Atomic insights into the electrocatalytic properties of LaBO₃ perovskite oxides for lithium-sulfur battery...

The intricate shuttle effect and sluggish conversion kinetics of lithium polysulfides (Li₂S, n = 1, 2, 4, 6, and 8) present significant challenges for the practical applications of lithium-sulfur batteries (LSBs). Introducing electrocatalysts to enhance the anchoring ability for Li₂S and accelerate its conversion is an effective strategy. To gain a deeper understanding of the underlying mechanisms of the anchoring effect and to identify optimal electrocatalytic materials for enhancing the performance of LSBs, the interactions between Li₂S and electrocatalysts should be studied at the atomic level. In this study, density functional theory calculations were performed to explore cubic LaBO₃ (B = Cr, Mn, Fe, Co, and Ni) perovskite oxides as potential electrocatalysts for boosting the electrochemical performance of LSBs. The results show that LaFeO₃ exhibits the lowest energy barrier (0.37 eV) for the rate-determining step of the sulfur reduction reaction, while LaCoO₃ achieves the lowest decomposition energy barrier for Li₂S (1.67 eV) during sulfur oxidation, effectively facilitating Li₂S dissociation. Further structural deformation and charge transfer analyses demonstrate that LaBO₃ (B = Cr, Mn, Fe, and Co) effectively activates the O and B sites by enabling O to capture electrons initially transferred from Li to S. This process promotes the formation of Li-O and B-S bonds, thereby mitigating the shuttle effect, weakening the Li-S bonds, and enhancing the redox kinetics of LSBs. These findings offer valuable insights for the future design of more efficient perovskite-based electrocatalysts.