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论文类型：期刊论文
发表时间：2017-05-01
发表刊物：SCIENCE CHINA-MATERIALS
收录刊物：SCIE、EI
卷号：60
期号：5
页面范围：415-426
ISSN号：2095-8226
关键字：Li-O-2 battery; cathode catalyst; N-doped carbon nanotube; Fe nanorods; first-principles calculation
摘要：Rechargeable Li-O-2 batteries have attracted considerable interests because of their exceptional energy density. However, the short lifetime still remained as one of the bottle-neck obstacles for the practical application of rechargeable Li-O-2 batteries. The development of efficient cathode catalyst is highly desirable to reduce the energy barrier of Li-O-2 reaction and electrode failure. In this work, we report a facile strategy for the fabrication of a high-performance cathode catalyst for rechargeable Li-O-2 batteries by the encapsulation of high content of active Fe nanorods into N-doped carbon nanotubes with high stability (denoted as Fe@NCNTs). First-principles calculations reveal that the synergistic charge transfer and redistribution between the interface of Fe nanorods, the CNT walls and the active N dopants greatly facilitate the chemisorption and subsequent dissociation of O2 molecules into the epoxy intermediates on the carbon surface, which benefits the uniform growth of nanosized discharge products on CNT surface and thus boosts the reversibility of Li-O-2 reactions. As a result, the cathode with Fe@NCNT catalyst exhibits long cycling stability with high capacities (1000 mA h g(-1) for 160 cycles and 600 mA h g(-1) for 270 cycles). Based on the total mass of Fe@NCNTs + Li2O2, high gravimetric energy densities of 2120-2600 W h kg(-1) can be achieved at the power densities of 50-795 W kg(-1).