Free-standing MoS_x-based dual functional polysulfide catalyzer and immobilizer for high performance Li-S batteries

Inducing a multiple functionality/synergistic effect through rational design and utilization of functional materials is essential for high-performance prototype batteries. Herein, the controllable synthesis and simultaneous utilization of free-standing MoS₃@polypyrrole nanowires@carbon paper as a functional interlayer and 1T & 2H MoS₂@carbon nanowires@carbon paper as a catalytic sulfur host has been proposed. The multifunctional films of MoS₃@polypyrrole nanowires@carbon paper and 1T & 2H MoS₂@carbon nanowires@carbon paper can be synthesized via the same multi-step procedure based on electro- and chemical deposition. MoS₃ with outstanding adsorption to polysufides, 1T & 2H hybrid MoS₂ with good catalytic capability, and a 3D hierarchical crossing structure composed of polypyrrole/carbon nanowires on carbon paper build a strong barrier to lithium polysulfides and effectively promote the redox reaction. The prepared Li-S battery with simultaneous use of MoS₃@polypyrrole nanowires@carbon paper as the interlayer and 1T & 2H MoS₂@carbon nanowires@carbon paper as the sulfur host can achieve a high initial discharge capacity of 1447 mA h g⁻¹ at 0.2 C and stable long-term cycling at 1 C with a capacity decay rate of 0.035% per cycle after 500 cycles. The synergistic engineering proposed in this work provides new insight and opportunities for the development of advanced Li-S batteries towards their practical applications.