PMMA基凝胶聚合物电解质双电层电容器的研究

以碳酸丙烯酯(PC)和碳酸乙烯酯(EC)作增塑剂,LiClO4作支持电解质,高比表面积活性炭为电极,内聚合法制作PMMA-PC+EC-LiClO4体系凝胶聚合物电解质(GPE)双电层电容器.应用交流阻抗、循环伏安、恒流充放电等方法研究了该电容器的性能.结果表明,PMMA-GPE的离子电导率在室温下达3.7 mS.cm-1,电容器的工作电压达3 V,比容量达41.6 F.g-1(I=1 mA.cm-2),等效串联电阻仅为几欧姆.     

无机纳米粒子在复合聚合物电解质中作用的研究进展

聚合物电解质材料已经成为当前锂离子电池研究领域的热点之一。复合化是有效提高聚合物电解质材料性能的有效手段。本文从纳米粒子掺杂的角度,综述了近年来无机纳米粒子对复合聚合物电解质(CPE)体系的离子电导率、锂离子迁移数的影响,并介绍了四种初步解释了无机纳米粒子在复合聚合物电解质中的作用的机理;讨论了无机纳米粒子对CPE体系/电极界面稳定及相容性的影响;提出了无机纳米粒子掺杂的复合聚合物电解质研究的三个热点方向。     

锂离子电池LiBF4基液体电解质研究进展

LiBF4基电解质的热稳定性较好,对环境水分不太敏感,有希望发展成为被民用、军事、三航领域微型、储能及动力锂离子电池广泛采用的优秀电解质体系。本文综述了近期在改善LiBF4的电导率、拓宽应用温度范围、促进SEI膜的形成、提高其电解液电导率及与电极材料的相容性等方面所取得的进展,并对其未来发展方向作了展望。     

有机模板固相合成磷酸铝及其表征

用六次甲基四胺为模板,在150℃,2小时固相合成磷酸铝,并用化学分析,ICP分析,XRD和IR谱进行了表征.     

Solid-State nuclear magnetic resonance: performance of point-charge distributions to model intermolecular effects in 19F chemical shifts

This contribution presents results from applying two different charge models to take into account intermolecular interactions to model the solid-state effects on the ¹⁹F NMR chemical-shift tensors. The density functional theory approach with the B3LYP gradient-corrected exchange correlation functional has been used because it includes electron correlation effects at a reasonable cost and is able to reproduce chemical shifts for a great variety of nuclei with reasonable accuracy. The results obtained with the charge models are compared with experimental data and with results obtained from employing the cluster model, which explicitly includes neighboring molecular fragments. The results show that the point-charge models offer similar accuracy to the cluster model with a lower cost. Received: 3 October 1999 / Accepted: 3 February 2000 / Published online: 5 June 2000     

Solid-state synthesis of potassium β- and β″-gallates

Direct synthesis of K-β- and β″-gallates by Ga₂O₃–K₂O solid-state reaction is described. The formation of K-β- or β″-gallates depends on the initial Ga₂O₃ phase. -Ga₂O₃ leads to K-β-gallate; β-Ga₂O₃ leads to K-β″-gallate. K-β″-Gallate is stable <1200°C. The high temperature stability of K-β″-gallate can be enhanced by doping with aliovalent ions.     

Activity and Osmotic Coefficients from the Emf of Liquid Membrane Cells. IX: Mn(ClO4)2 and MnSO4 in Water at 25°C

The relative activity coefficients of MnSO₄ and Mn(ClO₄)₂ were measured downto about 5×10^–5 mol-kg^–1 by means of cells with ion-exchange liquid membranes.The measurements at high dilution provide an answer to the age-old problem ofabsolute values of the activity coefficients for MnSO₄. They also lead to acorrection of the activity coefficients for Mn(ClO₄)₂, whose literature values arefound to be biased by ca. 6.5%. Like other bivalent metal sulfates, MnSO₄does not obey the Debye—Hückel law inasmuch as negative instead of positivedeviations from the limiting law are observed in the dilute regions. The possibilityfor this kind of behavior to denote ion association is discussed. The best-fitparameters of Pitzer's equation, able to provide accurate values of the activityand osmotic coefficients of the two salts for any concentration, are reported.     

Comparison of Electrolytic Conductivity Theories: Performance of Classical and New Theories

Conductivity equations, based on the mean spherical approximation (MSA), haverecently been derived. We compare their performance with that of classicalequations at the level of experimental uncertainty using conductivity data forsome typical electrolyte solutions. For symmetrical electrolytes, the pictureisconsistent showing a better performance for the classical equations. The Leeand Wheaton equation also shows advantages at moderate concentrations. Forunsymmetrical electrolytes, the differences between MSA and classical equationsis larger. There is, however, an inherent inconsistency with the equilibriuminformation, which cannot be resolved at present.     

驱动电压频率对固态阴极射线发光影响的研究

固态阴极射线发光(SSCL)是发光学中一种新的激发方式,引发出一些发光学中的重要问题,但是固态阴极射线发光的性质还不是十分清楚,需要进一步研究。文章用SiO₂作为电子加速层, 有机材料MEH-PPV为发光层, 在正弦交流电压驱动下实现了固态阴极射线发光,得到410和580 nm两个发光峰。通过研究这两个发光峰的性质,证实它们分别符合能带理论和分子理论。改变驱动电压的频率时,长波峰的发光强度随频率的增加而增加,而短波峰的发光强度随频率的增加而减小,这是由于这两个发光峰对应的上能级寿命不同引起的。     

纳米NiO的制备及其谱学特性研究

以醋酸镍、氢氧化钠为原料,吐温80为分散剂,通过固相反应制备了纳米级NiO。 用X射线衍射仪、透射电子显微镜、傅里叶红外光谱、紫外-可见分光光度等方法对材料的粒径、晶格畸变率、形貌以及红外、紫外-可见光的吸收性能进行了表征。结果表明：制得的纳米NiO产物为球形、属立方晶系,粒径大小在9～30 nm左右;晶格畸变率随粒径的增大而减小;纳米NiO红外吸收峰出现在437 cm-1处,与普通粒径的NiO光谱纯(484 cm-1)相比,其吸收峰红移了47 cm-1,体现了纳米NiO的表面效应;不同粒径大小的NiO对紫外-可见光的吸收特性不同。普通粒径的NiO光谱纯在紫外-可见光区域没有吸收,颗粒尺寸越小吸收波长越短,10 nm NiO的紫外-可见光吸收峰位于309 nm处,直接跃迁的光学能带隙约为4.2 eV,比体相材料(3.65 eV)增加0.55 eV,表现出明显的量子尺寸效应。对纳米NiO的谱学特性研究表明该材料在光电领域具有潜在的应用价值。