钴修饰碳纳米管瓶刷助力锂硫电池多硫化物转化

Cobalt-decorated carbon nanotube bottlebrushes for boosting polysulfide conversion in lithium-sulfur batteries

开发具有多层次结构(包括多孔结构、杂化骨架和/或拓扑形貌)的超结构碳材料,对于满足电化学储能和转换系统中复杂催化反应的需求非常关键.在本文中,我们以钴纳米颗粒为催化位点,在杂化碳纳米管骨架表面可控接枝毛发状碳纳米管,开发了一类层次化多孔的钴修饰碳纳米管瓶刷(Co/CNTBs).其中,精确的瓶刷状拓扑形貌和分级多孔结构能够有效地提供可及表/界面和高导电网络,钴修饰的杂化骨架可以促进硫的氧化还原反应动力学.因此,基于Co/CNTBs功能化隔膜的锂硫电池具有优异的倍率性能(在10 C下比容量为707 mA h g^(-1))和长效的循环稳定性.更重要的是,基于Co/CNTBs催化剂的高硫载量电池(6.72 mg cm^(-2))在0.1 C下循环100圈后仍具有4.81 mA h cm^(-2)的高面积容量.本工作为高性能超结构杂化碳材料的原位接枝合成策略带来了新的思路,有望用于众多具有挑战性的应用.

Developing superhierarchical carbon materials with multiple levels of structural hierarchy including porous structure,hybrid skeleton and/or topological morphology,is highly desirable to fulfill the demands of complex catalytic reactions in electrochemical energy storage and conversion systems.Herein,a class of hierarchical porous cobalt-decorated carbon nanotube bottlebrushes(Co/CNTBs)have been developed by controllably grafting hairy CNTs from the surface of a hybrid CNT backbone with Co nanoparticles as catalytic sites.The well-defined bottlebrush-like topology with hierarchically porous structure provides efficiently accessible surfaces/interfaces and highly conductive networks,while the Co-decorated hybrid skeleton promotes the reaction kinetics of sulfur redox conversion.As a result,an excellent rate capability of 707 mA h g^(−1)at 10 C and long-term cycling stability can be achieved for lithium-sulfur(Li-S)cells with Co/CNTBsfunctionalized separators.Remarkably,the Li-S cell with Co/CNTBs-functionalized separator can deliver a high areal capacity of 4.81 mA h cm^(−2)after 100 cycles at 0.1 C with a sulfur loading of 6.72 mg cm^(−2).These findings may shed light on the facile in situ grafting strategy for the fabrication of high-performance superhierarchical carbon hybrids towards numerous challenging applications.