Leaf-like interconnected network structure of MWCNT/Co9S8/S for lithium-sulfur batteries

Abstract Lithium-sulfur batteries have several disadvantages, such as intrinsic insulation of sulfur and Li 2 S, large volume expansion, and inevitable shuttle effect, which lead to low utilization of active materials and rapid capacity decay. Herein, leaf-like interconnected network structure of MWCNT/Co 9 S 8 was synthesized by a simple hydrothermal method. The MWCNT/Co 9 S 8 /S delivers a high specific capacity and good cycling stability. The initial discharge capacity of MWCNT/Co 9 S 8 /S is 1124 mAh g −1 and retains at 503 mAh g −1 after 100 cycles at 0.1 C. The improved electrochemical performance of MWCNT/Co 9 S 8 /S could be attributed to the interconnected network MWCNT and polar Co 9 S 8 . As conductive skeletons, the interconnected network structure of MWCNT midribs provide fast conduction paths for electron and additional space for volume expansion of sulfur. Furthermore, sulfur particles well-distributed on the MWCNT/Co 9 S 8 scaffold facilitate Li + ions storage and release for energy delivery, which is beneficial to excellent activation of sulfur and high rate capacity. In addition, the polar Co 9 S 8 leaves provide strong binding sites to trap polar polysulfide intermediates, which can suppress the shuttle effect effectively.