Design of Co-doped hollow multi-channel carbon fibers for high performance lithium sulfur batteries

摘要

The low conductivity of active material and the detrimental shuttle effect of lithium polysulfides (LiPSs) intermediates in lithium sulfur batteries (LSBs) mainly limit their practical application. In this work, the welldesigned "tube-in-fiber" structure is fabricated via confining carbon nanotubes (CNTs) in Co-doped hollow multi-channel carbon fibers (MCCFs-Co) as sulfur host material for LSBs. As a result, the MCCFs-Co/CNTs composite with hierarchically porous structure and high specific surface area demonstrate excellent electrolyte wettability and rapid Li ion diffusion rate. The addition of CNTs and Co nanoparticles improves the absorption capability and catalytic conversion activity of the composite towards LiPSs, thereby enhancing the redox kinetics and alleviating the shuttle effect. Consequently, the MCCFs-Co/CNTs/S cathode delivers remarkable cycling stability (843 mAh g-1 after 150 cycles at 0.5 C) and outstanding rate capability (698 mAh g-1 after 300 cycles at 2.0 C).

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