Electrochemical investigation of LiNi0.5Mn1.5O4 thin film intercalation electrodes

This work provides kinetic and transport parameters of Li-ion during its extraction/insertion into thin film LiNi_0.5Mn_1.5O₄ free of binder and conductive additive. Thin films of LiNi_0.5Mn_1.5O₄ (0.2 μm thick) were prepared on electronically conductive gold substrate utilizing the electrostatic spray deposition technique. High purity LiNi_0.5Mn_1.5O₄ thin film electrodes were observed with cyclic voltammetry, to exhibit very sharp peaks, high reversibility, and absence of the 4 V signal related to the Mn³⁺/Mn⁴⁺ redox couple. The electrode subjected to 100 CV cycles of charge/discharge delivered a capacity of 155 mAh g⁻¹ on the first cycle and sustained a good cycling behavior while retaining 91% of the initial capacity after 50 cycles. Kinetics and mass-transport of Li-ion extraction at LiNi_0.5Mn_1.5O₄ thin film electrode were investigated by means of electrochemical impedance spectroscopy. The apparent chemical diffusion coefficient (D_app) value determined from EIS measurements changed depending on the electrode potential in the range of 10⁻¹⁰-10⁻¹² cm² s⁻¹. The D_app profile shows two minimums at the potential values close to the peak potentials of the corresponding cyclic voltammogram.     

2000m3低温丙烯球罐球壳板型式和材料的选择

大型球罐球壳板型式和材料的选择是设计的首要环节,从这两方面论述了设计时选择的过程。     

一种带局部搜索功能的入侵杂草优化算法

为了改善入侵杂草优化算法解的质量,提出一种带局部搜索功能的入侵杂草优化算法。该算法按照一定概率对每代产生的最优个体执行球体局部搜索算子或Logistic映射搜索算子,在最优个体周围进行精细搜索,并用搜索到的较优个体代替最优个体,提高了算法的局部搜索能力和优化精度。并对7个测试函数进行了仿真实验,结果表明:该算法具有较高的优化性能。     

不同Li/Nb摩尔比In∶Fe∶LiNbO_3晶体的生长及其光学性能

在Li NbO3(LN)中掺摩尔分数为1%的In和掺质量分数为0.03%的Fe,用提拉法技术生长具有不同n(Li)/n(Nb)[n(Li)/n(Nb)=0.94,1.05,1.20,1.38]的In∶Fe∶LN晶体。测试不同n(Li)/n(Nb)的In∶Fe∶LN晶体的吸收光谱、抗光致散射能力和指数增益系数,并计算晶体的有效载流子浓度。结果表明晶体样品随着n(Li)/n(Nb)增加,吸收光谱的吸收边发生紫移,抗光致散射能力增加,指数增益系数和有效载流子浓度增大。采用n(Li)/n(Nb)=1.38的In∶Fe∶LN晶体作记录介质,n(Li)/n(Nb)=1.05的In∶Fe∶LN晶体作位相共轭镜进行全息关联存储实验。实验表明存储系统具有实时处理,成像质量好,信噪比高和能反复使用等优点。     

改进β-紫罗兰酮的合成方法

以氢氧化锂/助催化剂为催化剂体系,柠檬醛为原料合成β-紫罗兰酮。此催化剂体系有良好选择性,用量少、成本低、对环境污染小。同时对反应溶剂、温度、反应时间等因素进行优化,使其适用于工业生产,最终摩尔收率可达86%以上。     

四氟硼锂和六氟砷锂的合成与拉曼光谱分析

介绍了合成高纯无水的ＬｉＢＦ４和ＬｉＡｓＦ６的新方法，并讨论了其合成条件，指出制备多孔状ＬｉＦ和控制反应温度是合成的关键。     

Improved electrochemical redox performance of 2,5-dimercapto-1,3,4-thiadiazole by poly(3-methoxythiophene)

High electrocatalytic activity of an electropolymerized film of poly(3-methoxythiophene) (PMOT) is reported toward the redox reaction of 2,5-dimercapto-1,3,4-thiadiazole (DMcT) as a promising cathode material for the lithium ion battery. Cyclic voltammetry showed improved electrochemical performance of DMcT on PMOT-coated Pt electrode, indicating accelerated redox kinetics. Moreover, charge-discharge tests exhibited higher discharge capacity and slower capacity fading of the PMOT-doped DMcT composite cathode compared with pure DMcT.     

Zwitterion effect in polyelectrolyte gels based on lithium methacrylate-N,N-dimethyl acrylamide copolymer

Zwitterionic compounds such as those based on 1-butylimidazolium-3-(n-butanesulfonate) have previously been shown to have positive effects on the transport properties of polyelectrolytes. The addition of the zwitterion has been found to, in some cases, increase the dissociation of the lithium ion and enhance the conductivity by almost an order of magnitude. In this work, we report the effects of adding the above-mentioned zwitterion into the polyelectrolyte gel system poly(lithium methacrylate-co-N,N-dimethyl acrylamide); the anionic group being a stronger base leads to different behaviour for this copolymer compared to previous work. Polyelectrolyte gels based on dimethyl sulfoxide and polyether solvents were investigated to determine the breadth of applicability of the zwitterion in improving lithium ion transport. Impedance spectroscopy and pulse field gradient-NMR diffusion indicate an increase in the number of available charge carriers with zwitterion addition in some gel systems, however, the effect is not universal.     

Performance of a magnesium–lithium alloy as an anode for magnesium batteries

In this work, we describe an evaluation of an Mg–Li alloy (Li: 13 wt %) for possible use in magnesium primary reserve batteries. Higher OCP for the Mg–Li alloy have been observed in 2 M MgCl₂ and MgBr₂ electrolyte. The corrosion rate of the Mg–Li alloy is found to be in the order: MgCl₂ < Mg(COOCH₃)₂ < MgSO₄ < MgBr₂ < Mg(ClO₄)₂. Mg–Li alloys exhibit higher (81%) anodic efficiencies even when the current density is increased to 8.6 mA cm ^–2. It has been observed that Mg–Li/MgCl₂/CuO cells offer higher operating voltage and capacity than those with the conventionally used Mg–Al alloy.