کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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5432007 | 1508829 | 2017 | 9 صفحه PDF | دانلود رایگان |
In spite of the ultrahigh theoretical energy density, non-aqueous Li-O2 batteries are still constrained by their inefficient cathodes. Here, we report the synthesis of a distinctive hierarchical carbon architecture (HOM-AMUW) for Li-O2 batteries, which consists of highly ordered macropores (250Â nm) with abundant mesopores on their ultrathin walls (4-5Â nm). This carbon architecture exhibits unprecedented discharge capacity of 37523Â mAh gâ1 and 12686Â mAh gâ1 at the current density of 500Â mAÂ gâ1 and even 2000Â mAÂ gâ1, respectively. After further functionalization by low crystalline Ru nanoclusters, the resulted Ru-HOM-AMUW architecture presents a much low charge polarization and outstanding cycling stability. The significant performance enhancement is mainly attributed to the unique hierarchical porous structure, wherein the ordered macropores and ultrathin mesoporous walls remarkably enhance the access capability of O2 or Li+ to the numerous active sites, and the large pore volume easily accommodates the discharge products. Moreover, the hierarchical porous structure modulates the morphology of discharge products to three-dimensional porous structure with high charge transport, which also contributes to the striking rate capability. This HOM-AMUW architecture is a promising scaffold to design the gas electrodes with ultrahigh rate performance not only for Li-O2 batteries but also for other metal-air batteries.
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Journal: Carbon - Volume 118, July 2017, Pages 139-147