静电纺丝纳米纤维基超级电容器电极材料的研究进展

静电纺丝纳米纤维具有比表面积大、孔隙率高及密度低等优势,是电化学储能材料的理想候选者之一.本文综述了近年来静电纺丝碳纳米纤维、金属氧化物/硫化物/氮化物、导电聚合物及其复合材料在超级电容器领域的研究及应用进展,探讨了材料组成、结构与电化学电容性能之间的关系,并对静电纺丝纳米纤维基电极材料的发展前景进行了展望.这将为新型高性能超级电容器电极材料的结构设计与可控制备提供新思路.     

导电聚合物超级电容器电极材料*

导电聚合物（聚苯胺,聚吡咯,聚噻吩）作为超级电容器电极材料的研究引起了人们广泛的兴趣,该类材料制备的超级电容器具有成本低、容量高、充放电时间短、环境友好和安全性高等优点。本文综述了近年来基于导电聚合物及其与无机材料（碳材料/金属氧化物材料）复合所得电极材料在超级电容器中的应用进展,指出具有纳米结构导电聚合物材料及导电聚合物与无机纳米材料的复合是超级电容器电极材料研究的重要发展方向。     

静电纺纳米纤维基超级电容器无粘合剂电极材料的研究进展

对高性能超级电容器不断增长的需求促进了无粘合剂电极材料的快速发展。静电纺纳米纤维由于具有良好的柔性、大比表面积、高孔隙率、容易制备等优点引起了研究者们的强烈关注。本文综述了静电纺纳米纤维基无粘合剂电极材料在超级电容器领域的研究进展,阐述了不同材料的设计制备过程和提升电化学性能的诸多方法,并指明了静电纺纳米纤维基超级电容器无粘合剂电极材料的发展机遇与挑战,为性能优异的无粘合剂超级电容器电极材料的进一步开发与应用拓宽了思路。     

用于超级电容器电极材料的石墨烯基纳米复合物的种类和研究现状

超级电容器是目前研究较多的新型储能元件,其大的比电容、高的循环稳定性以及快速的充放电过程等优良特性,使其在电能储存及转化方面得到广泛应用。超级电容器的电极材料是它的技术核心。石墨烯作为一种新型的纳米材料,具有良好的导电性和较大的比表面积,可作为超级电容器的电极材料。利用其他导电物质对石墨烯进行改性和复合,可以在保持其本身独特优点的同时提高作为电极材料的导电率、循环稳定性等其他性能。本文从半导体/石墨烯复合材料、金属及金属氧化物/石墨烯复合材料、石墨烯/导电聚合物复合材料3个方面综述了复合改性后的石墨烯在超级电容器电极材料方面的研究进展。通过对各复合物电极材料的制备方法和性能的对比分析,指出石墨烯基复合物作为超级电容器的电极材料的未来研究内容是开发低成本、高比容量和高循环稳定性的复合物。     

超级电容器用碳化物骨架碳/导电聚合物复合材料的研究进展

碳化物骨架碳是近年来开发的一种具有纳米结构的新型多孔碳材料。由于该材料比表面积大、孔径大小可调、表面化学结构稳定以及成本较低等优点,被认为是超级电容器的理想电极材料之一。骨架碳材料与金属氧化物的复合,或者与导电聚合物的复合,能够将双电层电容与法拉第电容结合,既可提高超级电容器的比电容,改变其充放电电压,又可以提高其循环...     

静电纺丝技术在新能源电池中应用的研究进展

简要介绍了五种新能源电池和静电纺丝技术,综述了静电纺丝技术用于锂电池的正负极材料和燃料电池电极材料的现状,以及应用静电纺丝技术制备电极隔膜材料。静电纺丝制备纳米纤维具有直径小、比表面积大、孔隙率高等特点,用于正负电极和隔膜材料将大大提高电池的比容量、充放电速率和充放电电流,从而提高电池的蓄电能力、循环性能、离子导电性、力学稳定性和化学稳定性。最后总结了静电纺丝技术产业化需要解决的问题,并展望了在新能源电池中的进一步应用。     

基于碳材料的超级电容器电极材料的研究

超级电容器作为一种新型的能源存储装置,因为其比容量大、充放电速度快、循环寿命长等优点,在储能领域引起了极为广泛的关注。电极材料是决定超级电容器性能的核心因素,其中,常用的超级电容器电极材料主要有如下三类:碳基材料、金属氧化物及氢氧化物材料和导电聚合物材料。本文综述了超级电容器的工作原理并详细介绍了基于碳材料及其二元、三元复合体系的电极材料的研究进展。     

超级电容器用细菌纤维素基电极材料

超级电容器由于能提供比电池更高的功率密度,比传统电容器更高的能量密度而备受关注。但目前其应用仍存在能量密度低的问题。碳材料、金属氧化物和导电聚合物是常见的三种超级电容器电极材料,而其中不同形式碳材料是电容器中研究和应用最广泛的电极材料。细菌纤维素是由细菌分泌产生的具有一定纳米级孔径分布的多孔生物材料,具有高强度和模量、高孔隙率、极好的尺寸和热稳定性的特性。以细菌纤维素为原料制备电极材料是近年来超级电容器领域的热点研究方向之一。本文以细菌纤维素基电极材料的种类、制备方法和性能为线索,综述了国内外细菌纤维素基超级电容器电极材料的研究进展,并归纳总结了电极材料最优的形态和制备方法,进一步对该类电极材料的发展趋势进行了展望。     

碳纳米管的修饰及其在超级电容器中的应用

碳纳米管以其窄孔径分布、高有效比表面积、良好导电性能、良好力学性能、优良化学稳定性和良好热稳定性以及较低成本等优点,被认为是超级电容器的理想电极材料之一.本文结合碳材料具有的双电层电容和金属氧化物、导电聚合物具有的准法拉第电容,综述了碳纳米管的修饰处理技术及碳纳米管/金属氧化物、碳纳米管/导电聚合物复合材料、碳纳米管原位再生长技术的研究进展,指出碳纳米管的修饰能更好地改善其电化学性质,因此碳纳米管复合材料是超级电容器电极材料研究的一个重要发展方向.     

静电纺丝制备醋酸纤维素复合纳米纤维的研究进展

静电纺丝技术就是通过带电聚合物溶液或熔体的喷射来制备纳米纤维,是一种制备纳米纤维材料简单有效的技术。醋酸纤维素(CA)易溶于有机溶剂,常作为纤维素的替代材料应用于静电纺丝领域。本文总结了近年来国内外采用静电纺丝技术制备CA复合纳米纤维的研究新进展,重点介绍了CA/CNTs复合纳米纤维、CA/金属粒子复合纳米纤维、CA/金属氧化物复合纳米纤维、CA基载药复合纳米纤维、CA/PAN复合纳米纤维、CA/PVA复合纳米纤维、CA/CS复合纳米纤维等CA复合纳米纤维的研究进展以及潜在的应用领域。     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.