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《化学进展》2017,(6)
在环境问题日益严峻,化石能源日益枯竭的今天,开发具有高比能的二次电池系统显得尤为重要。锂硫电池以其高理论能量密度和低环境影响的优势成为最有潜力的下一代电化学储能系统之一。然而受制于硫的绝缘性质以及由多硫化锂的溶解所引起的穿梭效应,锂硫电池的实用化进程还面临着诸多困难。为弥补常用的碳质载体对稳定硫电极的物理限制作用的不足,近年来对多硫化物具有强烈化学结合作用的载体材料的应用,显著提升了复合硫电极的综合性能,为锂硫电池正极材料的设计提供了新的思路。本文综述了各种具有化学吸附特性的载体材料在复合硫电极中的应用进展,具体包括:基于极性-极性作用固定多硫化物的金属氧化物、改性的碳质材料、能够与硫发生硫化作用的有机聚合物以及对多硫化物具有路易斯酸碱作用的金属有机骨架,重点阐述了这类载体材料与多硫化物的作用机理,并展望锂硫电池的发展方向。 相似文献
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锂硫电池(LSBs)由于单质硫正极具有超高能量密度(2600 Wh/kg)和超高理论比容量(1675 mAh/g),且环境友好、成本低廉,被认为是最有前景的储能体系之一。然而,硫正极的绝缘性和严重体积膨胀以及多硫化物(LiPSs)的“穿梭效应”等问题导致活性物质利用率低、循环稳定性差及电化学反应动力不足,严重阻碍了LSBs的商业化发展。最新研究表明,过渡金属硫化物作为载体或添加剂能够显著改善LSBs正极材料的电化学性能。本文从等效/共正极作用、导电性增强作用、LiPSs吸附作用和电化学反应催化作用四个方面梳理了过渡金属硫化物在LSBs正极材料中的改性机理,并指出多元过渡金属硫化物复合﹑纳米结晶和量子化作为增加比表面积和活性位点的方法是过渡金属硫化物用于锂硫电池正极材料的重要发展方向,可大幅提升LSBs的电化学性能。 相似文献
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随着全球经济快速发展对高效绿色能源需求的不断增长,锂-硫电池因具有较高的能量密度,成为了下一代高能量密度二次电池研发的重点.然而,锂-硫电池面临的循环寿命短、库仑效率低、安全性能差、较高自放电等问题,使其目前还很难实现商品化.锂-硫电池存在的这些问题主要与正极活性硫材料的高绝缘性、放电过程中产生的多硫化物溶解于电解液、硫正极在充放电过程中的体积膨胀与收缩、以及锂负极支晶化等有关.通过从锂-硫电池硫复合正极、电解液、黏结剂和负极等4个方面综述了高比能锂-硫电池的最新研究进展,其中重点介绍了硫正极复合材料的进展情况. 相似文献
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二次锂硫电池被视为最具有发展潜力的下一代高能量密度二次电池之一. 但由于正极硫的电导率低(5×10-30 S·cm-1),且在放电过程中产生的中间体多硫化物易溶于有机电解液,致使锂硫电池活性物质利用率降低,溶解后的多硫化物还会迁移到负极,被还原成不溶物Li2S2/Li2S而沉积于负极锂,使电极结构遭受破坏,造成电池容量大幅衰减,循环性能差,从而限制了进一步的开发应用. 研究表明,以碳作为导电骨架的硫碳复合正极材料能在不同程度上解决上述问题,从而有效提高了锂硫电池的放电容量和循环性能. 本文综述了近年来国内外报道的各种锂硫电池正极材料的研究进展,结合作者课题组的研究,重点探讨了硫碳复合正极材料,并对其今后的发展趋势进行了展望. 相似文献
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电动汽车行业的迅速发展,逐步提高了对二次电池容量的要求,因此急需发展新型高容量锂电池。锂硫电池具有高理论比容量(1675mAh/g)和高理论比能量(2600Wh/kg),使其能够实现锂离子电池3~5倍的能量密度。但是,正极长链多硫化物溶解引起的容量衰减快、循环寿命短等因素限制了锂硫电池的实用化进程。本文针对正极聚硫锂溶解问题,从正极材料表面包覆、表面吸附、表面催化的角度对近年来提高锂硫电池循环性能的正极材料研究思路和研究进展进行综述,最后对提高锂硫电池性能的发展趋势提出展望。 相似文献
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锂硫电池具有能量密度高、价格低等优势,有希望应用于下一代储能领域. 但锂硫电池仍然存在一些问题,如多硫化物穿梭效应、缺乏有效的锂硫电池规模制备工艺等. 为了解决这些问题,作者以不同商用碳材料(乙炔黑、科琴黑与碳纳米管)和单质硫复合作为正极材料,探究正极制备工艺对多硫化物穿梭效应抑制效果及锂硫电池性能的影响. 通过研究,作者得出以下结论:科琴黑作为单质硫的载体,与单质硫球磨8 h后,匹配粘结剂聚乙烯吡咯烷酮(PVP)制备的正极浆料可实现在涂布和辊压后极片的厚度达到500 μm、压实密度达到991.65 mg·cm -3. 作者将最终得到的正极极片应用于高硫载量锂硫软包电池,电池首圈放电容量为137.4 mA·h,经过10圈循环后,放电容量为115.5 mA·h,表现出优异的电化学性能. 该碳硫复合正极材料制备工艺有望在锂硫电池的宏量制备中获得应用. 相似文献
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使用硫化物固体电解质的全固态锂硫电池由于多硫化物不溶于硫化物固体电解质及硫化物电解质不可燃的特性,得以完全避免穿梭效应并显著提高了电池的安全性能而被认为是极具潜力的下一代储能电池。如何建立并平衡复合正极中离子/电子导电网络且维持复合正极中较高活性物质含量对于全固态锂硫电池至关重要。本文以单质硫为活性物质研究了复合导电添加剂对全固态锂硫电池性能的影响,发现以乙炔黑(AB)为导电碳材料明显优于Super P和Ketjen Black;优化复合正极的组成,发现硫:乙炔黑:固体电解质的质量比为40:20:40时,全固态锂硫电池在室温和60℃下均具有良好的电化学性能。 相似文献
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A lamellar vermiculite separator assembled with exfoliation vermiculites is developed for lithium sulfur batteries. The vermiculite separator can simultaneously suppress the parasitic reactions induced by polysulfide intermediate shuttle, and prevent the short circuit by potential lithium dendrite penetration with the ultrahigh Young's modulus. 相似文献
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Metal-sulfur batteries are a promising next-generation energy storage technology, offering high theoretical energy densities with low cost and good sustainability. An active area of research is the development of electrolytes that address unwanted migration of sulfur and intermediate species known as polysulfides during operation of metal-sulfur batteries, a phenomenon that leads to low energy efficiency and short life-spans. A particular class of electrolytes, gel polymer electrolytes, are especially attractive for their ability to repel polysulfides on the basis of structure, electrostatics, and other polymer properties. Herein, within the context of magnesium- and lithium-sulfur batteries, we investigate the impact of gel polymer electrolyte cation solvation capacity, a property related to network dielectric constant and chemistry, on sulfur/polysulfide-polymer interactions, an understudied property-performance relationship. Polymers with lower cation solvation capacity are found to permanently absorb less polysulfide active material, which increases sulfur utilization for Li−S batteries and significantly increases charge efficiency and life-span for Li−S and Mg−S batteries. 相似文献
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基于第一性原理计算, 探究了未掺杂、 Co单掺杂、 Co, P共掺杂MoS2表面上多硫化物的吸附和转化, 揭示了Co, P共掺杂对MoS2材料吸附能力和催化能力的影响. 研究结果表明, 共掺杂使得MoS2吸附能力增强, 特别是对产物Li2S的稳定吸附提供了多硫化物转化动力, 进而增强了催化能力. Co, P共掺杂表面与长链、 中链、 短链多硫化物之间均存在Li—S和S—P双重成键, 具备最大的吸附能力; 另一方面, 共掺杂表面对于产物Li2S的显著稳定化作用降低了多硫化物转化过程中解离步骤的能量需求, 增大了转化过程的能量释放, 为多硫化物转化提供了驱动力. 上述两方面因素共同增强了MoS2的催化活性, 有效抑制了穿梭效应, 提升了电池的电化学性能. 相似文献
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A MoO2-ordered mesoporous carbon (M-OMC) hybrid was designed as the sulfur host, in which MoO2 is inlaid on the surface of ordered mesoporous carbons that can store active materials and provide fast electron transfer channel due to its ordered porestructure. The MoO2 can effectively prevent the migration of polysulfides through the chemical adsorption and promote the conversion of polysulfides towards Li-sulfur battery. 相似文献
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《中国化学快报》2021,32(12):4063-4069
More and more attentions have been attracted by lithium-sulfur batteries (Li-S), owing to the high energy density for the increasingly advanced energy storage system. While the poor cycling stability, due to the inherent polysulfide shuttle, seriously hampered their practical application. Recently, some polar hosts, like single metal oxides and sulfides, have been employed as hosts to interact with polysulfide intermediates. However, due to the inherent poor electrical conductivity of these polar hosts, a relatively low specific capacity is obtained. Herein, a spinel-type bimetal sulfide NiCo2S4 through a Prussian blue analogue derived methodology is reported as the novel host of polysulfide, which enables high-performance sulfur cathode with high Coulombic efficiency and low capacity decay. Notably, the Li-S battery with NiCo2S4-S composites cathode still maintains a capacity of 667 mAh/g at 0.5 C after 300 cycles, and 399 mAh/g at 1 C after 300 cycles. Even after 300 cycles at the current density of 0.5 C, the capacity decays by 0.138% per cycle at high sulfur loading about 3 mg/cm2. And the capacity decays by 0.026% per cycle after 1000 cycles, when the rate is 1 C. More importantly, the cathode of NiCo2S4-S composite shows the outstanding discharge capacity, owing to its good conduction, high catalytic ability and the strong confinement of polysulfides. 相似文献
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Bin Guan Xun Sun Yu Zhang Xian Wu Yue Qiu Maoxu Wang Lishuang Fan Naiqing Zhang 《中国化学快报》2021,32(7):2249-2253
Lithium-sulfur battery is strongly considered as the most promising next-generation energy storage system because of the high theoretical specific capacity.The serious "shuttle effect" and sluggish reaction kinetic limited the commercial application of lithium-sulfur battery.Many hetero structure s were applied to accelerate polysulfides conversion and suppress their migration in lithium-sulfur batteries.Nevertheless,the effect of the interface in heterostructure was not clear.Here,the Co_2B@MXene heterostructure is synthesized through chemical reactions at room temperature and employed as the interlayer material for Li-S batteries.The theoretical calculations and experimental results indicate that the interfacial electronic interaction of Co_2B@MXene induce the transfer of electrons from Co_2B to MXene,enhancing the catalytic ability and favoring fast redox kinetics of the polysulfides,and the theoretical calculations also reveal the underlying mechanisms for the electron transfer is that the two materials have different Fermi energy levels.The cell with Co_2B@MXene exhibits a high initial capacity of1577 mAh/g at 0.1 C and an ultralow capacity decay of 0.0088% per cycle over 2000 cycles at 2 C.Even at5.1 mg/cm~2 of sulfur loading,the cell with Co_2B@MXene delivers 5.2 mAh/cm~2 at 0.2 C. 相似文献
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锂硫电池因其较高的理论比容量和能量密度而成为最有前途的下一代储能系统之一。然而,硫和放电产物硫化锂的低导电率、可溶性多硫化锂(LiPSs)的穿梭以及缓慢的反应动力学致使锂硫电池的循环寿命短、倍率性能低。近年来,研究表明具有强催化活性的单原子(SAs)是理想的LiPSs锚定中心和催化位点。用SAs修饰正极和隔膜有助于吸附多硫化物并催化其转化,修饰负极则可显著提高锂的剥离/沉积效率,抑制锂枝晶的生长。本文综述了SAs在锂硫电池中的研究进展,包括材料合成、表征方法以及应用方向。最后,对SAs应用在电池中所面临的挑战和未来发展方向进行总结。 相似文献