Sn4P3-Decorated 2D N-Doped Carbon Nanosheets as Efficient Polysulfide Barriers for Li-S Batteries

Abstract

A novel Sn₄P₃-decorated nitrogen-doped carbon nanosheet (Sn₄P₃@NCS) was engineered as a multifunctional separator for lithium-sulfur batteries (LSB). The high-surface-area NCS enables physical adsorption through van der Waals interactions, while the nitrogen dopants and Sn₄P₃ nanoparticles collectively ensure strong chemical interactions with lithium polysulfides (LiPSs) via polar coordination bonds, effectively mitigating the polysulfide shuttle effect. The resulting LSB with Sn₄P₃@NCS modified separator achieved outstanding electrochemical performance with a high initial discharge capacity of 1250 mAh g⁻¹ at 0.2 C, exceptional rate capability with a reversible capacity of 753.08 mAh g⁻¹ at an ultrahigh current density of 4 C, and high initial specific capacity of 1000.85 mAh g⁻¹ even under a high sulfur loading of 3.8 mg cm⁻² at 0.1 C.