共查询到18条相似文献,搜索用时 55 毫秒
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锂硫电池在电动汽车、无人机等领域受到极大的关注,因其环境友好、材料成本低、理论容量高等特点而被广泛研究,但因硫的导电性能不佳、多硫化物的穿梭效应以及充放电过程中硫的体积变化等阻碍了锂硫电池的商业化。为改善硫不良的导电性及多硫化物的穿梭效应,基于碳材料优异的导电性与氧化物较强的吸附性,采用水合肼在CNT表面还原氯化镍,通过热处理后得到NiO/CNT复合物作为硫的载体,充当电池的正极。物理及电化学表征的结果表明,多孔结构的NiO/CNT比表面积达到48.49 m2·g-1,在电流密度为1C下,NiO/CNT的首圈比容量达到825 mAh·g-1,循环100圈后,比容量保持在617 mAh·g-1且库伦效率在99.3%以上,说明两种材料的复合提高了电池库伦效率和循环性能。 相似文献
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硅材料具有高理论容量、低工作电压、储量丰富和环境友好等优点,是最有潜力的锂离子电池负极材料之一。然而,硅在锂化/去锂化过程中会产生超过300%的体积膨胀,从而导致硅颗粒粉化和容量快速衰减。近年来,一类新型的蛋黄-壳结构硅碳复合材料引起了广泛的研究关注,这种结构可缓解嵌锂过程中的体积膨胀,提高材料的循环稳定性。本文对蛋黄-壳结构的硅碳负极材料进行了分类和介绍,分析了蛋黄-壳结构硅碳材料的制备方法。阐述了蛋黄-壳结构参数对材料储锂性能的影响。指出通过开发低成本和环境友好的制备工艺、纳-微结构设计和结构参数优化,有望获得性能更优的新型蛋黄-壳结构硅碳负极材料,进一步推动硅碳负极材料的产业应用。 相似文献
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透射电镜作为当代最常用的材料表征手段之一,有着高的分辨率,可以较清晰地在原子尺度表征材料的微观结构与化学成分,在许多学科中发挥着关键作用.新型电池作为高效、清洁的储存装置,给现代生活带来了许多便利,拥有极大的科研与商用价值.而作为电池重要部件的正极材料,是否能高效、安全地工作,时刻影响着新型电池的商业化前景.本文综述了... 相似文献
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为了改善锂硫电池的循环性能,将单质硫分别与纳米金属氧化物(V2O5,TiO2)机械混合。用XRD对材料的晶体结构进行了表征。通过循环伏安、交流阻抗和电池性能的对比,对材料的电化学性能进行了分析。结果表明:采用V2O5改性的硫材料,首次放电比容量达844.68 mAh.g–1,样品循环容量衰减明显改善,30次后比容量保持在696.71 mAh.g–1。而TiO2/S复合材料,初始放电比容量为578.21 mAh.g–1,30次循环后比容量为347.71 mAh.g–1。 相似文献
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Current lithium (Li) ion batteries consisting of graphite as the anode and intercalation materials (such as LiCoO2, LiNixCoyMn1-x-yO2, LiNi0.8Co0.1Al0.1O2) as the cathodes have almost reached their theoretical energy density of 300 Wh/kg. As a result, exploring high energy density batteries is urgent. Li-metal taking place of the graphite as the anode has several advantages. On one hand, it has a low operational voltage (-3.04 V versus standard hydrogen electrode) and a high specific capacity of 3860 mAh/g offering the battery with high energy density. On the other hand, when the Li-metal as the anode, the cathodes can be extended to Li-free or Li-deficient materials, which means the cathodes have more choices. For instance, S, O2, conversion reaction-type materials can be optional. While, the introduction of Li-metal anodes brings in several challenges [1–3]. Firstly, Li-metal is highly electrochemical and electrochemical active to have undesirable reactions with conventional carbonate-based liquid electrolytes, leading a low Coulombic efficiency and large polarizations. Secondly, the formed Li dendrites due to uneven Li+ distribution during plating and stripping has the chances of percolating separators leading to short circuits. Thirdly, Li metal is a host-free material (~5 μm have a capacity of 1 mAh/cm2), thus it suffers from a huge volume change, which brings in difficulty in the cell design. 相似文献