The sulfur cathode utilizes black phosphorus nanosheets encapsulated in an amorphous carbon layer loaded with ultrafine CoP nanoparticles. This structure enhances the stability and catalytic activity of black phosphorus, especially with the added carbon layer. Additionally, the uniformly dispersed ultrafine CoP nanoparticles improve adsorption and catalysis of lithium polysulfides. This synergistic effect ensures satisfactory long-term cycling stability of the sulfur cathode.

Abstract

The pursuit of efficient host materials to address the sluggish redox kinetics of sulfur species has been a longstanding challenge in advancing the practical application of lithium-sulfur batteries. In this study, amorphous carbon layer loaded with ultrafine CoP nanoparticles prepared by a one-step in situ carbonization/phosphating method to enhance the inhibition of 2D black phosphorus (BP) on LiPSs shuttle. The carbon coating layer facilitates accelerated electron/ion transport, enabling the active involvement of BP in the conversion of soluble lithium polysulfides (LiPSs). Concurrently, the ultra-fine CoP nanoparticles enhance the chemical anchoring ability and introduce additional catalytic sites. As a result, S@BP@C-CoP electrodes demonstrate exemplary cycling stability (with a minimal capacity decay of 0.054 % over 500 cycles at 1 C) and superior rate performance (607.1 mAh g⁻¹ at 5 C). Moreover, at a sulfur loading of 5.5 mg cm⁻², the electrode maintains an impressive reversible areal capacity of 5.45 mAh cm⁻² after 50 cycles at 0.1 C. This research establishes a promising approach, leveraging black phosphorus-based materials, for developing high-efficiency Li-S batteries.