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

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 18; no. 27; pp. e2202037 - n/a
• Main Authors: Pei, Huayu, Yang, Quan, Yu, Jingkun, Song, Haoqiang, Zhao, Siyuan, Waterhouse, Geoffrey I. N., Guo, Junling, Lu, Siyu
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.07.2022
• Subjects: Agglomeration; carbon dots; Carbon fibers; Catalytic activity; Dispersion; high sulfur loading; Lithium; Lithium sulfur batteries; low electrolyte/sulfur ratio; Nanofibers; Nanoparticles; Nanotechnology; self‐supporting carbon nanofibers; Sulfur; carbon dots; high sulfur loading; low electrolyte/sulfur ratio; lithium-sulfur batteries; self-supporting carbon nanofibers
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202202037

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 (NiSA) and uniformly dispersed Ni‐nanoparticles (NiNP) of small sizes as multifunctional sulfur hosts is reported. The NiSA sites coordinated by such NiNP 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. Scalable sulfur hosts featuring high catalytic activity and easy‐to‐infiltrate structure are synthesized by using carbon dots as in situ aggregation limiting agents. Such hosts enable sulfur cathodes to exhibit high performance at a high sulfur loading (50 mg cm–2) and low electrolyte/sulfur ratios (5 µL mg–1).