Self‐Supporting Carbon Nanofibers with Ni‐Single‐Atoms and Uniformly Dispersed Ni‐Nanoparticles as Scalable Multifunctional Hosts for High Energy Density Lithium‐Sulfur Batteries

Abstract

Abstract The energy density of lithium‐sulfur batteries (LSBs) is currently hampered by modest sulfur loadings and high electrolyte/sulfur ratios (E/S). These limitations can potentially be overcome using easy‐to‐infiltrate sulfur hosts with high catalytic materials. However, catalytic materials in such hosts are very susceptible to agglomeration due to the lack of efficient confinement in easy‐to‐infiltrate structures. Herein, using carbon dots as an aggregation limiting agent, the successful fabrication of self‐supporting carbon nanofibers (CNF) containing Ni‐single‐atoms (Ni SA ) and uniformly dispersed Ni‐nanoparticles (Ni NP ) of small sizes as multifunctional sulfur hosts is reported. The Ni SA sites coordinated by such Ni NP offer outstanding catalytic activity for sulfur reactions and CNF is an easy‐to‐infiltrate sulfur host with a large‐scale preparation method. Accordingly, such hosts that can be prepared on a large scale enable sulfur cathodes to exhibit high sulfur utilization (66.5 mAh cm −2 at ≈0.02 C) and cyclic stability (≈86.1% capacity retention after 100 cycles at ≈0.12 C) whilst operating at a high sulfur loading (50 mg cm −2 ) and low E/S (5 µL mg −1 ). This work provides a blueprint toward practical LSBs with high energy densities.