Progress on High Voltage PEO-based Polymer Solid Electrolytes in Lithium Batteries

Polymer electrolytes have attracted great interest for next-generation lithium-based batteries on account of safety and high energy density. In this review, we assess recent progress on the design of poly(ethylene oxide)(PEO)-based solid polymer electrolytes in high voltage lithium batteries and identify possible side reactions between PEO-based electrolytes and existing cathodes. We provide an overview of the ways to enhance high voltage resistance of PEO-based electrolytes. Those include components blend, molecular design and interface modification. With these efforts, we want to present new insights into rational design of PEO-based electrolytes to develop solid-state lithium batteries for advanced performance.     

Electric field induced metal–insulator transition in VO2 thin film based on FTO/VO2/FTO structure

A VO₂ thin film has been prepared using a DC magnetron sputtering method and annealing on an F-doped SnO₂ (FTO) conductive glass substrate. The FTO/VO₂/FTO structure was fabricated using photolithography and a chemical etching process. The temperature dependence of the I–V hysteresis loop for the FTO/VO₂/FTO structure has been analyzed. The threshold voltage decreases with increasing temperature, with a value of 9.2 V at 20 °C. The maximum transmission modulation value of the FTO/VO₂/FTO structure is 31.4% under various temperatures and voltages. Optical modulation can be realized in the structure by applying an electric field.     

The effect of applied negative bias voltage on the structure of Ti-doped a-C:H films deposited by FCVA

Ti-doped hydrogenated diamond-like carbon (DLC) films were deposited on Si(1 0 0) substrates by a filtered cathodic vacuum arc (FCVA) method using Ar and CH₄ as the feedstock. The composition and microstructure of the films were investigated by Raman spectroscopy, X-ray photoelectron spectroscopy and IR spectroscopy. The internal stress was determined by the radius of curvature technique. The influence of the bias voltage on the microstructure of the as-deposited films was investigated. It was found that the graphite-like bonds was dominated in the Ti-doped DLC film deposited at 0 V bias voltage. When bias voltage was increased to −150 V, more diamond-like bond were produced and the sp³ content in film reached the maximum value, after which it decreased and more graphite-like bonds feature produced with further increase of the negative bias voltage. The compressive internal in the Ti-doped DLC films also exhibited a maximum value at −150 V bias voltage. IR results indicated that CH bonded intensity reduced, and H atoms bonded with C atoms were substituted for the Ti atoms as the negative bias voltage increasing. All the composition and microstructure change can be explained by considering the plasma conditions and the effect of negative bias voltage applied to the substrate.     

新农村建设中农村电网建设的探讨

为了解决新农村建设中农村用电水平的不断提高,特别是随着农村经济水平的不断发展,当前实际运行中农村配电网已出现的诸如网络损耗较大而导致供电成本过高、供电可靠性较低、供电电压和频率不满足要求等问题,作者通过对一个典型的农村电网的潮流进行分析,从网络的整体规划布局到局部的输配电设备(如:线路、变压器及无功补偿装置等)方面提出了关于降低网络损耗、提高电压质量和可靠性的具体措施.通过对改建前后的线损率和电压合格率进行计算,表明笔者所提出的方法对现有农村电网改造是有效的.最后,提出了农村电网的发展趋势.     

改进的节点电路分析法

在节点分析法的基础上,用标准支路和纯电流源相结合,对大规模电路的计算方法进行了分析。     

Remarkably improved cycling stability of 3D porous Cu–Sn anode for lithium-ion full cells by adjusting working voltage range

Numerous studies confirm that three dimensional porous Cu–Sn (3DP Cu–Sn) anode possesses good application prospect in light of its desirable electrochemical performance on lithium ion half cells, but there are a few related systematic researches on lithium ion full cells until now, which is indispensable before its commercialization. Herein, the effects of galvanostatic charge-discharge voltage range on the cycling stability of 3DP Cu–Sn anode for lithium ion full cells are investigated systematically. The results show that the suitable charge-discharge voltage range plays a key role in improving the reversible capacity and cycling stability of the 3DP Cu–Sn||LiCoO₂ full cell, which is closely related to maintaining the electrode structure stable by controlling the amount of Li⁺ extracted and inserted. Especially, in the voltage range of 1.2–3.9 ​V, the full cell exhibits remarkably improved electrochemical properties with the high initial reversible capacity of 2.71 ​mAh cm⁻² and 71.95% capacity retention upon 80 cycles. We believe that this work can provide a significant reference for the practical application of porous Sn-based anodes.     

二硫化锡纳米片阻变存储器的制备与性能

采用水热法合成了尺寸为50~100 nm的二硫化锡纳米片,并首次以二硫化锡作为阻变层材料的阻变存储器（Cu/PMMA/SnS₂/Ag,PMMA=聚甲基丙烯酸甲酯）,对其阻变性能进行了研究。结果表明： Cu/PMMA/SnS₂/Ag阻变存储器的开关比约10⁵,耐受性2.7×10³。在上述2项性能指标达到较优水平的同时,开态与关态电压分别仅约为0.28与-0.19 V。     

Sulfone-based high-voltage electrolytes for high energy density rechargeable lithium batteries:Progress and perspective

Further enhancement in the energy density of rechargeable lithium batteries calls for high-voltage cathode materials and stable anodes,as well as matched high-voltage electrolytes without compromising the overall property of batteries.Sulfone-based electrolytes have aroused great interest in recent years owing to their wide electrochemical window and high safety.However,significant challenges such as the complexity of synthesis,high melting point(typically above room temperature),high viscosity,and their poor compatibility with graphite-based anodes have drastically impeded their practical applications.In this review,recent progress of sulfone solvents in high energy density rechargeable lithium batteries is summarized theoretically and experimentally.More importantly,general improvement methods of sulfone-based electrolytes,such as adding additives and cosolvents,structural modifications of sulfo ne,superconcentrated salt strategy are briefly discussed.We expect that this review provides inspiration for the future developments of sulfone-based high-voltage electrolytes(SHVEs) and their widespread applications in high specific energy lithium batteries.     

Effect of relative humidity on current–voltage characteristics of monopolar DC wire-to-plane system

This paper deals with the DC monopolar corona discharge in wire-to-plane geometry under variable humid air conditions. The classical formulas of Townsend commonly used for the current–voltage characteristics were used to determine the various corona parameters for the both polarities of the corona discharge. A circular biased probe has been adapted to the plane and is used to measure the ground plane current density and electric field during the monopolar corona discharge. A new approach to the problem of corona discharge in transmission system has been described in this paper. The effect of varying the humidity and wires diameter is also investigated. The values of the electric field and the current density are maximum beneath the corona wire and decrease when moving away from them and the current–voltage characteristics follow the quadratic Townsend's law. The experimental results show that the monopolar corona discharge is strongly affected by the air humidity. The current density and the electric field are measured and compared with the computed values. The agreement between the calculated values and those obtained experimentally is satisfactory. The per unit electric field and current density are also represented by a unique function.     

关于开设内光电效应实验的探索与思考

介绍了开设以内光电效应为理论基础的半导体光电器件的重要性和迫切性,并详细介绍了内光电效应的理论与半导体光电器件的分类和应用前景。