共查询到19条相似文献,搜索用时 125 毫秒
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锂离子电池已经广泛应用于各种便携式设备的电源,为提高锂离子电池的充放电速率和容量,纳米硅材料被视作重要的用于锂离子电池的阳极材料。本文列举了当前常见的纳米级硅阳极材料,并介绍了这些结构的制备方法,并对纳米硅阳极材料的发展方向进行了展望。 相似文献
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石墨烯及复合材料具有比表面积大、电导率高、导热性能和力学性能良好等优点,在电极材料、传感器、储氢材料等领域具有广泛的应用。但以高碳含量的天然资源煤为前体制备煤基石墨烯及复合材料达到煤炭清洁高效利用的研究目前报道有限,尤其是将其作为电极材料应用到储能领域的研究较少。本文重点总结了以不同煤质及衍生物为原料构建不同形貌和结构的煤基石墨烯及复合材料的方法以及存在的问题,详细介绍了煤基石墨烯及复合材料在储能领域,尤其是超级电容器、锂离子电池及钠离子电池领域的应用研究现状,最后提出了当前煤基石墨烯及复合材料的主要研究方向。该综述旨在为煤基新型石墨烯及复合材料的制备开发以及在储能领域的应用提供一定的思路。 相似文献
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锂离子电池以其优异的性能而成为近年来研究热点之一,而正极材料是锂离子电池性能提高的关键所在,本文综述了近年来发展起来的典型锂离子电池正极材料的制备、特点及性能,并对锂离子电池正极材料的发展趋势进行了展望。 相似文献
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硅基阳极材料具有超高的理论比容量,是替代石墨类材料、提高锂离子电池能量密度的有效途径。但与石墨类材料相比,硅基阳极材料在首次嵌锂过程中,会大量消耗来自正极的锂离子,造成活性锂损失,形成较大的初始不可逆容量,影响材料的首次库伦效率,严重降低了锂离子电池的能量密度。预锂化技术,通过使电极材料接触额外的锂源,可以补偿锂离子电池在首次循环过程中造成的活性锂损失,是目前提高锂离子电池首次库伦效率的最有效手段,可使锂离子电池获得更高的能量密度和更好的循环性能。对当前主要的预锂化手段进行了概述,总结了各种预锂化技术的优缺点,并提出预锂化技术未来面临的挑战,为预锂化策略的实际性应用提供方向。 相似文献
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锂离子电池作为一种电源应用很广泛,但是在应用中存在一些不足,选取电化学性能良好的正负极材料是提高和改善锂离子电池电化学性能最重要的因素。从新型碳材料、硅基负极材料、锡基负极材料三方面介绍了目前锂离子电池的研究状况,并展望了锂离子电池负极材料的发展趋势。 相似文献
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针状焦是碳素材料中的优质品种,是生产超高功率石墨电极的主要原料。原料预处理的目的是脱除煤沥青的喹啉不溶物,溶剂法和改质法是已经实现工业化生产的煤系针状焦原料预处理方法。文章主要就这两种方法在我国煤系针状焦生产企业中的研究进展进行介绍。 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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Nanomaterials have some disadvantages in application as Li ion battery materials, such as low density, poor electronic conductivity and high risk of surface side reactions. In recent years, materials with core-shell nanostructures, which was initially a common concept in semiconductors, have been introduced to the field of Li ion batteries in order to overcome the disadvantages of nanomaterials, and increase their general performances in Li ion batteries. Many efforts have been made to exploit core-shell Li ion battery materials, including cathode materials, such as lithium transition metal oxides with varied core and shell compositions, and lithium transition metal phosphates with carbon shells; and anode materials, such as metals, alloys, Si and transition metal oxides with carbon shells. More recently, graphene has also been proposed as a shell material. All these core-shell nanostructured materials presented enhanced electrochemical capacity and cyclic stability. In this review, we summarize the preparation, electrochemical performances, and structural stability of core-shell nanostructured materials for lithium ion batteries, and we also discuss the problems and prospects of this kind of materials. 相似文献
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Nacer Badi Abhinay Reddy Erra Francisco C Robles Hernandez Anderson O Okonkwo Mkhitar Hobosyan Karen S Martirosyan 《Nanoscale research letters》2014,9(1):360
The specific energy of the existing lithium ion battery cells is limited because intercalation electrodes made of activated carbon (AC) materials have limited lithium ion storage capacities. Carbon nanotubes, graphene, and carbon nanofibers are the most sought alternatives to replace AC materials but their synthesis cost makes them highly prohibitive. Silicon has recently emerged as a strong candidate to replace existing graphite anodes due to its inherently large specific capacity and low working potential. However, pure silicon electrodes have shown poor mechanical integrity due to the dramatic expansion of the material during battery operation. This results in high irreversible capacity and short cycle life. We report on the synthesis and use of carbon and hybrid carbon-silicon nanostructures made by a simplified thermo-mechanical milling process to produce low-cost high-energy lithium ion battery anodes. Our work is based on an abundant, cost-effective, and easy-to-launch source of carbon soot having amorphous nature in combination with scrap silicon with crystalline nature. The carbon soot is transformed in situ into graphene and graphitic carbon during mechanical milling leading to superior elastic properties. Micro-Raman mapping shows a well-dispersed microstructure for both carbon and silicon. The fabricated composites are used for battery anodes, and the results are compared with commercial anodes from MTI Corporation. The anodes are integrated in batteries and tested; the results are compared to those seen in commercial batteries. For quick laboratory assessment, all electrochemical cells were fabricated under available environment conditions and they were tested at room temperature. Initial electrochemical analysis results on specific capacity, efficiency, and cyclability in comparison to currently available AC counterpart are promising to advance cost-effective commercial lithium ion battery technology. The electrochemical performance observed for carbon soot material is very interesting given the fact that its production cost is away cheaper than activated carbon. The cost of activated carbon is about $15/kg whereas the cost to manufacture carbon soot as a by-product from large-scale milling of abundant graphite is about $1/kg. Additionally, here, we propose a method that is environmentally friendly with strong potential for industrialization. 相似文献