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Effective Trapping of Polysulfides Using Functionalized Thin-Walled Porous Carbon Nanotubes as Sulfur Hosts for Lithium–Sulfur Batteries
journal contribution
posted on 2020-05-22, 22:29 authored by Wenhao Liang, Yakun Tang, Lang Liu, Caixia Zhu, Rui ShengOwing
to their high aspect ratios and structures of high-mechanical-strength
conductive scaffolds, carbon nanotubes (CNTs) are considered to be
one of the most promising hosts for sulfur in lithium–sulfur
batteries (LSBs). However, traditional CNTs with impermeable walls
are not conducive to the penetration of sulfur, resulting in a large
number of sulfur exposures to the electrolyte. Therefore, it is difficult
to effectively limit the shuttle effect of polysulfides. Here, a kind
of thin-walled porous amorphous carbon nanotube (HCNT) is adopted
as the host for sulfur in LSBs. To further alleviate the shuttle effect,
oxygen-containing functional groups (OCFGs) are introduced to modify
HCNTs to form HOCNTs. The S/HOCNT composite with the embedded structure
is successfully constructed. The S/HOCNT cathode demonstrates glorious
cycling and rate performance (798.5 mAh g–1 at 0.2
C after 100 cycles and 511.6 mAh g–1 at 1 C after
500 cycles). The excellent electrochemical performance of S/HOCNT
can be attributed to the embedded structure of sulfur in HOCNTs, which
avoids direct contact with the electrolytes and strong bonding action
of OCFGs and polysulfides, effectively limiting the shuttle effect
of polysulfides.