钠离子电池炭基负极材料研究进展

钠离子电池是目前新兴的低成本储能技术,因在大规模电化学储能中具有较好的应用前景而受到了国内外学者广泛的关注与研究。作为钠离子电池的关键电极材料之一,非石墨的炭质材料因具有储钠活性高、成本低廉、无毒无害等诸多优点,而被认为是钠离子电池实际应用时负极的最佳选择。本文详细综述了目前钠离子电池炭基负极材料的研究进展,重点介绍了炭质材料的储钠机理与特性,分析了炭材料结构与电化学性能之间的关系,探讨了其存在的问题,为钠离子电池炭基负极材料的发展提供有益的认识。     

钠离子电池用高性能锑基负极材料的调控策略研究进展

锑(Sb)具有高的理论比容量、较小的电极极化、合适的Na⁺脱嵌电位、价格低廉以及环境友好的优势,而成为一种具有较大应用前景的钠离子电池负极材料。但是,Sb基负极材料的一个重要挑战是在循环过程中高比容量伴随着大的体积变化,进而导致活性材料粉化,并从集流体上脱落,这大大限制了其在钠离子电池领域的大规模应用。因此,如何解决Sb基负极材料充放电过程中体积膨胀问题对于高性能的钠离子电池设计是至关重要的。本文详细综述和讨论了Sb基材料的结构-性能关系及其在钠离子电池中的应用,详细介绍了钠离子电池Sb基负极材料在氧化还原反应机理、形貌设计、结构-性能关系等方面的最新研究进展。本综述的主要目的是探讨影响Sb基负极材料性能的决定因素,从而提出有前途的改性策略,以提高其可逆容量和循环稳定性。最后,对Sb基钠离子电池负极材料的未来发展、面临的挑战和前景进行了展望。本文可为Sb负极材料的构建和优化提供具体的观点,阐明了Sb基负极材料未来的发展方向,从而促进钠离子电池的快速发展和实际应用。     

空间限域和化学键锚定协同作用提高红磷储钠(钾)性能

正在高性能钠/钾离子电池负极材料的研究中,合金类负极材料红磷因其高的理论容量和合适的氧化还原电位受到研究者的广泛关注~(1,2)。当用作钠离子电池负极材料时,三电子转移反应伴随Na3P的生成,表现出高达2596 m Ah·g~(-1)的理论容量。在研究钾离子电池负极材料时,郭再萍等人首次通过实验提出基于K-P合金(K3-xP)的形成,红磷可提     

钠离子电池硬碳负极储钠机理及优化策略

钠离子电池因具有成本低、安全性高等优势,被认为是一种非常适合应用于大规模储能领域的电化学储能技术.合适的负极材料是促进钠离子电池实现商业化的关键之一.硬碳材料由于具有丰富的碳源、低成本、无毒环保,且储钠电位低而被认为是最可能被实用化的钠离子电池负极材料.然而硬碳负极的实际应用中也面临着首周库伦效率低、长循环稳定性不足以及倍率性能较差等问题,近年来众多研究者致力于硬碳负极的性能优化研究,本综述从结构调控、形貌设计、界面构造、电解液优化四方面总结了近年来钠离子电池硬碳负极的性能优化策略研究进展,分析了每种优化策略的优点和不足,并进一步讨论了钠离子电池硬碳负极实用化进程中面临的瓶颈问题和挑战.     

钠离子电池碳负极材料的研究进展

钠离子电池具有资源丰富和成本低等优势,在大规模储能领域受到广泛的关注.开发具有高比容量和长循环稳定性的电极材料是钠离子电池走向应用的关键.碳材料作为钠离子电池的负极材料,具有可调控性高与稳定性好等优势,具有应用潜力.目前,研究较为广泛的碳材料主要包括石墨、无定形碳、杂原子掺杂碳、生物质合成碳,但这些碳负极材料存在着钠-...     

钠离子电池硬炭负极材料的研究进展

钠离子电池凭借着丰富的钠资源、低廉的物料成本以及良好的低温性能等优势,在储能领域与锂离子电池兼容互补.因此,加速推进钠离子电池商业化可以降低锂资源供应风险,确保新能源行业的长期健康发展.由于钠离子的半径较大,而负极材料作为其插层的宿主材料,对相关的设计和发展要求则更高.目前,硬炭材料是公认的钠离子电池负极材料的理想选择之一,也是最有可能实现大规模商业化生产的负极材料.本文以钠离子电池商业化的瓶颈作为切入点,对硬炭的材料特点、储钠机理及功能化设计策略进行了综合评述.最后,对这一技术领域的未来发展和挑战进行了展望.     

钠离子电池关键材料研究及应用进展

钠离子资源丰富,分布广泛,价格低廉,因而钠离子电池被认为是下一代大规模储能技术的理想选择之一. 然而,钠离子较大的半径和质量不利于它与电极材料的可逆反应. 开发能够快速、稳定储钠的基质材料是提升钠离子电池性能的关键之一. 此外,如何合理地优化电解质,匹配正负极材料,以实现高性能、高安全、低成本钠离子全电池的构建,切实将其推向市场,也是亟待解决的问题. 本文综述了国内外钠离子电池关键材料（包括正极材料、负极材料和电解质）的研究进展,介绍了一些具有代表性的钠离子全电池实例. 对钠离子电池的基础研究和实际应用具有一定参考价值和借鉴意义.     

钠离子电池用碳负极材料研究进展

相较于目前主流的锂离子电池,钠离子电池成本相对较低,因而有望在未来大规模储能系统中获得重要应用,然而其实用化进程仍受制于缺少合适的正负极材料,特别是性能优异且实用化的负极材料.钠离子电池与锂离子电池具有相似的工作原理,但钠离子和锂离子在碳负极材料中的储存行为却有着很大的不同.总体而言,碳材料仍是目前最有望促进钠离子电池实用化的关键负极材料.本文系统总结并分析了目前已有碳材料中钠离子的储存机制,对负极材料的设计思路和研究进展进行了概述,着重阐述了商用化碳分子筛在钠离子电池中的实用化前景.最后,本文对钠离子电池中碳负极材料的未来发展方向进行了展望.     

钠离子电池用生物质基硬碳的研究进展

生物质基硬碳具有原材料资源丰富、可持续、成本低和储钠容量高等特点,是钠离子电池的理想负极材料。生物质基硬碳材料的微结构是决定钠离子存储性能的关键。本综述回顾了硬碳负极对钠离子存储机理的研究现状。从生物质原料的角度,分类总结了高性能生物质基硬碳材料的制备方法。探讨了生物质基硬碳结构的调控与钠离子存储性能提升的关系,对钠离子电池用生物质基硬碳负极材料的研究方向进行了展望。     

钠离子电池:储能电池的一种新选择

钠离子电池在20世纪70年代末80年代初得到关注,但因锂离子电池优异的电化学性能而没有得到广泛研究.随着电动汽车、智能电网时代的到来,锂资源短缺将成为制约其发展的重要因素.因此,亟需发展下一代综合性能优异的储能电池体系.钠和锂具有相似的物化性质,且钠资源丰富,成本低廉,是非常有发展潜力的电池体系,近年来得到了国内外研究人员的广泛关注.简要综述了近年来钠离子电池的研究成果,就层状Nax MO2(M=Co,Ni,Fe,Mn,V等)材料、聚阴离子型材料、金属氟化物等正极材料及碳基负极材料、合金和金属氧化物等负极材料的电化学性能进行了介绍,阐述了有机体系电解质和凝胶电解质在钠离子电池中的应用,并对其存在的问题以及未来发展方向作了探讨.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.