Vanadium disulfide-modified lithium aluminum titanium phosphate/polymethyl methacrylate composite separator with hierarchical interface architecture for advanced lithium-sulfur batteries: A synergistic strategy for enhanced electrochemical performance and interfacial stability

Abstract

Lithium‑sulfur batteries have attracted significant attention as next-generation energy storage solutions due to their exceptional theoretical energy density (2600 Wh/kg) and economic viability. However, two fundamental challenges have hindered their practical application: the formation of lithium dendrites at the anode interface, which compromises safety and longevity, and the “shuttle effect” of polysulfide intermediates at the cathode, resulting in capacity deterioration and compromised cycling performance.

This study presents an innovative bifunctional separator design that simultaneously addresses these critical limitations through interface engineering. The separator architecture features a rationally designed vanadium disulfide (VS₂) composite layer functionalized with boron nitride nanosheets at the anode interface, which effectively suppresses dendrite nucleation and growth. Concurrently, at the cathode interface, a lithium aluminum titanium phosphate/polymethyl methacrylate/polyvinylidene fluoride (LATP/PMMA/PVDF) composite structure has been engineered to enable effective polysulfide confinement and enhance electrochemical reaction kinetics.

This bifunctional separator demonstrates excellent electrochemical performance, achieving a specific capacity of 677.8 mAh g⁻¹ at 2C rate while maintaining exceptional cycling stability over 800 cycles. These results represent a significant advancement toward the commercial realization of high-performance lithium‑sulfur batteries.