Facile and low-temperature strategy to prepare hollow ZIF-8/CNT polyhedrons as high-performance lithium-sulfur cathodes

Great efforts have been devoted to developing novel cathodes to alleviate the shuttle effect of lithium poly-sulfides (LiPSs). The limited intrinsic conductivity of metal-organic frameworks (MOFs) compels their utilization as the templates to prepare carbonaceous Li-S battery cathodes after high-temperature treatments. The facile and low-temperature fabrication methods of MOF-derived cathodes are largely unexplored. Herein, the hybrid of hollow zeolitic imidazolate framework-8 (ZIF-8) polyhedron functionalized with carbon nanotube (HZIF/CNT) cathode is fabricated via facile tannic acid (TA) etching and low-temperature treatment. The conductive HZIF/CNT structure with ordered hollow ZIF-8 morphology, rich heteroatoms functionalities, and hydrophilic surface endow strong adsorption of LiPSs, boosted LiPSs conversion kinetics, and regulated Li2S deposition. As a result, S@HZIF/CNT cathode delivers a superior initial capacity of 1371 mAh g(-1) at 0.1C and excellent rate retention at 3.0C (696 mAh g(-1)). The remarkable cycling stability is evaluated for 500cycles at 0.5C with a 0.073% capacity decay per cycle. Moreover, the cathode with a high sulfur loading of 3.41 mg cm(-2) delivers an initial capacity of 696.4 mAh g(-1) at 1.0C and stable cycling performance over 200cycles. This work opens a facile and low-energy route to design advanced sulfur cathodes for high-performance Li-S batteries.

Automated summary

This study developed a HZIF/CNT cathode via facile TA etching and low-temperature treatment, which showed strong LiPSs adsorption capability and excellent battery performance.