Beijing Computing Center , Beijing Academy of Science and Technology , Beijing 100094 , P. R. China.
ACS Appl Mater Interfaces. 2019 Oct 30;11(43):39772-39781. doi: 10.1021/acsami.9b11419. Epub 2019 Oct 18.
A low-cost in situ formed FeO-FeC heterostructure highly dispersed in carbon nanofiber was delicately designed via a facile one-pot electrospinning method. The intense anchoring (by FeO) and rapid electron transfer (by FeC) for lithium polysulfides transformation can be simultaneously achieved on the FeO-FeC heterostructure interface, thus preventing the amassment of lithium polysulfides benefiting from its excellent interfacial contact and improving sulfur utilization. Experimental characterizations and DFT calculations confirmed the restrained polysulfides shuttle and enhanced redox kinetics. Therefore, the battery containing optimal FeO-FeC heterostructure delivered a high capacity of 776.2 mA h g after 300 cycles at 1 C at a low fading rate of 0.037% per cycle. Even at a high sulfur loading of 3.5 and 4.5 mg cm, high capacities of 773.6 and 533.6 mA h g at 0.5 C can be achieved with capacity retentions of 91.7 and 94.2%, respectively. This distinctive heterostructure proposes an effective design of high-performance lithium-sulfur batteries contributing to the excellent electrochemical performance, which can synergize the virtues of effectively adsorptive metal oxides and appealing conductive metal carbides.
通过简便的一锅法静电纺丝方法，精心设计了一种在碳纤维中高度分散的低成本原位形成的 FeO-FeC 异质结构。在 FeO-FeC 异质结构界面上，同时实现了对多硫化物转化的强烈锚定（通过 FeO）和快速电子转移（通过 FeC），从而防止了多硫化物的聚集，有利于其优异的界面接触并提高了硫的利用率。实验表征和 DFT 计算证实了对多硫化物穿梭的限制和增强的氧化还原动力学。因此，含有最佳 FeO-FeC 异质结构的电池在 1 C 下经过 300 次循环后，具有 776.2 mA h g 的高容量，在 0.037%/循环的低衰减率下。即使在高硫载量为 3.5 和 4.5 mg cm 时，在 0.5 C 下仍可实现 773.6 和 533.6 mA h g 的高容量，容量保持率分别为 91.7%和 94.2%。这种独特的异质结构提出了一种高性能锂硫电池的有效设计，有助于实现卓越的电化学性能，同时结合了有效吸附金属氧化物和有吸引力的导电金属碳化物的优点。
