Semi-Embedded Ni₂P Nanoparticles in N,P Codoped Porous Carbon Nanofibers Enable Efficient 3D Li₂S Deposition for Low-Temperature Lithium–Sulfur Batteries

Lithium–sulfur batteries (LSBs) are recognized as one of the most promising energy storage systems for low-temperature applications, yet the sluggish conversion kinetics of lithium polysulfides and undesirable insulating film-like Li₂S deposition severely impede their performance. Herein, we report a robust interlayer comprising nitrogen–phosphorus codoped porous carbon nanofibers with semi-embedded Ni₂P nanoparticles (NPCNF@s-Ni₂P), which provides abundant catalytic sites and excellent structural stability to maintain sufficient Li₂S deposition. The semi-embedded Ni₂P nanoparticles ensure maximal exposure of active sites, promoting adsorption and catalytic conversion of polysulfides. Importantly, this interlayer architecture facilitates 3D deposition of Li₂S, significantly alleviating catalyst surface passivation, especially at low temperatures. Additionally, the partial embedding of Ni₂P nanoparticles ensures strong adhesion with carbon fibers, markedly improving the structural robustness and electrochemical stability. Consequently, at −30 °C, batteries incorporating the NPCNF@s-Ni₂P interlayer achieve an initial discharge capacity of 730 mAh g^–1at 0.2 C, maintaining a stable capacity of 263 mAh g^–1even at 2 C. This study provides an effective strategy to achieve rapid and efficient Li₂S deposition at low temperatures, offering valuable insights into the structural design of interlayers for LSBs in extreme climatic scenarios.