Self-Supporting Nanoporous Carbon Films with Single-Atom Co–N–C Sites as Hosts for Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries are potential candidates as next-generation batteries for their high theoretical specific energy density, environmental friendliness, and low cost. However, the low utilization of active material and the limited sulfur loading prevent their practical applications. Herein, we design and synthesize self-supporting aligned nanoporous carbon films decorated with single-atom Co–N–C moieties as the additive- and binder-free sulfur cathodes. Within the design, the Co–N–C sites serve as catalytic centers for expediting the sulfur conversion kinetics, while the aligned nanoporous architectures and interconnected carbon networks facilitate the penetration of electrolyte and electronic and ionic transport. Additionally, this film electrode enables high loadings of sulfur by circumventing issues typically encountered with powdery electrodes. With the combined merits, the film electrode demonstrates high specific capacities of 1310.1 and 857.7 mAh g–1 at 0.2 and 1 C rates, respectively, and achieves an average areal capacity of 5.6 mAh cm–2 at a high sulfur loading of 6.7 mg cm–2.