Petroleum Coke-Derived Carbon as the Separator Coating for Fast Capture and Conversion of Lithium Polysulfides in Lithium–Sulfur Batteries

Electrocatalyst engineering is pivotal for inhibiting lithium polysulfides’ (LiPSs) shutting effect and reducing the conversion energy barrier, thus achieving high-performance lithium–sulfur (Li–S) batteries. However, the high cost and limited electrocatalyst lifetime hinder the commercialization of Li–S batteries. Herein, we propose a low-cost carbon-based electrocatalyst that makes sustainable use of petroleum coke (PC), a petrochemical byproduct, as the functional separator coating to achieve fast capture conversion of LiPSs. A high carbonization temperature facilitates the removal of impurities from PC, thereby enhancing both electronic conductivity and specific surface area. Simultaneously, N/O/S atoms are incorporated into the carbon lattice at high temperatures, which increases the active sites and promotes the conversion of lithium sulfide (Li 2 S). Consequently, the sample carbonized at 900 °C (PC-900) exhibits the highest specific surface area and optimal catalytic activity among the series. Thus, the Li|PC-900@PP|S cells deliver a high initial discharge capacity of 547.5 mAh g –1 at 3.0 C, and retain 877.1 mAh g –1 after 100 cycles at 0.2 C. This work presents a low-cost PC-derived carbon as an efficient electrocatalyst for Li–S batteries, offering a promising route toward the commercialization of high-performance Li–S batteries.