Conductive and catalytic multi-metallic interlayer for high-performance lithium–sulfur batteries

Lithium–sulfur batteries (LSBs) have emerged as a promising candidate for high-energy-density storage due to their high theoretical specific capacity (∼2600 Wh/kg) and the low cost of sulfur. However, their practical application is limited by significant challenges, including the polysulfide shuttle effect, sluggish redox kinetics, and low sulfur utilization, all of which lead to rapid capacity degradation. To overcome these issues, interlayer engineering has been investigated as an effective strategy to improve electrochemical stability. In this study, a multi-metallic interlayer (Zn 0.4 Fe 0.6 Co 2 O 4 /carbon cloth (CC)) was synthesized via a hydrothermal method followed by annealing. ZnFeCo 2 O 4 offers strong polysulfide affinity and catalytic activity, promoting both the immobilization and conversion of lithium polysulfides, while CC serves as a conductive matrix to enable efficient charge transport. The optimized LSBs deliver a high specific capacity (1330.2 mAh/g at 0.2C) with extended cycle life under lean electrolyte and high sulfur loading conditions, demonstrating the effectiveness of this multi-metallic interlayer design. • A novel Zn₀.₄Fe₀.₆Co₂O₄/CC interlayer was synthesized via a hydrothermal method for LSBs. • The interlayer exhibits strong polysulfide adsorption and catalytic conversion due to its multivalent metal spinel structure. • Carbon cloth offers excellent conductivity and structural support for efficient electron and polysulfide transport. • The hybrid interlayer enables high specific capacity and low capacity decay under lean electrolyte conditions. • Excellent cycling stability and rate capability were achieved at a high sulfur loading.