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Metal‐Organic‐Framework‐Derived Porous Carbon Embedded with TiO2 Nanoparticles as a Cathode for Advanced Lithium–Sulfur Batteries
ChemElectroChem ( IF 3.5 ) Pub Date : 2020-09-22 , DOI: 10.1002/celc.202001122
Chu Qi 1 , Huilan Li 1 , Jia Wang 1 , Chengcheng Zhao 1 , Cuimei Fu 1 , Lina Wang 2 , Tianxi Liu 1
Affiliation  

The undesired internal shuttling of soluble polysulfide intermediates (Li2Sn, 2<n≤8) remains the primary challenge hindering the development of lithium‐sulfur (Li−S) batteries. Engineering and functionalizing the cathode structure to trap Li2Sn is a straightforward approach to address this issue. Metal‐organic framework (MOF)‐derived materials are applausive candidate host materials of sulfur, owing to the highly porous characteristic. In this work, a Ti−MOF‐derived micro‐sized cake‐like carbon skeleton with in situ generated hierarchical pores and anatase TiO2 crystalline grains is applied as an effective sulfur host in Li−S batteries. In this rational design, the pyrolytic porous carbon provides fast ion diffusion and physical confinement of polysulfides. The polar TiO2 affords abundant anchoring sites to achieve chemical encapsulation of sulfur species and accelerate polysulfide conversion kinetics. Benefiting from the fast reaction kinetics, the hybrid sulfur cathode delivers an elevated cycling performance with a capacity decay of only 0.39 % per cycle at 0.5 C (1 C=1675 mA g−1) over 100 cycles. In addition, an improved rate capability of 620 mAh g−1 at 2 °C is obtained. This work affords a facile method to design optimized cathodes towards advanced Li−S batteries.

中文翻译:

嵌入TiO2纳米粒子的金属,有机框架衍生的多孔碳作为高级锂硫电池的阴极

可溶性多硫化物中间体(Li 2 S n,2 <n≤8)的不希望的内部穿梭仍然是阻碍锂硫(Li-S)电池发展的主要挑战。对阴极结构进行工程化和功能化以捕获Li 2 S n是解决此问题的直接方法。金属有机骨架(MOF)衍生的材料由于具有高度多孔性而成为鼓掌的硫磺候选主体材料。在这项工作中,Ti-MOF衍生的微米级蛋糕状碳骨架具有原位生成的分层孔和锐钛矿型TiO 2晶粒被用作Li-S电池中的有效硫主体。在这种合理的设计中,热解多孔碳提供了快速的离子扩散和多硫化物的物理限制。极性TiO 2提供了丰富的锚固位点,可实现硫物种的化学封装并加快多硫化物的转化动力学。得益于快速的反应动力学,杂化硫阴极提供了更高的循环性能,在100个循环中,在0.5 C(1 C = 1675 mA g -1)下,每个循环的容量衰减仅为0.39%。另外,在2℃下获得了620mAh g -1的提高的倍率能力。这项工作提供了一种简便的方法来设计针对高级Li-S电池的优化阴极。
更新日期:2020-09-22
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