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–1 at 0.2 C, maintaining a stable capacity of 263 mAh g–1 even 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.