Design of filamentous conductive catalyst as separator coating for high-efficiency lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries is considered to be an promising alternative for next-generation battery systems because of the high theoretical energy density. However, the “shuttle effect” causes electrode passivation and rapid capacity decay. In this work, a kind of filamentous catalyst, CNTs@COF-SO3H, is prepared by combining in situ growth and post-modification strategy for the first time. Such catalyst can decrease the activation energy of electrolytes, accelerate the multiphase conversion of sulfur, decrease the agglomeration of soluble polysulfides in electrolytes, and thereby inhibit the “shuttle effect”. The catalytic conversion is well proved by both experiments and theoretical calculations. When equipped with CNTs@COF-SO3H the batteries exhibit stronger capacity at 1 C with a attenuation rate of only 0.04256 % for each cycle after 1500 cycles. Meanwhile, the battery provides a reversible capacity of 596 mAh/g in 150 cycles, though the sulfur content is as high as 6.9 mg cm−2. This research provides a new insight into the synthesis of multifunctional catalysts by combining compositing organic framework materials with conductive carbon materials.