Employing synergetic effect of ZnSe quantum dots and layered Ni(OH) 2 to boost the performance of lithium–sulfur cathodes

Abstract The low sulfur utilization, cycling instability, and sluggish kinetics are the critical obstructions to practical applications of lithium–sulfur batteries (LSBs). Constructing sulfur hosts with high conductivity, suppressed shuttle effect, and rapid kinetics is essential for their practical application in LSBs. Here, we synthetically utilized the merits of ZnSe quantum dots (QDs) and layered Ni(OH) 2 to boost the performance of LSBs. A novel core–shell ZnSe-CNTs/S@Ni(OH) 2 was constructed using the ZnSe-CNTs network as framework to load sulfur and following with Ni(OH) 2 encapsulation. The CNT network decorated with ZnSe QDs not only serves as a conductive framework providing fast electron/ion transfer channels, but also limits polysulfide diffusion physically and chemically. Layered Ni(OH) 2 , the wrinkled encapsulation, not only permits fast electron/ion transfer, but also buffers the expansion, confines active materials, and limits the polysulfide dissolution chemically. When used as a cathode, ZnSe-CNTs/S@Ni(OH) 2 presents enhanced electrochemistry performance compared with ZnSe-CNTs/S and CNTs/S. The average specific capacity decreases from 1021.9 mAh g −1 at 0.2 C to 665.0 mAh g −1 at 2 C, showing rate capacity much higher than ZnSe-CNTs/S and CNTs/S. After 150 cycles, the capacity at 0.5 C slowly reduces from 926.7 to 789.0 mAh g −1 , showing high retention of 85.1%. Therefore, our investigation provides a new strategy to construct a promising sulfur cathode for LSBs.