共查询到18条相似文献,搜索用时 93 毫秒
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自2004年被发现以来,石墨烯及其纳米复合材料因其特殊的结构和优异的性能而受到广泛关注,并在锂离子电池负极方面展现出巨大的应用价值。首先简单介绍了石墨烯及其常用制备方法,然后详细介绍了石墨烯及其纳米复合材料作为锂离子电池负极材料的研究现状,并阐述了各自的优势与不足,提出了一些改进方案,最后展望了其在锂电负极的应用前景和未来面临的挑战。 相似文献
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石墨烯作为一种锂离子电池负极材料表现出优异的电化学性能,但石墨烯在充放电过程中容易团聚,导致其容量衰减特别快。而金属氧化物在充放电过程中体积膨胀大,因此其容量衰减也非常快;另外,金属氧化物的电导率低,导致其倍率性能差。将金属氧化物与石墨烯复合,两者性能互补,石墨烯可提高复合材料的电导率,缓解金属氧化物在充放电过程中的体积效应;金属氧化物可提高复合材料的储锂容量,并能阻止石墨烯在充放电过程中团聚。本文介绍了石墨烯/CuO锂离子电池负极材料的制备方法,分析了石墨烯与氧化铜及其复合材料的储锂机制,展望了石墨烯/CuO锂离子电池负极材料的应用前景,并指出了当前研究中存在的问题。 相似文献
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采用直流电弧放电法制备出一种三维石墨烯纳米球材料。采用扫描电镜(SEM)、透射电镜(TEM)、拉曼光谱和X射线衍射光谱(XRD)等测试方法对三维石墨烯纳米球的形貌和结构进行了表征和研究。通过交流阻抗(EIS)、恒流充放电和循环稳定性测试等电化学测试手段来研究三维石墨烯纳米球作为锂离子电池负极材料的电化学性能。结果表明, 在电流密度为0.05 A/g下, 三维石墨烯纳米球作为锂离子电池负极材料的首次放电容量为485.9 mAh/g, 高于炭黑作负极的放电容量(401 mAh/g); 当电流密度为1 A/g时, 三维石墨烯纳米球负极材料仍然具有185.4 mAh/g的放电容量。在电流密度分别为0.5 A/g和2.5 A/g下, 充放电循环100次以后, 三维石墨烯纳米球的比容量几乎没有衰减, 这表明三维石墨烯纳米球作为锂离子电池的负极材料比炭黑具有更大的容量, 同时具有优异的循环稳定性。 相似文献
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Shuhua Jiang Wenbo Yue Ziqi Gao Yu Ren Hui Ma Xinhua Zhao Yunling Liu Xiaojing Yang 《Journal of Materials Science》2013,48(10):3870-3876
Mesoporous metal oxides such as SnO2 exhibit a superior electrochemical performance as anode materials for lithium-ion batteries due to their large surface areas and uniform pores. However, they suffer from the capacity fading in varying degrees during cycles because their partial pores may collapse during the charge–discharge process. Herein, graphene-encapsulated mesoporous SnO2 composites have been simply synthesized using a modified stepwise heterocoagulation method. These graphene-based SnO2 composites exhibit not only higher capacities and better rate capabilities but also improved cycle performances, suggesting that the electrochemical performance of mesoporous SnO2 can be further enhanced by graphene encapsulation. 相似文献
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P25/graphene nanocomposites were successful synthesized in a water-ethanol solvent under hydrothermal conditions. During the process of the reduction of GO into graphene (GR), the P25 nanoparticles were decorated on graphene sheets simultaneously. Moreover, the GR content in the as-synthesized nanocomposites can be easily adjusted by changing the dosage of P25. The interesting P25/GR nanocomposites were found to be a promising anode material for lithium-ion batteries and showed significantly enhanced Li-ion insertion/extraction performance. The optimal weight percentage of GR was found to be 29.9%, which resulted in a high capacity of 282.8 mAh g−1 after 50 cycles at a current rate of 0.5 C. The improved capacity may be attributed to the synergetic effect between graphene sheets and P25 nanoparticles. 相似文献
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石墨烯是一种具有大比表面积、高电导率和良好的力学性能的二维材料,在高容量和大功率储能器件方面具有广阔的应用前景。然而现有的各种石墨烯电极制造技术无论从技术层面还是在生产率、性能方面都难以满足当前工业应用的需求。石墨烯增材制造(石墨烯3D打印)在复杂三维石墨烯结构的制造方面具有突出的优势和潜力,而且还具有设备简单、成型结构可控性高等优点。关于石墨烯基电极材料的增材制造及应用在近两年内迅速发展。概述了基于增材制造制备石墨烯结构的典型技术——直写成型(DIW)的机理和优点,介绍了基于该技术制备的石墨烯基电极材料在超级电容器和锂离子电池领域的应用,最后对石墨烯基电极材料的增材制造面临的挑战和未来发展趋势进行了展望。 相似文献
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通过真空驱动自组装法及蒸汽处理得到结构疏松的硅/碳纳米管/石墨烯自支撑负极材料(Si/CNTs/GP)。纳米硅颗粒(50 nm)为活性物质, 均匀分布在石墨烯片层结构中间; 石墨烯作为碳基体, 通过自组装构筑形成二维导电网络; 碳纳米管(CNTs)具有超高导电性和良好的力学强度, 它通过吸附作用均匀分布在石墨烯基体上形成导电的支撑网络结构。经过蒸汽处理后, 石墨烯层间距明显增大, 层与层之间不再是紧密堆叠的结构, 而是形成一种疏松、褶皱、内部空隙丰富的片层结构。Si/CNTs/GP负极材料中丰富的内部空穴和贯穿孔洞, 提供了材料很高的比表面积, 能有效提高电解液对材料的浸润性, 极大缩短了离子传输距离。同时这些内部空穴也有效缓冲硅充放电时的体积膨胀, 提高了材料的结构稳定性和电化学性能。该负极材料在4 A/g的大电流密度下容量维持在600 mAh/g, 表现出良好的大电流循环稳定性能。 相似文献
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碳作为单一元素可形成像零维碳纳米球、一维碳纳米管、二维石墨烯等多种碳纳米结构,它们在锂离子和锂硫电池中的表现也有所不同。需要阐明的是,碳纳米管和石墨烯由于具有以下缺点不适合直接作为锂离子或锂硫电池电极材料:(1)第一次不可逆容量大,首次充放电效率低;(2)在充放电曲线中电压滞后现象严重;(3)缺少稳定的电压平台;(4)容量衰减快。科学家们一直在为获得具有更高能量密度和更广阔应用前景的锂离子电池和锂硫电池而努力,由于可充电电池的性能主要取决于阴极和阳极的性能,因此,设计先进的电极材料以及制备具有特定成分和结构的电极成为近年来的研究热点。本文综述了碳纳米材料在构建高性能锂离子、锂硫电池电极材料和特定电极方面的作用。首先,从促进电子和离子传输、固定多硫化物位置以及缓冲体积膨胀三个方面讨论了碳纳米材料在修饰电活性材料的作用;其次,从作为导电添加剂、电流集流体和导电中间层三个方面讨论了碳纳米材料在最优化非活性组分的作用;然后,从作为非导电基体上的导电相、柔性电流集流体和自支撑复合电极三个方面讨论了碳纳米材料在柔性电池设计的作用。最后,本文对碳纳米材料的未来发展趋势作了概述,兼具多种功能的碳纳米材料被认为是今后的研究重点。 相似文献
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Haegyeom Kim Sung-Wook Kim Young-Uk Park Hyeokjo Gwon Dong-Hwa Seo Yuhee Kim Kisuk Kang 《Nano Research》2010,3(11):813-821
SnO2/graphene nanocomposites have been fabricated by a simple chemical method. In the fabrication process, the control of surface
charge causes echinoid-like SnO2 nanoparticles to be formed and uniformly decorated on the graphene. The electrostatic attraction between a graphene nanosheet
(GNS) and the echinoid-like SnO2 particles under controlled pH creates a unique nanostructure in which extremely small SnO2 particles are uniformly dispersed on the GNS. The SnO2/graphene nanocomposite has been shown to perform as a high capacity anode with good cycling behavior in lithium rechargeable
batteries. The anode retained a reversible capacity of 634 mA·h·g−1 with a coulombic efficiency of 98% after 50 cycles. The high reversibility can be attributed to the mechanical buffering
by the GNS against the large volume change of SnO2 during delithiation/lithiation reactions. Furthermore, the power capability is significantly enhanced due to the nanostructure,
which enables facile electron transport through the GNS and fast delithiation/lithiation reactions within the echinoid-like
nano-SnO2. The route suggested here for the fabrication of SnO2/graphene hybrid materials is a simple economical route for the preparation of other graphene-based hybrid materials which
can be employed in many different fields. 相似文献
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High-rate anode materials for lithium-ion batteries are desirable for applications that require high power density. We demonstrate
the advantageous rate capability of few-layered graphene nanosheets, with widths of 100–200 nm, over micro-scale graphene
nanosheets. Possible reasons for the better performance of the former include their smaller size and better conductivity than
the latter. Combination of SnO2 nanoparticles with graphene was used to further improve the gravimetric capacities of the electrode at high charge-discharge
rates. Furthermore, the volumetric capacity of the composites was substantially enhanced compared to pristine graphene due
to the higher density of the composites. 相似文献