Structure-engineered amorphous MoS3 catalysts for enhanced sulfur conversion kinetics in wide-temperature lithium-sulfur batteries

Lithium-sulfur batteries have garnered significant attention due to their high theoretical energy density. However, their widespread application across a wide temperature range is still hindered by the exacerbated lithium polysulfide shuttle effect and slow reaction kinetics. Although crystalline materials currently dominate the design of highly catalytically active sulfur hosts, their inherent structural anisotropy often induces lattice strain and structural degradation during electrochemical cycling. This study presents an engineered two-dimensional heterostructure combining amorphous molybdenum sulfide (MoS3) with reduced graphene oxide (MoS3-rGO) as sulfur host. The abundant defect vacancies and unsaturated bonds in amorphous MoS3 can enhance the adsorption of lithium polysulfides, substantially reducing the shuttle effect. The exposed rich catalytic active sites within the two-dimensional architecture effectively accelerate the electrochemical reaction processes, promoting rapid lithium polysulfides adsorption-transfer-conversion kinetics. Such synergistic mechanism effectively suppresses the intense shuttle effect induced at high temperature while simultaneously improving the sulfur redox reaction rates at low temperature. When implemented as a sulfur host, the MoS3-rGO/S cathodes exhibit high specific capacity (1263 mAh g−1 at 0.2C), exceptional rate performance (645 mAh g−1 at 5C) and cycling stability (642 mAh g−1 after 800 cycles at 2C) at room temperature. With high sulfur loading of 8.8 mg cm−2 and lean electrolyte volume of 5.5 μL mg−1, the MoS3-rGO/S cathodes achieve a remarkable areal capacity of 9.7 mAh cm−2 and stably cycle over 100 cycles. Even in a wide temperature range (−25–70 °C), the as-constructed MoS3-rGO/S cathodes still maintain above 70 % capacity retention over 500 cycles at 2C, outperforming most reported catalyst modified Li-S batteries reported to date. Such amorphous metal sulfide-based electrocatalyst design provides a pathway towards realizing wide-temperature Li-S batteries.