Abstract
Heterogeneous catalysis promises to accelerate sulfur-involved conversion reactions in lithium-sulfur batteries. Solid-state Li(2)S dissociation remains as the rate-limiting step because of the weakly matched solid-solid electrocatalysis interfaces. We propose an electrochemically molecular-imprinting strategy to have a metal sulfide (MS) catalyst with imprinted defects in positions from which the pre-implanted Li(2)S has been electrochemically removed. Such tailor-made defects enable the catalyst to bind exclusively to Li atoms in Li(2)S reactant and elongate the Li-S bond, thus decreasing the reaction energy barrier during charging. The imprinted Ni(3)S(2) catalyst shows the best activity due to the highest defect concentration among the MS catalysts examined. The Li(2)S oxidation potential is substantially reduced to 2.34 V from 2.96 V for the counterpart free of imprinted vacancies, and an Ah-level pouch cell is realized with excellent cycling performance. With a lean electrolyte/sulfur ratio of 1.80 μL mg(S) (-1), the cell achieves a benchmarkedly high energy density beyond 500 Wh kg(-1).