Co/CoSe Junctions Enable Efficient and Durable Electrocatalytic Conversion of Polysulfides for High-Performance Li–S Batteries

摘要

Lithium–sulfur (Li–S) batteries are regarded as promising candidates fornext-generation energy storage systems. However, the slow kinetics andshuttle effects of polysulfides hinder their practical applications. Designinghigh-efficiency catalysts to enhance the kinetics and suppress shuttling isone major task for the building of durable Li–S batteries. Here, a Co/CoSejunction is reported to catalyzepolysulfide conversion efficiently because thejunction has metallic electron mobility and field-enhanced catalytic activity.The mechanistic investigation reveals that the difference in the work functionsof Co and CoSe rearranges the charge distribution in the junction andstrengthens the interaction between polysulfides and CoSe, thereby yieldinghigh catalytic activity. In addition, the relative stability of CoSe, as comparedto Co, renders the junction durable upon cycling; therefore, demonstratinglong-term catalytic activity. Such a junction makes full use of metal-like conductivityand field-enhanced catalysis and provides an alternative approach toenhancing the catalytic conversion of polysulfides.