Ultrafine Ni12P5 nanoparticle-embedded carbon with abundant catalytic activity sites as separator modifiers in high-performance lithium–sulfur batteries

The further development of lithium–sulfur (Li–S) batteries suffers from the notorious shuttle effect and sluggish reaction kinetics. Herein, ultrafine Ni12P5 nanoparticle-embedded carbon nanospheres (uNi12P5/C NSs) were used as modifiers for commercial separators to inhibit the diffusion of polysulfides. The uNi12P5/C//PP modified separator not only effectively traps polysulfides by polar interaction and enhances the kinetic conversion of lithium polysulfides but also provides strong physical confinement. As a result, the cell with uNi12P5/C//PP modified separators shows excellent cycling stability (708.6 mA h g−1 at 1.0C after 500 cycles with an ultralow capacity decay of 0.048% per cycle) and glorious rate performance (618.4 mA h g−1 at 5.0C). In addition, even under a high sulfur mass loading of 4.5 mg cm−2, the cell also has an outstanding capacity retention rate of 96.1% after 100 cycles at 0.2C. This work could accelerate the application of phosphides in the separator modification of Li–S batteries.