Porous carbon nanotubes can not only provide a large surface area for anchoring sulfur and restraining polysulfides, but also provide continuous conductive networks to facilitate ion transport in lithium-sulfur batteries (LSBs). In order to improve the performance of LSBs, the surface-modified groups can be exploited to restrict shuttle effect of polysulfides. Therefore, a kind of thin-walled porous carbon nanotubes with low cost and high yield were successfully prepared from polymer nanotubes. The sulfonic groups were modified on the walls of the thin-walled porous carbon nanotubes by reacting with concentrated sulfuric acid. The sulfonic groups modified thin-walled porous carbon nanotubes were utilized as the sulfur-deposited cathode matrix for LSBs, the discharge capacity of 617.7 mA h g-1 is obtained after 100 cycles at 0.5 C, showing a good rate performance. Based on DFT calculation, sulfonic groups on surfaces can enhance the binding energy between porous carbon nanotubes and sulfur, and strengthen the adsorption capacity of porous carbon nanotubes for polysulfides as well, which further proves the effectiveness of the system in optimizing the performance of LSBs.

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