Chemisorption-catalysis synergy driven VN-V2O3 anchored on reduced graphene oxide heterostructure for stable lithium-sulfur battery separators

Abstract

The poor electrical conductivity of sulfur, volume expansion and shuttle effect during charging and discharging are the main reasons affecting the commercialization of lithium-sulfur batteries (LSBs) at present. In this paper, a heterostructured vanadium nitride-vanadium(III) oxide anchored on reduced graphene oxide composite (VN-V₂O₃@rGO) is developed as a modified multifunctional separator for LSBs. The VN-V₂O₃@rGO material not only enhances electrical conductivity but also effectively accelerates reaction kinetics and suppresses the shuttle effect through strong chemical adsorption and catalytic conversion of lithium polysulfides (LiPSs). When applied as a coating on a commercial separator, the VN-V₂O₃@rGO modified cell delivers an initial discharge capacity of 1174.6 mAh g⁻¹ at 2.0C and maintains a capacity of 685.1 mAh g⁻¹ after 1000 cycles with an average capacity degradation of only 0.05 % per cycle. This work demonstrates the potential of metal nitride-metal oxide heterostructures in designing high-performance LSBs and provides a feasible strategy for developing advanced battery separators.