Metal-Organic-Framework-Derived N-Doped Hierarchically Porous Carbon Polyhedrons Anchored on Crumpled Graphene Balls as Efficient Selenium Hosts for High-Performance Lithium–Selenium Batteries,ACS Applied Materials & Interfaces

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Metal-Organic-Framework-Derived N-Doped Hierarchically Porous Carbon Polyhedrons Anchored on Crumpled Graphene Balls as Efficient Selenium Hosts for High-Performance Lithium–Selenium Batteries
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2018-04-25 00:00:00 , DOI: 10.1021/acsami.8b03104
Seung-Keun Park ₁ , Jin-Sung Park ₁ , Yun Chan Kang ₁

Affiliation

Developing carbon scaffolds showing rational pore structures as cathode hosts is essential for achieving superior electrochemical performances of lithium–selenium (Li–Se) batteries. Hierarchically porous N-doped carbon polyhedrons anchored on crumpled graphene balls (NPC/CGBs) are synthesized by carbonizing a zeolitic imidazolate framework-8 (ZIF-8)/CGB composite precursor, producing an unprecedented effective host matrix for high-performance Li–Se batteries. Mesoporous CGBs obtained by one-pot spray pyrolysis are used as a highly conductive matrix for uniform polyhedral ZIF-8 growth. During carbonization, ZIF-8 polyhedrons on mesoporous CGBs are converted into N-doped carbon polyhedrons showing abundant micropores, forming a high-surface-area, high-pore-volume hierarchically porous NPC/CGB composite whose small unique pores effectively confine Se during melt diffusion, thereby providing conductive electron pathways. Thus, the integrated NPC/CGB-Se composite ensures high Se utilization originating from complete electrochemical reactions between Se and Li ions. The NPC/CGB-Se composite cathode exhibits high discharge capacities (998 and 462 mA h g^–1 at the 1st and 1000th cycles, respectively, at a 0.5 C current density), good capacity retention (68%, calculated from the 3rd cycle), and excellent rate capability. A discharge capacity of 409 mA h g^–1 is achieved even at an extremely high (15.0 C) current density.

中文翻译：

金属有机框架衍生的N掺杂分层多孔碳多面体锚固在皱纹石墨烯球上，作为高性能锂-硒电池的高效硒基质

研发出具有合理孔隙结构作为阴极主体的碳支架对于实现锂硒（Li-Se）电池优异的电化学性能至关重要。锚固在皱缩的石墨烯球（NPC / CGBs）上的分层多孔N掺杂碳多面体是通过将沸石咪唑酸酯骨架8（ZIF-8）/ CGB复合前驱物碳化而合成的，从而为高性能的Li-Se产生了前所未有的有效基质电池。通过一锅法喷雾热解获得的中孔CGB用作高导电性基质，可实现均匀的多面体ZIF-8生长。在碳化过程中，介孔CGB上的ZIF-8多面体被转化为N掺杂的碳多面体，表现出丰富的微孔，形成高表面积，高孔体积的分级多孔NPC / CGB复合材料，其独特的小孔在熔体扩散过程中有效地限制了Se，从而提供了导电电子路径。因此，集成的NPC / CGB-Se复合材料可确保源自Se和Li离子之间完全的电化学反应，从而提高Se的利用率。NPC / CGB-Se复合阴极展现出高放电容量（998和462 mA hg在第1次和第1000次循环中电流密度为0.5 C时分别为^–1，良好的容量保持率（从第3次循环计算得出为68％），以及出色的倍率能力。即使在极高的电流密度（15.0 C）下，放电容量也可达到409 mA hg ^–1。

更新日期：2018-04-25

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