Construction of composite separator with 3D hierarchical spinel structure in Lithium-Sulfur batteries

Lithium-sulfur (Li-S) batteries are considered the most promising candidate for achieving a low-cost high-energy–density system. One of the biggest deterrents during the practical application of Li-S batteries is the shuttle effect which causes fast capacity degradation and poor rate performance. 3D CoNi 2 S 4 with 3D interconnected porous nitrogen doping carbon was prepared by sulfurizing the precursor Prussian blue analogues. The CoNi 2 S 4 nanoparticles are confined in the carbon framework, affording interconnected macro-mesoporous channels. The constructed 3D CoNi 2 S 4 modified separator effectively accommodates enough electrolytes and provides more exposed active sites that suppress the shuttle effect through trapping polysulfides and accelerating the lithiation of S 8 to Li 2 S. Thus, Li-S batteries with 3D CoNi 2 S 4 -PP separators exhibit high-rate capacity and remarkable cycle stability. Furthermore, based on the modified separators, a high sulfur loading cathode delivers an areal capacity of 5.62 mAh cm −2 . The separator size expands further to assemble the 1Ah Li-S pouch cell, confirming the practicality. This work provides an efficient strategy with a modified separator for high-performance Li-S batteries.