共查询到19条相似文献,搜索用时 125 毫秒
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锂硫电池具有很高的能量密度[2 600(W·h)/kg],其正极材料硫具有储藏丰富、对环境友好等优点,因此锂硫电池成为下一代二次电池的研发重点。然而,硫的高绝缘性、反应过程中体积的变化以及中间产物多硫离子溶解等难题,使其目前很难实现商品化。石墨烯具有超高的导电性和优异的力学性能,其与硫制成的复合材料作为电池正极材料可以有效地解决上述问题。从石墨烯–硫复合材料、石墨烯–碳–硫复合材料、石墨烯–聚合物–硫复合材料、石墨烯–氧化物–硫复合材料等方面出发,总结了石墨烯在锂硫电池中作为正极材料的最新进展,并且提出了未来石墨烯在锂硫电池中应用的研究主要在探索石墨烯简捷的制备方法、研究石墨烯新的应用方式、开发多种材料复合等方面。 相似文献
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《化工进展》2017,(9)
锂硫电池采用硫化锂作为正极材料时,不仅具有较高的理论比容量(1166m A?h/g),还可用高嵌锂能力的碳或硅材料代替金属锂负极,有效避免锂枝晶刺穿隔膜造成的短路现象,故该储能体系为国内外学者所广泛关注。本文围绕硫化锂/金属、硫化锂/碳、硫化锂/导电聚合物3类复合材料体系综述硫化锂正极复合材料近年来的研究现状。同时,对电极材料的设计和功能化制备进行了阐述,指出了硫化锂正极复合材料未来的研究方向应注重不同导电复合材料的协同使用,并注重电极材料的结构设计,向多元复合、多级结构方向发展。另外,还要通过降低硫化锂的粒径以提高活性物质负载量和循环稳定性,最终获得高性能的锂硫电池。 相似文献
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锂硫电池因其理论能量密度高、原材料丰富、成本低廉等优点而受到广泛关注。然而硫正极电导率低、体积膨胀、以及脱嵌锂过程中多硫化物产生的穿梭效应等问题限制了锂硫电池的商业化应用。其采用导电材料作为硫载体,一方面可缓解体积膨胀,另一方面可改善正极导电性,同时一定程度上限制多硫穿梭。多级孔碳由于具有导电性优良、结构稳定、孔径及形貌可控等优点,被认为是一种理想的硫载体。从锂硫电池的发展背景出发阐述了多级孔碳作为硫载体的研究意义,首先介绍了多级孔碳材料的制备方法如硬模板法、软模板法和活化法等,进一步介绍了碳材料中的微孔、介孔及大孔在锂硫电池中提升导电性、稳定结构和抑制多硫穿梭效应的作用机理,最后对多级孔碳作为硫载体推进锂硫电池的发展前景进行了展望。 相似文献
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锂硫电池凭借高理论能量密度和高理论比容量的优势成为极具发展前景的储能设备。然而,单质硫和硫化锂的绝缘性、放电过程中产生的体积膨胀及多硫化物溶解导致的“穿梭效应”等问题,限制其商业化发展。为解决上述问题,采用低温液相法合成中空硫球(HS),通过水热法制备纳米花状MoS2/还原氧化石墨烯(MoS2/rGO),随后将MoS2/rGO包覆在HS表面获得HS-MoS2/rGO复合正极材料。利用XRD、SEM、TEM、XPS等对该材料的晶体结构、形貌等性质进行表征,采用循环伏安法、交流阻抗法以及恒流充放电对复合正极进行电化学测试。研究表明,MoS2/rGO对多硫化物具有强吸附能力和高催化活性,能够有效限制多硫化物的穿梭;同时硫球的中空结构能够缓解体积膨胀,保持正极结构稳定。HS-MoS2/rGO正极展现出优异的倍率性能和循环稳定性。 相似文献
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锂硫电池凭借高理论能量密度和高理论比容量的优势成为极具发展前景的储能设备。然而,单质硫和硫化锂的绝缘性、放电过程中产生的体积膨胀及多硫化物溶解导致的“穿梭效应”等问题,限制其商业化发展。为解决上述问题,采用低温液相法合成中空硫球(HS),通过水热法制备纳米花状MoS2/还原氧化石墨烯(MoS2/rGO),随后将MoS2/rGO包覆在HS表面获得HS-MoS2/rGO复合正极材料。利用XRD、SEM、TEM、XPS等对该材料的晶体结构、形貌等性质进行表征,采用循环伏安法、交流阻抗法以及恒流充放电对复合正极进行电化学测试。研究表明,MoS2/rGO对多硫化物具有强吸附能力和高催化活性,能够有效限制多硫化物的穿梭;同时硫球的中空结构能够缓解体积膨胀,保持正极结构稳定。HS-MoS2/rGO正极展现出优异的倍率性能和循环稳定性。 相似文献
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锂硫电池因具有超高的理论比容量(1675 mA·h·g-1)而被认为是最具有应用前景的二次电池。但硫基正极面临着硫导电性差、利用率低、正极结构稳定性差等问题。采用KOH化学活化法将廉价易得的农业废弃物玉米苞叶制备为多孔碳材料后,与升华硫复合获得硫/碳复合材料。利用XRD、SEM、TEM和BET对该硫/碳复合材料的微观结构、形貌等进行表征发现,玉米苞叶制备的多孔碳材料具有类石墨烯片层结构,且表面具有大量的介孔结构,硫元素均匀分布在多孔碳材料中。采用恒流充放电和交流阻抗法对该复合材料正极电化学性能进行测试发现其具有较高的放电比容量和良好的循环性能,这是由于类石墨烯片层结构的多孔碳材料提高了硫正极的导电性,且其极大的比表面积大幅增加了电化学反应位点,提高了硫的利用率。 相似文献
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采用改进的Hummers法制备了氧化石墨(GO),对GO进行碳酸浸渍后,通过微波固相法剥离其为少层的还原氧化石墨烯(MRGO)。并采用低温原位化学沉积法制备微波还原氧化石墨烯/纳米硫(MRGO/NS)锂硫电池正极复合材料。通过FT-IR、XRD、SEM、TEM、BET对所制备的MRGO和MRGO/NS的微观结构、形貌等进行表征,采用恒流充放电测试和交流阻抗测试对复合材料的电化学性能进行研究。结果表明,通过微波固相法剥离碳酸浸渍后的GO所制备的MRGO为少层的折扇状还原氧化石墨烯,可为锂硫电池的硫和多硫化物提供足够的容纳空间,从而缓解穿梭效应,提高了电极材料的循环性能和倍率性能。 相似文献
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金属有机骨架材料(MOFs)由于其高比表面积、可调孔结构以及多样的组成等引起了学者们的极大关注,尤其在电化学储能领域取得了较大的研究进展。本文综述了近几年MOFs基材料在锂硫电池、锂离子电池和超级电容器等电化学储能领域中的应用。详细介绍了MOFs及其复合材料作为锂硫电池正极载体时与活性物质的作用机理,探讨了MOFs对活性物质硫的物理封装和化学配位作用。此外,阐述了MOFs衍生碳材料因独特孔结构、较强导电性和丰富活性位点等作为电极材料时对电池性能的提升。最后对MOFs基材料在电化学储能中的研究前景作出了展望,指出MOFs基材料中杂原子比例的控制和孔道设计是未来研究的重点。 相似文献
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Xiangming He Weihua Pu Jianguo Ren Li Wang Jiulin Wang Changyin Jiang Chunrong Wan 《Electrochimica acta》2007,52(25):7372-7376
The charge and discharge characteristics of lithium batteries with sulfur composite cathodes have been investigated. The sulfur composites showed novel electrochemical characteristics. The analysis of the differential capacity indicated that the discharge process showed two voltage plateaus of 2.10 V and 1.88 V, and the charge process also presented two voltage plateaus of 2.22 V and 2.36 V. The overcharge test showed that the composite cannot be charged over 4.0 V, the voltage always stopped at about 3.9 V during charging, indicating that the composite presented the intrinsic safety for the overcharge of lithium batteries. The overcharge can cause serious safety problem for the conventional Li-ion batteries. The overcharge test also showed that the batteries with sulfur composite were destroyed when the upper cut-off voltage was over 3.6 V. However, the composite presented good reversible capacity after it was deep discharged even to 0 V. It showed stable cycleability and high cycling capacity of 1000 mAh g−1 when cycling between 0.1 V and 3.0 V, indicative of the different characteristic from the conventional oxide cathode materials. The prototype polymer battery with the composite cathode material presented the energy density of 246 Wh kg−1 and 401 Wh L−1. 相似文献
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Gelatin, a natural biological macromolecule, was successfully used as a new binder in place of poly(ethylene oxide) (PEO) in the fabrication of the sulfur cathode in lithium-sulfur batteries. The structure and electrochemical performance of the two types of sulfur cathodes, with gelatin and PEO as binders, respectively, were compared in 1 M LiClO4 DME/DOL (V/V = 1/1) electrolyte. The results showed that the gelatin binder had multifunctional effects on the sulfur cathode: it not only functioned as a highly adhesive agent and an effective dispersion agent for the cathode materials, but also an electrochemically stable binder. The gelatin binder-sulfur cathode achieved a high initial capacity of 1132 mAh g−1, and remained at a reversible capacity of 408 mAh g−1 after 50 cycles, all of which were better than with the PEO binder-sulfur cathode under the same conditions. 相似文献
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《Carbon》2014
The preparation of sulfur/carbon composite materials for lithium–sulfur batteries is currently a very active research field. Thereto, nanoporous carbon materials are mixed with or infiltrated by sulfur to provide a close contact between both compounds. The characterization of these often complex and on the nanoscale structured composite materials is usually done by vacuum based methods such as nitrogen physisorption or scanning electron microscopy, for example. In this study we show that results from these measurements can be misinterpreted. The reason is the volatility of sulfur that leads to a rapid migration and continuous redistribution effects, especially at low pressures and/or elevated temperatures. For nitrogen physisorption this means that virtually identical isotherms are found for S8/C samples, irrespective of their pre-treatment, making it impossible to prove intentional nanostructuring by pore filling. Similar effects are found for scanning electron microscopy studies where sulfur migration and contamination of originally sulfur free samples is evidenced in situ. Further evidence is provided by macroscopic experiments combined with elementary analysis. The results show that characterizing the structure of S8/C composite materials or electrodes is very challenging. In addition, the observed rapid sulfur redistribution might also have important consequences for the performance of practical lithium-sulfur batteries. 相似文献