;在NaCl浓度高于0.3%时,KLa随NaCl浓度升高下降明显。而固定浓度的正丁醇的KLa随NaCl的浓度改变变化不甚显著。虽然SDBS和正丁醇都可以对传质产生影响,但是效应却不一样,表明机理也不相同。     

Performance of anode-supported solid oxide fuel cell using novel ceria electrolyte

The potential of a novel co-doped ceria material Sm_0.075Nd_0.075Ce_0.85O_2−δ as an electrolyte was investigated under fuel cell operating conditions. Conventional colloidal processing was used to deposit a dense layer of Sm_0.075Nd_0.075Ce_0.85O_2−δ (thickness 10 μm) over a porous Ni-gadolinia doped ceria anode. The current-voltage performance of the cell was measured at intermediate temperatures with 90 cm³ min⁻¹ of air and wet hydrogen flowing on cathode and anode sides, respectively. At 650 °C, the maximum power density of the cell reached an exceptionally high value of 1.43 W cm⁻², with an area specific resistance of 0.105 Ω cm². Impedance measurements show that the power density decrease with decrease in temperature is mainly due to the increase in electrode resistance. The results confirm that Sm_0.075Nd_0.075Ce_0.85O_2−δ is a promising alternative electrolyte for intermediate temperature solid oxide fuel cells.     

锂离子电池电解液及功能添加剂的研究进展

从电解液的组成和功能添加剂两大方面,综合阐述了锂离子电池电解液的研究进展。在电解液组成方面,找到具有高的介电常数和能在石墨类电极表面形成有效SEI的有机溶剂,并且找到具有良好电导率、稳定电化学性能的电解质。而电解液功能添加剂方面,重点研究是找到改善电池安全性能的添加剂。     

Electrolyte optimization for a Li ion battery by charge profile analysis

Electrolyte design for Li ion batteries was approached by means of comparison of faradaic and non-faradaic currents. The faradaic current by the movement of Li⁺ ions was dependent on the composition of the electrolyte and was related to the battery capacity; the higher the capacity, the greater the current by the faradaic reaction. The open circuit potential of the electrode with a greater faradaic current decreased at a slower rate than that of the electrode with a smaller faradaic current. This analysis method can be used to prepare an optimal electrolyte of an actual Li ion battery, especially when developing batteries with excellent high-rate discharge capabilities and low temperature discharge properties.     

锂离子电池电解质锂盐双草酸硼酸锂的研究进展

介绍了新型锂盐双草酸硼酸锂（LiBOB）的基本性质,归纳了其合成、检测和提纯方法,重点阐述了LiBOB在石墨类负极上的成膜性能,综述了LiBOB的溶解性和电导率、热稳定性及在固体电解质中的应用,总结了LiBOB基电解质的不足,指明了其未来的研究方向。     

镍电解液中杂质铅和锌的行为及脱除方法

探讨了铅、锌在镍电解过程中的行为,以及利用化学沉淀和离子交换除铅锌的方法,并结合现有工艺提出改进意见。     

Time-dependent modelling and asymptotic analysis of electrochemical cells

A (time-dependent) model for an electrochemical cell, comprising a dilute binary electrolytic solution between two flat electrodes, is formulated. The method of matched asymptotic expansions (taking the ratio of the Debye length to the cell width as the small asymptotic parameter) is used to derive simplified models of the cell in two distinguished limits and to systematically derive the Butler–Volmer boundary conditions. The first limit corresponds to a diffusion-limited reaction and the second to a capacitance-limited reaction. Additionally, for sufficiently small current flow/large diffusion, a simplified (lumped-parameter) model is derived which describes the long-time behaviour of the cell as the electrolyte is depleted. The limitations of the dilute model are identified, namely that for sufficiently large half-electrode potentials it predicts unfeasibly large concentrations of the ion species in the immediate vicinity of the electrodes. This motivates the formulation of a second model, for a concentrated electrolyte. Matched asymptotic analyses of this new model are conducted, in distinguished limits corresponding to a diffusion-limited reaction and a capacitance-limited reaction. These lead to simplified models in both of which a system of PDEs, in the outer region (the bulk of the electrolyte), matches to systems of ODEs, in inner regions about the electrodes. Example (steady-state) numerical solutions of the inner equations are presented.     

Prediction of electrolyte viscosity for aqueous and non-aqueous systems: Results from a molecular model based on ion solvation and a chemical physics framework

Electrolyte viscosity is a macroscopic property, although its foundation lies on molecular-scale interactions between solvent and ionic species. A comprehensive understanding of viscosity behavior with respect to solvent composition, salt concentration and temperature is only possible with correct interpretations of molecular interactions and related quantities. This work introduces a new methodology for predicting electrolyte viscosity under a wide range of conditions, based on molecular, physical, and chemical properties. The general formalism is universal for aqueous and non-aqueous systems alike. Although the immediate application of the resultant model is candidate electrolytes for lithium ion batteries, other applications abound in the areas of industrial fluids, biological systems, and other electrochemical systems whose performance characteristics are tied to viscosity. Viscosity predictions are compared to experimental data for a number of electrolytes, demonstrating exceptional accuracy of predictions over wide temperature ranges and broad ranges of salt concentration.     

铝合金等离子体电解着色工艺的研究

通过对不同电解液成分和浓度的选取,制备氧化和着色兼容的微弧氧化膜。不同种类的电解液所得到的微弧氧化膜层颜色也不同,同种体系中的主要成分浓度的不同是影响微弧氧化膜颜色和生成速率的原因之一。