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

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.