Synergistic adsorption and catalytic effects of Ti3C2Tx/CoO/MoO3 composite on lithium polysulfides for high-performance lithium–sulfur batteries

Abstract

The shuttle effect of lithium polysulfides (LiPSs) and their sluggish kinetic processes lead to rapid capacity fading and poor cycling stability in lithium–sulfur (Li–S) batteries, limiting their commercial viability. This study proposes a functionalized separator with adsorption and synergistic catalysis ability for Li–S batteries. The modified separator comprises Ti₃C₂T_x sheets, CoO, and MoO₃. Experimental and theoretical calculations demonstrate that Ti₃C₂T_x/CoO/MoO₃ composite not only effectively inhibits the shuttle effect of LiPSs, ensuring efficient utilization of active materials, but also enhances reversibility and reaction kinetics among LiPSs. The full exposure of active sites in the Ti₃C₂T_x/CoO/MoO₃ composite and the synergistic action of different catalysts enable efficient capture and conversion of LiPSs molecules at the material surface. Besides, the lithium–sulfur batteries with Ti₃C₂T_x/CoO/MoO₃@PP separator exhibited only a 0.042% capacity decay per cycle at 0.5 C (800 cycles). Moreover, a high areal capacity of 6.85 mAh cm⁻² was achieved at high sulfur loading (7.9 mg cm⁻²) and low electrolyte-to-sulfur ratio (10 μL mg⁻¹).