共查询到19条相似文献,搜索用时 109 毫秒
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中间相沥青炭微球是一种特殊形态的炭材料前驱体,在众多领域有着广泛的应用。本文介绍了中间相沥青炭微球的制备、结构及性质,在此基础上重点综述了近年来中间相沥青炭微球在高性能锂离子二次电池电极材料方面的应用进展,并指出今后的研究方向。 相似文献
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介绍中间相沥青炭微球的制备方法和发展现状,分析了其在锂离子二次电池等方面的应用及国内外市场前景。 相似文献
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介绍中间相沥青炭微球的制备方法和发展现状,分析了其在锂离子二次电池等方面的应用及国内外市场前景. 相似文献
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煤焦油中吡啶不溶物及聚合条件对中间相炭微球收率,球径及其分布的影响 总被引:1,自引:1,他引:0
研究了煤焦油聚合制备中间相炭微球过程中,原料中PI的含量及聚合条件对中间相炭微球的球径及球径分布的影响。发现中间相炭微球的球径,随原料中PI的含量增加而减少,球径分布变窄,随聚合时间的延长,所产生的中间相炭微球球径增大,球径分布变宽。通过控制原料中一次PI的含量及聚合条件,获得较窄粒径分布的中间相沥青炭微球。 相似文献
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石墨添加对中间相炭微球电化学性能的影响 总被引:4,自引:0,他引:4
以煤焦油沥青为原料,采用聚合法制备中间相炭微球。研究了不同天然鳞片石墨添加量在相同热处理条件下得到的中间相炭微球作为锂离子电池炭负极材料的电化学性能。研究结果表明,石墨的添加使中间相炭微球内部结构变的复杂,X衍射显示石墨的添加降低了炭微球的石墨化度和晶形尺寸。随石墨添加量的增加,电池的首次充放电容量和效率有所减小,三次循环后充放电效率趋于一致。 相似文献
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中间相炭微球研究进展 总被引:13,自引:3,他引:13
中间相炭微球是一种新型炭材料,它是在研究中间相的过程中发展起来的,其理论基础是中间相理论。系统地介绍了中间相炭微球的发展过程,制备原料和制备方法,此外,还对中间相炭微球的分析方法,应用领域进行了介绍,并对其发展前景作了预测,指出了几个重要的发展方向。 相似文献
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中间相炭微球在锂离子电池负极材料的应用进展 总被引:1,自引:0,他引:1
中间相炭微球(MCMB)具有良好锂离子扩散性、导电性和机械稳定性等优势,是目前应用广泛、综合性能优异的锂离子电池负极材料,但较低理论比容量是制约其发展的关键因素。为了获得性能优良的MCMB基锂离子电池负极材料,改性修饰和复合材料已然成为目前研发重点。笔者论述了碳结构、表界面和复合材料等微观结构设计对MCMB负极材料电化学性能的影响。从碳堆积结构类型、有序性、层间距以及球体粒径大小等方面,论述了碳结构微观设计对MCMB电化学性能的影响。发现具有乱层结构的MCMB在充放电过程中内部产生应力较小,且碳结构较稳定,具有优异循环稳定性;内部具有大量微孔或碳层间距较大的MCMB,在充放电过程中可提高锂离子在电极中的迁移速率,并提供更多的储锂空间,一般具有优良的充放电比容量和倍率性能;小粒径MCMB具有较短的锂离子迁移路径和随之增加的比表面积,通常具有较好倍率性能,伴随着可逆比容量和充放电效率的衰减。从表界面碳层改性、包覆和掺杂改性等方面,论述了表界面改性对MCMB电化学性能的影响。表面碳层修饰可增加MCMB与电解液的相容性及其比表面积,提高了与电解液的接触面积及贮锂容量,改善了锂离子电池负极材料的电化学性能;另外,MCMB表面包覆一层无定型碳,可避免其表面与电解液直接接触,减少电化学副反应的产生,提升其可逆比容量。从碳活性物质复合材料、非碳活性物质复合材料等方面,论述了复合材料微观结构设计对MCMB电化学性能的影响。碳活性物质可降低MCMB内部碳层结构的有序性,减少锂离子嵌入过程中的内部应力,提升MCMB循环稳定性。非碳活性物质诱导MCMB生成更加有序的碳层结构,提高MCMB的比表面积,从而改善MCMB表面与电解液分子的接触能力及其嵌锂性能,有利于提升MCMB负极材料可逆比容量、循环性能和倍率性能。MCMB具有高碳层间距和多缺陷位点等结构特征,有利于钠离子自由脱嵌,应用于钠离子电池时具有良好的可逆比容量、循环稳定性和倍率性能。MCMB的不规则定向层状结构经活化等处理具有较高比表面积,可应用于超级电容器电极材料。最后提出在高性能锂离子电池电极材料快速发展的需求下,从微观结构角度设计MCMB纳米复合材料将是MCMB负极材料的研究重点。 相似文献
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Jeong-jin Yang Jong-hwan Choi Han-joo Kim Masayuki Morita Soo-gil Park 《Journal of Industrial and Engineering Chemistry》2013,19(5):1648-1652
The recent developments in lithium ion secondary batteries (LIBs) have been achieved by using selected carbon materials as the anode. Mesophase carbon microbead (MCMB) anode materials have stable Li intercalation and de-intercalation characteristics, making them a good anode material for use in LIBs. However, batteries with pure MCMB anodes are known to have a low power density. Multiwalled carbon nanotubes (MWNTs) are one of the most promising materials for improving a range of electrochemical energy conversion and storage devices because of their unique physical properties, including high electrical conductivity and superior chemical and mechanical stability. Therefore, in this study, MWNTs were deposited on the surface of MCMB anodes to improve their electrical conductivity. The anode materials were separately functionalized using carboxylic acid and amine groups to form MWNT-COOH and MCMB-NH2, respectively, providing them with surfaces of opposite charge. The surface morphology was assessed using scanning electron microscopy, and the electrochemical characteristics were analyzed by cyclic voltammetry and AC impedance measurements in a coin cell. The AC impedance and cyclic voltammetry measurements indicated that MCMBs with MWNTs deposited on their surfaces are promising electrode materials, providing high power density for LIBs. 相似文献
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The sintering and graphitization behavior of mesocarbon microbeads (MCMB) at high temperatures (1900-2800 K) is investigated. It is shown that while the low temperature sintering performance of MCMB is unique, at high temperature it appears to be similar to that of conventional materials. In contrast, the obtained activation energy for MCMB high-temperature graphitization is ∼100 kcal/mol, which is smaller than that (∼240 kcal/mol) for typical carbon systems. It is concluded that the combination of such unique properties as excellent compressibility, low temperature sinterability, and rapid graphitization makes MCMB an attractive precursor for manufacturing carbon-based materials. 相似文献
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Graphite–silicon carbide (G–SiC), carbon/carbon–silicon carbide (C/C–SiC) and mesocarbon microbeads–silicon carbide (MCMB–SiC) composites were produced using liquid silicon infiltration (LSI) method and their physical and mechanical properties, including density, porosity, flexural strength and ablation resistance were investigated. In comparison with G–SiC and C/C–SiC composites, MCMB–SiC composites have the highest bending strength (210 MPa) and ablation resistance (9.1%). Moreover, scanning electron microscopy (SEM) and optical microscopy (OM) are used to analyze the reacted microstructure, pore morphology and pore distribution of carbon-based matrices. As a result, SiC network reinforcement was formed in situ via a reaction between liquid silicon and carbon. The unreacted carbon and solidified silicon are two phases present in the final microstructure and are characterized by X-ray diffraction (XRD). Based on the results obtained and the low-cost processing of pitch-based materials, the MCMB–SiC composite is a promising candidate for aerospace applications. 相似文献
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The mesocarbon microbead (MCMB) fluorides with different fluorine contents were obtained in the temperature range of 100–110 °C in the presence of the mixed gas containing fluorine and nitrogen. The MCMB fluorides were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and elemental analysis. The results showed that the carbon lamination of the MCMBs was severely destroyed, which was indicated by a dramatic increase in the interlayer spacing of the resultant materials from 0.345 nm of the MCMBs to the range of 0.656 to 0.722 nm. Further studies on diversity of functional groups indicated that the whole fluorination reaction process comprises two steps: include a first diffusion of fluorine gas molecules inside the voids formed due to loose packing of MCMB molecules, and then fluorination. The two steps interacted with each other and jointly determined the apparent speed of the reaction. The original lamination structure of the MCMBs was completely destroyed for volume expansion of the resultant materials and diffusion of fluorine/nitrogen mixed gases. The final MCMB fluorides are themselves a conglomeration of particles with diameters ranging from 1 to 3 μm. 相似文献
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The processing of carbon-ceramic composites by utilizing the unique sintering ability of mesocarbon microbeads (MCMB) is reported. The ceramic constituents (silicon nitride and silicon carbide) are formed in situ by reactions between MCMB and silicon in different atmospheres. In comparison with direct addition of ceramic (SiC, Si3N4) phases, in situ formation shows several appealing features. By inducing the reaction of silicon with MCMB, the sintering ability of the composite is enhanced via reaction bonding mechanisms. Similarly, it is demonstrated that composite porosity is limited owing to silicon reaction with nitrogen. The reactive formation of nanoscale ceramic reinforcements via decomposition of the silicon-containing polymer (e.g. poly-carbomethyl-silane) is also reported. This approach results in formation of uniform nanosized (>100 nm) SiC layers strongly bonded to the surface of the carbon particles. The presented results contribute to the development of carbon-ceramic materials with high-operational properties. 相似文献