Construction and catalysis role of a kinetic promoter based on lithium-insertion technology and proton exchange strategy for lithium-sulfur batteries.

The high theoretical energy density and specific capacity of lithium-sulfur (Li-S) batteries have garnered considerable attention in the prospective market. However, ongoing research on Li-S batteries appears to have encountered a bottleneck, with unresolved key technical challenges such as the significant shuttle effect and sluggish reaction kinetics. This investigation explores the catalytic efficacy of three catalysts for Li-S batteries and elucidates the correlation between their structure and catalytic impacts. The results suggest that the combined utilization of lithium-insertion technology and a proton exchange approach for δ-MnO can optimize its electronic structure, resulting in an optimal catalyst (H/Li inserted δ-MnO, denoted as HLM) for the sulfur reduction reaction. The replacement of Mn sites in δ-MnO with Li atoms can enhance the structural stability of the catalyst, while the introduction of H atoms between transition metal layers contributes to the satisfactory catalytic performance of HLM. Theoretical calculations demonstrate that the bond length of LiS adsorbed by the HLM molecule is elongated, thereby facilitating the dissociation process of LiS and enhancing the reaction kinetics in Li-S batteries. Consequently, the Li-S battery utilizing HLM as a catalyst achieves a high areal specific capacity of 4.2 mAh cm with a sulfur loading of 4.1 mg cm and a low electrolyte/sulfur (E/S) ratio of 8 μL mg. This study introduces a methodology for designing effective catalysts that could significantly advance practical developments in Li-S battery technology.