KOH‐assisted microwave post‐treatment of activated carbon for efficient symmetrical double‐layer capacitors

It is important to tune the surface and pore structures of carbon materials for their application in capacitors. Herein, a novel microwave‐based approach is demonstrated to significantly increase the capacity of a supercapacitor. After activated carbon (AC) with KOH was treated by microwave heating only for 8 min, its symmetrical double‐layer capacitor increased from 68.6 to 107.9 F/g at current density of 0.2 A/g with 2 M KOH aqueous solution. The excellent capacity retention of 96% was obtained even after 4000 galvanostatic charge/discharge cycles at current density of 5 A/g. This microwave approach is much more efficient than the conventional heating process to tune the electrochemical properties of AC. Copyright © 2016 John Wiley & Sons, Ltd.     

A comparative study of tunable Ba1−x Sr x TiO3 thin film capacitors prepared by rf-sputtering and liquid-phase deposition

Abstract

Ba_1?x Sr _x TiO₃ thin film capacitors have been successfully prepared using rf-sputtering and a metal organic deposition (MOD) method. The structure, microstructure and composition of the BSTO films are presented. Films grown on lanthanum aluminate LAO(100) showed c-axis preferred growth orientation. Broad paraelectric-to-ferroelectric transitions were observed in films prepared by both methods. The tunability of the capacitance by means of an appplied electric field is examined using various capacitor geometries. A decrease in the capacitance exceeding 75% at 77 K was obtained from the MOD deposited films under an electric field strength of 0.3 MV/cm. On the other hand, the tunability of the capacitance in the rf-sputtered films ranged from 5 to 10% at 77 K and at 20 kV/cm, while it exceeds 50% in some films. The results are compared with the predictions of Devonshire's phenomenological theory.     

铌基氧化物锂离子电容器负极材料研究进展

在现有的各类锂离子电容器(LICs)负极材料中,铌基氧化物被认为是很有前景的电极材料。本文以Nb_2O_5、M-Nb-O(M=Ti, Cr, Ga, Fe, Zr, Mg, Li, Na, K等)和(H, Li, K)-Ti-Nb-O等负极材料为例,介绍了铌基氧化物作为锂离子电容器负极材料的优势、储锂机制和常见的合成方法,并提出了该材料目前存在的问题和相应的解决方案,以促进其在新兴储能器件领域的进一步推广和发展。     

家用变频空调室外机控制器PFC电路设计

PFC电路是家用变频空调室外机控制器基本的单元电路之一,根据控制电路的不同,分为无源和有源PFC两大类,有源PFC电路因其优点多而得到很好的发展。目前,有源PFC的整流滤波电路通常用少量大容值的铝电解电容组成,存在成本高和寿命短的问题。本论文介绍一种新的有源PFC高压整流滤波电路,它由多数量小容值铝电解电容并联组成,辅以电流均流化设计,有效降低电容的ESR值,减小电容的发热,提升控制器寿命。     

Adaptive Boolean Logic Using Ferroelectrics Capacitors as Basic Units of Artificial Neurons and Its Implementation in FPGA

In this work we propose the implementation of boolean logic through artificial neurons with Ferroelectric Capacitor (FeCapacitor) as its basic unit on a reconfigurable hardware platform. Two neurons were implemented: the Perceptron and the Spiking Neuron model. Both neurons use the phenomenon of the hysteresis loop as an activation function and were embedded on a Field Gate Programmable Gate Array (FPGA) hardware platform. The implementations were carried out by Simulink models and hardware synthesizable blocks from DSP Builder software and the results are shown in the form of the models and the boolean functions implemented by them.     

基于改进粒子群算法的配网电容器优化配置

随着国民经济发展,配电网规模不断扩大。依照经验配置电容器的局限性日益显著,具体表现为电容器容量配置的不足或过剩,部分电容器需要时由于局部电压的限制而不能投入。将模拟退火粒子群算法用于解决配电网电容器优化配置问题,建立了相应的数学模型,目标函数为配电网有功网损费用、电容器的购置及安装总费用最小,该算法将电容器的安装位置及安装容量离散化,采用基于适应度值的动态阈值来控制实施局部搜索的粒子数目,来改善算法摆脱局部极值点的能力,提高算法的收敛速度和精度。对一个33节点配电网的电容器优化配置结果表明了模拟退火粒子群算法的合理性和优越性。     

Microstructure evolution during the co-sintering of Ni/BaTiO3 multilayer ceramic capacitors modeled by discrete element simulations

Electrode discontinuities are a critical issue for manufacturing ultrathin multilayer ceramic capacitors (MLCCs). The Discrete Element Method is used to simulate, at the particle length scale, the microstructure evolution during the co-sintering of state-of-the-art nickel based-MLCCs. Electrode discontinuities are considered to originate from the heterogeneities in the initial powder packing and to grow because of the constraint imposed by adjacent dielectric layers. A parametric study demonstrates that: (i) fast heating rate leads to lower electrode discontinuity during heating, (ii) green density and thickness of the electrode should be optimized to improve the electrode connectivity, (iii) rearrangement of the nickel particles plays a significant role in electrode discontinuity, and (iv) the addition of non-sintering inclusions can improve the electrode connectivity. These findings can be generalized to other multilayer components.     

双电层电容器用中微双孔活性炭的研究进展

文章介绍了中微双孔活性炭的制备方法,综述了用作双电层电容器的最新应用研究,为中微双孔活性炭在双电层电容器中的应用提供参考。     

淀粉模板法辅助合成二氧化锰纳米棒及其电容特性研究

以淀粉为模板,结合浸渍-煅烧法合成了MnO2纳米棒,对产物晶型结构、形貌大小和电容特性等进行表征。测试结果表明所得样品为α-MnO2纳米棒,其平均直径为20 nm左右,平均长度约为75 nm。在1.0 mol/L的Na2SO4电解液中,01.0V电位区间内,充放电电流为2.0、5.0、10.0 mA时,所制备的α-MnO2放电比电容分别达到了186、120、90 F/g。2 mA恒流充放电1 000次后,MnO2的放电比容量保持率为91%。     

美国CDE公司表面安装(SMT)电容及其应用选型

文章简要介绍了美国CDE公司表面安装电容的分类和特点，并详细讨论了ESRD和ESRE系列电容的结构和机理，最后向读者推荐了不同应用时表贴电容的选型参考。