Metallic WO2-Promoted CoWO4/WO2 Heterojunction with Intercalation-Mediated Catalysis for Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries require efficient catalysts to accelerate polysulfide conversion and mitigate the shuttle effect. However, the rational design of catalysts remains challenging due to the lack of a systematic strategy that rationally optimizes electronic structures and mesoscale transport properties. In this work, we propose an autogenously transformed CoWO4/WO2 heterojunction catalyst, integrating a strong polysulfide-adsorbing intercalation catalyst with a metallic-phase promoter for enhanced activity. CoWO4 effectively captures polysulfides, while the CoWO4/WO2 interface facilitates their S-S bond activation on heterogenous catalytic sites. Benefiting from its directional intercalation channels, CoWO4 not only serves as a dynamic Li-ion reservoir but also provides continuous and direct pathways for rapid Li-ion transport. Such synergistic interactions across the heterojunction interfaces enhance the catalytic activity of the composite. As a result, the CoWO4/WO2 heterostructure demonstrates significantly enhanced catalytic performance, delivering a high capacity of 1262 mAh g-1 at 0.1 C. Furthermore, its rate capability and high sulfur loading performance are markedly improved, surpassing the limitations of its single-component counterparts. This study provides new insights into the catalytic mechanisms governing Li-S chemistry and offers a promising strategy for the rational design of high-performance Li-S battery catalysts.