Metal-Organic Frameworks derived Pr2O2S-doped porous carbon nanosheets as efficient adsorption-catalytic separator coating materials for lithium-sulfur batteries

Abstract

Pr₂O₂S, a rare-earth sulfide with a unique layered structure and excellent catalytic properties, has demonstrated immense potential in various catalytic fields, yet its application potential in lithium-sulfur batteries remains largely unexplored. Here, we innovatively utilized Pr-BTC (Benzene Tricarboxylic Acid) as a precursor to successfully synthesize Pr₂O₂S-doped 2D (two-dimensional) porous carbon nanosheets, which were then applied as a coating for lithium-sulfur battery separators. Comparative experiments with Pr₂O₃-C/PP (Polypropylene) and bare PP separators revealed the outstanding electrochemical performance of the Pr₂O₂S-C/PP separator. In cycling tests at a current density of 0.2C, the Pr₂O₂S-C/PP separator exhibited remarkable cycle stability, maintaining a discharge capacity of 893 mAh g⁻¹ after 200 cycles with a high Coulombic efficiency of 99.3 % and a capacity retention rate of 63 %. Furthermore, DFT (density functional theory) theoretical calculations indicated that Pr₂O₂S exhibits superior polysulfide adsorption and catalytic effects compared to Pr₂O₃. The exceptional performance of Pr₂O₂S-C can be attributed to multiple advantages: accelerated lithium-ion diffusion reduces ion transport resistance within the system; the metal-O and metal-S bonds in Pr₂O₂S enhance material stability and confer efficient polysulfide adsorption capabilities, effectively inhibiting the shuttling effect and prolonging battery lifespan.