The Multi‐Functional Effects of CuS as Modifier to Fabricate Efficient Interlayer for Li‐S Batteries

The shuttle effect of lithium polysulfides in lithium‐sulfur batteries (LSBs) has a detrimental impact on their electrochemical performance. To effectively mitigate the shuttle effect, in this study, the coral‐like CuS is introduced to modify the carbon nanotube (CNTs), which is coated on commercial separator and served as the S cathode interlayer (PE@CuS/CNTs). The CuS/CNTs interlayer possesses efficient physical impediment and chemisorption to polysulfide anions. When achieving maximum adsorption to polysulfide anions, a “polysulfide‐phobic” surface would be formed as a shield to restrain the polysulfide anions in the cathode region. Simultaneously, the CuS/CNTs interlayer can improve the lithium ion diffusion and guarantee desirable electrochemical reaction kinetics. Consequently, the LSBs with PE@CuS/CNTs show an initial discharge capacity of 1242.4 mAh g(−1) at 0.5 C (1 C = 1675 mA g(−1)) and retain a long‐term cycling stability (568.5 mAh g(−1) after 1000 cycles, 2 C), corresponding to an ultra‐low capacity fading rate of only 0.05% per cycle. Also, the LSBs with PE@CuS/CNTs exhibit high resistance to self‐discharge and favorable performance under high S loading (4.5 mg cm(−2)) and lean electrolyte (9.4 mL(Electrolyte) g (S) (−1)).